My Twin-Amp's Reverb doesn't work...

[JT19]

I just bought a used Twin-Amp (the current incarnation)... and to my dismay the reverb isn't working. When I turn the reverb button, all I get is hiss. The more I turn it up, the more hiss I get. But there is still no reverb.

I checked the connections between the amp and the reverb tank, and everything looked fine.

What other culprits could there be?

I can't live without the reverb.

 

[RomanS]

Check teh tube that drives the reverb tank - migh have gone bad.
Or unmount the tank, and check the thin wires going from the input & output plugs to the transducers - often these wires break exactly at the clip where they are mounted to the transducers.

 

[jazzguitar14]

I had a reverb tank make a ton of noise because of interfearence w/ the speaker magnet... The fix was simply some velcro to hold the tank down...

Sounds like you may have a more serious problem, but this fix worked for me after I checked cables, replaced tubes, and many a headache...

 

[Ringo]

Try another tank

Assuming that the new Twin RI's use the phono plugs for the reverb, I haven't ever looked at one so they might have a different arrangement.

If they do and you have access to another Fender amp with reverb that you know works, put the amps back to back so the cables will reach, swap the cables and see if the Twin works with the other tank, that will tell you if the problem is the tank in the Twin.

First suspect as someone mentioned is the driver tube, then the tank and or cables .

 

[JT19]

If they do and you have access to another Fender amp with reverb that you know works, put the amps back to back so the cables will reach, swap the cables and see if the Twin works with the other tank, that will tell you if the problem is the tank in the Twin.

Duh! I actually have a second Twin, so I will try this when I get home. I didn't even think of using the other Twin to help isolate the problem.

Thanks!

 

[EMan]

There's a few things you can do to aide in trouble shooting this -

As mentioned, try a new tank.
Replace V4 (12AT7) and/or V5 (12AX7).
Replace cables to/from tank.

The reverb tank driver section is an 8 ohm output, and will drive a speaker. this is a way to test the driver side.
The recovery side ought to 'buzz' if you touch the center pin of the cable that is the reverb tank return.

 

[JT19]

I still haven't had a chance to test it at home, but I found a thread on the FDP where someone was having the same symptoms. The culprit turned out to be a broken connection at the input jack on the reverb tank, and re-soldering solved the problem.

I am not handy with a soldering gun, so I will probably just buy a new reverb tank, and eventuallly I'll get someone to fix the other one so that I can have a spare.

I went to the Accutronics site, but was easy confused by all of the specs that you need to know in order to create the part number for a replacement. Does anyone know what the part code would be for a direct replacement (I have the current version of the Twin-Amp)?

Also, the site says that a style 9 tank is more lush sounding than a style 4... but they recommend it for sound reinforcement or pedal steel, etc. No mention of guitar. A lusher reverb intrigues me, though. Anyone tried a style 9 in a guitar amp? I'd be willing to pay extra to get a really rich reverb sound, but I'm hesitant because there must be a reason why they don't mention electric guitar amps as an application for that particular style tank.

 

[0le FUZZY]

...Make sure the rite plug iss inna rite hole.

...The tube kin be the prollem fer sure .

...Most of the time for me its been jes behind the RC jack where the cable bends sharp and a rite angle connector solved the prollem.

...Yes dew plug that reverb tank into yer udder Twin and check it.

...Lettus noe watt chew fine out.

...OH! and yes I haff repaired a transducer connection and I dew knott reccomend it iffin yew aren't really skilled with solderin tiny wires.



(image removed)

(deranged internet-based alter ego, with my own lexicon and all.)

Please visit my page

 

[Oster]

The reverb on my old Traynor Mark Three (similar to a twin) wasn't working. I was told that often the connections simply need cleaning.

Sure enough, after I cleaned the RCA jacks/connectors to and from the tank, the Reverb sprang to life (use Contact Cleaner & a few Q-Tips).

Could work for you, too.

 

[EMan]

There's a couple of critical items concerning a tank. One is that the input and output impedance of the tank has to match the amp, the other is the mounting...vertical or horizontal.

If the tank in this amp is an Accutronics, it will have an alphabet soup model number on it. You can decode these letters/numbers at the Accutronics website.

The -9 tank has an extra set of springs in it for that lush-er.sound.

One final note on tanks...they really need those cardboard spacers on the bottom. New tanks do not come with these spacers. If your old tank still has it's, re-use it. If not, you can get one from Uncle Spot, or...as in my case (a cheapskate), I made one out of some cardboard strips and elmers glue.

 

[jeffM]

no man that type '9' will wash out very quickly - it is way too much - stick with the type 4 tank also Antique Radio or Hoffman Amps sell the accutronics tanks at a good price. First, try out the 'good tank' from the Twin that reverb works on the "no verb Twin" may be tubes, or cables as suggested in other replies. G'luck !!!

 

[JohnnyCrash]

It's very probably a bum tube.

This kinda thread pops up once a month or so, so do a search here.

Do you know which tubes are for the Reverb? Buy a few new ones and replace them. Even if it's not a bum tube, you'll need backups anyways, so it's always a good idea to buy backups anyways.

Once you've eliminated the tube, you can then focus on the stuff you may need to solder, or a new tank...

 

[blue metalflake]

If its the transducer wires, its easy fixed if you can get someone who is used to fine wire work.

Seems over the top to consider a new tank, if this is your only problem.

 

[JT19]

One final note on tanks...they really need those cardboard spacers on the bottom. New tanks do not come with these spacers.

The new Twin (the one with the reverb problem) definitely has one... so it's likely that the previous owner put on in there. So I'm set for that amp. I will check my other Twin, too, to see if it has one. Thanks for the suggestion.

no man that type '9' will wash out very quickly - it is way too much - stick with the type 4 tank also Antique Radio or Hoffman Amps sell the accutronics tanks at a good price.

Thanks... I think I'll stick with the type 4. I figurred there must be a reason why the type 9 tank wasn't recommended for guitar amps.

Do you know which tubes are for the Reverb? Buy a few new ones and replace them. Even if it's not a bum tube, you'll need backups anyways, so it's always a good idea to buy backups anyways.

I don't know which tube is for the reverb, but I think I've seen a list somewhere--either on the sticker on the inside of the cab or in the manual.

I will definitely get some spare tubes, regardless of whether that ends up being the issue here or not. Good advice.

I'll start with connecting the other Twin's tank to the jacks on this one and seeing if I get the same results. If not, it'll obviously be an issue with the tank. If so, I'll hope that a bum tube is the problem.

At the risk of sounding totally ignorant (which I am when it comes to tubes), can you tell whether a tube is good or not by looking at it (like you can with a light bulb--by seeing the broken filament), or only by testing it?

 

[Big White Tele]

Is this a 65 RI Twin Or a Pro Tube Twin with the gain channells?

 

[JT19]

Is this a 65 RI Twin Or a Pro Tube Twin with the gain channells?

The one with the issue is the current Pro Tube Twin-Amp with one-input, 2-channels, and tremolo.

My other twin (the one with the working reverb) is the previous incarnation--the Professional Tube Twin-Amp that I believe is also known as the Evil Twin. 2 channels, plus an additional "yellow" gain switch on the clean channel. No temolo. Instead it has a "Mix" knob to blend in the effects loop. Still has the blackface cosmetics... it's not the red-knob "The Twin" amp.

 

[JT19]

Well, I hooked the other Twin's reverb tank up and it worked fine... so it was obvuously not a tube issue. I took the reverb tank out again, and this time I looked closer at the solder joints for the input jack of the tank. Sure enough, one of the joints was bad.

I'll get somebody to fix it for me eventually and make that a spare... in the meantime, I'll just pick up a new reverb tank.

Thanks for all the suggestions.

 

[agraebner]

your other twin with the "vintage"channel is a model 94 twin I have the same amp. I replaced the tank and tubes in mine still no verb a local "repairman" counldnt find the prob on it I also replaced the transformer for it. The recovery works fine touch the tank you hear the verb. Just no driver circuit anyone know what voltafes are supposed to be at which pins for the driver tube so I can track it further. I really would rather just drop it off at a repairman but the two around me are jokes. The one real fender dealer says it could take months to get too it.........

 

[Clive Hugh]

I have The Twin and it has blown the reverb transformer 3 times, it's a small one and not very expensive.