Welcome To the Hoffman Amplifiers Forum

September 07, 2025, 02:26:10 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Reverb Problems  (Read 1704 times)

0 Members and 1 Guest are viewing this topic.

Offline Wanabejimi

  • Level 2
  • **
  • Posts: 100
  • I love tube amps
Hoffman Amps Forum image
Reverb Problems
« on: October 16, 2020, 09:14:53 am »
I have a 6L6 Princeton Reverb build and I'm having problems with the reverb.  The amp sounds fine without the reverb driver tube in.  With the driver tube in, the signal is very low and tons of noise.  I did the audio probe and I got full signal of V1 without the driver and no signal (that I could hear) with it in.  I have 440 vdc going into the reverb transformer.  I have 80 volts on the cathode.  I replaced the cathode resistor and the 12at7 with no change.  I don't have another 25/50 by pass cap (kind surprised it didn't blow).  Could the cap be the problem?  Any other thoughts?  Thanks!  I should also mention the amp makes an audible squeal...both the amp itself and through the speaker when the b+ hits it.
I have also traced with circuit and checked with a multimeter for any shorts and I have not seen any problems.

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Reverb Problems
« Reply #1 on: October 16, 2020, 09:28:23 am »
Measure resistance between V2 pin 8 and chassis. Put meter probe directly on the socket pin 3. What have you?
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline Wanabejimi

  • Level 2
  • **
  • Posts: 100
  • I love tube amps
Hoffman Amps Forum image
Re: Reverb Problems
« Reply #2 on: October 16, 2020, 03:32:41 pm »
2.3k

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Reverb Problems
« Reply #3 on: October 16, 2020, 05:10:05 pm »
Something bad wrong if you have 80V on the cathode. Should only be 8V. I'd look for wiring errors.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

 


Choose a link from the
Hoffman Amplifiers parts catalog
Mobile Device
Catalog Link
Yard Sale
Discontinued
Misc. Hardware
What's New Board Building
 Parts
Amp trim
Handles
Lamps
Diodes
Hoffman Turret
 Boards
Channel
Switching
Resistors Fender Eyelet
 Boards
Screws/Nuts
Washers
Jacks/Plugs
Connectors
Misc Eyelet
Boards
Tools
Capacitors Custom Boards
Tubes
Valves
Pots
Knobs
Fuses/Cords Chassis
Tube
Sockets
Switches Wire
Cable


Handy Links
Tube Amp Library
Tube Amp
Schematics library
Design a custom Eyelet or
Turret Board
DIY Layout Creator
File analyzer program
DIY Layout Creator
File library
Transformer Wiring
Diagrams
Hoffmanamps
Facebook page
Hoffman Amplifiers
Discount Program


password