Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 05:09:02 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Another PR build post with questions…  (Read 1635 times)

0 Members and 1 Guest are viewing this topic.

Offline Jalmeida

  • Level 2
  • **
  • Posts: 303
  • I love Tube amps
Hoffman Amps Forum image
Another PR build post with questions…
« on: December 06, 2022, 11:00:13 pm »
So I am in the middle of building an A1164 while waiting on some parts to fix some noise on my Vox AC10reverb build.

So I am just building a pretty run of the mill Princeton Reverb circuit. I plan to use a really nice OT and Reverb Transformer. But I do have a few things I want to change.

1. Replace the RCA jack style footswitch for a 1/4” TPS pootswitch jack for the Tremelo and reverb.

2. Add a bias Pot



So my questions are:

1. Is there any safeguards I can implement with a bias pot install to avoid a PT failure if a bias pot fails?

2. In the way of Power Transformers, are Hammonds good, bad or meh? Does it matter?

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Another PR build post with questions…
« Reply #1 on: December 06, 2022, 11:18:05 pm »
Hammond makes good transformers.

Build the bias circuit in this amp. If the bias pot fails, the bias voltage defaults to max negative and avoids any stress on tubes or transformers.

     http://sluckeyamps.com/phoenix/phoenix.pdf
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