Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jalmeida on December 06, 2022, 11:00:13 pm

Title: Another PR build post with questions…
Post by: Jalmeida 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?

Title: Re: Another PR build post with questions…
Post by: sluckey 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