How to repair Ampeg Reverb Tube guitar amp no output d-lab electronics
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- čas přidán 23. 09. 2018
- Reissue Ampeg Reverb Rocket in need of repair. Came to the shop, no output. Owner had replaced the output tubes 6L6. Still nothing. I suspected loss of screen voltage. Normally, I do not like to work PCB based amps, however this was the first of this model that has came my way, so what the heck. Well, it turned out to be a minor repair. Simply a open screen power supply feed resistor and a few cracked solder joints. The amp is working fine now with minimum cost. As an upgrade, I installed a nice glass jewel lamp rather than the melted cheap stock plastic one. Fun project! Hey all, I have a new website, search for D-labelectronics.com. Just launched it, so there may be a delay before it appears. I plan to give sneak peaks of new projects. This site is hosted by Reverb.com. Hey everyone, check out Paul McCartneys new CD release! Great stuff..
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Good for you, never stop being afraid of electricity, it's a sign of good sense.
That was impressively smart that you checked more after finding the initial problem, and found out there was another issue. Saved you a lot of time. Experience is great and thanks for sharing it so we all don’t have to learn the hard way. I will definitely remember that it’s dumb to assume there is only one failure. Thanks!
I've had repairs like this come back with the same power resistor open. It's a good idea to check the current and calculate the power dissipation. See if there's a reason the power resistor failed. Otherwise the amp will just keep coming back to the shop after a few weeks use. I learned that lesson the hard way.
Great root cause analysis and technique , Love it.Becoming a lost art !
I've been watching you for a while now, I appreciate the videos, the knowledge and the servicing info on electronics. I'm just getting back into electronics since 5 years now. God bless.
That was nice content, and a relatively quick fix. Loved the addition of the new power lamp. Thanks, Terry! Thumbs up!
Amped Rockets are kick @as amps, great repair Terry!
It's rare to see tubes and those damn ribbon cables in the same chassis.
Thanks again,I purchased the same amp back in 1996 in Salisbury Maryland in Thompson store wish is B&B Salisbury and once I got it back from a stolen never worked again and this tip's of yours may be I'll be able to make it work again.
Thanks for another great video! Bought the tickets for his show in Poland in December, can't wait to see him live for the first time.
Ram's always been my favourite, I'm definitely going to follow your advice (as well as SO many others!)... Thanks again for your videos and all the knowledge and humour shared! Cheers Terry!
Laurent
Easy fix, nice repair tips on how not to screw pots. Thanks for sharing
Hey Mr D! Great vid as ever. Thanks for the Paul McCartney recommendation too.
Am in the process of designing my own tube amp, fun side project - pick and choosing things I do and don't like. But I really love the little extras you do like adding the replaceable jewel lamp! So simple, adds a lot to the aesthetic and would never cross my mind!
Long live the mighty snozoramus (sp?)!!
I actually sold a 1960s Ampeg jet J12 d, the later version with 7591 tubes, to a recording engineer who worked on John Hiatt's "Little Head" recording. he told me they were using a reissue Ampeg for some of the songs, but it sounded a little bit buzzy, especially for slide, however, he figured out a microphone placement technique that help them get a good sound out of the amp. I should have asked him if that was the amp and mic technique they used for the slide guitar solo on Hiatt's song Woman Sawed In Half, which is one of the strangest and best songs on the record.
Watching you work is like reading a Sherlock Holmes novel!😂😁
I would love to have this amp switched over to a point to point circuit. I is a great sounding amp but when I had one in about 2004 it only lasted maybe 10 gigs before I was having problems with solder joints cracking and causing issues. I went back to my 1968 super reverb and 100 watt Twin Amp for shows. But I really liked the tone of that reverb rocket. I liked that Twin amp too but it literally weighed 88 pounds and I would have to actually sit on it and ride it’s casters down the sidewalk on my way to the clubs. It was loud as shit and HEAVY!
Terry your the best I'm really excited to pick it up!
Great video Terry! Amateur electronics tinkerer with a love for analogue circuits. Sincerely appreciate your videos!
These are great amps in general. They went through several iterations, but the ones that sound and hold up the best are the “Made in USA” ones with 6L6 output tubes. Just a tip for the owners here, put an eq pedal in effects loop and season to taste. This makes the lead channel much more usable. These also had an upgraded jewel light like you installed, but with a blue lens.
I have this amp I just purchased mine has el34 tubes in it I don't know if that's original or if they were changed I don't know if that's even possible?
Nice job Terry. I bought one of these new in the late 90's. I absolutely loved it. Beautifully fat and warm. Then it was stolen :(
Great video-I have a similar problem and really great detail on how you traced the signal loss back!
Nicely done!
Você trabalha muito bem colega....Parabéns.........as vezes simplesmente refazendo a solda se resolve o problema...!!!! É isso ai.......
A good lesson as always !
Nice Reissue with Opamamps and DSP....
Here are a few footnotes I would add. Whenever you find a burnt-out resistor always figure out what caused it to burn out. If you don't, the new one may also burn out in a short amount of time and you are having to redo the repair. looking at the schematic the main thing I see that would cause the failure would be one of the original 6L6 power tubes shorted. This is the most likely cause of the failure. C23 could be going bad but is less likely to be the cause of failure. I would advise the customer to get rid of the old 6l6 tubes. Second I would be careful about putting the jumpered resistor on top of the amp since power resistors get hot and could damage the amp covering. I know it was only for a very short time and no damage was done but I would not do it. Putting WD 40 on the control shafts may help to put the knobs on but after a few years when the WD 40 has dried out, it could make the knobs impossible to remove.
Re issues should be made like the originals, I'm on the look out for a vintage Ampeg
Nice amp, nice job sir.
Thanks Terry.
Love your videos!
Nice vid!! It looks identicall to a hot rod deluxe
Hey Terry :-)
there was some great tone from the old GVT series, I know they had a special EQ and some sonic thing, and sure the darn circuit board... but if they only had built it properly, ( Point to point),it could've been great also.
Great content!
Great job, buy miss “”d” lab a nice glass of Sangria!
Am I seeing things? At 1:08 when Terry turns off the standby there is a large spark under the guitar input jacks.
i like loopy Dlab... i actually had the same amp... here's the thing... a lot of amps are Circus board.. my guy doesnt like working on them either... so i found a guy who does...
Must have been a night of Ampeg repairs. I worked on a pristine VT22 tonight from around 1976. Customer said it had no power and really nasty distortion even after a total re-tube by him. Pulled the chassis and put it on the scope, sure enough a horrible looking wave form with about 8vrms. I'm thinking a bad screen resistor or a bias issue or phase inverter tube. Everything checked out perfect resistance wise and voltage wise, checked all the tubes on my 539C Hmmm??? while looking over the PCB and some nice re-capping from a previous tech I found a bent terminal on the impedance switch grounding out against the one opposite when it should have no connection on that terminal. Sure enough, bent it out of the way and bam!! 112 watts clean out of those 4 7027A's. Looks like the previous tech might have pulled on a lead and bent the terminal over or something. Must have been ok for a while but cab vibration and or transporting made it short. Too bad the last guy didn't replace the caps with the original can type since this amp looks like it just came off the showroom floor. If it was a beater not an issue to cut a few bucks off the cap job but this thing was cherry. Oh well, works like it should with no issues. That's what it's all about.
When did they start using ribbon connectors of reverb o rockets. Had a 66 model I don't recall any in any old amp and I had a bunch of them. I missing something??
Nevermind just arrived at it is a repro. To quick on the thought
Terry I have a suggestion when recapping an old amp I think we as viewers need help in types and values of some common caps on common tubes circuits because we are not experts on types can't always read values I have learned ebay is a place where one can buy caps ty
Nice!!
That's a good sine (sign).
So, it looks like you changed the color of the lamp jewel from blue to red. While not functionally a problem, how do most customers feel about that kind of thing? #aesthetics
Can you tell more about the E6000? Is it non conductive? Why is it your go to? Also this is the second video I’ve seen with Ampeg Reverbrocket power light being bad or looking bad. Is that a known problem?
😎👍
I wonder what caused the resistor to go bad?
No rebias? Are these cathode bias? What would be the proper setting/reading, 35mA?
Ever get a jolt from metering and having hold of that standby switch when it's open?
Hey there, could you kindly point me in the right direction, my amp is a reverberocket r12r reissue, reverb does not kick on 1-3 on dial. Weak until 7 1/2. 8-10 got reverb. New yank just installed. No change, changed 3rd preamp tube. No change. So I'm wondering what I should be looking at, failing rca could be culprit but it's a rca into tank and quick disconnect to board. I'm having trouble making that. Is this reverb circuit capacitor driven or tube? Bad capacitors? I'm so lost here man. And greatly could use your help. I do realize this is a older post. Hope you see this..thanks. randy
I purchased a Ampeg reverb a rocket in 1963 I still have it. It needs some work on it never been touched I’m in Troy Michigan would you help me out. The tremolo does not work. And then if you shut the amp off at the power toggle switch it makes a loud crack sound through the speakers. Still has all the original tubes and capacitors. Thanks
Hello, sounds like some great issues to fix. Any chance you will be coming by Battle Creek in the future? My guess, new caps, clean up connections, pots, etc.
I have a Reverbojet...any chance we could do something long distance? I'm in Texas, no longer near any amp techs.
I’m saddened (but not surprised) about the cheesy construction of these reissue amps. Not knocking any particular brand, just in general -- But they do look nice.
Super Het, it doesn't seem too much matter what the brand is, from Ampeg to Crate to Fender, if they have printed circuit boards, they suck!!!!! The crappy build quality equals poor reliability, and they suck to work on, even for simple problems like replacing a bed resistor or resoldering a broken input jack connection. Nearly all of these reissue amplifiers require you to completely unbolt all the pots in order to remove the board to get to the backside of it ( the foil side, typically). Undersized, hot running resistors and diodes cause their own solder joints to dry out, crack and fail ( lead-free solder is particularly failure prone); and the heat dries out the capacitors (invariably, cheap quaility miniature caps that won't tolerate long-term exposure to high heat) that are often mounted right next to and nearly touching the hot running components. Tube sockets are being soldered directly to the circuit board; the expansion and contraction from the heat of the tubes will cause those solder joints to break down..... and besides which, tube pins are supposed to float inside the socket assembly a little bit so that they can better self align to the tube pins which might be slightly bent or not arrayed in a perfect semicircle, and which might not be exactly the proper size wire stock either, but the circuit board holds tube socket contacts rigidly in place! Pots with plastic shafts, those can be easily sheared off, and the interface of knob to shaft ought to be of the set screw type and not splined. And all those plug-in connectors and ribbon cables, uggh; even in a solid-state amp with far less self-generated heat those plug-in connections tend to tarnish and oxidized and become intermittent. Speaking of connections that oxidize, small relays are being used to switch channels or turn on Distortion and effects (I saw one on the PCB of this amp); how long do you think those relays will last before the contacts become intermittent? (Most older equipment has relays that can be opened up for cleaning but miniature sealed relays are almost impossible to cut open without damaging the contacts). The heat of a tube amp will also cause the metal plug- in contacts to prematurely tarnish and oxidize, and if the molded plastic that holds the connector pins in proper alignment shows any signs of discoloration from heat, it will probably outgas something that causes the metal pins to oxidize and corrode even more quickly then you would expect. And then there's those globs of glue holding components to the board, if it's hot glue than it doesn't hold very well or softens and flows with time, and some of the rubbery tan or yellowish Brown glues become conductive and corrosive with exposure to heat. The worst case scenario is when the circuit boards are double sided, having solder connections on both sides. Good luck fixing such amplifiers yourselves, even swapping out a few simple parts becomes a major hassle unless you have vacuum operated solder sucking equipment. In short, Friends Don't Let Friends Buy Mass-Produced Reissue Amplifiers!
Super Het, it would of course be possible to build tube amps with circuit boards and make them more reliable without increasing the manufacturing cost excessively. it's not that it can't be done, it's just that whoever designs and builds these amps doesn't care to do it right and in a manner that will increase reliability and Longevity and make it possible for people to actually fix them if they break. if you gave me any amp that has a circuit board type construction, I could tell you in minutes what they should change to make it reliable and more easily serviceable. Any decent technician could tell them the same.
@@goodun6081 Manufactured electronics in general (along with a broad variety of other products) are not designed to last. That business model was abandoned some 40+ years ago. They are also not designed to make service easy; nor do the manufacturers want anyone fixing their products. They would rather you buy another one. The modern model is to dazzle the consumer with features that are not needed (and rarely used) at a cheap price with an outrageous markup (That the customer is unaware of) in attempt to convince them that this is a great deal for the money.
That looks a little easier for a circus board amp
New subscriber ... Did I win anything ? Lol ... Good fix ...
Any idea if the plastic in those pots reacts to WD-40? I tried to look up what kind of plastic is in those and the data sheet said Conductive Plastic. I've heard that Wd-40 is corrosive to certain plastics, but I wasn't able to find anything conclusive....
No WD 40 is fish oil . It wont harm paint or plastics
i wished i had watched this before and used the ever popular WD-40 LOL, i busted one of the pots of my marshall amp trying to take it off.
There's also a "fork" tool that helps to pull evenly on these.
molson12oz, try cleaning the faceplate with Never Dull, it's the only thing we have found that you can use on really early McIntosh Hi-Fi equipment that won't remove the silk screening (Windex will take it off in a heartbeat, we found that out the hard way). Of course, be very careful the first time you try it on any amp chassis...
Anyone know the value of that amp ? I have one but cant find info
I love your videos, they are some of the best! But your titles are insanely wordy... You don't need to put "d-lab electronics" in every video title - the title is always shown next to your channel name. Also, you can use tags, so less words in the title, more information about the video in tags.
Hello, Thanks for the tip, I will reduce the titles
@@d-labelectronics Your videos really are awesome! So much great info :)
I would love to be your apprentice andwork for free
Awesome videos by D Lab electronics
VA6RDR
the video image is too poor, you need to fix it more