• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Counterpoint SA 3.1

Hello

I read some inspiration here about some Counterpoint SA 3.1 and 5.1 mods and repairs.

I had a chance to pick up a 3.1 and although I did not need it, it reminded me of some of the Counterpoint gear I had in the 80s. I love the form factor.

The object was to totally mod the power supply. Isolate the stock B+ and filament supply and replace it with a tube rectified , series pass with voltage reference and a separated heater supply.

The size comparison of the old transformer box to the new reg is comical.

This was meant to be an all out assault with no practical sense as all it took was money and time.

5AR4 rectifier, OB3 voltage reference, 12au7 error amp and el84 pass

After a few months of collecting parts and working part time at it ... It finally came together and is testing well

I added a pair of sowter step ups as well for MC and it is switchable for 1:10 and 1;20

Everything is totally reversible. Sounds Sweet ... better than the 5.1 I had .

New coupling caps, audio note sockets, TKD pot and balance, RCAs, solens for decoupling etc..

Hopefully this will inspire some one else. I don't usually take on projects like this but I thought the SA 3.1 would benefit and I would have some fun-- time to burn it in and have some fun with it.
 

Attachments

  • IMG_3227.jpg
    IMG_3227.jpg
    105.8 KB · Views: 193
  • IMG_3221.jpg
    IMG_3221.jpg
    114.7 KB · Views: 181
  • IMG_3285.jpg
    IMG_3285.jpg
    125 KB · Views: 186
  • IMG_3396.jpg
    IMG_3396.jpg
    125 KB · Views: 189
  • IMG_3414 (002).jpg
    IMG_3414 (002).jpg
    123.5 KB · Views: 191
  • IMG_3413 (002).jpg
    IMG_3413 (002).jpg
    76.7 KB · Views: 145
It would be better to talk elsewhere about that amp.

I am not naturally a SET fan. The Wyetech is the most unlikely SET sounding SET that I have heard keeping all the attributes and giving up very little. Its a beast for a commercial product and with very robust power supplies- weighs well over 100lbs. I like it alot.