Noisy ol Deluxe reverb

[Valvehead]

Ive got a 66 DR here...owner wanted it re-capped , cleaned, re-tubed , etc...

Ive replaced every cap in the amp , the resistors above the 6v6 sockets and plate resistors. Verified all grounds
.
Ive been chasing crazy noises and a low freq hum today. Whooshing , ocean noises ..odd radio signal frequencies , random cliks and pops.....static on and off....

I went through it with cold spray and i dont hear anything change when hitting each component.

I will try swapping out all the new tubes tonight .

I read somewhere that if these old fiber boards get warped they can cause all kinds of crazy noises.......exactly what i have.....and yes ..the boards in this are very , very warped .

Think this might be the problem ??

[Leo_Gnardo]

It's not so much the warped, it's conductivity in the circuit boards. And every summer in the US, well heck, anywhere, it seems humidity makes it worse. A MUCH DISCUSSED TOPIC on these pages! The boards are black, because they're loaded with carbon black to make them look that way. And carbon - - - is conductive. Not as much as metals, but enough to raise hob with old Fenders, and even brand new kit builds that use this material. Ask Randall...

Enzo sez, shoot hot air from a hair dryer or heat gun onto the board, might help out. Sometimes yes, sometimes not so much.

What I do, is move the sensitive portions of the audio circuit onto tie strips. Looks a little messy but solves the problem at a reasonable price. If the amp's owner has deep pockets & a willingness to spend on a permanent solution, you can rip out the offending circus boards & replace with a point to point board made of epoxy-fiberglass or some other material that won't conduct at random. One source is Doug Hoffman in North Carolina - he was one of the first to offer these back in the early 90's. Probably a dozen or more other sources across the USA and I'm sure in other parts of the world. Doug might even point out who - you oughta contact him if this solution is in the amp's future.

[Chuck H]

This^^^^^^^^^^^^^^^

And... Why did you replace all the caps? It's predominantly the electrolytic caps that fail with age. Some posts by our local Randall have revealed a great deal more film cap failures than we're use to seeing, but they should still be tested before being arbitrarily replaced. I guess my point is, if you didn't test something and find it in need of replacement, why did you replace it? It's true enough that seasonal humidity can cause problems with old, black paper circuit boards. But in my experience too much soldering and resoldering can solidify conductive pathways that can no longer be mitigated by drying out. In this light the arbitrary replacement of parts, that seems to be VERY common on vintage amps, can be of tremendous detriment. Creating a situation where the only solution is to tank everything you've already done and replace the entire circuit board (as Leo mentioned). Because I do modifications I've seen this on a number of black paper boards. And I've replaced all of them with boards I've had to make myself. There's a chance you could have saved yourself the trouble if you hadn't done any unnecessary soldering, but it's too late for that now. Now you may be in the same boat I've found myself in on so many occasions. I hope not. The good news is that there IS a solution. Troublesome as it might be.

[Valvehead]

the amp made all that noise before i evened opened it. Replaced caps because the owner wanted all NEW caps. Im saving all the old parts for him .

i was looking at the Mojo boards. I wonder if they are made from a different/ better material than the factory ?

https://www.mojotone.com/amp-parts/F...-with-Reverb_2

[SoulFetish]

Couple of things to check:
- The 820Ω feedback resistor. Sometime this warped boards can stress the solder joints and leads. pull it off the board to give it a little strain relief.
- The coupling caps. I've chased noises around in circles in some of these old fenders. Visually checking all the solder joints on the board, and they look find upon visual inspection only to have one of the cap leads pull right out leaving a pin sized hole in the solder where the lead was.

[Leo_Gnardo]

i was looking at the Mojo boards. I wonder if they are made from a different/ better material than the factory ?

No, they most emphatically are not! Randall, please step up and tell the man! Valvehead, prepare yourself for a sad tale of woe and intrigue.

Of course, if you don't want to take good advice, prepare to relive the experience. What we try to do here - and sometimes actually manage to accomplish - is to learn from other people's mistakes. Saves a lot of grief. And wasted time.

[SoulFetish]

the amp made all that noise before i evened opened it. Replaced caps because the owner wanted all NEW caps. Im saving all the old parts for him .

i was looking at the Mojo boards. I wonder if they are made from a different/ better material than the factory ?

https://www.mojotone.com/amp-parts/F...-with-Reverb_2

So, you replaced all the film caps?

[Chuck H]

Well it's easy to see if a conductive board may be responsible. First, hit it with a hair dryer for about a half hour. Just find something to do while you're at it and keep waving the hair dryer across the board (headphones help ). Then poke your red probe into the board near high voltage eyelets that are in proximity to signal eyelets. If you read significant voltages you're in for it. If you don't...

Have you cleaned all the contacts yet? Tube sockets, pots and jacks? The amp is OLD and everything gets dirty or oxidized given enough time.

[SoulFetish]

another thing I've also seen which is more rare, but can still cause problems is a faulty reverb transformer.

[Valvehead]

all caps.

any joints i didnt use i re-flowed. No change in noise

the noises are without the rev tank plugged in and rev pot on 0 ....if that matters. I do have a fender reverb transformer around here somewhere

[Valvehead]

No, they most emphatically are not! Randall, please step up and tell the man! Valvehead, prepare yourself for a sad tale of woe and intrigue.

Of course, if you don't want to take good advice, prepare to relive the experience. What we try to do here - and sometimes actually manage to accomplish - is to learn from other people's mistakes. Saves a lot of grief. And wasted time.

ok - thanks !!

[Valvehead]

Well it's easy to see if a conductive board may be responsible. First, hit it with a hair dryer for about a half hour. Just find something to do while you're at it and keep waving the hair dryer across the board (headphones help ). Then poke your red probe into the board near high voltage eyelets that are in proximity to signal eyelets. If you read significant voltages you're in for it. If you don't...

Have you cleaned all the contacts yet? Tube sockets, pots and jacks? The amp is OLD and everything gets dirty or oxidized given enough time.

yes all sockets/ jacks/ pots. There are 2 pots that are still scratchy,,after several attempts. Both Volumes

[Chuck H]

yes all sockets/ jacks/ pots. There are 2 pots that are still scratchy,,after several attempts. Both Volumes

Test for DC on those pots. Maybe the pots are scratchy, but maybe there's voltage on them causing the noise. Maybe it's the board. Maybe a hair dryer will help, maybe not. Maybe it's the coupling caps. Just because a part is new doesn't always mean it works.

[SoulFetish]

yes all sockets/ jacks/ pots. There are 2 pots that are still scratchy,,after several attempts. Both Volumes

checked all the ground lead connections to the brass L bracket? I should have mentioned that in the "common problems" post.

[Valvehead]

Test for DC on those pots. Maybe the pots are scratchy, but maybe there's voltage on them causing the noise. Maybe it's the board. Maybe a hair dryer will help, maybe not. Maybe it's the coupling caps. Just because a part is new doesn't always mean it works.

ill try the hair dryer thing.

i do have 2vdc at the outside lug of the volume on the vibrato ch.