You wouldn't be able to compare them. In the preamp, gain overdrives the tubes and distorts the signal. A volume control can't distort or alter the signal in any way. The signal going in to the power amp should be the same coming out of it. The power amp tubes distort because they are run to failure. They can't keep up with the volume you're asking them to play at. The way the pre and power tubes distort are completely different.
Very usable tones at about all settings. I never get tired of seeing the sound pressure levels shaking the camera! My fave was probably the preamp dimed and the master on 2-3. Both knobs on 5 was very nice as well. God bless and rock on 👍😎🎸
The top end content really smoothed out when the master was above 3 on the dial (9o' clock) and the preamp was at 5 or above. Really good video. Thanks.
Maybe I’m crazy but every master volume amp I’ve owned including this one and my OR-120 sounded best when the master is just backed off to around 7-9. That nastiness goes away but it’s still plenty loud!!! Thanks Johan 👊
@@JohanSegeborn absolutely, if you want it it sounds good, back it off for Clarity though, not much change after around 6-7 except compression in my opinion
Their is a certain type of creaminess with the pre dimed to 10 and mv at around 1. Definitely a full range of tones can be coaxed out of these amps especially when also utilizing the low sensitivity as well.
I'm with you! As the 2204 has this 1nF bright cap on pre-amp gain pot it will start mellow out nicely (more and more out of circuit) at around 6-7 at the dial. In my builds I always omit that cap; gives you nice sounds even at lower gain settings. Eventually you can put a 100pF cap there, it's up to your ear. Not a fan of PI or power tube distortion myself, often too much un-musical mushiness. But there IS musical mushiness made sometimes (TPS).
I agree and I'm surprised as well. Perhaps the size of the room will determine the master volume amount. Maybe this muscle amp is more than enough to fill the room with 10, 20% of the power. That's why the "brown sound voltage reduction" is so discussed.
I’ve always preferred the power tube distortion from my Marshall. I like to turn the master up to about 8 or 9 and bring up the pre-amp volume up to gigging volume
I imagine you have a notepad on your bedside table. You wake at 3am with a great light bulb moment and experiment, and write it down. The next day you put it into action. So many cool ideas, and experiments Johan. I really dig your channel.
Hi Johan, Regarding the question "Is there power tube distortion/clipping with the master turned up?": the answer is definitively yes. Tubes will start to draw significant grid current when the grid voltage approaches zero volts with respect to the cathode. The bias voltage for EL34s in a Marshall-style circuit is around -40V, so the phase inverter only needs to swing about ±40V in order to drive the power tubes into grid clipping. If you do the calculations, you'll find that the phase inverter is easily capable of that. In fact, it will do close to ±80V into a 220k load. There's a second kind of clipping that happens when the power tube anode voltage swings down below 100V or so. The screen grid (which is still at high voltage) starts to "steal" current from the anode, so the anode current starts to drop while the screen grid current goes up. This usually starts to happen slightly before the grid clipping described above into the nominal load, but remember that a guitar speaker's impedance varies significantly with frequency. At frequencies where the impedance is high, this clipping mode happens very early since it takes much less current to pull the anode voltage down. A third kind of distortion that occurs only in the power amp is dynamic crossover distortion caused by operating point shift. There are two things that contribute here: the grid current mentioned above and power supply sag. When the tubes are driven to grid clipping, the grid current charges the coupling capacitors, shifting the bias colder (this is often called bias excursion). Power supply sag contributes because it causes the screen grid voltage to drop, which again reduces the current through the tube. All these behaviors can be observed with real circuits, or (much more easily) in SPICE simulation with accurate tube models.
@@mike42356 I attempted to reply but it was deleted or hidden (probably because of the links). This is a test to see if my reply will actually stay visible. Edit: Okay, it seems to be staying up now. I guess waiting a few days worked. Regarding your question: For triodes, a guy named Adrian Immler has some models that appear to be very accurate. You should be able to find his stuff by searching his name and "tube". Pentodes are more tricky if you want high accuracy. Immler has some models, but they run quite slow and tend to have convergence problems (at least with LTspice). There's a big thread about vacuum tube SPICE models on diyAudio with some pentode models. No promises regarding accuracy, but at least some of them are perfectly fine for analysis of general behaviors.
@@mike42356 I assume you saw my edit as well. If you're interested in the details behind Immler's triode models (as well as previous approaches), he has a paper on his site.
I have a '78 JMP 2204 and '81 JCM800 2204. My Master Volume sweet spot for both amps is around 7. If I put the MV on 10, I get too much high frequencies and zero low end. If I set the MV on 4 or less, I get a "weaker" sound. Master Volume from 5 to 8 = best sound in my opinion
The pre amp seems to be the heart of the sound, even when the master is down, you're still getting the tonal character of what the amps supposed to sound like! The power part though ads the muscle and fat to fill out the 'sound' the amp should have... In medical terms- a bionic man essentially... Since I'm referencing fat, muscles and hearts... 😂👍🏻 Thanks Johan!
Johan, after rewinding your demo a couple of times, I actually preferred the first demo. The one with both Pre and Master volume knobs set on 5. Thanks for a very interesting video, Cheers!
My Marshall #2204 (it’s a magical one) starts cooking with the master at noon at it has the best power tube distortion ever! I’ll NEVER sell that amp and it has a stellar pedalboard to get any tone I desire. 🔥 Thanks Johan and best always!!! ✌🏼
Some of the best tones have been gotten from power overdrive. Initially Hendrix was all about overdrive the amp! The early Marshall amps were designed for this, as was the Class A Vox amps and particularly the smaller Magnatone combos of the 50s and 60s... when Chuck Berry started out, he played his guitar through a small Les Paul Tube combo, and drove the PISS out of it! Those records sound like they could have been made today... so GRUNGY!! AND NONE OF THOSE AMPS were using preamp distortion. I have a Magnatone Custom 440 that I use to record, and my GOD, there's never been a better amp! Same is almost true of the Fender Deluxe... it was an amp that COULD be driven, but Leo b Never quite understood the need for distortion... and the deluxe by extension is remarkably clean for a 6v6 amp... until it hits that WALL... but the Super Reverb was one that had that mojo... and alnico speakers are a big part of this as well... alnico speakers are typically more efficient lower wattage speakers. They break up pleasantly and gradually... they also tend to have less bass because of the shape of the magnetic field in most designs (JBL found a way around this, but with a LOT more magnetic mass). But if you take an amp like the super reverb and put FOUR very small ten inch alnico it, make sure they're only rated about a two thirds of the amps total output, and BOOM... best amp Fender made! And the biggest factor in overdrive TRULY is the output Transformer... that is where your overdrive truly emanates from. The tubes themselves never really distort that much on the power side, if you compared the sound of the power tubes before the tranny... the two biggest factors of overdrive are the output tyranny and the speakers. Every time play my Maggie, people ask me what pedal I use to get that sound, because miked up it sounds like a forest of plexi Marshall's, on steroids... and raging, and I've never heard 18 watts be so loud and truly painful! Lol... it was used on a song that got me signed to republic records... and it's truly just plugging straight in... and one thing this amp and the VOX AC30 have in common is their rather dull lack of high end and high mids in the amp... the amp distorts high mids quickly going into the power tubes... and the output tyranny is quite dark and compresses highs and mids and the tone comes out "tubby" which is why it uses a very bright alnico bulldog twin speaker arrangement, both rated at 15 watts so they ad a huge part of that sound... and rhe Maggie too had a stock alnico 15 watt Jensen, which was very bright. When it blew, it was tough to replace. I wound up using a Heppner Full range alnico, with aluminum dust cap (you fund these not in guitar amps but in old tube amp systems made for schools in a system called FILMOSOUND... and I'm not the only one that searches the earth for these speakers... they are grail speakers. Lol
When I was a kid I had a Fender Twin master volume pull out. Fizzy and thin but I had the opportunity to run the amp flat out a lot! Master pulled out. Much better! Once a friend left his basket weave Marshall 412 over and I ran the Twin through it dimed. Impedance mismatch aside it sounded like a Marshall! Great stuff! I like tube amps pushed but not flat out anymore with some preamp distortion. A blend so it feels good but still articulate, tight and not too mushy. Like a great Plexi on maybe 7. Awesome! Great tones on your demo!
When I toured in the 70’s I had this amp. Wish I had the knowledge I have know. Now I rock an 1987x and there is a whole new tone at every knob position even though they seem to do nothing at all. And the inputs and not for show.
I like to keep my pre at between 5 and 6 and then mv to whatever level is required when using my original cabinet. But I do also cut bass and treble from 5 back 1 and boost mids 1. When using my cabinet loaded with evh labeled greenbacks I do boost the preamp level up 1 to try and achieve the same general tone.
I had a 2204 in late '80 and for me the MV was always higher than the preamp. Got more focus and dynamic that way. The best tone i had was mv at 7-9 and preamp at 4-6.
When I had this amp,I would keep the Preamp at 6-7 and master at 3-4...master had to be at or above 3 to breath and the preamp got a bit buzzy and congested past 7....one of several amps I regret letting go
I love that the camera shakes when a 100W Marshall is on 2. I find my Marshall heads sound best (sparkle and sustaining overdrive) with the Master around 6 ne the pre-amp between 3 and 4. If I want more drive for a Slash tone, I throw an override pedal in front, like an OD808 or a Fulltone OCD, or even stack two OD pedals, like the OD808 and the Tone City Durple to get some real nice sustaining mids on the neck pickup of my Les Paul. Great video!
In my observations, most of the "tube amp tone" comes from the preamp. That is because the preamp tubes perform a gradual gain compression - that typical tube soft clipping - reaching headroom limit gradually. The power section, on the other hand, amplifies more linearly and then abruptly limits the signal (hard clipping), pretty much like a solid state distortion pedal. There's no right or wrong distortion, but the setting that impresses me the most is when the master volume is set at the level at which the power amp breaks up exactly at the loudest strokes of the song. We may call this technique "headroom matching", some call it "finding the sweet spot". :)
I think the setting PreV 5 MV 5 is close to the sweet spot of these JMP master volume amps. You demonstrated that well. The point of the MV is to obtain distortion at bedroom volume, but of course you sacrifice a bit on the quality of the sound.
Power amp/ pre amp is really subjective to each amp and what kind of tone is desired and where it fits frequency wise in the context of in a band.. and also if multiple amps are being used at the same time to fill frequency gaps.. But this was a awesome video showing how interactive master volume and pre amp can be for some amp circuits ..
Power tube distortion is crunchy and preamp distortion is creamy. It just depends on what tone you are looking for. Simple. Thanks Johan! I appreciate what you do in tone quest.Cheers!
Glad I kept my 77 JMP MV I’ve done the 330uf FAT CAP MOD on mine, and one extra cap brings out a thickness across the low end and slight top end that it sounds way better.
Liked the initial pre/power at 5 each. Nice balance. As far as power distortion sounding great, I think it's more everything sounds better at higher volumes as the amp opens up rather than power tube distortion. Too much and it flubs out. On my newer Marshalls, between 4 and 6 seem optimal.
I have always felt that by keeping the first preamp stage a little cooler, it gives asymmetrical distortion, where 1/2 of the signal is distorted while the other half is less so and carries a more musical content. That signal is then inverted in the next stage where a warmer tube expands on that. That musical quality is so, so Marshally. It sounds like that kind of equals out around 5 on your preamp. So, yeah - pre on 5 seems to be the sweet spot.
I agree. I only need so much of the power amp to open up and give it real girth. Pre amp without this sounds and feels (especially) too thin IMHO. I think this shows this pretty clearly.
I thought I'd prefer the Master up and the Pre at 9:00, but the first setting you had with both knobbies at noon definitely sounded the most balanced to my ears. Or at least, that's what sounded the best to mem.
This is great idea, I have a plexi with the ppimv, at 230 that’s it the power tube turned up has a fat kinda flabby tone and always sounds in my mind like a big glass bubble like the big power tube, and the pre amp just screams like always when you hear more in non master volume amps, I always wondered what ratio of pre amp to power is built into the one master volume amps, anyway playing at a time when I can’t turn it I like the fat plucky bubbly power tube sound and it’s fun to test that setting against different pickups like burst buckers vs 57 classics vs custom shop slash etc, on my amp this really brings out the character of different pickups, and thanks as usual for turning it up for all of us out here, pce, oh and I’m thinking of getting a 40-50 watt speaker to play with and start to learn about speaker breakup as I can’t go loudloud very often, oh and the presence setting shines when maxing out the power tube,
I have found that the sweet spot on the preamp is at 7, and mv from 3 to 6 is pretty magical with the eq settings as you mentioned. I personally have found that a pedal can help or on the last year I've actually utilized the hot mod evo from legendary tones to achieve delicious results. Excellent job again brother Johan
I liked a good number of these sounds, but I'm kind of surprised with how much I liked the pre amp dimed and the MV nearly all the way down. It was obviously not as punchy, but it was consistent... and in a mix I think it'd work well.
I like Volume 5/Pre 5 as a base. Would definately play with the volume up to 8 while rolling the pre back as far down as 3. Somewhere in that range that allows enough clean up (guitar volume) with fullness and sparkle and enough room with guitar volume full up to accept a pedal to boost or add character. I've almost always used NMV amps and end up with volume around the 6 range (1959 RI with bright cap removed) for similar effect.
I just got a little hybrid amp for the bedroom it has a 12ax7 pre amp tube and another in the power amp so a power tube volume then a ss volume. When i crank the volume (not gain) it sounds like my silver face champ from when i was a kid very fuzzy/mooshy. There is a few great combinations of volume/gain to really hit the "era" i want. Its fun
I loved MV dimed with preamp at 4. Maybe not the most useable sound but what a sound. When I had a '79 2204 I usually settled on pre at 4-5 and mv 6-7.
Power tube distortion is kind of like licorice, people who love it really love it, others *bleh* (to paraphrase Jerry Garcia). Also it is very guitar and amp dependent. If you start with a non-MV amp and low output pickups (maybe throw in a Dallas Rangemaster), you're on the right track. MV amp with half a dozen tone controls and DiMarzio Super Distortions and it's a quick trip to Fart City. And even with the right setup, you can still get fairly flatulent. Of course all cool guitar tones involve some tradeoffs. Sometimes a little flabbiness is small price to pay for that singing growl and sizzle.
Hello Johan, of course the best is in a sort of middle of interaction between preamp and power amp distortion, with a slight predominance of preamp distortion to tame bass flubbiness or on the other hand too much fizziness, cheers!
these amps just scream! I'm a big fan of Master and Pre-amp both on 5, I don't put all EQs at 5 though, I usually turn Bass and Treble below 5 and put the mid above 5 and Presence at 5, I'm mostly using JCM800 2203 and 4101. I almost always use a pedal in front, like a Boss Overdrive or Tube Screamer. When I used to play Metal, I would put an Ibanez parametric EQ pedal in front, I had great results with that. Thanks for sharing, Johan and have a great weekend!
Hi, Johan! According to my experience its better to put the pre-amp on maximum, and to play with master volume. Because in my phones pre-amp after 5 is equal to 10. And when you are doing it with master, the listenable level can be heard till 7. So, you have more range and more control. I am doing the same way. And if you was putting high bottom on 9, it could make your distortion really agressive! Its my patent: bass5/middle,5/trebble 9. And than you can play a big big music mountains. From Deep Purple to Pantera (I don't know, how it goes in Randall, but Marshall makes you this option. Hope, I wrote it bright enough... Have a nice weekend and see you! Z.
This was looked at comprehensively on TGP a decade ago and it was proven on an oscilloscope that its phase Inverter distortion that it important. Power tube distortion sounds terrible. The verdict was that PPIMV’s sound great. Past that you need a decent dab workjng to get that feeling, regardless.
My favourite settings were toward the end: master on 2.5 and preamp cranked. The 5/5 at the beginning was still bloated, with too much sag in my opinion - like you pointed out, it could greatly benefit from a pedal tightening at the front end. I thought it was less so with the 2.5/10 setting… Better yet, perhaps, would be 2.5/8 and a treble boost (smith as flexible as the Fulltone Ranger) in the front set to taste. Cheers, and thank you for an experiment most of us could never do in person…
I think I remember a video from Bad Cat amps where they claimed that most 'classic' poweramp distortion was actually due to the phase splitter (so technically part of the poweramp, but not actually the powertubes).
Hi Johan, I play bass and what works for me is to set the gain (preamp) on the brink of saturation, depending at what volume you intend to play : for low master volume the gain has to be quite high, and for high master settings the gain must be lower ...actually they seem to be interactive. At least on my Ashdown CTM200r 200 Wrms KT88 tube amp. Yet I find overdriven preamp or pedal though a clean amp is missing the "big fire" effect of overdriven power stage and speakers' breakup grit...
It’s the distortion from the phase inverter (3rd preamp tube). The master volume control comes right before this tube in the circuit. The signal is then sent to either 2 or 4 (50 or 100w) EL34s so I highly doubt the power tubes are actually causing that much noticeable distortion
I have been known to vary my pre and post settings on my JCM 800 (no diode’s) but generally I like the pre up at 7 or so and just set the post depending on the amount of loudness I need.
Quite a few players prefer lower watt amps because they can push the power section towards wanted harmonics with the preamp also to the same sweet spot. Basically stacking harmonics through different sections while not being too loud on stage..
I would like to hear an extremely high headroom (tons of clean volume) pedal or clean preamp of some kind placed in the effects loop of an amp, to hear what driving only the power section sounds like
Justin, that is pretty much what Johan does at 2:28. If you compare to 2:12, you can tell the preamp is almost completely clean - in fact, the preamp is set even lower at 2:28 than at 2:12!
@@mike42356 But its not a very clean preamp. I'm taking about a preamp that is clean when cranked, to really push the power section. Because a preamp on 2 or 3 isn't pushing it enough to break up.
@@justinpaquette224 the preamp is clean as much as you push it. Depending on the number and configuration of its gain stages, the preamp reaches headroom (maximum volume, breakup point) quite early, when dialing up the Gain control. Over that threshold, it only distorts more. While I have not investigated the maximum voltage swing of a "typical" preamp, let alone of this particular Marshall, my guess is it's probably higher than a 9V DC powered booster or EQ pedal - maybe a 18V pedal would do, still not sure. So, it might be the other way around, actually. 😛 While you are technically correct because, with preamp tubes, there's no clear cut separation between clean and clipped, as is the case with transistor devices, choosing a reasonable amount of preamp gain that the listener qualifies as definitely clean, one may say the test you ask for was performed by Johan, for all purposes, particularly when you consider a few more things: - there's normally a circuit you can't control between the FX return input and the power section, more often than not an op amp or 12AT7 buffer. - like other people mentioned already, there is a phase splitter in front of the power tubes, usually a 12AX7 preamp tube. - this vintage amp doesn't have an FX loop. 😅 I hope you can now enjoy the comparison as much as I do 🤗
Great topic. I'd like to hear it with pre and master roughly matched between 6 and 8, maybe pre a little higher, and with the guitar volume backed off a bit.
Love your vids Johan! I have a 1978 JMP MKII like yours and it’s got 6550 Tungsols from 58 and 61, considered to be the holy grails of 6550’s! On that note, I use them to their fullest potential! When I can, the master is always dimed and then I feather in the pre-amp dial to taste. Huge difference on this amp! Since 6550’s are noted for their low end vs 34’s, you have to get them pumping! The sound is huge this way versus a lower master setting and then creating volume with your preamp. I think this is the only way to run an amp if you don’t have to worry about killing your neighbors! My real question for you is what the heck do you actually do for a living where you can afford all this EXPENSIVE gear???
Without some way of looking at the signal levels in the amp itself it is hard to tell where how much and what form of distortion is occuring in different stages of the chain. I’d be tempted to sample signals in many locations: amp input, preamp output, power output pre transformer, post transformer. My guess is that that the guys who build algorithms for guitar amp modelers have done this kind of work.
"Power amp distortion" = phase inverter distortion. The problem with phase inverter distortion is that it is hard to achieve without the amp being played very loudly. There are PPIMV's that allow the phase inverter to distort but they have disadvantages: adding unpleasant crossover distortion and causing the NFB and Prescence circuits to stop working. Using an attenuator is another option to keep the volume down, but those will also mess up your tone because of the different impedance compared to a real speaker.
@@semdallinga69 Most ppimv's use a dual-pot, which because of manufacturing tolerance will have a difference between the pot traces, thus the inverted vs non inverted signals will become mismatched. When these signals are then sent trough the powertubes and mix together in the output transformer, this difference will be amplified. Basically a distortion around the crossover (zero) points of the sinewave. Amps still usually have a little crossover dist because of mismatches in the PI tube triodes, output tubes or OT also.
"Flying debris on the top". Amazing!! Great video, thanks Johan! I definitely prefer a combination of the two shown here, and I've never played a non-master Marshall but isn't that basically what you're getting when you crank one of those? So it seems like the combination of both cranked up is actually the sound everyone is familiar with from the 60s until master volume Marshalls were introduced. Could you also do this with a Hiwatt? I'd be curious to see the difference (I'm too scared to crank mine). I've done it once or twice and all I remember is it was REALLY hard to get it to break up on its own.
This is a lot easier to understand, and to predict what's going to happen if you have an understanding of the differences between gain and volume. Here's why the bass softens up with too much volume. In the preamp, the input tubes are pushed to distort using excess gain. The gain is distorting the signal itself. Power amp distortion doesn't work like that. A volume control is a passive device and can't alter the signal in any way. Its transparent. Even if a volume control is completely maxed out, it won't effect the signal. All a volume control can do is work like a gate on a dam that lets more water through the opening the more you open it. The pressure that pushes the water through the gate, has nothing to do with the gate itself. Its the same thing with the electricity that passes through a volume control. The reason the power amp tubes distort isn't from gain. At some point, opening the volume will be asking the power amp to play louder than it can normally handle, and the output tubes get pushed to failure. Its no different than going to your home or car stereo and turning the volume up until it breaks up. The signal itself isn't distorting. You're just playing it too loud. When you distort the signal in the preamp with gain, and you are not pushing the power tubes too hard, the power amp is working correctly and just amplifies the signal given to it by the preamp. When you push the power amp too hard, the tubes fail and you loose fidelity as a direct result. It can't amplify the signal from the preamp accurately when pushed beyond its limits. So, your mushy bass is the result of your power amp not being able to do its job properly. I understand that you are probably doing this on purpose, for the effect it has on the sound. But that's what's actually happening inside the amp. This is also why some people use pedals to tighten up the bass. When the power tubes distort, there are both advantages and disadvantages sonically. You use the pedal to retain the benefits of distorting your power tubes, while trying to fix the downsides, like mushy bass.
There is something with the tone when you go beyond certain volume, that I really like. More than MV or preamp, I think it has to do with some other thing (speakers, room sound, maybe transformers). Of course, this is a totally different experience in person, you can not translate 105dB through youtube...
I recently built an amp where if I have a boost at the end of the effects loop, I hit the 3rd stage of the pre, and the phase inverter. It seems to have some really nice body to the distortion there, which the first two stages and eq don't really have on their own. (Though it has to be said all together, the pre and power amp tones are amazing (those being an orange or120 front end, and a pair of el84 tubes in the output section)
Who needs pedals, when you have a collection of great amps..! I mainly use non-master volume amps, which are designed to be played clean (as the 50s/60s all was mainly about clean loud guitar tones), but when you crank them, the whole thing overdrives in a special way that gives you more dynamic range, than the modern driven preamp tones. Sure, you can't do hard rock on a Tweed Deluxe, but rock n' roll, blues rock I believe sound better with such tones. As you pointed, though, when you push the whole amp beyond its limits it may sound mushy, so you need to tame low frequencies a little, be it a EQ pedal, or a Treble Booster style pedal, or eq the amp itself. By the way, no amp I've tried sounds as focused and defined, when cranked, as Hiwatt style amps. Not a plenty of distortion, but they can handle themselves great when pushed beyond their clean tones! Nice to see informative videos, like this one! Cheers!
My favorite was the master at around 2, and the preamp all the way up. Interestingly, this is how I like running the JCM 800 model in the Line 6 Pod Go. Too much master volume makes the sound too dark and mushy in my opinion
@@JohanSegeborn yep. Be interested to hear that comparison done with someone sweeping the 2 gains up and down continuously. If you get me drift. Nice sounds you got got as ever.
I've always had such a hard time dialing in my '84 JCM 800 2204, that I rarely play it. ( A lot of that is because I only have 2x12 cabs these days ) I've always been partial to power tube distortion, but I guess alot depends on the particular amp.
Gain isn't responsible for power tube distortion. In the preamp, excessive gain overdrives the input tubes, and distorts the signal directly. A volume control can't alter the signal in any way. Its a passive device. When you raise the volume, it allows a more powerful signal to pass through it like a gate. When the volume lets more signal pass than the power amp can handle, the tubes get driven to failure. That's the distortion you're hearing. Its a different kind of distortion.
I don't care much of Marshall master volume amps. Currently I have basically a 1959 with cascaded preamps which I like very much (not the same circuit as 2203). That amp have perfect gain staging between preamp and poweramp. When you turn it up ( I usually keep both volumes at the same position), it's loud without any fizzyness or mushiness. For me the best thing when turning up is the output transformer compression that happens. a great firm sustain.
Sounded great when neither was at full. Prob best to use it with power volume just over half and preamp just above that. Power amp volume tends to add more low end and preamp volume tends to add more presence, so if your using a single coil guitar or a humbucker guitar it might be better to use the settings differently to make the overall tone work for you
It would be interesting to probe the stages with an oscilloscope to measure how much distortion each stage adds at different settings.
You wouldn't be able to compare them. In the preamp, gain overdrives the tubes and distorts the signal. A volume control can't distort or alter the signal in any way. The signal going in to the power amp should be the same coming out of it. The power amp tubes distort because they are run to failure. They can't keep up with the volume you're asking them to play at. The way the pre and power tubes distort are completely different.
I'm really impressed with how good it sounded with the pre-amp high and the master low
Very usable tones at about all settings. I never get tired of seeing the sound pressure levels shaking the camera! My fave was probably the preamp dimed and the master on 2-3. Both knobs on 5 was very nice as well. God bless and rock on 👍😎🎸
Rock on my friend!
I feel like with the master volume at 10, it immediately had that Let There Be Rock dirt. Love it!
Glad to hear it!
The top end content really smoothed out when the master was above 3 on the dial (9o' clock) and the preamp was at 5 or above. Really good video. Thanks.
That thud when the MV goes past 5-6 is so satisfying
Maybe I’m crazy but every master volume amp I’ve owned including this one and my OR-120 sounded best when the master is just backed off to around 7-9. That nastiness goes away but it’s still plenty loud!!! Thanks Johan 👊
Hi Andy! Yeah over 7.5 they mainly just compress. Have a great weekend!
I've found most valve amps, seem to have a SWEET spot between 6-7 on the volume! (Regardless of their power! )
@@DMSProduktions agreed
@@JohanSegeborn absolutely, if you want it it sounds good, back it off for Clarity though, not much change after around 6-7 except compression in my opinion
Ah ok, you dont mean clock XD
At 6+ / 1 o'clock my ears are blown away XO.oX
Their is a certain type of creaminess with the pre dimed to 10 and mv at around 1. Definitely a full range of tones can be coaxed out of these amps especially when also utilizing the low sensitivity as well.
This is very cool but they the opposite too . It’s really cool as well
Another great demonstration from Mr. Segeborn. I love seeing the camera shake! Great name of a new tune for you...Camera Shakes!
Wow! I’m surprised to be saying this, but my favorite tones were with MV at nearly zero and pre-amp at 6 or higher. Thanks, Johan!
I know. I've heard so many times that power amp distortion is basically like the gold standard. Not sure if that's true.
Thanks Keith!
I'm with you! As the 2204 has this 1nF bright cap on pre-amp gain pot it will start mellow out nicely (more and more out of circuit) at around 6-7 at the dial. In my builds I always omit that cap; gives you nice sounds even at lower gain settings. Eventually you can put a 100pF cap there, it's up to your ear. Not a fan of PI or power tube distortion myself, often too much un-musical mushiness. But there IS musical mushiness made sometimes (TPS).
I agree and I'm surprised as well. Perhaps the size of the room will determine the master volume amount. Maybe this muscle amp is more than enough to fill the room with 10, 20% of the power. That's why the "brown sound voltage reduction" is so discussed.
I’ve always preferred the power tube distortion from my Marshall. I like to turn the master up to about 8 or 9 and bring up the pre-amp volume up to gigging volume
I imagine you have a notepad on your bedside table. You wake at 3am with a great light bulb moment and experiment, and write it down. The next day you put it into action. So many cool ideas, and experiments Johan. I really dig your channel.
I always enjoy when the camera wobbles from distortion, it's like you can feel it.
Hi Johan,
Regarding the question "Is there power tube distortion/clipping with the master turned up?": the answer is definitively yes. Tubes will start to draw significant grid current when the grid voltage approaches zero volts with respect to the cathode. The bias voltage for EL34s in a Marshall-style circuit is around -40V, so the phase inverter only needs to swing about ±40V in order to drive the power tubes into grid clipping. If you do the calculations, you'll find that the phase inverter is easily capable of that. In fact, it will do close to ±80V into a 220k load.
There's a second kind of clipping that happens when the power tube anode voltage swings down below 100V or so. The screen grid (which is still at high voltage) starts to "steal" current from the anode, so the anode current starts to drop while the screen grid current goes up. This usually starts to happen slightly before the grid clipping described above into the nominal load, but remember that a guitar speaker's impedance varies significantly with frequency. At frequencies where the impedance is high, this clipping mode happens very early since it takes much less current to pull the anode voltage down.
A third kind of distortion that occurs only in the power amp is dynamic crossover distortion caused by operating point shift. There are two things that contribute here: the grid current mentioned above and power supply sag. When the tubes are driven to grid clipping, the grid current charges the coupling capacitors, shifting the bias colder (this is often called bias excursion). Power supply sag contributes because it causes the screen grid voltage to drop, which again reduces the current through the tube.
All these behaviors can be observed with real circuits, or (much more easily) in SPICE simulation with accurate tube models.
Thanks for the insights, Michael!
Any recommended models for simulating 12AX7 and EL84?
@@mike42356 I attempted to reply but it was deleted or hidden (probably because of the links). This is a test to see if my reply will actually stay visible.
Edit: Okay, it seems to be staying up now. I guess waiting a few days worked. Regarding your question: For triodes, a guy named Adrian Immler has some models that appear to be very accurate. You should be able to find his stuff by searching his name and "tube". Pentodes are more tricky if you want high accuracy. Immler has some models, but they run quite slow and tend to have convergence problems (at least with LTspice). There's a big thread about vacuum tube SPICE models on diyAudio with some pentode models. No promises regarding accuracy, but at least some of them are perfectly fine for analysis of general behaviors.
@@michaelbarbour9594 roger that! (I mean I can read your post)
@@mike42356 I assume you saw my edit as well.
If you're interested in the details behind Immler's triode models (as well as previous approaches), he has a paper on his site.
@@michaelbarbour9594 could not see any edit of these comments, but found that essay of Immler's. Thank you, and I hope I see you around! ☺️
I have a '78 JMP 2204 and '81 JCM800 2204. My Master Volume sweet spot for both amps is around 7. If I put the MV on 10, I get too much high frequencies and zero low end. If I set the MV on 4 or less, I get a "weaker" sound. Master Volume from 5 to 8 = best sound in my opinion
The pre amp seems to be the heart of the sound, even when the master is down, you're still getting the tonal character of what the amps supposed to sound like!
The power part though ads the muscle and fat to fill out the 'sound' the amp should have...
In medical terms- a bionic man essentially... Since I'm referencing fat, muscles and hearts...
😂👍🏻
Thanks Johan!
Thanks Jamie! ;-)
I was so surprised how well it worked when the master was at 10 And the preamp was only 1 to 3. To me that was the most balanced.
Johan, after rewinding your demo a couple of times, I actually preferred the first demo. The one with both Pre and Master volume knobs set on 5. Thanks for a very interesting video, Cheers!
I think me too…
The shaking camera…I love it.
Master sweetspot between 4 and 6. 🤘
Great video btw, thanxx Johan!
Your right. You are the Analogman King of tone.
My Marshall #2204 (it’s a magical one) starts cooking with the master at noon at it has the best power tube distortion ever! I’ll NEVER sell that amp and it has a stellar pedalboard to get any tone I desire. 🔥
Thanks Johan and best always!!! ✌🏼
Superb demonstration.
Thanks!
Some of the best tones have been gotten from power overdrive. Initially Hendrix was all about overdrive the amp! The early Marshall amps were designed for this, as was the Class A Vox amps and particularly the smaller Magnatone combos of the 50s and 60s... when Chuck Berry started out, he played his guitar through a small Les Paul Tube combo, and drove the PISS out of it! Those records sound like they could have been made today... so GRUNGY!! AND NONE OF THOSE AMPS were using preamp distortion. I have a Magnatone Custom 440 that I use to record, and my GOD, there's never been a better amp! Same is almost true of the Fender Deluxe... it was an amp that COULD be driven, but Leo b
Never quite understood the need for distortion... and the deluxe by extension is remarkably clean for a 6v6 amp... until it hits that WALL... but the Super Reverb was one that had that mojo... and alnico speakers are a big part of this as well... alnico speakers are typically more efficient lower wattage speakers. They break up pleasantly and gradually... they also tend to have less bass because of the shape of the magnetic field in most designs (JBL found a way around this, but with a LOT more magnetic mass). But if you take an amp like the super reverb and put FOUR very small ten inch alnico it, make sure they're only rated about a two thirds of the amps total output, and BOOM... best amp Fender made! And the biggest factor in overdrive TRULY is the output Transformer... that is where your overdrive truly emanates from. The tubes themselves never really distort that much on the power side, if you compared the sound of the power tubes before the tranny... the two biggest factors of overdrive are the output tyranny and the speakers. Every time play my Maggie, people ask me what pedal I use to get that sound, because miked up it sounds like a forest of plexi Marshall's, on steroids... and raging, and I've never heard 18 watts be so loud and truly painful! Lol... it was used on a song that got me signed to republic records... and it's truly just plugging straight in... and one thing this amp and the VOX AC30 have in common is their rather dull lack of high end and high mids in the amp... the amp distorts high mids quickly going into the power tubes... and the output tyranny is quite dark and compresses highs and mids and the tone comes out "tubby" which is why it uses a very bright alnico bulldog twin speaker arrangement, both rated at 15 watts so they ad a huge part of that sound... and rhe Maggie too had a stock alnico 15 watt Jensen, which was very bright. When it blew, it was tough to replace. I wound up using a Heppner Full range alnico, with aluminum dust cap (you fund these not in guitar amps but in old tube amp systems made for schools in a system called FILMOSOUND... and I'm not the only one that searches the earth for these speakers... they are grail speakers. Lol
When I was a kid I had a Fender Twin master volume pull out. Fizzy and thin but I had the opportunity to run the amp flat out a lot! Master pulled out. Much better! Once a friend left his basket weave Marshall 412 over and I ran the Twin through it dimed. Impedance mismatch aside it sounded like a Marshall! Great stuff! I like tube amps pushed but not flat out anymore with some preamp distortion. A blend so it feels good but still articulate, tight and not too mushy. Like a great Plexi on maybe 7. Awesome! Great tones on your demo!
Recently discovered my love of power amp distortion. Gives it some sparkle!
When I toured in the 70’s I had this amp. Wish I had the knowledge I have know. Now I rock an 1987x and there is a whole new tone at every knob position even though they seem to do nothing at all. And the inputs and not for show.
I like to keep my pre at between 5 and 6 and then mv to whatever level is required when using my original cabinet. But I do also cut bass and treble from 5 back 1 and boost mids 1. When using my cabinet loaded with evh labeled greenbacks I do boost the preamp level up 1 to try and achieve the same general tone.
I had a 2204 in late '80 and for me the MV was always higher than the preamp. Got more focus and dynamic that way. The best tone i had was mv at 7-9 and preamp at 4-6.
How loud was that?
@@martonjancsak
😄 crazy crazy loud !!! LOUD !!! 😄
@@francoisdallaire5424 What i thought. Thx
When I had this amp,I would keep the Preamp at 6-7 and master at 3-4...master had to be at or above 3 to breath and the preamp got a bit buzzy and congested past 7....one of several amps I regret letting go
I totally agree these settings, these are my favourites on my '77 2203
Totally agree with this
I agree with these settings as well
I love that the camera shakes when a 100W Marshall is on 2. I find my Marshall heads sound best (sparkle and sustaining overdrive) with the Master around 6 ne the pre-amp between 3 and 4. If I want more drive for a Slash tone, I throw an override pedal in front, like an OD808 or a Fulltone OCD, or even stack two OD pedals, like the OD808 and the Tone City Durple to get some real nice sustaining mids on the neck pickup of my Les Paul. Great video!
Excellent was looking for this from your setup. Cheers!
Cheers!
In my observations, most of the "tube amp tone" comes from the preamp. That is because the preamp tubes perform a gradual gain compression - that typical tube soft clipping - reaching headroom limit gradually. The power section, on the other hand, amplifies more linearly and then abruptly limits the signal (hard clipping), pretty much like a solid state distortion pedal.
There's no right or wrong distortion, but the setting that impresses me the most is when the master volume is set at the level at which the power amp breaks up exactly at the loudest strokes of the song. We may call this technique "headroom matching", some call it "finding the sweet spot". :)
I think the setting PreV 5 MV 5 is close to the sweet spot of these JMP master volume amps. You demonstrated that well. The point of the MV is to obtain distortion at bedroom volume, but of course you sacrifice a bit on the quality of the sound.
Power amp/ pre amp is really subjective to each amp and what kind of tone is desired and where it fits frequency wise in the context of in a band.. and also if multiple amps are being used at the same time to fill frequency gaps.. But this was a awesome video showing how interactive master volume and pre amp can be for some amp circuits ..
Power tube distortion is crunchy and preamp distortion is creamy. It just depends on what tone you are looking for. Simple. Thanks Johan! I appreciate what you do in tone quest.Cheers!
Johan here giving us the news that really matters.
Glad I kept my 77 JMP MV
I’ve done the 330uf FAT CAP MOD on mine, and one extra cap brings out a thickness across the low end and slight top end that it sounds way better.
Excellent! Very excellent demo! Thank you!
I loved both knobs on 6 when I had my 2204. Took pedals well too.
Liked the initial pre/power at 5 each. Nice balance. As far as power distortion sounding great, I think it's more everything sounds better at higher volumes as the amp opens up rather than power tube distortion. Too much and it flubs out. On my newer Marshalls, between 4 and 6 seem optimal.
I have always felt that by keeping the first preamp stage a little cooler, it gives asymmetrical distortion, where 1/2 of the signal is distorted while the other half is less so and carries a more musical content. That signal is then inverted in the next stage where a warmer tube expands on that. That musical quality is so, so Marshally. It sounds like that kind of equals out around 5 on your preamp. So, yeah - pre on 5 seems to be the sweet spot.
I agree. I only need so much of the power amp to open up and give it real girth. Pre amp without this sounds and feels (especially) too thin IMHO. I think this shows this pretty clearly.
Thanks Vagen
I thought I'd prefer the Master up and the Pre at 9:00, but the first setting you had with both knobbies at noon definitely sounded the most balanced to my ears. Or at least, that's what sounded the best to mem.
Master and Pre-Amp both on 5 sounded like the sweet spot to me. I'll be annoying the neighbours later. Thanks Johan!
Hahaha! That was my favorite too! Cheers Eddie!
This is great idea, I have a plexi with the ppimv, at 230 that’s it the power tube turned up has a fat kinda flabby tone and always sounds in my mind like a big glass bubble like the big power tube, and the pre amp just screams like always when you hear more in non master volume amps, I always wondered what ratio of pre amp to power is built into the one master volume amps, anyway playing at a time when I can’t turn it I like the fat plucky bubbly power tube sound and it’s fun to test that setting against different pickups like burst buckers vs 57 classics vs custom shop slash etc,
on my amp this really brings out the character of different pickups, and thanks as usual for turning it up for all of us out here, pce, oh and I’m thinking of getting a 40-50 watt speaker to play with and start to learn about speaker breakup as I can’t go loudloud very often,
oh and the presence setting shines when maxing out the power tube,
I have found that the sweet spot on the preamp is at 7, and mv from 3 to 6 is pretty magical with the eq settings as you mentioned. I personally have found that a pedal can help or on the last year I've actually utilized the hot mod evo from legendary tones to achieve delicious results. Excellent job again brother Johan
Very Rock n Roll how the Camera is shaking... hahha
I love my 1978 JMP too
Greets from Germany
I liked a good number of these sounds, but I'm kind of surprised with how much I liked the pre amp dimed and the MV nearly all the way down. It was obviously not as punchy, but it was consistent... and in a mix I think it'd work well.
I like Volume 5/Pre 5 as a base. Would definately play with the volume up to 8 while rolling the pre back as far down as 3. Somewhere in that range that allows enough clean up (guitar volume) with fullness and sparkle and enough room with guitar volume full up to accept a pedal to boost or add character.
I've almost always used NMV amps and end up with volume around the 6 range
(1959 RI with bright cap removed) for similar effect.
I just got a little hybrid amp for the bedroom it has a 12ax7 pre amp tube and another in the power amp so a power tube volume then a ss volume. When i crank the volume (not gain) it sounds like my silver face champ from when i was a kid very fuzzy/mooshy. There is a few great combinations of volume/gain to really hit the "era" i want. Its fun
The first setting by far was the best!
I loved MV dimed with preamp at 4. Maybe not the most useable sound but what a sound. When I had a '79 2204 I usually settled on pre at 4-5 and mv 6-7.
Both setup Sounds Awesome
I’ll take both anytime 🙌🏻
I've read that it's the phase inverter breaking up that really is what generates the juice in a plexi.
Power tube distortion is kind of like licorice, people who love it really love it, others *bleh* (to paraphrase Jerry Garcia). Also it is very guitar and amp dependent. If you start with a non-MV amp and low output pickups (maybe throw in a Dallas Rangemaster), you're on the right track. MV amp with half a dozen tone controls and DiMarzio Super Distortions and it's a quick trip to Fart City. And even with the right setup, you can still get fairly flatulent. Of course all cool guitar tones involve some tradeoffs. Sometimes a little flabbiness is small price to pay for that singing growl and sizzle.
I like the sound of the master about 3 and the preamp 10.
LET'S GO!
Hello Johan, of course the best is in a sort of middle of interaction between preamp and power amp distortion, with a slight predominance of preamp distortion to tame bass flubbiness or on the other hand too much fizziness, cheers!
Cheers Vincenzo!
Balance. Both on 5 sounded great!
Thanks!
these amps just scream! I'm a big fan of Master and Pre-amp both on 5, I don't put all EQs at 5 though, I usually turn Bass and Treble below 5 and put the mid above 5 and Presence at 5, I'm mostly using JCM800 2203 and 4101. I almost always use a pedal in front, like a Boss Overdrive or Tube Screamer. When I used to play Metal, I would put an Ibanez parametric EQ pedal in front, I had great results with that. Thanks for sharing, Johan and have a great weekend!
Hi, Johan!
According to my experience its better to put the pre-amp on maximum, and to play with master volume. Because in my phones pre-amp after 5 is equal to 10. And when you are doing it with master, the listenable level can be heard till 7. So, you have more range and more control. I am doing the same way. And if you was putting high bottom on 9, it could make your distortion really agressive! Its my patent: bass5/middle,5/trebble 9. And than you can play a big big music mountains. From Deep Purple to Pantera (I don't know, how it goes in Randall, but Marshall makes you this option. Hope, I wrote it bright enough... Have a nice weekend and see you!
Z.
Thanks Zigfrid, have a great weekend you too!
This was looked at comprehensively on TGP a decade ago and it was proven on an oscilloscope that its phase Inverter distortion that it important.
Power tube distortion sounds terrible.
The verdict was that PPIMV’s sound great.
Past that you need a decent dab workjng to get that feeling, regardless.
I liked it with the master cranked and the pre amp anywhere above 4.
Thanks!
My favourite settings were toward the end: master on 2.5 and preamp cranked. The 5/5 at the beginning was still bloated, with too much sag in my opinion - like you pointed out, it could greatly benefit from a pedal tightening at the front end. I thought it was less so with the 2.5/10 setting… Better yet, perhaps, would be 2.5/8 and a treble boost (smith as flexible as the Fulltone Ranger) in the front set to taste. Cheers, and thank you for an experiment most of us could never do in person…
Love all you do bro!
I think I remember a video from Bad Cat amps where they claimed that most 'classic' poweramp distortion was actually due to the phase splitter (so technically part of the poweramp, but not actually the powertubes).
Could explain why some of the cleaner tube bass amps, like Ampeg, use 12AU7's as their PI tube.
Yeah PPIMV untilizes that. Cheers
Hi Johan, I play bass and what works for me is to set the gain (preamp) on the brink of saturation, depending at what volume you intend to play : for low master volume the gain has to be quite high, and for high master settings the gain must be lower ...actually they seem to be interactive. At least on my Ashdown CTM200r 200 Wrms KT88 tube amp.
Yet I find overdriven preamp or pedal though a clean amp is missing the "big fire" effect of overdriven power stage and speakers' breakup grit...
It’s the distortion from the phase inverter (3rd preamp tube). The master volume control comes right before this tube in the circuit. The signal is then sent to either 2 or 4 (50 or 100w) EL34s so I highly doubt the power tubes are actually causing that much noticeable distortion
After hours of playing around with this myself I feel like I've only just unlocked the beauty and potential of speaker distortion.
I feel it is more more about cascading gain stages than about preamp VS power amp . (of course, I am discounting the speaker distortion) Cheers !
I have been known to vary my pre and post settings on my JCM 800 (no diode’s) but generally I like the pre up at 7 or so and just set the post depending on the amount of loudness I need.
Quite a few players prefer lower watt amps because they can push the power section towards wanted harmonics with the preamp also to the same sweet spot. Basically stacking harmonics through different sections while not being too loud on stage..
I would like to hear an extremely high headroom (tons of clean volume) pedal or clean preamp of some kind placed in the effects loop of an amp, to hear what driving only the power section sounds like
Justin, that is pretty much what Johan does at 2:28. If you compare to 2:12, you can tell the preamp is almost completely clean - in fact, the preamp is set even lower at 2:28 than at 2:12!
@@mike42356 But its not a very clean preamp. I'm taking about a preamp that is clean when cranked, to really push the power section. Because a preamp on 2 or 3 isn't pushing it enough to break up.
I’m guessing the tone would suffer
@@justinpaquette224 the preamp is clean as much as you push it. Depending on the number and configuration of its gain stages, the preamp reaches headroom (maximum volume, breakup point) quite early, when dialing up the Gain control. Over that threshold, it only distorts more. While I have not investigated the maximum voltage swing of a "typical" preamp, let alone of this particular Marshall, my guess is it's probably higher than a 9V DC powered booster or EQ pedal - maybe a 18V pedal would do, still not sure. So, it might be the other way around, actually. 😛
While you are technically correct because, with preamp tubes, there's no clear cut separation between clean and clipped, as is the case with transistor devices, choosing a reasonable amount of preamp gain that the listener qualifies as definitely clean, one may say the test you ask for was performed by Johan, for all purposes, particularly when you consider a few more things:
- there's normally a circuit you can't control between the FX return input and the power section, more often than not an op amp or 12AT7 buffer.
- like other people mentioned already, there is a phase splitter in front of the power tubes, usually a 12AX7 preamp tube.
- this vintage amp doesn't have an FX loop. 😅
I hope you can now enjoy the comparison as much as I do 🤗
1:57 preamp distortion
2:19 poweramp distortion
Your guitar volume knob is your friend here. Still though let that camera shake
Great video Johan
Cheers Brent!
Great topic. I'd like to hear it with pre and master roughly matched between 6 and 8, maybe pre a little higher, and with the guitar volume backed off a bit.
Love your vids Johan! I have a 1978 JMP MKII like yours and it’s got 6550 Tungsols from 58 and 61, considered to be the holy grails of 6550’s! On that note, I use them to their fullest potential! When I can, the master is always dimed and then I feather in the pre-amp dial to taste. Huge difference on this amp! Since 6550’s are noted for their low end vs 34’s, you have to get them pumping! The sound is huge this way versus a lower master setting and then creating volume with your preamp. I think this is the only way to run an amp if you don’t have to worry about killing your neighbors! My real question for you is what the heck do you actually do for a living where you can afford all this EXPENSIVE gear???
Yeah Man !!!!!! Power Tubes !!!! Master up and Preamp between 4 or 5 !!!!
Without some way of looking at the signal levels in the amp itself it is hard to tell where how much and what form of distortion is occuring in different stages of the chain. I’d be tempted to sample signals in many locations: amp input, preamp output, power output pre transformer, post transformer. My guess is that that the guys who build algorithms for guitar amp modelers have done this kind of work.
"Power amp distortion" = phase inverter distortion. The problem with phase inverter distortion is that it is hard to achieve without the amp being played very loudly. There are PPIMV's that allow the phase inverter to distort but they have disadvantages: adding unpleasant crossover distortion and causing the NFB and Prescence circuits to stop working. Using an attenuator is another option to keep the volume down, but those will also mess up your tone because of the different impedance compared to a real speaker.
I was about to comment something similar, but what do you mean by crossover distortion?
@@semdallinga69 Most ppimv's use a dual-pot, which because of manufacturing tolerance will have a difference between the pot traces, thus the inverted vs non inverted signals will become mismatched. When these signals are then sent trough the powertubes and mix together in the output transformer, this difference will be amplified. Basically a distortion around the crossover (zero) points of the sinewave. Amps still usually have a little crossover dist because of mismatches in the PI tube triodes, output tubes or OT also.
@@infectionsman Ah right, that makes sense.
@@semdallinga69 also remember that NFB helps reduce crossover distortion, so loss of NFB is problematic with ppimvs
@@infectionsman Yeah fair, but there are definitely small modifications to be made to increase nfb, though most people like to keep their amps stock.
"Flying debris on the top". Amazing!! Great video, thanks Johan! I definitely prefer a combination of the two shown here, and I've never played a non-master Marshall but isn't that basically what you're getting when you crank one of those? So it seems like the combination of both cranked up is actually the sound everyone is familiar with from the 60s until master volume Marshalls were introduced.
Could you also do this with a Hiwatt? I'd be curious to see the difference (I'm too scared to crank mine). I've done it once or twice and all I remember is it was REALLY hard to get it to break up on its own.
Oh nevermind I just found your Pete Townshend video on his signal chain! Sweet!
This is a lot easier to understand, and to predict what's going to happen if you have an understanding of the differences between gain and volume. Here's why the bass softens up with too much volume. In the preamp, the input tubes are pushed to distort using excess gain. The gain is distorting the signal itself. Power amp distortion doesn't work like that. A volume control is a passive device and can't alter the signal in any way. Its transparent. Even if a volume control is completely maxed out, it won't effect the signal. All a volume control can do is work like a gate on a dam that lets more water through the opening the more you open it. The pressure that pushes the water through the gate, has nothing to do with the gate itself. Its the same thing with the electricity that passes through a volume control. The reason the power amp tubes distort isn't from gain. At some point, opening the volume will be asking the power amp to play louder than it can normally handle, and the output tubes get pushed to failure. Its no different than going to your home or car stereo and turning the volume up until it breaks up. The signal itself isn't distorting. You're just playing it too loud.
When you distort the signal in the preamp with gain, and you are not pushing the power tubes too hard, the power amp is working correctly and just amplifies the signal given to it by the preamp. When you push the power amp too hard, the tubes fail and you loose fidelity as a direct result. It can't amplify the signal from the preamp accurately when pushed beyond its limits. So, your mushy bass is the result of your power amp not being able to do its job properly. I understand that you are probably doing this on purpose, for the effect it has on the sound. But that's what's actually happening inside the amp. This is also why some people use pedals to tighten up the bass. When the power tubes distort, there are both advantages and disadvantages sonically. You use the pedal to retain the benefits of distorting your power tubes, while trying to fix the downsides, like mushy bass.
There is something with the tone when you go beyond certain volume, that I really like. More than MV or preamp, I think it has to do with some other thing (speakers, room sound, maybe transformers). Of course, this is a totally different experience in person, you can not translate 105dB through youtube...
I recently built an amp where if I have a boost at the end of the effects loop, I hit the 3rd stage of the pre, and the phase inverter. It seems to have some really nice body to the distortion there, which the first two stages and eq don't really have on their own. (Though it has to be said all together, the pre and power amp tones are amazing (those being an orange or120 front end, and a pair of el84 tubes in the output section)
Rock on! Thank-you.
BTW “flying debris” would make a great name for a band.
Preamp dimed, take it from there. That to me was the best sounding drive/distortion.
Who needs pedals, when you have a collection of great amps..!
I mainly use non-master volume amps, which are designed to be played clean (as the 50s/60s all was mainly about clean loud guitar tones), but when you crank them, the whole thing overdrives in a special way that gives you more dynamic range, than the modern driven preamp tones. Sure, you can't do hard rock on a Tweed Deluxe, but rock n' roll, blues rock I believe sound better with such tones.
As you pointed, though, when you push the whole amp beyond its limits it may sound mushy, so you need to tame low frequencies a little, be it a EQ pedal, or a Treble Booster style pedal, or eq the amp itself.
By the way, no amp I've tried sounds as focused and defined, when cranked, as Hiwatt style amps. Not a plenty of distortion, but they can handle themselves great when pushed beyond their clean tones!
Nice to see informative videos, like this one!
Cheers!
Heaven on Earth! No pedals needed
I love that the sound is so loud that the camera shakes
My favorite was the master at around 2, and the preamp all the way up. Interestingly, this is how I like running the JCM 800 model in the Line 6 Pod Go. Too much master volume makes the sound too dark and mushy in my opinion
Johan! Your hearing! I hope you wore protection! Nice vid 👍
As a great man once said: loud is more good
Hahahaha! I love Joshua too!
@@JohanSegeborn yep. Be interested to hear that comparison done with someone sweeping the 2 gains up and down continuously. If you get me drift.
Nice sounds you got got as ever.
I've always had such a hard time dialing in my '84 JCM 800 2204, that I rarely play it. ( A lot of that is because I only have 2x12 cabs these days )
I've always been partial to power tube distortion, but I guess alot depends on the particular amp.
Pre amp gain is what ost people use since gain from the power section involved higher volumes. The best is when you can combine the two.
Gain isn't responsible for power tube distortion. In the preamp, excessive gain overdrives the input tubes, and distorts the signal directly. A volume control can't alter the signal in any way. Its a passive device. When you raise the volume, it allows a more powerful signal to pass through it like a gate. When the volume lets more signal pass than the power amp can handle, the tubes get driven to failure. That's the distortion you're hearing. Its a different kind of distortion.
I don't care much of Marshall master volume amps. Currently I have basically a 1959 with cascaded preamps which I like very much (not the same circuit as 2203). That amp have perfect gain staging between preamp and poweramp. When you turn it up ( I usually keep both volumes at the same position), it's loud without any fizzyness or mushiness. For me the best thing when turning up is the output transformer compression that happens. a great firm sustain.
Loved pre at 4 master at 9-10 with TH-cam compression
Sounded great when neither was at full. Prob best to use it with power volume just over half and preamp just above that. Power amp volume tends to add more low end and preamp volume tends to add more presence, so if your using a single coil guitar or a humbucker guitar it might be better to use the settings differently to make the overall tone work for you
Just different sounds of awesome