Fender Reverb Feedback

[lespaulnmarshall]

Hi All,

New user here!
I recently converted my beloved Bandmaster Reverb into a Vibroclone. The amp has always had a little issue with the reverb feedbacking at high levels. The feedback starts from 6 or 7 up to 10 on the reverb control. I've replaced the tank already. When I got it it had a TAD 9AB3C1B which I changed to a TAD 4AB3C1B. Unfortunately it has the issue with both tanks. It did it as a head, and it still does it now as a combo (hasn't gotten any worse in the vibroverb cab). If I remove the tank from the combo, the feedback goes away, when I put it back in, it comes back. The amp already has the 2000pf cap installed at the RCA jacks to reduce feedback and noise. I've tried various positions of the tank inside the cab, I've messed with how tightly the tank is screwed down and I've wrapped it with various materials, added rubber washers under the screws, added weather stripping on the tank itself etc.. nothing seems to solve the issue. Does anyone have any ideas what I should be trying next?

Thanks!

[lespaulnmarshall]

Problem sorted! For anyone wondering, this last batch of tanks from TAD seems to have this issue apparently... Both my TAD tanks seem to do this (with this amp and other amps as well) but my Accutronics and whatever is in my Super Reverb (not sure, too lazy to check ) are problem free! I now have a new Accutronics tank on the way!

[norburybrook]

Problem sorted! For anyone wondering, this last batch of tanks from TAD seems to have this issue apparently... Both my TAD tanks seem to do this (with this amp and other amps as well) but my Accutronics and whatever is in my Super Reverb (not sure, too lazy to check ) are problem free! I now have a new Accutronics tank on the way!

Funnily enough I had exactly the same issue on my Princeton build. It drove me nut's I swapped out the tank and all was well.



M

[lespaulnmarshall]

Problem sorted! For anyone wondering, this last batch of tanks from TAD seems to have this issue apparently... Both my TAD tanks seem to do this (with this amp and other amps as well) but my Accutronics and whatever is in my Super Reverb (not sure, too lazy to check ) are problem free! I now have a new Accutronics tank on the way!

Funnily enough I had exactly the same issue on my Princeton build. It drove me nut's I swapped out the tank and all was well.



M

Interestingly enough, the new tank I ordered does it too. I know it's really the tank though. NOS US made Accutronics work without issues somehow...

[pompeiisneaks]

There's a tech I see on facebook, Lyle Caldwell, that has ranted on about the absolutely horrid quality of every single new manufactured tanks out there. every brand he tested were garbage...

someone needs to step up the game.

~Phil

[norburybrook]

the one I ended up with in my Princeton sounds great, as good as my vintage fender ones. Can't remember what it is/was now.


I had an old acusonics US one for my Princeton but it was the wrong independence so had to buy a new one.



M

[Stevem]

Many new and old tanks have the wire coils too loose on the iron core/ transducer Assy!

This makes you have to turn up the reverb more then needed and the combo this and the core vibrating makes for the feedback.

If you shave down a Tooth pick and super glue it into the gap of the iron laminate core and coil this issue will be gone and you will have the added plus of a better stringer sounding reverb that has a faster attack.

[norburybrook]

Many new and old tanks have the wire coils too loose on the iron core/ transducer Assy!

This makes you have to turn up the reverb more then needed and the combo this and the core vibrating makes for the feedback.

If you shave down a Tooth pick and super glue it into the gap of the iron laminate core and coil this issue will be gone and you will have the added plus of a better stringer sounding reverb that has a faster attack.

Steve could you draw a diagram to show what you mean?


M

[sluckey]

Does this help? I would try it without glue first. If it helps then I'd just put a small drop of your favorite fingernail polish to cement in place.

[pompeiisneaks]

Does this help? I would try it without glue first. If it helps then I'd just put a small drop of your favorite fingernail polish to cement in place.

What's your favorite color sluckey?

~Phil

[sluckey]

I used to like fucia but now I prefer Twilight Black.

[lespaulnmarshall]

I used to like fucia but now I prefer Twilight Black.

We all know vintage purple nail polish gives the very best tone!

Thanks for the toothpick advice, I'll definitely try that one of these days!! Will report back after!!

[norburybrook]

I used to like fucia but now I prefer Twilight Black.

We all know vintage purple nail polish gives the very best tone!

Thanks for the toothpick advice, I'll definitely try that one of these days!! Will report back after!!

I still have the old tank that gave me issues so as I've some time on my hands I'm going to give this a go as well


I shall report back at some point.

Great thread by the way, very useful knowledge being shared here. Could have saved me hours , hopefully it will help others,

M

[Stevem]

The other thing a do to all the tanks that I rebuild is to place a good size blob of silicone bath Tub sealer on the coil where the wires enter it since many times from hard usage and age they will snap off there, but I also place a dab of the sealer at the folded over wire strainer near each RCA jack to reduce the travel vibrations from snapping the wires off at that jack which takes place. Bunch also, once again the color of the sealer you use is whatever floats your Boat!

On a side note as I posted if you have a vintage tank that has a busted spring or 2 I can fix these so you don't have to chuck them.

[Timmmmmm]

Amazing thread- this fixed my problem!
On one side the coil slid freely along the laminated magnet, on the other it appeared to be fixed (glued?)

A tiny toothpick sliver helped to immobilize the loose coil, and a dab of hot glue secured it for ages to come.

Now I can dial up the reverb and volume to 10 without the tank feeding back, many thanks!