dude honestly this is the best guitar hangout and chill channel for me. this is like going to a dudes house who knows a shit ton about amps and getting the real info. brilliant.
This is easily the best video about Marshall's MKIII and SLX amps. Not a lot of people even know about these two models in the 900 series anymore. I have the same 2501 MKIII combo, and I really love it. For me, it's the perfect combination of being simple to operate with modern features like a loop and built-in boost. The dual master volume controls are also very handy to make a solo jump out in a mix without changing the tone at all.
This is one of my favorite videos. I have a 50-watt MKIII head going into a 4x4 Marshall cabinet. I think this video will help people understand their 900s better. Well done!
I have the Mark III 100 watt head. It's dated Feb-1990. Great amp with 2 JCM900 4x12 cabs. Tried many different tubes, new, newer and NOS. Found testing and mixing the power and preamp tubes is the way to go. Great video!
I got a 50w 2500 mkiii head in a trade, continues to surprise me. Rush tones are so easy. I usually keep the sensitivity off but you nailed it when you compared it to a tube screamer utility. Great video, I love when people love on these amps!
I would recommend getting a legendary tones lynch mod or hot mod for your 2204. It doesn't require any modding just slides into V2, it increases to the gain by up to double and the amp sounds better at low volume. Before I got my Lynch mod my 2203 was never played and I play it a lot.
@@andrewspade7969 Great suggestion. I have always wanted to try one of those. I use a distortion pedal in front of everything. I can use the pedal volume to keep the amp vol. where I want it.
I've had a Mk iii since I bought it from a buddy in the mid 90s. I brought it over from the UK when I moved to Canada in 06 and we rewired the transformer to 110 in 2012 it has a double output transformer. Love it. Play it through a 1936 2x12 and it's all you could ever need.
Had both these amps, the combo first then the SLX - I thought that the SLX took pedals really well, I used to use with a Rat and it sounded phenomenal.
Completely genius brother……I love my 900 MK iii…….I also have the 800 and the 2000 dual. Really well done overview of how great the 900 mkiii is and it shows you how these are real sleepers. Even though the trend is lunch box and 20 watt versions of these amp..the 50 and 100 sound so much fuller. When the Ox Box came out it changed my ability to capture the full sonic joy without blowing my audience out of their seats. Great job
Great video! Love the MK3 and would like to buy an SLX. People crap on the diode clipping but seem to forget how many albums use a modded Marshall plexi with diode clipping 😅
Absolutely, and people praise amps like Cameron's, Ceriatone Chupa/Yeti, etc. and those all have clipping too. It's just a flavor thing, some prefer no diodes and that's fine but it doesn't make it a bad amp to have them - I wish more amps did it like the Mk III where you can basically turn the diodes completely off if you want. My Ceriatone KK also has a switch that turns off the diodes as well so you have both options - very nice to have.
Really in depth video with good helpful discussion of both amps. I also like that you actually riff; nice job! Had an encounter with a MKIII 900 head to record with a band I was in this year and that was a really special amp. Gain and Sensitivity at half just gave it this thick, strong punch but still with clarity. Ended up using for the vast majority of the guitars on the record, beastly sounding thing.
Thanks! The Mk III is really a beast, I couldn't believe how good it sounded recorded just from these clips - I actually taped my mic stand to the floor after recording this so I wouldn't lose the spot! Now this is an amp they should reissue.
great video. I do use a JCM 900 mk 3 myself . I prefer it with the diode clipping off and boosted with an overdrive or distortion in front . Great sound
Cool video! I sold my 100w SL-X for a 100w MK3, and I loved the tone from both. I received quite a bit of complements from each as well, but I do favor the MK3 for the time I was wanting to achieve
It's a hell of a guitar! I actually used it for the Vintage Modern video then realized in editing that I clipped the mic the whole time. Doh! So I re-recorded that one and had already put this one back in the case. It deserved to be in a video, super well taken care of too.
Had a MK3 50w head back in the 90s. Never should have got rid of it. JUST (TODAY) acquired a 50w Dual Reverb 900 combo, traded in a JCM2000 head.. NEVER could get the right sound on the 2000. Had the 900 dialed in within 3 knob turns in the shop. Walked away with it, without a look back. WAY underrated amp.
I've had one of these since they came out and I just love it. I treat it like an 800 and keep the Sensitivity right off. Marshall really dropped the ball by having 3 different versions of these amps. The 2100 and 2500s are great. The Dual Reverbs were…not good and the SLX is fine but it's just not the same (I think it's a "it's not mine" bias). Really great video.
..funny statements ... yes, exactly what I found out for myself: my JMP MkII is hard to tell as a different amp used when blindtested in comparison to the JCM 900 MKIII with diodes turned off. I had this in mind as a hope looking at the scheme when buying the MKIII and have not been dissappointed .... I can use the MKIII as a low cost JMP here without any problem :D
Oh and I haven’t got it yet but I figured the master b (or however)could be set louder.. to compensate for your guitar being rolled back so that would actually be your clean sound..
Great idea, I never thought of that. I'm bad at doing two things at once (i.e. stepping on footswitch while also rolling down volume) but with some practice it would work really smoothly.
I now have an SL-X (5881) and an MKIII (EL-34) The MKIII sounds identical to my '90 JCM800 2204, I can't tell them apart. The SL-X is still my favorite, but that comes down to personal preference.
This was one of the videos i checked before buying Marshall 2500 head a week ago. Glad I did. Such a sleeper amp, sounds fantastic. 500 with new tubes in excellent condition. That’s just silly, more than grand less than jcm800 or silver jubilee. I briefly even considered selling my old silver jube but realised that’s propably stupid idea. Should SLX pop up for sale locally, I think I’ll get one of those as well. Unfortunately those are usually more expensive.
They are killer amps. I lucked out and got a JCM800 2203 before the prices went nuts on them and while I'm glad I have it, I'd be just as happy with a 2500/2100 (either SLX or Mk III) especially at current prices!
Man. So true. I also used to have 2x12 jcm800 i forget the model but basically 2203 but combo. Nice amp, absolute nighmare to carry around. Hey bwt, in your 2500, if you set master a and b the same, b is quite a bit louder? In mine master at 9 o’clock A=barely on while master B takes your head clean off. I have stared the schematic but I dont fully understand how the 2 masters operate and if that is supposed to be like that. Anyway, thank you for the informative video content!!
@@vl292 I don't have this combo anymore, but I have a 2100 Mk III Head instead. On that amp, the volumes are incredibly close when set the same - nearly impossible to tell. I *think* I hear Master B (footswitch on) being the tiniest, slightest bit louder, but only by a little bit. There is a little tonal shift, it feels punchier on Master B to me. I'm also not an expert once the opamps get involved, and both masters run through opamps in this circuit. It looks to me like the footswitch jack is grounding Master B out when not engaged from the + voltage line of the opamp there, but then when it's disengaged it looks like both volumes are active... But I don't find that to be the case on the amp itself (I.e. if I have Master B on via footswitch, and I turn Master A up or down, I don't notice any volume/tone change). Looking at the schematic, if I didn't have the amp in my hands right now, I'd expect to hear a slight tone/volume change if I were on Master B and started turning up Master A, but that's not what I'm hearing. It's possible I'm just using my ears too much and not my eyes, or it's also possible there is a schematic revision/update I don't have or it's just missing a part on there. If there's a drastic difference as you describe though, I would take a look at the area around Master A: R16, C19, VR3 pot, and see if there are any loose solder connections or any sign of damage. If those components are good, then I'd really start to suspect the opamp on that side. Of course, the usual safety speech goes here, don't touch anything with two hands, don't hurt yourself, it's not worth it, take it to a tech if you're not comfortable! Cheers!
If you look at the slx schematic the 2nd gain stage has a plate resistor of 27k instead of (the standard) 100/220k. This is why they have a lot less gain than a dual rec etc
I’ve had the mk iii as my first tube amp in the 90’s and I swear it was brighter and more classic sounding than the el34 SLX I had a few years ago. The SLX sounded more low mid and really didn’t wow me as much. I traded it for a Mesa OS cab back when you could still pick up 900’s for $600 or so. Now that they’re 1100 and up I almost feel stupid but it’s God’s cab so not really, lol. Nothing sounds bad thru it and I’ve got a 2204 modded Origin to play with.
@@R3dbudd I have a Mesa cab, traditional size but it’s still one of the best sounding cabs I’ve heard, so I can’t fault you there. As long as you’re still enjoying it, it was a great trade!
Does anyone have a pdf of the document that contains the schematics? I can find user manuals for the SLX 2100, but I'm having a hard time with the mark iii 2100
Hey, check here: www.drtube.com/marshall-jcm900/ The very first one is the 2100 Mk III preamp, if you look at the second link down "CD0109 Issue 9 JMP51B PCB, Marshall, 1990" Power amp schematic on a separate page below that "CD0192 Issue 10 JMP50C PCB"
I have already had it open and checked most of the values in the circuit and nothing looks wrong, and when I listen to other youtube demos mine has about the same amount of gain so I doubt anything is wrong. When I say it doesn't have much gain, I meant that compared to other amps also available in 1993 - like the SLO, Dual Rectifier, Peavy 5150, Steavens Poundcake, etc it does not have nearly the same type of heavy, chug palm mute type gain that those have, yet that's what I expected based on other online reviews before I owned it.
@@totallyradguitars959 I totally agree with your second paragrah. However, what speakers is it running through. I have both the G12t-75's & the Marshall Vintage Speakers. The Vintage speakers sound way better with the SL-X as it tends to be a little darker and the Vintage brightens it up.
@@guitarexpert2245 I’m very lucky and happen to have a huge selection of speakers too - I just really love the ‘86 T75’s so I use those most of the time (and in this video). I have a quad of ‘96 V30’s (same as Marshall Vintage speakers) and they certainly brighten up this amp and others. They have an aggressive sounding boost in the high high mids that really cuts and can make some amps sound piercing, but some amps get more presence and cut with them. I’ve actually been meaning to do a speaker comparison video but what can they are mounted in has a noticeable effect too so it’s going to take me a while to get it all tracked since I’ll have to rotate speakers through the same cab. Also, I’m going to check through the SLX again when I have a little spare time and just check. You’re not the first to mention it seems to have less gain than theirs now so I think that merits a follow up on it.
Great job! Love my SL/X 2100. It is a little different flavor, very underrated and versatile. Not sure when was actually looking at the schematics ages ago (terrible to read), but the input stage if I'm correct, is like a standard gain stage into a follower. Really, it's more like a 4-stager (not five), as the extra follower won't contribute any gain. So, agree, there isn't any more gain as in some of the HG amps like an SLO (I have one) or a 5150 (had a 5150II). Have to say, mine will have gobs of gain with both of those controls together past 12 noon, and it's not so good there for mine. If it can be done, better off more conservative with those controls, and cranking the thing up old fashion Marshall-style. It breaths more, sounds great, and your ears will thank you next day with joyous tinitus!
I was curious about that too - I’ve been learning a lot lately about gain stage dragon and this circuit always confused me whether it was 4 or 5 stages and it seems like there’s one stage that isn’t adding any additiona distortion characteristics so I’m glad I’m not crazy in thinking that. I have a 6100LM I need to do a video on soon. The lead mode on that amp with the gain boost is what I thought the SLX would be - it’s extremely high gain especially for 1992. The SLX is a little more classic and less “modded” sounding, if that makes sense, to my ears at least. Love them both
@@totallyradguitars959 Played a 6100 nearly 30 years ago. It was killer, back then I couldn't afford one. I like the Marshalls from that era. At least back then they were trying different things circuit-wise. But us guitar players are fickle, and terribly un-accepting of things different or new.
I have a JCM 900 MKIII Model 2100. The amp is great the only complaint I have is you can't use a foot switch to switch from clean to dirt. For that reason, I have bypassed the preamp and just use a pedal board 100% in the effects loop. But now I think I will start using the preamp again for the dirt and use an ABY switch to switch from the 900 and a solid state amp and use the 900 as my dirt amp and the other for clean. Thanks.
I had an early 90’s SLX 100w w/el34’s briefly…..only thing I wish was that it would clean up a little better with the guitar volume, but it wouldn’t. Had a lot of low end though…..live I ran the bass on like 4…..🤘🏼
Nice review , got me thinking , how hard would it be too put a extra pre amp tube in place of the clipping diode on the MK III , , the controls are the same ,the sensitivity controls the extra tubes in the SL-X and the clipping diode in the MK III , besides drilling an extra hole in the chassis for a 4th tube ,and adding the socket , doesn't serm like a major project since the controls are all the same , basically a Tube for diode swap no ?? Then you have an SL-X Still with the MK III label , but who cares About what the front panel says !!!
(Trick at the bottom) The problem isn't the amps. The problem is the amp snobs. Instead of lissuning to an amp, they check the schematics first. And then there are ultra snobs, who look at the 2555X Silver Jubilee amp (which has diodes, BUT is played by Sl00sh (slash)) and it's all gud... I owned a Model 2100 Dual MV MkIII from 2002 to 2013 (gigged and lent it to friends who gigged it (Alt-Rock to Fuzzed out Stonerrock to Black Metal)). So I dunno what the factual problem is with some people. Trick: Stick a patch cable in the FX-Loop (which is serial/parallel (which is why this works)) and set the sensitivity of the loop to taste. You will find it really comes alive... (works with all 900 models and other amps which have this type of loop) th-cam.com/video/SKsTNSm4st4/w-d-xo.html
Very nice, totally agree. I love to look at schematics, but I'm no snob - if it sounds good, I'm happy. The Mk III and 2210/2205 are my favorite Marshalls and they are both diode clipper circuits. On the other hand I've heard all tube amps I didn't like. It's all up to how it gets used!
I have but I didn’t notice a massive difference. I know on the dual reverbs it pulls another tube into the chain (just a buffer tube though not a gain stage). I’m not saying it doesn’t work but I’ve had 4 Mk III’s now and can’t say I would be able to tell the difference between any of them patch cable vs no patch.
@@totallyradguitars959 yeah, I tried it and it did get slightly louder maybe but I’m not sure if jumping the loop improves the tone. They are great amps, compared to my 2204 though the mk iii is a bit thinner, more brittle sounding. Still really good though, especially after I changed the resistor in the bias circuit so it can be biased more to specs. Cheers
@@vintagesound8112 There are a couple of cap/resistor changes you could do that would make it sound nearly identical to a 2204, but it would make the diodes/sensitivity muddier in the low end. I think that's why the Mk III's are thinner by default, to make them more usable if you max both gains out. I had some thoughts about altering the values to match 2203/2204 and then adding a high pass filter across the diode circuit only to prevent it from getting muddy as you add the diode gain... but that's more in depth modding than I'm willing to do to a vintage amp at this point. Maybe if I built one from scratch though...
@@techdeathhippie6319maybe some models are better I had the slx with 3 gain stages or 4 can't remember not the highest one one back from that lol but anyway it was not even as good as my stock TSL. It was a bit underwhelming and disappointing and I had other issues with it but I know his work is good and a lot of people love it just was not a good experience for me wizard on the other hand are something else huge crushing and tear ur face off I really should have kept a wizard around now they are ridiculously priced probably never own another but my engl special edition gets me close and does more
They kind of fly under the radar, especially since the Dual Reverb's are so poorly regarded I think these got lumped in with those since they are both in the same range and use clipping diodes. The thing is, diodes aren't bad on their own, it's how they are used, but the SLX was clearly much more popular (it ran from 93-99)
22 years ago I bought an 50 watt SLX. and sold it around 2005 when I switched to Beach Music and switched to my Fender Twin that I've since sold. But 2 years ago I bought a JCM 900, Mkiii 2500 head and run in stereo with a Laney GH50L and a Marshall JCM900 1960A cab and a JCM 1960AX cab misspeakered with V30s Not able to do a side by side, but I'm having more fun with the Mkiii 2500. I've got pictures of me using a Fender/Sun Model T and a Laney AOR 50 Lead and the SLX sitting as a backup amp. But I did use the SLX in the studio here on a 11 song demo of originals in 1999.
Awesome story! I’m a big fan of the Mk III. It’s the only Marshall combo I still have and I wish I’d kept the head I had of it. I also had a Laney AOR50 but sold it before I started making videos. It had a lot of gain but very loose low end - but also really cool pull switches to shape the tone. Definitely a unique amp but I couldn’t quite get along with it - which may change now that I have more cabs. I think it just didn’t sound good with V30’s to my ear because that’s all I had for a long time
Thanks man! I'm a little partial to the Mk III but neither are particularly low volume friendly, well depending on what you mean. I play about 90-100 db at home but I have very understanding neighbors, if you need to go quieter, and attenuator or even just going down to a 1x12 can make even the loudest Marshall feel a little more manageable. There are 50w versions of both of these amps, including the SLX (model 2500). Cheers!
I had a slx 50 watts head that sound pretty good. I replaced it with a 4210 jcm 800 combo. I find the 4210 sound a bit better plugged in a closed back cab in comparison tonthe slx, it has a more direct punch in the low mid when you hit the notes. It is more direct, which the slx was missing a bit to my taste. I see what you mean when you say the slx and mkiii are a bit softer. This is the thing that was missing to the slx to be almost perfect for me. On other hand the slx has way more gain. (I was shocked how little gain/distortion your slx has with both pre volume and sensitivity at 5.) The slx I didn't need to boost. The 4210 need a little help /boost to be where I like it soundwise. I might try a lengendarytones hot mod in it...
I've had a few comments about my SLX being lower gain so it's possible I have some component or tube out of spec. It still sounds really great - thick and full to me, but one of these days I'll get it up on the bench and check it out again. What I will say though is that your 4210 - I have the head versions (2205 or 2210) - is my all time favorite Marshall sound. Direct, great boosted or unboosted, I don't care about the diodes.... just a beast of an amp. Working on a video for them right now actually.
Also if you put a eh 12ax7 h tube in slot one you will notice a great gain difference.I had to run a class A tube stereo power amp to get my 900s into the zone of what I call real .there quite a great distortion but without a serious power amp section on there own wimpy and plastic sounding
Hey, this SLX ('93) has EL34's. Later ones usually had 5881 unless they were converted, and then very very late ones would be back to EL34 again. Cheers!
I regret trading off my SLX head about 20 years ago. Recently found one on GC’s site, got excited and ordered it but they canceled it with the bs reason of “it got damaged in shipping” 😑. I have a 4100 but still really want another clean SLX.
I’ve heard a few BS reasons like that, but I suppose it may have been a return that was already damaged. Always a 50/50 chance when ordering anything from GC. I’m sure you’ll find another one, it’s well worth having in addition to the 4100 since they do sound a lot different!
@@totallyradguitars959 I decided to try a JCM 2000 DSL since I’ve seen some pretty interesting videos comparing them to JCM 800s. We will see if this one actually gets delivered and if I decide to keep it. Would really like to find a nice 800 but I literally just play in my spare room so it seemed foolish to spend that much at this time.
A few people have told me mine has less gain than theirs too. Something I've been meaning to look at internally forever but I'm happy with the way the amp sounds and haven't had it opened up in a long time, other priorities.
Scooped and bright???? Hahaha dude its 97% a JB wind with an A8. That Pacer must be what’s bright or you got a lemon Alt8. Thanks for the great info on these amps! Definitely going to be checking back in for more!
Hi! 1986 G12-T75’s, the ones with the vented back, in the Marshall 4x12 underneath is what I used for both amps. The internal speaker of the Mk3 wasn’t used in this demo but it is a G12-H100 which I also love
Great video! I'm thinking about picking up a MKIII at the minute, but I'm wondering if it has much clean headroom? Would it be possible to have those nice warm Marshall cleans if I cranked the master volume and used the gain knob to adjust the 'loudness' of the amp?
It's certainly a LOUD amp but I'm not sure I'd describe it as having a lot of clean headroom. It's similar to a single channel 800 - you can get it loud with the preamp gain set low, but the master is already at almost full tilt by "5" and if that's not loud enough for whatever purpose (recording, gigging, etc) then you're out of luck. I've had a HIwatt DR103 and THAT is clean headroom, but it was also so ungodly loud that I never got to find the limit in any reasonable setting I could play it in. So it probably depends on A) where you are going to be using it like that and B) if you need really pristine cleans or can put up with a little bit of sparkle/grit Either way, try to swing the 100w version if that's a concern. There is a 50w on guitar center used listings right now at the time of writing this comment, I don't think the price is terrible but not an incredible deal either - so if that's the one you're looking at and clean headroom is the concern, be patient and wait for a 100w. (or get the 50w from GC and try it out, and if it doesn't work for you, return it - but you'll loose the shipping cost to find out) Cheers.
@@totallyradguitars959 Ah, OK. My main amp at the minute is a Bluesbreaker run clean with a T Rex Mudhoney fir crunch/dirt, but I've always fancied a 900. I used tonown a horizontal input JCM800 bass head, clean for days. Should have kept it! Thanks for the reply!
Hi, great review, I have a JCM 900 MKII Combo as well. There is an issue with earlier ones with the bias resistor (R30) being too large (56k) instead of (47K) do you have the same issue in yours ?
I will have to check and get back to you on that one after I have a chance to open it up again. I remember some of the TSL's had a similar problem with resistor values on earlier units too.
Hey, I don't think they really help the low volume. Some amps that have two volumes active at the same time, you can manipulate them a bit to get the tone at lower volumes - I use that trick on my VHT Pittbull and others a lot. These amps though, each master volume doesn't have any effect on the other, and they are both identical tapers and pot values. So if you are using "Master A" and turn it down to lower volume, it's the same exact tone if you used "Master B." That also means regardless of which master you are using, if they are both set to "5" and you footswitch between them there's no tone or volume change either. Hope I explained that clearly haha cheers
I had a MK III for a while. I modified it, simply disconnected some of the diodes, the first two groups. WAY better sound, smoother, more bass less fizz. Nothing fancy, just disconnected them. The later diode groups are more difficult to get out o I left them. Also added a choke. They aren't anything like a JCM 800 at all except they have a cathode follower but so does a Bassman. Still not "more polite" than an 800 either. The 800 is just more expensively built, and they sound like a more "grown up" amp.
A lot of people lift the first leg on D1 but that's just an input clipper, not what the "sensitivty" knob controls (that's the second group you mention, between V1B and V2A). Not sure what you mean that they aren't anything like a JCM800 - the 900 Mk III is almost exactly a 2203 preamp with a few different values to change the voicing, and diodes crammed in between gain stages 2 and 3 with a level knob. Maybe "polite" isn't the right word to use, but the 900 Mk III with diodes off is smoother and lacks the grittier, angrier sounding mids that a 2203 has. You can get a different flavor of that grit back a bit by adding in the diodes, but the amp alone is just a smoother-voiced 2203 circuit.
Thanks for the reply. I may get an SL-X next, because they aren't too expensive and gig with that a while. Right now my main gig amp is a PRS HDRX 20 which surprisingly loud and is way better sounding than my Granger 1987. The amps in your video sound really nice.@@totallyradguitars959
i have the mkiii combo 1x12 100watt ... i love it , it costed me 350 euros last year ... amazing find and it cand do metal with a boost ... i want to put a hotmod v2 in it but i dont know if it will fit in the smaller chassi of the 1x12 combo ... anyone knows?
Sorry - I don't think the hotmod will fit on the 1x12, the tube sockets are extremely close together. If there were a way to rotate the hotmod by 90° it could work though, just not sure how to accomplish that.
I've never seen a 900 Mk "2." Mine is a very early one with the circles around the knobs - maybe yours is even earlier and it got a re-used or mislabeled silk screen plate?
Yes definitely, I think the Jubilee was a hit and this was their way of taking the success of the 2203/2204's and bringing in some of the experience they had with diodes in the Jubilee and 2205/2210 amps. The biggest difference is the Jubilee used some LED's for clipping, just like a JCM900 DR ChA, the Mk III is all more "traditional" diodes, so the clipping is a little harder. The Jubilee also has a little asymmetry to the clipping on the lead channel which gives it its unique tone, plus some different EQ/voicing. I still have a 2555 Jubilee, probably need to do a detailed video on it (my original Jubilee video doesn't talk about the circuit and is definitely a bit unpolished!)
@@totallyradguitars959 I just watched your older video comparing these to the Jubilee. Would love an updated overview of the Jubilee to understand how it changed the 2203 circuit and why the EQ is so responsive compared to other Marshalls. Loving your videos!
Hey, I don't have a JVM anymore but I'm sure I'll get one again - I tried to buy one recently but the deal fell through. I will say that while I had the JVM410, the OD1 channel sounded nearly *identical* to my TSL. I did not like the lower mid scoop of OD2, which is the JVM2xx channel as well. Clean and Crunch channels were "just ok" - I didn't hate the amp or anything but my TSL was half the price and I felt sounded so similar that it wasn't worth keeping the JVM so I sold it. That said, I want another JVM410 so I can do a circuit analysis on it. It has some really cool switching depending on the channel and mode you are using. Cheers
your slx sounds like it's got a lot less gain than mine when both knobs are at noon, maybe it's modded or the preamp tubes got swapped out The slx's first gain knob has a bright cap on it which lets more highs through when the gain isn't all the way up, it's critical in setting up how clear or girthy you want the amp to sound. The bright cap also applies to a jcm 800 and the bright input on plexis, pretty sure a lot of metal guys turn the gain a down a bit and boost to get a tighter sound that way
You’re the second person to mention that my SLX seems to have less gain - when I got it a few years ago I checked the tubes and the values in the circuit to make sure they were right but now I’m second guessing myself! When I have a little spare time I’ll open it up again and give it a good run-through and report back if I find something out of order.
I have 2 JCM800 2210's and a JCM900 SL-X 2500 and the SL-X has a lot more gain than the 800's. It's got a bit more gain than my 2203 with a Legendary tones Lynch mod, so I don't think your SL-X is running quite right.
You're not the first to mention that but I'm not sure - just today I had the amp open, rolled all of the tubes, checked voltages internally, it's been recently recapped, nothing appears out of spec or out of order. It definitely has more gain than my 2210 or 2203.... not sure what else there would be to check. Most of the other ones I've heard on TH-cam sound just like mine too. Maybe it has something more to do with my recording or guitar but either way, I'm quite happy with the tone so I'm not going to mess with it any more haha
@@xvx6663 I haven't because the preamp tubes are closer together on the SLX than the 2203. The base on the Lynch mod can swivel and I have been told it can swivel enough to go into the SLX and it will work, but when I got it about halfway there it felt too tight to go any more.
@@andrewspade7969 I asked because I also have a SL-X 2500 and I used the lynch mod on it and it made the amp tighter. Yeah you can rotate the lynch mod while it’s connected to the tube socket to make it fit Rigth in between the other tubes. I did not even know, the guy that made the lynch mod told me how to do it over email. I was just wondering if you had tried it and if you also liked the sound. Only thing is that i think the extra tube the lynch mod provides may have burned the Br3 in the circuit and now my amp won’t play so I need to get that part replaced with something that will be able to take all that heat. I been on forums and asked questions and they all said that eventually the Br3 malfunctions and needs to be replaced and that most likely the lynch mod caused the issue in my SLX. This just happened too… it worked good for months and just last week it stopped working. I’m gonna take my amp to tech to have him work on it and see if it was the Br3. But man does the lynch mod sound good with the SLX.
If you have to use a lynch mod on an slx to make it tight then you are the problem, not the amp. Ridiculous. You guys really cant play amps anymore without either a boost or a hot mod.... even when the amp is already a hotrod. You just cant dial it or play it right... its so funny. Amp breathes fire without any of it under the right hands.
Umm it’s nothing like the 800s for a start it’s 80% a solid state pre amp .the only thing they share in common is the 800s where the first of the low voltage Marshall’s .up till then they were high voltage amps and tbh the super leads are the best easily
It is not an 80% solid state preamp, I think you might be confusing the JCM900DR with the JCM900MkIII, which are completely different amps. In fact, the JCM900SL-X is an all tube signal path. If you look at the schematic section of this very video, you will notice that the JCM900MkIII schematic is nearly identical in layout to the JCM800 2203's schematic, with the exact same basic topology. I am not sure what you mean by low voltage vs high voltage. All tube amplifiers have lethal high voltage components within them, including both JCM800's and all variants of JCM900's. In case you confused voltage with wattage, I'd like to point out that the first popular Marshall was a tube rectified JTM45, as in 45 watts of output. Almost immediately after that, the amps were made in 50w and 100w varieties, starting in the late 60s all the way to the present day. There was never a time of "high wattage only" and then low wattage amps came later - they have been available both ways since inception.
@@totallyradguitars959 sorry for my original comment it was very vague i admit. i was no0t either talking about whether there was a time im talking strictly marshall.pre amp voltage definitely matters imo.just so your not confused by what i was saying.it matters heaps actually and when modding its a great place to start
@@totallyradguitars959 are you aware of 4 ohm tapping your amps.that was also part of earlier marshall mods and design.i tried to reply with a great link here from a really good builders site but it keeps getting removed weird,type in rob robinette marshall ,how a jcm 800 works.he covers what ive said in extensive detail .if your interested.
Hey, I’m familiar with that site (tons of great info I agree) and the voltages - ex. lower voltages to preamp tubes usually mean less headroom and more drive etc. Just pointing out that I think you meant the 900DR when saying it’s mostly solid state, because this video is about a different amp (the Mk III and SLX)
@@totallyradguitars959 nah i got that i know that model..nothing wrong with diodes mate.look at boogies total pre amp tube gain but lack that brite crunch of any diode based marshall imo..i love diodes but there solid state in the tech jargon of it all..cheers
Thanks for your feedback. After watching your videos I can see that you know best when it comes to noodling in front of your phone camera for 30 seconds, very high quality
dude honestly this is the best guitar hangout and chill channel for me. this is like going to a dudes house who knows a shit ton about amps and getting the real info. brilliant.
Thanks! That's what I'm going for
He's the Johan Segeborn but for 80's rock
@@1thess523 haha I appreciate that but I'm not quite as cool as he is I think!
@@totallyradguitars959 you need a baseball hat and crocs and bingo, oh and come up with a "let's go" saying 🤣. Try Autobots roll out 🤔
This is easily the best video about Marshall's MKIII and SLX amps. Not a lot of people even know about these two models in the 900 series anymore.
I have the same 2501 MKIII combo, and I really love it. For me, it's the perfect combination of being simple to operate with modern features like a loop and built-in boost. The dual master volume controls are also very handy to make a solo jump out in a mix without changing the tone at all.
This is one of my favorite videos.
I have a 50-watt MKIII head going into a 4x4 Marshall cabinet.
I think this video will help people understand their 900s better.
Well done!
A 4x4 is a tiny cabinet!
I have the Mark III 100 watt head. It's dated Feb-1990. Great amp with 2 JCM900 4x12 cabs. Tried many different tubes, new, newer and NOS. Found testing and mixing the power and preamp tubes is the way to go. Great video!
Such an informative video, I would refer anyone considering a 900 to this.
I got a 50w 2500 mkiii head in a trade, continues to surprise me. Rush tones are so easy. I usually keep the sensitivity off but you nailed it when you compared it to a tube screamer utility. Great video, I love when people love on these amps!
Best description of a JCM 900 EVER! These amps are so overlooked and sound killer....
I love my SL-X. More than my 800 2204 or my 2205. Great job. Your channel is great keep it up.
I would recommend getting a legendary tones lynch mod or hot mod for your 2204. It doesn't require any modding just slides into V2, it increases to the gain by up to double and the amp sounds better at low volume. Before I got my Lynch mod my 2203 was never played and I play it a lot.
@@andrewspade7969 Great suggestion. I have always wanted to try one of those. I use a distortion pedal in front of everything. I can use the pedal volume to keep the amp vol. where I want it.
@@andrewspade7969 That’s what I did and to be honest my 2204 sounds better now at 7 o’clock than it at 11 o’clock.
Thanks for making this video. It's the best comparison and explanation I've seen on these amps by far.
I've had a Mk iii since I bought it from a buddy in the mid 90s. I brought it over from the UK when I moved to Canada in 06 and we rewired the transformer to 110 in 2012 it has a double output transformer. Love it. Play it through a 1936 2x12 and it's all you could ever need.
Had both these amps, the combo first then the SLX - I thought that the SLX took pedals really well, I used to use with a Rat and it sounded phenomenal.
Completely genius brother……I love my 900 MK iii…….I also have the 800 and the 2000 dual. Really well done overview of how great the 900 mkiii is and it shows you how these are real sleepers.
Even though the trend is lunch box and 20 watt versions of these amp..the 50 and 100 sound so much fuller. When the Ox Box came out it changed my ability to capture the full sonic joy without blowing my audience out of their seats. Great job
Great video! Love the MK3 and would like to buy an SLX. People crap on the diode clipping but seem to forget how many albums use a modded Marshall plexi with diode clipping 😅
Absolutely, and people praise amps like Cameron's, Ceriatone Chupa/Yeti, etc. and those all have clipping too. It's just a flavor thing, some prefer no diodes and that's fine but it doesn't make it a bad amp to have them - I wish more amps did it like the Mk III where you can basically turn the diodes completely off if you want. My Ceriatone KK also has a switch that turns off the diodes as well so you have both options - very nice to have.
Tube Screamer or Maxon 808 in front of pure tube Marshalls is a classic sound.
Really in depth video with good helpful discussion of both amps. I also like that you actually riff; nice job! Had an encounter with a MKIII 900 head to record with a band I was in this year and that was a really special amp. Gain and Sensitivity at half just gave it this thick, strong punch but still with clarity. Ended up using for the vast majority of the guitars on the record, beastly sounding thing.
Thanks! The Mk III is really a beast, I couldn't believe how good it sounded recorded just from these clips - I actually taped my mic stand to the floor after recording this so I wouldn't lose the spot! Now this is an amp they should reissue.
great video. I do use a JCM 900 mk 3 myself . I prefer it with the diode clipping off and boosted with an overdrive or distortion in front . Great sound
This channel makes me put the 900 higher on the wish list. Thank you. Great reviews
I'm lucky to own all 3 versions of the JCM 900 series. I love em all!
Cool video! I sold my 100w SL-X for a 100w MK3, and I loved the tone from both. I received quite a bit of complements from each as well, but I do favor the MK3 for the time I was wanting to achieve
That Marshall JCM900 Mk III really sounds good.
Took about a year but my old 83 Pacer finally made the channel!
It's a hell of a guitar! I actually used it for the Vintage Modern video then realized in editing that I clipped the mic the whole time. Doh! So I re-recorded that one and had already put this one back in the case. It deserved to be in a video, super well taken care of too.
Had a MK3 50w head back in the 90s. Never should have got rid of it. JUST (TODAY) acquired a 50w Dual Reverb 900 combo, traded in a JCM2000 head.. NEVER could get the right sound on the 2000. Had the 900 dialed in within 3 knob turns in the shop. Walked away with it, without a look back. WAY underrated amp.
your explanations are very understandable. thank you. very educational.
I've had one of these since they came out and I just love it. I treat it like an 800 and keep the Sensitivity right off. Marshall really dropped the ball by having 3 different versions of these amps. The 2100 and 2500s are great. The Dual Reverbs were…not good and the SLX is fine but it's just not the same (I think it's a "it's not mine" bias). Really great video.
..funny statements ... yes, exactly what I found out for myself: my JMP MkII is hard to tell as a different amp used when blindtested in comparison to the JCM 900 MKIII with diodes turned off. I had this in mind as a hope looking at the scheme when buying the MKIII and have not been dissappointed .... I can use the MKIII as a low cost JMP here without any problem :D
Oh and I haven’t got it yet but I figured the master b (or however)could be set louder.. to compensate for your guitar being rolled back so that would actually be your clean sound..
Great idea, I never thought of that. I'm bad at doing two things at once (i.e. stepping on footswitch while also rolling down volume) but with some practice it would work really smoothly.
Guess I’ll find out .. maybe it wasn’t such a bonkers idea afterall lol
I now have an SL-X (5881) and an MKIII (EL-34) The MKIII sounds identical to my '90 JCM800 2204, I can't tell them apart. The SL-X is still my favorite, but that comes down to personal preference.
This was one of the videos i checked before buying Marshall 2500 head a week ago. Glad I did. Such a sleeper amp, sounds fantastic. 500 with new tubes in excellent condition. That’s just silly, more than grand less than jcm800 or silver jubilee. I briefly even considered selling my old silver jube but realised that’s propably stupid idea. Should SLX pop up for sale locally, I think I’ll get one of those as well. Unfortunately those are usually more expensive.
They are killer amps. I lucked out and got a JCM800 2203 before the prices went nuts on them and while I'm glad I have it, I'd be just as happy with a 2500/2100 (either SLX or Mk III) especially at current prices!
Man. So true. I also used to have 2x12 jcm800 i forget the model but basically 2203 but combo. Nice amp, absolute nighmare to carry around. Hey bwt, in your 2500, if you set master a and b the same, b is quite a bit louder? In mine master at 9 o’clock A=barely on while master B takes your head clean off. I have stared the schematic but I dont fully understand how the 2 masters operate and if that is supposed to be like that. Anyway, thank you for the informative video content!!
@@vl292 I don't have this combo anymore, but I have a 2100 Mk III Head instead. On that amp, the volumes are incredibly close when set the same - nearly impossible to tell. I *think* I hear Master B (footswitch on) being the tiniest, slightest bit louder, but only by a little bit. There is a little tonal shift, it feels punchier on Master B to me.
I'm also not an expert once the opamps get involved, and both masters run through opamps in this circuit. It looks to me like the footswitch jack is grounding Master B out when not engaged from the + voltage line of the opamp there, but then when it's disengaged it looks like both volumes are active... But I don't find that to be the case on the amp itself (I.e. if I have Master B on via footswitch, and I turn Master A up or down, I don't notice any volume/tone change). Looking at the schematic, if I didn't have the amp in my hands right now, I'd expect to hear a slight tone/volume change if I were on Master B and started turning up Master A, but that's not what I'm hearing. It's possible I'm just using my ears too much and not my eyes, or it's also possible there is a schematic revision/update I don't have or it's just missing a part on there.
If there's a drastic difference as you describe though, I would take a look at the area around Master A: R16, C19, VR3 pot, and see if there are any loose solder connections or any sign of damage. If those components are good, then I'd really start to suspect the opamp on that side. Of course, the usual safety speech goes here, don't touch anything with two hands, don't hurt yourself, it's not worth it, take it to a tech if you're not comfortable! Cheers!
good info on the mark 3 as i have the 2500 head 1990 helped me understand it better
I like your channel . Talked to you on Rig Ralk about our TSL 2000 . We both got 1999 as first tube amp. Very cool
Thanks! Still need to do a video on that one - great amp. Just need a little more free time!
If you look at the slx schematic the 2nd gain stage has a plate resistor of 27k instead of (the standard) 100/220k. This is why they have a lot less gain than a dual rec etc
I’ve had the mk iii as my first tube amp in the 90’s and I swear it was brighter and more classic sounding than the el34 SLX I had a few years ago. The SLX sounded more low mid and really didn’t wow me as much. I traded it for a Mesa OS cab back when you could still pick up 900’s for $600 or so. Now that they’re 1100 and up I almost feel stupid but it’s God’s cab so not really, lol. Nothing sounds bad thru it and I’ve got a 2204 modded Origin to play with.
@@R3dbudd I have a Mesa cab, traditional size but it’s still one of the best sounding cabs I’ve heard, so I can’t fault you there. As long as you’re still enjoying it, it was a great trade!
im so happy your back to make more
Does anyone have a pdf of the document that contains the schematics? I can find user manuals for the SLX 2100, but I'm having a hard time with the mark iii 2100
Hey, check here: www.drtube.com/marshall-jcm900/
The very first one is the 2100 Mk III preamp, if you look at the second link down "CD0109 Issue 9 JMP51B PCB, Marshall, 1990"
Power amp schematic on a separate page below that "CD0192 Issue 10 JMP50C PCB"
SL-X 2500 owner here. Mine is really thick too. Doesn't sound right saying it doesn't have much gain. You should have the amp looked at by a tech.
I have already had it open and checked most of the values in the circuit and nothing looks wrong, and when I listen to other youtube demos mine has about the same amount of gain so I doubt anything is wrong.
When I say it doesn't have much gain, I meant that compared to other amps also available in 1993 - like the SLO, Dual Rectifier, Peavy 5150, Steavens Poundcake, etc it does not have nearly the same type of heavy, chug palm mute type gain that those have, yet that's what I expected based on other online reviews before I owned it.
@@totallyradguitars959 I totally agree with your second paragrah. However, what speakers is it running through. I have both the G12t-75's & the Marshall Vintage Speakers. The Vintage speakers sound way better with the SL-X as it tends to be a little darker and the Vintage brightens it up.
@@guitarexpert2245 I’m very lucky and happen to have a huge selection of speakers too - I just really love the ‘86 T75’s so I use those most of the time (and in this video). I have a quad of ‘96 V30’s (same as Marshall Vintage speakers) and they certainly brighten up this amp and others. They have an aggressive sounding boost in the high high mids that really cuts and can make some amps sound piercing, but some amps get more presence and cut with them. I’ve actually been meaning to do a speaker comparison video but what can they are mounted in has a noticeable effect too so it’s going to take me a while to get it all tracked since I’ll have to rotate speakers through the same cab.
Also, I’m going to check through the SLX again when I have a little spare time and just check. You’re not the first to mention it seems to have less gain than theirs now so I think that merits a follow up on it.
@@totallyradguitars959 Hey, sounds good. You certainly know your gear!
Great job!
Love my SL/X 2100. It is a little different flavor, very underrated and versatile. Not sure when was actually looking at the schematics ages ago (terrible to read), but the input stage if I'm correct, is like a standard gain stage into a follower. Really, it's more like a 4-stager (not five), as the extra follower won't contribute any gain.
So, agree, there isn't any more gain as in some of the HG amps like an SLO (I have one) or a 5150 (had a 5150II). Have to say, mine will have gobs of gain with both of those controls together past 12 noon, and it's not so good there for mine. If it can be done, better off more conservative with those controls, and cranking the thing up old fashion Marshall-style. It breaths more, sounds great, and your ears will thank you next day with joyous tinitus!
I was curious about that too - I’ve been learning a lot lately about gain stage dragon and this circuit always confused me whether it was 4 or 5 stages and it seems like there’s one stage that isn’t adding any additiona distortion characteristics so I’m glad I’m not crazy in thinking that.
I have a 6100LM I need to do a video on soon. The lead mode on that amp with the gain boost is what I thought the SLX would be - it’s extremely high gain especially for 1992. The SLX is a little more classic and less “modded” sounding, if that makes sense, to my ears at least. Love them both
@@totallyradguitars959 Played a 6100 nearly 30 years ago. It was killer, back then I couldn't afford one. I like the Marshalls from that era. At least back then they were trying different things circuit-wise. But us guitar players are fickle, and terribly un-accepting of things different or new.
I have a JCM 900 MKIII Model 2100. The amp is great the only complaint I have is you can't use a foot switch to switch from clean to dirt. For that reason, I have bypassed the preamp and just use a pedal board 100% in the effects loop. But now I think I will start using the preamp again for the dirt and use an ABY switch to switch from the 900 and a solid state amp and use the 900 as my dirt amp and the other for clean. Thanks.
It’s got a pretty great dirt sound that’s for sure. Rock on
Wow, thanks for showing how the preamp really works. The most people dont understand how to use it.
I had an early 90’s SLX 100w w/el34’s briefly…..only thing I wish was that it would clean up a little better with the guitar volume, but it wouldn’t. Had a lot of low end though…..live I ran the bass on like 4…..🤘🏼
The 900 MkIII is a great amp and sounds nothing like the dual reverb versions
Very helpful video thanks
Nice review , got me thinking , how hard would it be too put a extra pre amp tube in place of the clipping diode on the MK III , , the controls are the same ,the sensitivity controls the extra tubes in the SL-X and the clipping diode in the MK III , besides drilling an extra hole in the chassis for a 4th tube ,and adding the socket , doesn't serm like a major project since the controls are all the same , basically a Tube for diode swap no ?? Then you have an SL-X Still with the MK III label , but who cares About what the front panel says !!!
(Trick at the bottom)
The problem isn't the amps.
The problem is the amp snobs.
Instead of lissuning to an amp, they check the schematics first.
And then there are ultra snobs, who look at the 2555X Silver Jubilee amp (which has diodes, BUT is played by Sl00sh (slash)) and it's all gud...
I owned a Model 2100 Dual MV MkIII from 2002 to 2013 (gigged and lent it to friends who gigged it (Alt-Rock to Fuzzed out Stonerrock to Black Metal)).
So I dunno what the factual problem is with some people.
Trick: Stick a patch cable in the FX-Loop (which is serial/parallel (which is why this works)) and set the sensitivity of the loop to taste.
You will find it really comes alive... (works with all 900 models and other amps which have this type of loop)
th-cam.com/video/SKsTNSm4st4/w-d-xo.html
Very nice, totally agree. I love to look at schematics, but I'm no snob - if it sounds good, I'm happy. The Mk III and 2210/2205 are my favorite Marshalls and they are both diode clipper circuits. On the other hand I've heard all tube amps I didn't like. It's all up to how it gets used!
Thanks for this so much info about slx
Hi, great video. I have a 900 mk iii and it’s great. Have you tried the patch cable in the effects loop trick? Apparently it beefs up the low end.
I have but I didn’t notice a massive difference. I know on the dual reverbs it pulls another tube into the chain (just a buffer tube though not a gain stage). I’m not saying it doesn’t work but I’ve had 4 Mk III’s now and can’t say I would be able to tell the difference between any of them patch cable vs no patch.
@@totallyradguitars959 yeah, I tried it and it did get slightly louder maybe but I’m not sure if jumping the loop improves the tone. They are great amps, compared to my 2204 though the mk iii is a bit thinner, more brittle sounding. Still really good though, especially after I changed the resistor in the bias circuit so it can be biased more to specs.
Cheers
@@vintagesound8112 There are a couple of cap/resistor changes you could do that would make it sound nearly identical to a 2204, but it would make the diodes/sensitivity muddier in the low end. I think that's why the Mk III's are thinner by default, to make them more usable if you max both gains out. I had some thoughts about altering the values to match 2203/2204 and then adding a high pass filter across the diode circuit only to prevent it from getting muddy as you add the diode gain... but that's more in depth modding than I'm willing to do to a vintage amp at this point. Maybe if I built one from scratch though...
Awesome video. Keep up the good work!
Thanks dude!
best review
Could you do a review of the DSL?
Send them all too Hermanson fr . He made my marshals onto my favorite amps . Slight edge over my wizards
Had a hermansson modded one was just like a sharper tighter Marshall some might live them but not even close to wizard impressive regardless
@@josephbutler148 I like them about the same .
@@techdeathhippie6319maybe some models are better I had the slx with 3 gain stages or 4 can't remember not the highest one one back from that lol but anyway it was not even as good as my stock TSL. It was a bit underwhelming and disappointing and I had other issues with it but I know his work is good and a lot of people love it just was not a good experience for me wizard on the other hand are something else huge crushing and tear ur face off I really should have kept a wizard around now they are ridiculously priced probably never own another but my engl special edition gets me close and does more
@@josephbutler148 I have the 5 gain stage 800 and 4 gain stage dual rectifier . I love my wizards too . But these two brands definitely my top damage
@@techdeathhippie6319 try the diezel herbert mk3 destroys them all
I didnt know that this Mark III existed. I've always thought it was the high gain dual reverb and SLX models only on the JCM900 lineup
They kind of fly under the radar, especially since the Dual Reverb's are so poorly regarded I think these got lumped in with those since they are both in the same range and use clipping diodes. The thing is, diodes aren't bad on their own, it's how they are used, but the SLX was clearly much more popular (it ran from 93-99)
22 years ago I bought an 50 watt SLX. and sold it around 2005 when I switched to Beach Music and switched to my Fender Twin that I've since sold.
But 2 years ago I bought a JCM 900, Mkiii 2500 head and run in stereo with a Laney GH50L and a Marshall JCM900 1960A cab and a JCM 1960AX cab misspeakered with V30s
Not able to do a side by side,
but I'm having more fun with the Mkiii 2500.
I've got pictures of me using a Fender/Sun Model T and a Laney AOR 50 Lead and the SLX sitting as a backup amp.
But I did use the SLX in the studio here on a 11 song demo of originals in 1999.
Awesome story! I’m a big fan of the Mk III. It’s the only Marshall combo I still have and I wish I’d kept the head I had of it. I also had a Laney AOR50 but sold it before I started making videos. It had a lot of gain but very loose low end - but also really cool pull switches to shape the tone. Definitely a unique amp but I couldn’t quite get along with it - which may change now that I have more cabs. I think it just didn’t sound good with V30’s to my ear because that’s all I had for a long time
AMAZING video!!!! Which one would you recommend for a strictly at-home player with low-volume needs
Thanks man! I'm a little partial to the Mk III but neither are particularly low volume friendly, well depending on what you mean. I play about 90-100 db at home but I have very understanding neighbors, if you need to go quieter, and attenuator or even just going down to a 1x12 can make even the loudest Marshall feel a little more manageable. There are 50w versions of both of these amps, including the SLX (model 2500). Cheers!
@totallyradguitars959 Thank You :)
I had a slx 50 watts head that sound pretty good. I replaced it with a 4210 jcm 800 combo. I find the 4210 sound a bit better plugged in a closed back cab in comparison tonthe slx, it has a more direct punch in the low mid when you hit the notes. It is more direct, which the slx was missing a bit to my taste. I see what you mean when you say the slx and mkiii are a bit softer. This is the thing that was missing to the slx to be almost perfect for me. On other hand the slx has way more gain. (I was shocked how little gain/distortion your slx has with both pre volume and sensitivity at 5.) The slx I didn't need to boost. The 4210 need a little help /boost to be where I like it soundwise. I might try a lengendarytones hot mod in it...
I've had a few comments about my SLX being lower gain so it's possible I have some component or tube out of spec. It still sounds really great - thick and full to me, but one of these days I'll get it up on the bench and check it out again.
What I will say though is that your 4210 - I have the head versions (2205 or 2210) - is my all time favorite Marshall sound. Direct, great boosted or unboosted, I don't care about the diodes.... just a beast of an amp. Working on a video for them right now actually.
@@totallyradguitars959 looking forward to watch this video with your 2205 and 2210. :)
Also if you put a eh 12ax7 h tube in slot one you will notice a great gain difference.I had to run a class A tube stereo power amp to get my 900s into the zone of what I call real .there quite a great distortion but without a serious power amp section on there own wimpy and plastic sounding
Great vid. Not sure if you said, but does the SL-X have the el34 or 5881 tubes?
Hey, this SLX ('93) has EL34's. Later ones usually had 5881 unless they were converted, and then very very late ones would be back to EL34 again. Cheers!
I regret trading off my SLX head about 20 years ago. Recently found one on GC’s site, got excited and ordered it but they canceled it with the bs reason of “it got damaged in shipping” 😑. I have a 4100 but still really want another clean SLX.
I’ve heard a few BS reasons like that, but I suppose it may have been a return that was already damaged. Always a 50/50 chance when ordering anything from GC. I’m sure you’ll find another one, it’s well worth having in addition to the 4100 since they do sound a lot different!
@@totallyradguitars959 I decided to try a JCM 2000 DSL since I’ve seen some pretty interesting videos comparing them to JCM 800s. We will see if this one actually gets delivered and if I decide to keep it. Would really like to find a nice 800 but I literally just play in my spare room so it seemed foolish to spend that much at this time.
I have a SL-X 2100 and I can't get preamp vol and sensitivity on max. Its gets damn muddy. That didnt happen with yours...
A few people have told me mine has less gain than theirs too. Something I've been meaning to look at internally forever but I'm happy with the way the amp sounds and haven't had it opened up in a long time, other priorities.
Scooped and bright???? Hahaha dude its 97% a JB wind with an A8. That Pacer must be what’s bright or you got a lemon Alt8.
Thanks for the great info on these amps! Definitely going to be checking back in for more!
Nice Demo, great job!
what speaker do you use in this demo? mk3 stock t75?
Hi! 1986 G12-T75’s, the ones with the vented back, in the Marshall 4x12 underneath is what I used for both amps. The internal speaker of the Mk3 wasn’t used in this demo but it is a G12-H100 which I also love
Awesome video!
Great video! I'm thinking about picking up a MKIII at the minute, but I'm wondering if it has much clean headroom? Would it be possible to have those nice warm Marshall cleans if I cranked the master volume and used the gain knob to adjust the 'loudness' of the amp?
It's certainly a LOUD amp but I'm not sure I'd describe it as having a lot of clean headroom. It's similar to a single channel 800 - you can get it loud with the preamp gain set low, but the master is already at almost full tilt by "5" and if that's not loud enough for whatever purpose (recording, gigging, etc) then you're out of luck. I've had a HIwatt DR103 and THAT is clean headroom, but it was also so ungodly loud that I never got to find the limit in any reasonable setting I could play it in. So it probably depends on A) where you are going to be using it like that and B) if you need really pristine cleans or can put up with a little bit of sparkle/grit
Either way, try to swing the 100w version if that's a concern. There is a 50w on guitar center used listings right now at the time of writing this comment, I don't think the price is terrible but not an incredible deal either - so if that's the one you're looking at and clean headroom is the concern, be patient and wait for a 100w. (or get the 50w from GC and try it out, and if it doesn't work for you, return it - but you'll loose the shipping cost to find out) Cheers.
@@totallyradguitars959 Ah, OK. My main amp at the minute is a Bluesbreaker run clean with a T Rex Mudhoney fir crunch/dirt, but I've always fancied a 900.
I used tonown a horizontal input JCM800 bass head, clean for days. Should have kept it!
Thanks for the reply!
Hi, great review, I have a JCM 900 MKII Combo as well. There is an issue with earlier ones with the bias resistor (R30) being too large (56k) instead of (47K) do you have the same issue in yours ?
I will have to check and get back to you on that one after I have a chance to open it up again. I remember some of the TSL's had a similar problem with resistor values on earlier units too.
I'm not sure if you mentioned it, but does your SL-X have EL34s or 5881s?
Hey, it’s a ‘93 with el34’s
Could you explain a bit about the 2 master volumes? Specifically, do they help facilitate low volume home playing with overdriven sounds??
Hey, I don't think they really help the low volume. Some amps that have two volumes active at the same time, you can manipulate them a bit to get the tone at lower volumes - I use that trick on my VHT Pittbull and others a lot.
These amps though, each master volume doesn't have any effect on the other, and they are both identical tapers and pot values. So if you are using "Master A" and turn it down to lower volume, it's the same exact tone if you used "Master B." That also means regardless of which master you are using, if they are both set to "5" and you footswitch between them there's no tone or volume change either. Hope I explained that clearly haha cheers
@@totallyradguitars959 yes, that does indeed help/make sense. Thank You
I had a MK III for a while. I modified it, simply disconnected some of the diodes, the first two groups. WAY better sound, smoother, more bass less fizz. Nothing fancy, just disconnected them. The later diode groups are more difficult to get out o I left them. Also added a choke. They aren't anything like a JCM 800 at all except they have a cathode follower but so does a Bassman. Still not "more polite" than an 800 either. The 800 is just more expensively built, and they sound like a more "grown up" amp.
A lot of people lift the first leg on D1 but that's just an input clipper, not what the "sensitivty" knob controls (that's the second group you mention, between V1B and V2A).
Not sure what you mean that they aren't anything like a JCM800 - the 900 Mk III is almost exactly a 2203 preamp with a few different values to change the voicing, and diodes crammed in between gain stages 2 and 3 with a level knob.
Maybe "polite" isn't the right word to use, but the 900 Mk III with diodes off is smoother and lacks the grittier, angrier sounding mids that a 2203 has. You can get a different flavor of that grit back a bit by adding in the diodes, but the amp alone is just a smoother-voiced 2203 circuit.
Thanks for the reply. I may get an SL-X next, because they aren't too expensive and gig with that a while. Right now my main gig amp is a PRS HDRX 20 which surprisingly loud and is way better sounding than my Granger 1987. The amps in your video sound really nice.@@totallyradguitars959
Nice looking Pacer.
Thank you! It's one of my favorites for sure
i have the mkiii combo 1x12 100watt ... i love it , it costed me 350 euros last year ... amazing find and it cand do metal with a boost ... i want to put a hotmod v2 in it but i dont know if it will fit in the smaller chassi of the 1x12 combo ... anyone knows?
Sorry - I don't think the hotmod will fit on the 1x12, the tube sockets are extremely close together. If there were a way to rotate the hotmod by 90° it could work though, just not sure how to accomplish that.
I have the 2501 JCM 900 MK II. It’s the same size combo as the one you have but it says MK II. I wonder what the difference is.
I've never seen a 900 Mk "2." Mine is a very early one with the circles around the knobs - maybe yours is even earlier and it got a re-used or mislabeled silk screen plate?
It sounds like the MK3 is almost a continuation of the silver jubilee? I may be completely wrong but the optional clipping is similar.
Yes definitely, I think the Jubilee was a hit and this was their way of taking the success of the 2203/2204's and bringing in some of the experience they had with diodes in the Jubilee and 2205/2210 amps.
The biggest difference is the Jubilee used some LED's for clipping, just like a JCM900 DR ChA, the Mk III is all more "traditional" diodes, so the clipping is a little harder. The Jubilee also has a little asymmetry to the clipping on the lead channel which gives it its unique tone, plus some different EQ/voicing. I still have a 2555 Jubilee, probably need to do a detailed video on it (my original Jubilee video doesn't talk about the circuit and is definitely a bit unpolished!)
@@totallyradguitars959 I just watched your older video comparing these to the Jubilee. Would love an updated overview of the Jubilee to understand how it changed the 2203 circuit and why the EQ is so responsive compared to other Marshalls. Loving your videos!
Could you do a JVM review?
Hey, I don't have a JVM anymore but I'm sure I'll get one again - I tried to buy one recently but the deal fell through. I will say that while I had the JVM410, the OD1 channel sounded nearly *identical* to my TSL. I did not like the lower mid scoop of OD2, which is the JVM2xx channel as well. Clean and Crunch channels were "just ok" - I didn't hate the amp or anything but my TSL was half the price and I felt sounded so similar that it wasn't worth keeping the JVM so I sold it.
That said, I want another JVM410 so I can do a circuit analysis on it. It has some really cool switching depending on the channel and mode you are using. Cheers
@6:22 "I can't really tell for sure"... Why not? Check that the components match the schematic.
@6:17 "...And I looked in there and nothing is out of place"
Yes I already had cross checked the amp with the schematic before making this video.
your slx sounds like it's got a lot less gain than mine when both knobs are at noon, maybe it's modded or the preamp tubes got swapped out
The slx's first gain knob has a bright cap on it which lets more highs through when the gain isn't all the way up, it's critical in setting up how clear or girthy you want the amp to sound. The bright cap also applies to a jcm 800 and the bright input on plexis, pretty sure a lot of metal guys turn the gain a down a bit and boost to get a tighter sound that way
You’re the second person to mention that my SLX seems to have less gain - when I got it a few years ago I checked the tubes and the values in the circuit to make sure they were right but now I’m second guessing myself! When I have a little spare time I’ll open it up again and give it a good run-through and report back if I find something out of order.
I have 2 JCM800 2210's and a JCM900 SL-X 2500 and the SL-X has a lot more gain than the 800's. It's got a bit more gain than my 2203 with a Legendary tones Lynch mod, so I don't think your SL-X is running quite right.
You're not the first to mention that but I'm not sure - just today I had the amp open, rolled all of the tubes, checked voltages internally, it's been recently recapped, nothing appears out of spec or out of order. It definitely has more gain than my 2210 or 2203.... not sure what else there would be to check. Most of the other ones I've heard on TH-cam sound just like mine too. Maybe it has something more to do with my recording or guitar but either way, I'm quite happy with the tone so I'm not going to mess with it any more haha
Have you used your SL-X 2500 with the legendary tones lynch mod ?
@@xvx6663 I haven't because the preamp tubes are closer together on the SLX than the 2203. The base on the Lynch mod can swivel and I have been told it can swivel enough to go into the SLX and it will work, but when I got it about halfway there it felt too tight to go any more.
@@andrewspade7969 I asked because I also have a SL-X 2500 and I used the lynch mod on it and it made the amp tighter. Yeah you can rotate the lynch mod while it’s connected to the tube socket to make it fit Rigth in between the other tubes. I did not even know, the guy that made the lynch mod told me how to do it over email. I was just wondering if you had tried it and if you also liked the sound. Only thing is that i think the extra tube the lynch mod provides may have burned the Br3 in the circuit and now my amp won’t play so I need to get that part replaced with something that will be able to take all that heat. I been on forums and asked questions and they all said that eventually the Br3 malfunctions and needs to be replaced and that most likely the lynch mod caused the issue in my SLX. This just happened too… it worked good for months and just last week it stopped working. I’m gonna take my amp to tech to have him work on it and see if it was the Br3. But man does the lynch mod sound good with the SLX.
If you have to use a lynch mod on an slx to make it tight then you are the problem, not the amp. Ridiculous. You guys really cant play amps anymore without either a boost or a hot mod.... even when the amp is already a hotrod. You just cant dial it or play it right... its so funny. Amp breathes fire without any of it under the right hands.
It should be illegal to play anything but a Les Paul thru a Marshall.
Umm it’s nothing like the 800s for a start it’s 80% a solid state pre amp .the only thing they share in common is the 800s where the first of the low voltage Marshall’s .up till then they were high voltage amps and tbh the super leads are the best easily
It is not an 80% solid state preamp, I think you might be confusing the JCM900DR with the JCM900MkIII, which are completely different amps. In fact, the JCM900SL-X is an all tube signal path. If you look at the schematic section of this very video, you will notice that the JCM900MkIII schematic is nearly identical in layout to the JCM800 2203's schematic, with the exact same basic topology.
I am not sure what you mean by low voltage vs high voltage. All tube amplifiers have lethal high voltage components within them, including both JCM800's and all variants of JCM900's.
In case you confused voltage with wattage, I'd like to point out that the first popular Marshall was a tube rectified JTM45, as in 45 watts of output. Almost immediately after that, the amps were made in 50w and 100w varieties, starting in the late 60s all the way to the present day. There was never a time of "high wattage only" and then low wattage amps came later - they have been available both ways since inception.
@@totallyradguitars959 sorry for my original comment it was very vague i admit. i was no0t either talking about whether there was a time im talking strictly marshall.pre amp voltage definitely matters imo.just so your not confused by what i was saying.it matters heaps actually and when modding its a great place to start
@@totallyradguitars959 are you aware of 4 ohm tapping your amps.that was also part of earlier marshall mods and design.i tried to reply with a great link here from a really good builders site but it keeps getting removed weird,type in rob robinette marshall ,how a jcm 800 works.he covers what ive said in extensive detail .if your interested.
Hey, I’m familiar with that site (tons of great info I agree) and the voltages - ex. lower voltages to preamp tubes usually mean less headroom and more drive etc.
Just pointing out that I think you meant the 900DR when saying it’s mostly solid state, because this video is about a different amp (the Mk III and SLX)
@@totallyradguitars959 nah i got that i know that model..nothing wrong with diodes mate.look at boogies total pre amp tube gain but lack that brite crunch of any diode based marshall imo..i love diodes but there solid state in the tech jargon of it all..cheers
He finally stops flapping his jaws and plays at 12:12
And it sounds terrible
Thanks for your feedback. After watching your videos I can see that you know best when it comes to noodling in front of your phone camera for 30 seconds, very high quality
@totallyradguitars959 Thanks 2k subscriber man, I agree, I fucking rule
Haha well as long as you’re enjoying yourself, rock on 🤘