I will be venturing on a project to upgrade a pair of Acrosound Ultralinear II amplifiers soon with some new circuit boards and all new parts. One I have had for many years sitting out in the garage and just recently acquired a second unit from a past customer.

I will be replacing the circuit boards on both units with new circuit boards pictured below that I purchased from Brice Hammon who I found on the Audiokarma forum https://audiokarma.org/forums/index.php

Here is the first completed board. I am going to test it on the bench before I install it on the first chassis.

Just completed the smoke test with a pair of 6V6 tubes. All went well so I will get both chassis cleaned up and repaint the transformers over the next week before I install the first new board.

First board is installed and working fine. Less than .8% distortion and a max power out of about 75 watts.
Repainted the transformers with Krylon Metallic Gold spray paint but leaving the chassis stock.

Both amps completed, tested, burned-in, and aligned. They sound great!

Running E.I. KT90 tubes. Even though these tubes have many hours on them, they balanced out well and still sound good.