Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jack1962 on July 18, 2013, 11:08:47 am

Title: Fender Deluxe Reverb with Vibrato problems
Post by: Jack1962 on July 18, 2013, 11:08:47 am

my question is , will replacing the 6V6 tubes with 6L6's cause problems with the vibrato

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: phsyconoodler on July 18, 2013, 11:29:08 am

No,it shouldn't.

  I'm assuming you have  a trem problem and the only change you made was swapping tube types?
The bias circuit does have a tap going to the 2.2meg resistor near the roach, but unless the tubes were wayyyyy off in bias then I can't them causing an issue with the trem.

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: Ed_Chambley on July 18, 2013, 11:47:08 am

If it is Bias Vary Tremolo it will.  If it has the roach, is should not.

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: sluckey on July 18, 2013, 12:16:29 pm

Quote from: Ed_Chambley on July 18, 2013, 11:47:08 am

If it is Bias Vary Tremolo it will.  If it has the roach, is should not.

Bingo. And the DR uses a roach.

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: Jack1962 on July 18, 2013, 01:38:33 pm

well I didn't install the tubes it came to me that way , it is biased correctly for a 50 watt amp but the transformer is the original DR transformer . the vibrato works only when the intensity is turned to 10 , however the rate/speed control works perfectly , that is what I'm having trouble getting my head around .

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: plexi50 on July 18, 2013, 09:29:37 pm

I just changed out a roach on a 1978 Deluxe Reverb with the pull boost reverb. I thought that was the reason for the lack of thump the vibrato had. It wasnt the roach in my case. Then i looked at the later silverface schemo and the vibrato cathode used a 5uf cap (AB868) instead of the 25uf cap used in the AB763 circuit. I removed the 5uf and put in a 25uf. Deeper and more alive vibrato. Not sure if this is your case though

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: Jack1962 on July 19, 2013, 06:10:04 am

yeah I changed the roach too , no change , this is a AB763 , I'm thinking it is probably that 50k-ra intensity pot . nothing else seems to read bad , but I am using my bad ass Harbor Freight DMM lol

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: plexi50 on July 19, 2013, 07:56:04 am

Have you checked or tested the cathode cap for the vibrato?

I bought a cap tester a while back. Indispensable tool. Cheap too. You would be surprised when testing caps just how many new capacitors are beyond there rated value. This is the one i have in the pic. Those white Mallory 25uf cathode caps in my deluxe reverb were reading any where from 38-88uf.

Title: Re: Fender Deluxe Reverb with Vibrato problems
Post by: Jack1962 on July 20, 2013, 06:30:25 am

no I haven't , but I will now lol  I bought that same meter lol