EPIC SERVICE FAIL! - 1970 Fender Silverface Super Reverb Repair Gone Wrong
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- เผยแพร่เมื่อ 13 ก.พ. 2017
- Here's a repair that goes totally tits up at the end. We change all the caps, screen resistors, clean everything, etc., only to face an insurmountable roadblock at the end. Needless to say, there is no tone demo at the end of this one.
Interestingly, this example came to me with 7581 power tubes, which are an industrial version of the 6L6GC. - วิทยาศาสตร์และเทคโนโลยี
What happened to the amp ? Keeping us hanging. Thanks man.
heheheh...well the title did say "Epic Service Fail". It went back to the owner who bought a new baffle for around $80. He installed the speakers and everything is working ok, according to my last convo with him.
The Guitologist dude, you really need to teach your customers how to make follow up videos and send them in to you. incomplete stories suck hahahaha
The Guitologist The ultimate cliff hanger at the end of video. Thanks for telling us the end.
This video is like French cinema. Tragic ending.
Yeah - get the guy to post an update demo of it now then!!
Don't quit making repair videos.. every one is different and they are all a pleasure to watch!
I really dont want to know the type of people that thumbs down these videos...these videos are a wealth of knowledge for me and anyone who loves guitars or amps. Thanks for all the wisdom good sir.
I had a 1968 Fender Silverface Super Reverb and loved it. I used a 'Y' cord between channels 1 and 2 for some interesting effects. Thanks for the video.
big shot out to you amp techs. I had my totally rewired all new caps and resistor's. neg feedback loop eliminated. all new pots and basically gone completely over. I made the cabinet and 2 baffles. one for twin 8 inch and one for an old 12 Jensen from the late 50s. it's for harmonica so I had to go with lower value pre amp tubes. harp mics are much different than guitar pickups. but in a nutshell I payed 150$ for the rebuild and have a killer harp amp now. how he did it all for that price is beyond me. he said I was lucky I didn't catch fire. but this is all rocket science to me. wish I had the same results for an ampeg solid state amp. no one can get it totally figured out. but kudos to you techs
I can't believe I watched the whole thing. But that's how much I like the Super Reverb as an amp.
My dad bought me a mid 60s blackface Fender Super Reverb in 1968....l sold it in 2009 for 600$ ...it was in mint condition vinyl cover and all...another one of my regrets ..
Not to rub it in but boy, something that clean would be worth four times that now. But I'm sure you're already aware of that
Great Video Brad !!! These Fenders kick azz !! Keep those tubes glowing & much love
The old ones, yes. But to be honest, I think ever since Rivera came out with that solid state line of Fenders during the 80's that Fender's SS amps have been better sounding amps than their tube line for the past 40 years. It's like they've forgotten how to make tube amps.
After 72 they had a master volume and are less desirable to some. Still my favorite Fender amp and is amazing cranked. Listen to Weekend Warriors by Nugent. Best tone ever!
Great job of persevering through a cluster fornication, Brad. I'm constantly impressed by your ingenuity.
Just an FYI for future reference: I had a crusty old amp guru in Memphis show me this trick years ago. If you have a fairly small, relatively clean tear in the speaker cone, you can trim a bit of toilet paper just to cover, then affix it as you moisten it with just enough superglue to seal. If done neatly, this works quite well and for the most part, is sonically transparent. Costs a penny to do, and then the customer can decide if he still wants to recone or upgrade...
Thanks. I use hot glue for speaker cone repairs. th-cam.com/video/ZHo3v6N7Kog/w-d-xo.html
I really think Brad or anyone else is better off using hot glue vs. super glue. Reason being super glue will literally melt some materials. Seen it myself on a Boston acoustics sub I was attempting to repair years ago. And actually I've since done several recones and replaced a lot of surrounds and find that something like an Elmer's school glue is really all you need. That's what they used to build them (some brands). Other brands use a more clear, faster drying glue
Love the vids...keep 'em coming!! I only wish I could do half of what you do.
You can. Invest in a good multimeter, variac, soldering iron, and some books on amps, and get started! There are some "support groups" online for builders and repair people. THere are groups on Facebook too.
I had a 15" speaker replaced on a Fender speaker cabinet I had back in the 70's. When I looked at it closely a few years later, I found that there had been a hole in the cone of the new speaker and the repair shop had put a dab of some kind of clear paint, (finger nail polish?), over it. I can't say it effected the sound, but once I found out about it, I thought it didn't sound right. Probably all in my head.
Wow, interesting. When I saw you getting sound out of the board by tapping by the tremolo circuit, I did the exact video on the same problem. My solution was to disconnect the tremolo and also remove the tremolo tube. I use an external Supa-Trem if I ever need one. I need to watch more to see what you did. Thanks.
I had '65 silver face Super Reverb. Loved it. I bought it along with a Fender telecaster from Rondo Music, Linden, NJ. A real guitar candy store in the sixties.
these are sweet amps. i played one with a master volume and it just rocked. i personally have a 1970 or 71 silver face twin reverb that i love. all original wiring inside the chassis. these are affordable amps and worth it if you can find the pre-master volume as these are point to point. a very unique fender tone that hasn't become loved yet. i can't see why.
haha the speaker-climax at the end!
I have a bassman 135 looking kinda burnt too, all the ceramic caps in the rectifier seem pretty crisp.
Everythings original except the 470 screen resistors (which someone hacked), even the old Mallory silver cans are still under the doghouse.
Its almost a 40 year old amp so changing caps will be better than a broken down amp that I cant even sell later, I know it's the least sought after amp but this will probably be my first repair, gotta start somewhere i guess.
I think I like you channel the best, you explain everything very good with detail and its made me get into amps alot.
/Niels
Git er done Brad.
i can't wait to see part two of this one.
This amp had more fleas and ticks than a junkyard dog.
I am so glad I got a new 65 reissue!
Those AB763 tube charts in the cabinets are just leftovers. Coincidentally on my bench now is a Twin Reverb that looks exactly the same inside, and I've done the same full capacitor replacements. At this time they were transitioning through several variations of bias control (before they started on other tonal tweaks next in the phase inverter, also e.g. the 5uf trem bypass cap was correct) and the parts you have discovered in there may be based on one of the updated bias level or early bias balance style controls, but taking it back to AB763 there is a good move..
Other odd thing I have noticed on SF Fenders (but I don't check all of them) is seeing that they have reversed the hot and neutral AC wires at the extension socket terminals.
I have rebuilt so many very very dead SF Fenders, the usual retubing and cap jobs are one thing, but when it gets into speaker and cabinet replacement issues it turns into a labour of love, my Super Reverb is a *complete* rebuild, and it is still going to need a new cabinet soon due to woodlice :/
Thanks for the comment, Jonathan. Yeah, I don't have the tools for cabinetry really. I know I could learn anything I set my mind to, but I have not gotten much into cabinetry. Replaced the occasional baffle, but that's about it. Watcher of my channel know I like my old department store stuff and I'm no Fender expert. The few Fender vids I've done have taught me a lot, especially through the comments afterward. You kind of have to be an historian of sorts on all this stuff to know the best courses of action. When in doubt, I usually try to restore to factory original over modification, especially when I know the original circuits (at least the one on the tube chart) was a great sounding circuit.
Well I started out doing just those very things in the mid 90s, building my own speaker cabs, and refurbing old Fenders, and then later moving on to building guitars and amps entirely. Where I live most old amps that have been laying around have rotten cabinets, so I often produce a one off repro cab alongside my regular work. Thanks for doing these great refurb project vids.
Yikes!
You did a great job, and showed massive patience finding the source of the problems.
When you first showed the amp, I thought the grille cloth looked misaligned, as though it had a replaced baffle.
I hope you post a follow video, after sorting out the baffle and speaker problems.
The customer elected to take the amp and try to make or buy a baffle online.
The Guitologist I hope he finds a better solution than what was in there! Lee
You hit the nail on the head i had a few older amps when i was younger i kept in my garage (i was using a brit fender twin reverb deluxe 70ish back then) in the garage i had a old low watt silver tone with a 12 spk (sears) and what i remember as a old twin reverb(reg usa) any way there was a small fire in our boiler room led to the garage and though the amps were not burned they had heat damage that looked just like what i saw on that amp.any way keep up the good work.
Hey Brad, the 100/100 caps are the most common replacement for black/silverface amps. The voltages can exceed 75vdc in some circuits.
Good luck with this one man, what a clusterfuck!
Nice work! What a mess! Hopefully we get to hear the end result!
I told the owner that after he gets a baffle, I'll help him install it if he needs me to, so it might come back for that. If it does, it'll get a quick demo.
This breaks my heart. As I own a 1967 Super Reverb, I'm familiar with the restoration of this series. Mine came to me with no cabinet, no speaker, no tubes. I've rebuilt it twice (once as a 2x8" combo, and once again as a regulation 4 x 10" ) I have never regretted the cost or the effort. The last one I rebuilt for a customer was in rough shape and was close to $600 in parts and labor by the time it was completed. He was thrilled because nothing else sounds like this rig.
A good early SF Super is always worth a bit of effort to get right.
Howard Rose Big difference in price between a 67 and a 68. Resale is low on the 68 silver, but if you convert the handful of parts needed to make it a blackface, its the same tone, but you dont get mad if it gets fucked up on stage.
I have a a SF Bassman 100 - i replaced the choke the high power filter caps and every vol knob pedometers i think they are called - some were frozen and scratchy bad popping the speakers to even move 'em..and got the Blackface mod kit for this amp for guitar for 50 bucks comes with instructions also and caps.u can find on ebay...now its a 100 watt blackface rig !!..best mod kit i ever bought !! no tremolo and reverb..but thats what pedals are for !!.. and JBL d120f and d131 in a 2-12 Peavey cab, i sanded down to bare wood and stained it, and the amp fit perfect !! - had to cut for the slant of the amp and holes to bolt it in..and replaced the grill clothe .telefuken 12ax7 tubes makes a diff or Mullard for even more brightness...but Yeah man
fender red knob super 112 and a tube Sano 60's amp1-12 is what i go back n fourth with..and this ;:*)...love to have the real deal tho, maybe if i become famous or met with some people who even plays is my problem now days- in the 90's every one wanted to Jam..now..its just a hobby anymore
@TheGuitologist you are a wizard. That thing was a train wreck.
I had a blackface I got it back in 1965 and I loved it, I never had any problems with it at all, I used it for years, five nights a week on the road, for over ten years, had all the same parts that came in it new it was a great amp, I sold it and got a 50 watt Marshall stack.
"This really looks like it might've caught fire at one point" hahahaha wasn't expecting you to say that
Awesome videos!
I will say every super I have owned had a thunderstorm sound through the reverb. Modern 100k plate load resistors through the preamp cleans it right up.
Best sounding Super Reverbs I have had or played were the 1965 to 1968 depending on the speakers. The later master volume ones had particle board baffles integral to the cab and they cracked as far as I remember. The baffle/speaker cover came off instead of the baffle itself and those always cracked. We used to call those Fender brown caps turds LOL. The later chassis were not as strong as the earlier ones and did bend.
In my mind the latter version, such as the '79, would be optimal. Just due to 😅the fact that you would then have the ability to attenuate for lack of a better term.
If you've had experience with both earlier and latter versions,, I'd sure like to hear your thoughts
I'm from the old school of turn it up and let er rip. You cannot do that with an amp that has certain types of master volumes. The circuits were overbuilt and the master volume in those amps were poorly designed. I prefer the scooped mids of the early amps, so many modern sounds are too thick in the mids. Tweeds has much more midrange than the BF, even the white/brown had a thicker midrange then the BFs. I leave certain frequencies for the bass guitar. I don't want to fight the bass for room within the range so I layoff the lows and mids and allow the bass to fill that up along with the drums. To me most master volume amps are much more compressed and unnatural sounding. Just look at a schematic, those master volume amps had so much unnecessary circuitry. What was that doing to the sound? It was causing a muffled dead compressed sound. Unless you ever played an old Marshall stack and turned it up with a band you just don't know the power it has, you cannot fake that with a 40 watt amp with a master volume. The closest thing to that would be using a pair of Fender amps like a twin reverb and a bassman or super or even a dual showman. Now the huge sound systems they use now doesn't require much stage volume and that helped kill that early rock sound. I remember Alvin Lee blowing out Marshall Majors at a concert, it's easier to use a small master volume amp with a mic on it pumped through the system. I can see the difference on these TH-cam guitar players right away, the ones who have played with live bands and the ones who do not. @@incredifunk
Not for nothing this amp went through hell. Must have been hit by a truck while it was working or something like that. The baffle was funny. I am thinking If they did not care how the speakers were sitting why didn't they just drill holes so the speakers would be flush. I had a a mid 60s pro reverb and it was sweet sounding two 12 inch. Yah you had your hands full with this project. Thanks for sharing your videos with us.
You should replace the 100K plate resistors (that come together in that "V" shape) with 2 watt metal film resistors. Could do 470 ohm screen resistors in metal film as well. It is thermal noise from those older carbon comp resistors plate that makes the static in the amp. >>Guaranteed.
I have a 1974 super reverb that someone cut the baffel out. How would you replace it its let in to the sides. I found a replacement but wanted to check with you. Thanks
Freeze spray very good for locating noisy intermittent resistors and other components, too.
Would be interesting to Have a scope I the output to see if you had any parasitic oscillation going on.
That's typically what you find when you've got weird stuff when you merely change the position of wires.
I have a '68 Bassman Ten. It had a SS rectifier, and unused windings off the power transformer, I'm guessing for a tube rectifier. Probably blasphemous, but a Mullard GZ34 practically jumped in there.
@@mikecamps7226 You said so much things I have no idea what they mean.
For a techie like me this is by far the coolest channel yet. I have had a few bastardized amps in the past. I do have a question. Why is the death cap called a death cap?
The "death cap" is so-called because if the cap shorts (which is highly unlikely but theoretically possible) and if the power plug is oriented the right way, you could receive a 120VAC shock from the chassis.
In the early 1970s, we had a concert at our college. The band was Poco. They were mostly former members of the Buffalo Springfield. The pedal steel player was Rusty Young, and he ran his pedal steel through a leslie tone cabinet to generate a unique type of sound (reverb and organ like). I distinctly remember the band had Fender super reverbs, and they were loud. That leslie may have really beat up the amps. The band was great, and they were especially known for live concerts. They really rocked. Around this time, they had a live album called "Deliverin". It looks like that amp had a hard life, and there were many repairs and mods. It's possible that this was one of the road amps. The dating looks correct. If so, it may have some historical value. I don't know if you can trace Fender amp ownership; but it would be really cool if it could be established that this amp goes back to Poco. Organ sounding pedal steel solo begins at two and a half minute mark.
th-cam.com/video/4x7c2RI_XZU/w-d-xo.html
I have a Poco album. I forget which one.
Hi, I have a problem with my fender super Reverb amp by mistake I tried to turn it on at 220volt, and then when the on off switch is turned on it looks like everything work OK, but when I turn the standby switch on, it burns the fuse every time...do you have any idea what's going wrong? Thanks! Greetings from greece
Thank you.....Very informative.
That 100 watt vintage eminence speaker is one bad ass speaker!
Can I ask why the client didnt consider intsalling 4 JBL (E 110 ) 10 inch drivers instead of 4 different speakers that are not balanced for efficiency or wattage and matched Db output.Not only would the power wattage match as well as the db rating of 96 db but they would sound amazing and never have to be replaced? It seems with all the work you did on the amp the client over looked the most important part of the fix or refurbishment the weakest link the speakers
I forgot to ask. What brand of caps did you put in as replacements? They look like Orange drops. I'm this close to ordering parts for my next amp build. I have used carbon comp. resistors in the past but I am thinking about using metal film or metal oxide instead. Any thoughts on those? Are there good quality caps that are not as expensive as Orange drops? Thankz
My resistor stash is low and I did not have the right metal oxide value for those screen resistors, for instance, but made due. Anything metal should be used in power supply or as plate resistors. They will hold up better over time under higher voltages without drifting. I use carbons in signal paths.
The caps I used here were like a Panasonic style red cap. I get them at AES (Antique Electronic Supply,), but others supply them too.
What we used to do is patch holes in speakers with nail polish. It's nitrocellulose and great glue for paper and plus it shrinks tight. If that was my amp I'd just patch the speaker and see if that works before spending money on speakers. . Hey it's just rock n roll lol.
OK - but if you have to depend on your gear as you are a prof. musician you would think differently.
I patched a speaker with a small Tear in it with clear nail polish 20 years ago and and its still absolutely fine...
@@daveg2526 awesome
The baffle is baffling ! I mean Really ???
I had a 1974 that was non master volume, it was 1975 that the MV started on Super Reverbs, way earlier on Twins for some reason.
I have a 1973 I recently restored and have loaded up with Weber 10F150 and 10A125 speakers.
Tone to die for !
The amp your working on in this video looked like they did half of the "Black Face" on the bias , I saw also that you finished the job later in the video without mentioning it.
I've run into all kinds of crazy "modifications" to circuits that make you wonder how the people doing them survived LOL !
I am no amp tech but did you not replace the electrolytic caps with what look to me like polyester caps?
wow ,did they screw those overlapping speakers down .would surely distort the speakers frame leading to more probs.ouch.
Great video. Thanks. Despite what the tube chart said, could it be that was actually an AA270 circuit, so the stock bias supply circuit would include a bias balance and two 50 mfd 70 volt caps, including the one off the pot? As someone noted below, it's very common to upgrade the caps to 100/100.
I'm the first to admit I'm no Fender expert. But the AB763 circuit is the classic BF circuit. Not sure why the tube chart in this example has a 5U4 listed instead of a GZ34, but the AB763 ran thru 1969 in some Supers and had a 25uf cap in the bias. I think the bias was tinkered with. That resistor with the shrink tubed wire was not original, and neither were those two 100uf caps. Someone probably was tinkering and using a later Super schematic while doing so, maybe without realizing it, who knows. When in doubt, I restore to stock, and that's what I did in this case. Here's a good site with discussions of all the various Supers and differences: fenderguru.com/amps/super-reverb/
Thanks for the link.
Oh man, Ive gone through torture trying to sort out schematics. I get the feeling that they weren't all that well maintained throughout the years, esp after CBS and production ramped up.
What happened to the Eminence Legend speaker that was beside the Eminence Patriot speaker @ 33.00? It was in there when the video began.
I own a blackface super twin is the amp worth keeping?
do you think it has something to do with a broken trace?
I usually find your videos informative. For this one I have alot of questions. Heres a few that should be easy to answer.
First thing I do is test the PT. Why don't you ever do that?
Did you ever test any of the "brown turd" caps you dislike so much?
I have repaired speaker cones in far worse condition than those.
Did you try moving the speakers on the baffle?
Are there any Mesa Boogie mk iv switching logic and footswitch schematics out there?
I think there are 26 LDRs in that amp but ony a few clues how they are switched.
I'll soon be 60. I got to see Black Sabbath on the Sabbath Bloody Sabbath tour. I've been a Laney fan since 1970, right after a friends big brother turned me on to "Paranoid." I have seen bad customer service. I have seen great customer service. But I have never seen a company appreciate and take care of their customers like Laney. Laney tops everything I've ever been associated with. I'm not in the "Rock n Roll Hall of Fame." But Laney treated me as if I were. I'm not a touring rockstar. But Laney treated me like I am. You can have your M's and V's and all in between, but as for me, make mine LANEY. A Laney Lionheart.
That's messed up. You surely had an original receipt? Correspondence with Laney? Shipping receipts? Emails? Did you present them all the evidence and they still said they can't help?
Laney to the rescue!! Over the top!!! The first word in corporate level customer service it Laney!!
I bought a Fender Blues Deluxe RI. The one thing my Mesa 5:50Plus won't do is swamp. And the BDRI nails swamp!
I've been loving these videos. In this one, I was buckling in to get ready for you to talk about capacitors and which brands and materials you have tried and would recommend. Then suddenly there were shiny, puppy-poop colored caps in everywhere. (dang). I would LOVE to hear about your thoughts on capacitor replacements and where to spend your money. For example, if I only wanted to splurge for 2-4 fancy caps ($6 - $15ea), would those go in the tone-stack? or where do they make the biggest difference in sound? Then maybe a couple more ideas on mid-priced options? thanks!! big fan.
My take on caps has always been this - if the caps are working correctly and have the same value, 99.99% of all the people on the planet won't be able to tell the difference, so I just use what's inexpensive and works for me, unless directed to do otherwise. The place where caps really make a difference is when you use all ceramic caps in an entire amp, like a lot of old Valcos did, then you can hear a difference, but only because ceramic caps are notoriously microphonic, so you're actually getting feedback through the caps themselves, which can seem to highlight desirable harmonics and give them amps a 3D effect, even with no reverb turned on.
You will get more effect playing with coupling cap VALUES than you will playing with cap types, but if you want to experiment, experiment on the coupling cap between the first and second stages of your amp first. That cap will have the single greatest effect on overall tone of any cap in the signal path.
okay! Thank you very much! I'll pay special attention to that spot - once I find it.
I just picked up a 69 Drip Edge that’s been blackfaced. I separated the cathodes of V1 and V2 and this amp is killer on channel 1. Of course channel 2 with reverb is amazing as well.
Hey! I am about to buy a 69 drip edge with the tube chart of AB763. I know it is wrong. Can you tell me how to blackface it with the schematics so that I can tell my amp tech guy?
@@picapoyito I would recommend talking to the amp tech about it. If he/she isn’t familiar with that mod, they’re probably not qualified to work on tube amps as that is probably the most widely know mods of Fender amps.
Brad ...I have been fixing speakers for 25+ years and could have fixed those. Let me know if you have any projects that need recone or repair.
Dave
You should make some videos yourself Dave, sounds like good stuff for people to see
Ha, I was expecting smoke. I didn't see that coming. Would an easier cheaper fix for the customer be to make it a 2 X 12? The pricier, most proper and entertaining solution would be send it to uncle Doug and rusty for a new cab and some of that bluesy stuff he does. :-)
The Guitologist+ @ 13:26 is the tubes resting on the table?
My 66 baffle looks like a mix between MDF and chip/particle board. Those things suck up moisture like a sponge after the finish loses it's protection. I replaced it with some .30" 7 ply birch the first day I got it. . Are the mounting holes on those old Eminence speakers way huge? Or is it me? Probably why the speakers are trashed.
The #1 upgrade you can make to your BF or SF Fender is a new baffle, IMO. Even before screwing with circuit mods.
Boy, that one wuz really bashed, burned and chewed on...
Also is the 5AR4 an okay swap for a GZ34? ...and did the customer ever give the go ahead for you to bring this epic to a happy ending?
Anyway, thanx for another great video and...
cheers
Are those 12" speakers? Didn't they originally come with four 10"s?
With any old tube amp, I replace all anode resistors as a matter of course. They are typically the cause of intermittent crackle.
IIRC in a Silver Face Fender Super Reverb the top pair of speakers are offset in relation to the bottom pair in order to allow a proper fit for all four units with a modest space between each.
I noticed tube chart says 5u4. But the amp had a 5ar4 in it. Are they direct replacements? Or would that have caused any of that burning on the chassis running the power too hot?
Nice job on the chopstick troubleshooting.
Subbing a 5AR4 (GZ34) for a 5U4 is something that is done quite often. They are direct replacements. The GZ34 draws less current, so there's less chance of burning up a transformer you're unsure about. It will raise voltages on the tube plates, but not enough usually to be a problem. It certainly would not have cause that burning look on the chassis.
Thanks clarifying. Always something new to learn from your videos.
Brad, are there any books you can recommend on amp repair?
I own and have read this one: amzn.to/2lM0yZu
I have a couple of Gerald Weber's books, but to be honest, they are compilations of his magazine articles mostly, so they are random and not very effective in taking someone who knows nothing and turning them into someone who is competent.
A lot of people rave about Merlin's Amp books, but I am not familiar with them, personally.
Thanks!
The Ultimate Tone series- Kevin O Connor
Gerald Webers books are great from an amp mechanics point of view.
Merlin Blencowe's books, good luck finding his power supply book.
JAN textbooks
Elements of radio
Thanks!
right on}Brad. very good text. and graphic.I the book.
Whatever happened with this? Is there a part 2 somewhere?
When I worked retail repair we always tested the speakers BEFORE getting into the electronics by subbing out with a bench amp because sure as all get out you'd fix the amp then find the speaker was bogus and the customer would not want to fix it or couldn't hack the bill.
One little note - paralleling resistors does not increase the voltage rating.. Putting resistors in series does.
Resistors in parallel will each dissipate half the power being passed through them, therefore you have effectively doubled the power handling by putting two identical resistors in parallel. The opposite is true of capacitors. Caps in series doubles the power rating.
Whether you connect two identical resistors in parallel or in series, it will double the POWER capacity. P=V*I, so whether you half the current (parallel) or the voltage (series) the power dissipated per resistor is going to be halved too. However, in parallel connection, the voltage across both of them is obviously the same (unchanged), so it won't increase the VOLTAGE rating of the pair, whereas in series connection the voltages will be split between the two, thus increasing the VOLTAGE rating of the pair. And at 28:02 you say "double the value and put them in parallel, which gives me double the voltage" - which is incorrect. It gives you double the POWER rating, but not double the voltage.
Breakdown voltage rating of resistors is quite often misunderstood or forgotten. Capacitors have their voltage rating clearly marked, whereas the resistors do not - but they too have a voltage rating, which is specified by the manufacturer for each of their particular series/model. The rule of thumb is that higher wattage resistors, just because of their physical size, have a higher voltage rating - that's why in tube circuits one shouldn't use tiny modern 0.125W or 0.25W resistors (even if the calculated dissipated power would seem OK), because they tend to have a breakdown voltage rating starting at around 100V, clearly not suitable for circuits operating at 300-500V.
With capacitors it is the capacitance that behaves opposite to resistors: parallel - multiply, series - divide. Voltage/current/power in case of capacitors are a result of much more complicated factors, but generally regarding voltage it's similar to resistors (or anything else for that matter, even battery cells) - series connection will sum voltages, and parallel will not.
Yeah, I've seen that kind of thing too. At least the person who did that didn't recut the hole and use hot glue to fill in the gaps of the miss cut areas. You can imagine what happens next with black cabinet carpet covering the whole thing on a sunny 112° day with no cover tarp or canopy of any kind. That guy will never work on my gear again. The messed up part is that I could hear it before I could see it. Some kind of strange rattle at low frequencies. I got home and rattle checked the drivers by tapping on their cones and nothing so I dig deeper. I have never seen so much hot snot in a single speaker cabinet my whole life.
wish i had this video when i was working on mine lol i still need to recognize the original speakers I loaded it with ceramic Jensons to play it
Does it smell like cigarette smoke? That residue is probably a burnt PCB from the internals of the transformer of a least older electrolytic capacitors that may have been replaced. green in my shop for instance have been a major cause for faults.
That one was a chore... . Good job boss. I don't trust myself enough to video myself working on the bench.... I'm too much of a scatter brain.
I used to be weird about that too, but now I don't care. I just rattle on anyway. I make an average of 3 or 4 mistakes per video in my statements. Doesn't bother me like it used to.
Jokingly, I feel like Norm Abrham's show... he makes wood cabinets, and everything fits perfectly, the tooling never fails, the joints fit perfectly...I have to live up to that knowing that it was all fixed in editing. With my luck I'll cut my hand off on film, or run 400v through my arm. Unless I can concentrate, my project videos would look like the Electroboom channel. (look at it if you've never seen it)
If and WHEN I get hit with 400VDC or 120VAC on camera, you better believe I WILL leave it in the final cut! Fuck ups can be instructive too, and we ALL make them!
I took full B+ thru part of my hand... black spot on the in and out... yowzer!
I've done that with a Univox amp before. Damn thing didn't have ANYTHING shielding the primary leads of the OT. Full B+ through my finger. The other week I was fixing the neighbor's dishwasher and didn't realize there was 120VAC right on the damn door switch! That was a muscle spasm.
That speaker was salvageable I think. I recently fixed the alnico gold 10" in my Princeton. it got damaged because of a loose screw during a move, the cone had tears in 3 places. including a pretty bad one that went through the cone. I just put dabs of epoxy where the cracks were (on the back and front of the cone) and then used black paint over that. I let it cure overnight and it was good as new when I popped it back in.
Silicone would work too.
I have used pieces of paper glued on with nail polish. Worked flawlessly.
Terry D would call that baffle board the work of the Cobbler!
I've never heard the term "roach" in this context before. Is it some kind of relay associated with the tremolo controls?
Not a relay. It's a photocoupler or photovoltaic resistor coupled with a bulb to produce a varying voltage in a circuit.
Oh, I see. It's a self-contained optocoupler/light combination. I forgot Silverface amps had switched from bias oscillating tremolo to optical tremolo. Thanks for the clarification.
brad, is this the same amplifier from the other video? the one serviced properly that you waffled on a bout. why dont you show whats wrong with the amplifier? brad?
Very Good!
How do you have any hair left after this?
That pile of junk doesn't need repair, it needs restoration. If the customer doesn't want to pay for a full restore, I'd give him the thing back.
To this customer's credit, he's going to restore the baffle and put this one back in service. Electronically, it's ready to go, and as a favor, I told him he can bring it back and I'll help wire up the new baffle when he gets/makes it.
Chris Cunningham I would be more in tune with that idea if the face plate wasn't so effed up. I would cut it down to a two 12 or two ten maybe a head. Better yet build a hdpb head cab for it while ya restore the speaker cab.
Wasn't most of this CBS era stuff crap to start off with? I think the Champ and Vibro Champ were kept the same as the Blackface era but all the rest were redesigned to save money.
It wasn't crap at all. If anything, it made the stuff more reliable, safer and easier to work on.
It's just that the 1970s and 80s were The Age of Distortion, while Fender's conscious design philosophy during that time was to deliver a good clean sound. As Fender continued along that path, their stuff got better at loud clean tones, but not as good at distorting, because that's not what it was designed to do.
That's why people love Blackface amps, because they give a great balance of both worlds. Fender amp distortion is a thing of beauty in and of itself, and that's what was getting lost in the CBS era as they pursued loud and clean.
But as far as build quality, component quality and reliability goes, the Silverface era has it all over the Blackfaces. Heresy I know, but it's true. Silverface transformers are much beefier than blackface transformers, could take a LOT more abuse. That's not even debatable.
If the chassis caught on fire and had to be rebuilt from the ground up (and many of them did coming back from UL torture testing), their chief designer after Leo, Ed Jahns, wanted to make sure that they could be put back into service as quickly and easily as possible. That meant having heavy duty transformers that could take the abuse without failing. Even now, nearly 50 years later, having a bad transformer on a SF amp is almost unheard-of, even on amps that are fried worse than this one was.
keep searching ebay, once and a while you find a used silver faceplate, they make aftermarket black ones, but I only saw a couple aftermarket silver ones, gotta get them used.
That amp is a victim of too many nights in smoky bars, garages, bedrooms or basements....!
I had a '68 Super, sold it to make a mortgage payment. :o(
I miss it but my '62 Deluxe is actually a lot more useful.
Next riot just say you're for blm and take it back. It's for social justice.
Are those 12" speakers?
I think they were originally tens....
I would love to see someone out there put together a guitar amp out there with 8 x JBL E-110 drivers housed in a cabinet 48 " h x 26" w x 12" D and use a BGW 750 stereo power amp bridged to ( 900 watts RMS ).I believe that that configuration would kill a lot of guitar amps out there and sound awesome as well..
What is a roach? Never heard that term before refering to an electronic device. Only when someone I taking about an alligator clip.
It's the thing that makes vintage Fender tremolo circuits go.
Fender had a lamp next to a photoresistor, all taped together with electrical tape, with just the leads sticking out. Since it was small, black and had little "legs", amp techs started calling it "the roach" and the name stuck.
whoa Brad why not switch to four 10s - or use two 10 ceramics w two 12 alnicos to match volume levels - best though IMO, and w customer OK, recess the baffle, add rim for grille, meaning the speakers could drop in likely to these hole cuts
allows for mount on threaded axles through and through - chance to use a slim MDF or conversely something real lively & high-price Eg birch or maple
as I recall Supers are so heavy they wind up on casters, which they survive better than some - still a lighter-weight version (spkrs & baffle) would be sweet, mo?
Fortunately, they sent that road warrior to you!
There are other people who are more Fender specialist than I, but this one clearly needed someone to intervene.
16:04 There is absolutely no chance that all the places you're gonna play will be up to electrical code.
Somethings going on with a something. Sounds like me! Too funny.
Baffleboard ? did ya do it?
Do you ever just strip half of the components out?
I'm a R&D engineer myself and also have to do some repair stuff every ones in a while.
Occasionally I get amps like this, were I really can't be bothered troubleshooting the whole thing.
In that case it's easier, cheaper and less time consuming to rebuild things up again.
Also with a (much) better end result.
In the case of most amp makers, their usual problems are well known. Fender is the most studied amp maker there is, so any problem that can be had with a Fender has been had before by someone. Shotgunning caps (both electrolytic and signal) is usually a good place to start if you have a ghost in the machine. Then replacing all power resistors (all the ones in the power rail, all plate resistors, and output screen resistors) would cure a large percentage of issues. Also cleaning the connections between all the pots and jacks and the ground buss, cleaning all sockets and pots themselves cures another large chunk of the possible issues. This one would not have been nearly as bad had someone not simply abused the hell outta it.
Great question, by the way!
I was actually more talking about not even cleaning stuff, but just simply replacing them.
Same for most components.
If you have most components in stock (which I do), it's not so difficult to rebuild the internal 'guts' from scratch.
Maybe you'd call it more like a fully complete revision.
Although, some customers are not a big fan of it because you take the 'soul' away from an amp (not my words).
Because it's basically a completely new amp at that point (except for the transformers, tubes and some sockets)
I never take that approach because it isn't economical. I shotgun caps if they are known to have a high fail rate, like the brown caps in this model, but otherwise, I don't do that, not because it "steals the soul" but because of economics.
Bart B These 70's silverface amps are a great platform for a complete rebuild. Turning a birds nest of appliance wire and horrible lead dress into a really great sounding AB763 Blackface circuit isn't very expensive. Lots of companies make fiberboards/turret boards. The selection of parts ranges from NOS coupling caps and carbon comp resistors to modern parts that cost pennies.
If I'm presented with a complete and working amp, I'll do maintenance and testing, trying to retain originality. That situation is becoming far less common these days, especially with popular brands.
I have no problem gutting an amp if its been in the hands of a butcher. Sometimes you have to with the Fender style eyelet boards anyways. They'll become conductive by absorbing moisture. I will try my best to match the wire type and dress of an original example. I use parts that are the closest in appearance and construction.
As far as "Soul" goes, it's in the transformers. The amp has to be running at the right voltage and has to have the right size and reflected impedance output transformer. Original construction methods are important too.
We don't know how good we have it today with manufacturers like Classic Tone, Jupiter, Sozo, Weber, Mojotone, etc. You can build, repair or restore just about any old amp now.
That's the one that I would want.
It would be easier to relax when I took it out.
I was just about to correct you, since there was no master vol... but I see your title has the correct year
The homemade baffle guy most likely didn't figure on the magnet hitting the power trans? Or maybe it was fine with whatever was in there before that patriot.Nice amps,have a 67' blackface that's all stock. Probably bury me with it.
I didn't really look at the solder connections, but I bet the power transformer burnt up... There was even smoke exiting from the small reverb transformer lead holes.. the person probably dropped the chassi while working on it causing it to bend.. Could have been the output tubes and changing the bias resistors that caused the problem in the 1st place as it might have been too much current draw... Either way, that thing was a mess.. The chopsticks still amaze me at their effectiveness for diagnosing issue's.. Brad I was wondering if you own a signal tracer? Just curious if you ever use one for checking components...I'm sure you could have fabricated a new speaker baffle (i can't believe the mess in there) and straightened out the speakers.....but in this case it's probably for the best that the owner decided to repair it himself, as I have a feeling there were more issue's that were going to turn up with that amp...
My theory is this amp was dropped on its bottom, bending the tranny inward and probably breaking both output tubes at the same time. I'm trying to imagine a scenario where this could have happened and falling off someone's repair bench makes sense.
As for signal tracing, yes, I have an actual signal tracer I never use. It stays buried, but I have other methods for using my bench amp and an input signal (either guitar or ipod), but I rarely need to bust out that technique.
The PT is original, so it didn't burn up, I don't think, unless they tracked down an EXACT PT replacement, which isn't too likely. Anyway, the amp is operating perfectly now. Shouldn't have any more issues and customer left with my guarantee on that. I fix for free if it comes back in reasonable timeframe.
I know you warrantee your work Brad, I think you have even done a video repairing an amplifier you had done work on before... I wasn't implying any of the work YOU did to the Fender would have fault... but something happened to that amp involving heat, which is never good on components down stream... I asked you about the Tracer as I was thinking of getting one.. but you just answered my thoughts on it.... I probably wouldn't use it either. Thanks for another interesting video, Tom
I knew what you meant, and who knows...you might be right, but it seemed to operate fine on the bench, at least with my test speaker setup.
I'll fix them speakers to sound real good.
I will need a can of 1979 era AquaNet hairspray some Elmers SchooL Glue, Avon Nail Enamel(color match if possible), and a small bottle of Evan Williams Sour Mash Real Bourbon Whiskey (for mojo).
really it works!!!
I am really surprised you did not dig into checking B+ voltages first!. point
A couple of things.
-AMP in the name puts it 1970 or earlier
-AB763 is probably not the circuit on that amp. Fender used up their old lables, If the tube names are right then that was close enough. Internet will help you find the right circuit but you have to compare what you find to what is actually in the amp. here is a good source ampwares.com/amplifiers/fender-silverface-super-reverb/
- Good call on rewiring the power , not many guys do that anymore.
Keep up the good vids!
Looks like they may have intended to have 10" drivers?
FWIW I believe 72 and beyond will have a master volume so that should be a dead giveaway that this is pre 72 at first glance which you later discovered. the ab763 tube chart is baffling. i think this is the equivilent of a partscaster. super reverbs rule btw. mines a 68 i rebuilt from the ground up
I have suspected that as well. Cab may be from an earlier Super. Old cab might have been crushed in a wreck or other mishap. Maybe it fell off a stage?
lol, always fun to speculate the life of a piece of gear. this one looks like it was shot out of a cannon. hope you can bring it to its former glory. after a lot of head scratchin sometimes the best thing to do with a 70s fender is clean up that pile of spagetti. lead dress causes soo many issues on these. its essentially a network of antennas and capacitors that you dont want. and like you said the boards become conductive and the carbon comps retain moisture and pop. i would say those tube sockets were arcing too. good luck with this one man, glad its not on my bench
All good things to look out for, Dave. The money-is-no-object solution would be like you and others have suggested - completely rewire and clean up lead dress, replace old resistors, etc.
Dave Bolden No this is right, after 68 they changed a lot of circuit tweaks but no master volume for a couple years, the AB763 chart was continued in a lot of super Amps.
Amazing how the SovTek 7025 looks exactly like my actual soviet 6N2Ps. Looking at the specs, it's probably the exact same tube, rebranded.
Other than the heater pinout.
Do you actually use the 6n2p tubes in any of your amps? I was looking at them last nite, and pin 9 is a shield, it looks like you would have to rewire the heaters to just pins 4 and 5 to use them....... thus not being able to put 12ax7's in again without rewiring..... Just curious, Tom
I do use them all the time. I only do scratch builds and it is actually (marginally) easier to wire the heaters for them than for ECC83/12AX7. Other than the heater they're pretty much the same tube. The military spec ones are more or less indestructible and very good in terms of noise and microfonics.
Yes I could see their use in such projects, labeled for use, they are cheaper, probably better quality then generic new (12ax7's) tubes..... I just wouldn't move the heater wires on a 12AX7 designed amp to use them.
I definitely wouldn't use them for a vintage amp, and for a PCB amp it would be virtually impossible to do in a way that doesn't look like crap. For DIY stuff it's pretty much perfect. Used to be around 10x cheaper than an ECC83, now becomes more scarce and therefore pricey, not that I care much, I have a stash of them and I only do one or two amps a year these days anyway.
2.7 k, not 4.7 k. And B+ & filament voltages?