Twin Reverb Noise Issue Need Some Advice

Sp8ctre

Sp8ctre

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So the new Twin sounds great, but it has the motorboating sound and it increases speed with Reverb Speed Control.

I'm attaching an audio file. This is with no input to the amp and I am varying the Speed. At the end of the clip I am
also lowering the Master Volume. At the beginning Master Volume is at 10.
 

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Sp8ctre said:
So the new Twin sounds great, but it has the motorboating sound and it increases speed with Reverb Speed Control.

I'm attaching an audio file. This is with no input to the amp and I am varying the Speed. At the end of the clip I am
also lowering the Master Volume. At the beginning Master Volume is at 10.
Click to expand...

The vibrato is a neon light bulb and a photo-resistor.
The speed control is for the vibrato, not the reverb.
It could just as likely be the photo resistor, but first you should be testing not replacing.
If it was a coupling cap,
It would be a coupling capacitor, not a filter capacitor.
And that coupling cap would be in the tremolo circuit.

Not all the caps.
Don't usually replace all the caps, just the one that's bad. "If" it's bad.

Trying to fix the amp by random replacement is not recommended. It's a bad habit.
and blaming any problems on capacitors is also a bad habit.

The old coupling caps have a certain sound, and you really shouldn't change them all at once.

You might try changing pre amp tubes one at a time with a new one...and then re-test each time. It might be a tube...
 
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Amp Mad Scientist said:
The vibrato is a neon light bulb and a photo-resistor.
The speed control is for the vibrato, not the reverb.
It could just as likely be the photo resistor, but first you should be testing not replacing.
If it was a coupling cap,
It would be a coupling capacitor, not a filter capacitor.
And that coupling cap would be in the tremolo circuit.

Not all the caps.
Don't usually replace all the caps, just the one that's bad. "If" it's bad.

Trying to fix the amp by random replacement is not recommended. It's a bad habit.
and blaming any problems on capacitors is also a bad habit.

The old coupling caps have a certain sound, and you really shouldn't change them all at once.

You might try changing pre amp tubes one at a time with a new one...and then re-test each time. It might be a tube...
Click to expand...

Sounds like great advice. Did you listen to the sound clip?
 
Far Rider said:
Filter caps problem?
Click to expand...
After listening to Sp8ctre's clip, that's the first thing I thought of.

Sp8ctre said:
Put a new 12AX7 in the V5 slot and No Tremolo...
Click to expand...
Looks like you're going to be chasing your tail on this one. Eventually you'll find it and have fun for doing so!

Do the caps at least look good visually? No bubbles or bulge spots? Go ahead, and insert jokes here... :fingersx:
 
syscokid said:
After listening to Sp8ctre's clip, that's the first thing I thought of.


Looks like you're going to be chasing your tail on this one. Eventually you'll find it and have fun for doing so!

Do the caps at least look good visually? No bubbles or bulge spots? Go ahead, and insert jokes here... :fingersx:
Click to expand...

Caps all look good and I don't want to just change them all out for the hell of it. I lost some of the good sound
in my Princeton Reverb just doing a "Replace Everything" approach. I'm going go bit by bit with this one.

First thing is to try yet another tube...
 
Sp8ctre said:
Removed V5 and issue is gone. It is an original Fender marked tube. Marked C 3341
Click to expand...
OK well if coupling caps are leaking DC that would probably explain it....

Look inside the chassis.
Is there a 2 letter code stamped in ink, inside the chassis?
Is there a 2 letter code stamped with ink on the cabinet tube label?
 
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