Vintage Fender Twin Reverb issues

[emaccarthy]

My dad has an old pre-cbs Fender Twin Reverb combo he is trying to fix up and sell. It is in great condition but has not been used in many years. We took it out, plugged it in and found a few issues. The clean channel sounds full and clear but the reverb/vibrato channel is really quiet and the reverb and effect knobs do not seem to do anything. Any ideas as to what repairs are needed? Maybe power tubes are shot?....

 

[the guy who invented fire]

Re: Vintage Fender Twin Reverb issues

Please don't take this the wrong way but I can tell simply by reading your post that you and your father have no clue about the inner workings of a tube amp and with that in mind I HIGHLY suggest taking the amp to a pro.

However, I have a STRONG feeling that you are dead set on trying something at home on your own so...preamp tubes are step one!

If the normal channel works then the power tubes are fine...start with preamp tubes for the effects channel and see what happens.

 

[emaccarthy]

Re: Vintage Fender Twin Reverb issues

Thats a good idea thanks. We both have a modest amount of tube amp knowledge but at the same time have no time or expertise to seriously dive into the back of the thing. I was just thinking of getting a good idea as to how much it might cost and what to tell our local guitar shop to look into. Thats all

 

[the guy who invented fire]

Re: Vintage Fender Twin Reverb issues

Thats a good idea thanks. We both have a modest amount of tube amp knowledge but at the same time have no time or expertise to seriously dive into the back of the thing. I was just thinking of getting a good idea as to how much it might cost and what to tell our local guitar shop to look into. Thats all

No offense but with a modest amount of tube amp knowledge you'd know it can't be the power tubes...I'm just saying this is not something to be taken lightly.

Don't take the amp to just a guitar shop, find a good tube tech and let them do the trouble shooting.

Cost will vary...if it's something very simple it won't be much, maybe even just the cost of a tube or 2 and a bench fee...if it's complex up to several hundred dollars...

Also worth keeping in mind, an amp of that age even in "working order" might need some work anyway...general cleaning, cap job, tune up, etc...

If you want to get started try the premap tubes associated with the reverb channel of the amp and see what happens...

 

[Stratman]

Re: Vintage Fender Twin Reverb issues

Check the preamp tubes in this order...

V2 = 7025 (For best tone), 12AX7 (will work)

V3 = 12AT7 (You might want to also try a Mullard CV4024 to tame the reverb)​

V4 = 7025 (For best tone), 12AX7 (will work)
V5 = 12AX7

 

[zzmoore]

Re: Vintage Fender Twin Reverb issues

A "real" BF Twin is a fairly valuable amp.
You need a decent tech.
Where do you live.?
best

 

[Chickenwings]

Re: Vintage Fender Twin Reverb issues

http://fenderguru.com/amps/twin-reverb
Nice amp when its working correctly. Sounds like it needs (at least) new preamp tubes for your vibrato channel..but the problems might equally be found elsewhere. Take it to a tech for a once over.

 

[Funkfingers]

Re: Vintage Fender Twin Reverb issues

I would begin by making basic visual checks to see that what is supposed to be present really IS present.

Count the valves (tubes). Compare what you find to the types suggested by the white label on the inside of the amplifier cabinet.

Check that the reverb spring tray is connected. There should be two cables and they need to be in the right order. Shaking the amplifier is usually enough to get a loud spring rattling sound through the loudspeakers.

The opto thingamabob in the Vibrato circuit is a candidate for failure - especially after forty five years!

+1 for having the amplifier serviced professionally. Firstly, the job should be done safely and to a high standard. Secondly, a well-connected amp tech can probably bring your refurbished amplifier to the attention of possible buyers in your area.

 

[SlyFoxx]

Re: Vintage Fender Twin Reverb issues

Before visiting a tech I'd check the tubes and clean the tube sockets and all jacks including the jacks on the reverb pan and the reverb wires plugs. Pull the amp out of the cabinet and clean the cab well and blow out all the dust bunnies. Check your tube pins. Are they cruddy? Are the speakers caked in dust? After all this you might find that the amp works and looks well enough to sell. Consider letting the buyer eat the tech's fees for further work as you'll have to charge more for the amp if you get it fine tuned.