Help with biasing STAX SRM T1

[greendra]

Hi everyone,

First time posting,
I am trying to bias a STAX SRM T1, the old version of STAX SRM T1 with 2 transformers.

I am trying to bias the T1 Right Channel with my multimeter, I observed the voltage while biasing, fluctuates from -5 to 600 VDC. I proceeded to adjusted the trimpot to stop this fluctuation to no avail.

As the SRM T1 has 2 PRO- Stax Output, I plugged into one of the outputs and plugging my multimeter in, to bias. I notice that when the voltage was at 600VDC, there was a buzzing sound coming out of my earspeakers. However voltage was near zero, it was fine.

The left channel was ok, I was able to bias without an issue.
I have tried swapping out the tubes to no avail.


Any advice?

 

[duncan2]

Here is some information on your Stax ,by the way there are a lot worse more modern energizers than yours its definitely worth repairing.


Stax SRM-T1 Repair, Re-Cap, Mod | Headphone Reviews and Discussion - Head-Fi.org


More information.


Stax SRM-T1 Repair - Headphone Amplification - www.Head-Case.org


The schematic is available on-
Stax SRM-T1 - Manual - Headphone Driver Unit - HiFi Engine

 

[audiowize]

I would be looking at the grid voltages on the 6CG7 on that side of the circuit. Since you have one working channel, you have something to compare against.