Another Threshold Stasis 2 rebuild

AMV8 · 21st December 2006, 12:23 PM

Hi

I have just become the proud owner of a Threshold Stasis 2 that was upgraded in 1991 to "e" version of Stasis when balanced inputs were also added . I bought it from the original owner and it is generally in very good condition.

I have already tried it - I could not wait. The sound has a balanced quality that I have not often met. I am planning to change the capacitors and that should clean up the sound by adding more sparkle and clarity to the notes.

However the right channel plays ok but is running cool. At least I am assuming that the left channel is running at the normal temperature. After two hours use the left channel is warm and it is easy to keep a hand on. However the left channel is still cool and only slightly warm. By the way it is cold in the uk at present.

I have looked in diyaudio and found 4 threads on the Threshold stasis 2. These contain a schematic and pictures of the pcb which are very helpful. However mine is a different pcb and it does not seem to have an adjustment on the pcb for the bias - or if it has I have been missing it. I will take a more detailed look over the next week when I change the capacitors.

My questions are;
1) Does anyone have a schematic for my presumably later model?
2) What should the bias be set at.
3) Any ideas on why one channel is running cooler?

NOTE: With such a large transformer - it looks like 2kva and 24 output semiconductors I simply can not wait to get this amp back into proper action!!!

I do want to get this amplifier back to delivering what it looks as though it is capable of and all help and suggestions will be appreciated.

Thanks
Don

Nelson Pass · 21st December 2006, 09:45 PM

If you look at the files in www.passlabs.com/np you will
see the schematics for the later front ends for the Stasis
series, identified by year. The files start with thr_

Both channels should be biased for the same temperature,
about 45-50 deg C.

steenoe · 22nd December 2006, 05:13 AM

Hi Don
Install new electrolytics on the amplifier-boards(only) at first. As far as I recall there is 3 electrolytics in each channel. A friend of mine has a Stasis 2 that started to act strange, playing louder in 1 channel and running hotter also in 1 channel. After changing the 6 small electrolytics, all problems was solved and it was back in duty

Its ofcourse a good idea to adjust the amp when you are done.

Steen

21st December 2006, 12:23 PM	#1
AMV8 diyAudio Member Join Date: Jan 2005 Location: near london	Another Threshold Stasis 2 rebuild Hi I have just become the proud owner of a Threshold Stasis 2 that was upgraded in 1991 to "e" version of Stasis when balanced inputs were also added . I bought it from the original owner and it is generally in very good condition. I have already tried it - I could not wait. The sound has a balanced quality that I have not often met. I am planning to change the capacitors and that should clean up the sound by adding more sparkle and clarity to the notes. However the right channel plays ok but is running cool. At least I am assuming that the left channel is running at the normal temperature. After two hours use the left channel is warm and it is easy to keep a hand on. However the left channel is still cool and only slightly warm. By the way it is cold in the uk at present. I have looked in diyaudio and found 4 threads on the Threshold stasis 2. These contain a schematic and pictures of the pcb which are very helpful. However mine is a different pcb and it does not seem to have an adjustment on the pcb for the bias - or if it has I have been missing it. I will take a more detailed look over the next week when I change the capacitors. My questions are; 1) Does anyone have a schematic for my presumably later model? 2) What should the bias be set at. 3) Any ideas on why one channel is running cooler? NOTE: With such a large transformer - it looks like 2kva and 24 output semiconductors I simply can not wait to get this amp back into proper action!!! I do want to get this amplifier back to delivering what it looks as though it is capable of and all help and suggestions will be appreciated. Thanks Don

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21st December 2006, 09:45 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	If you look at the files in www.passlabs.com/np you will see the schematics for the later front ends for the Stasis series, identified by year. The files start with thr_ Both channels should be biased for the same temperature, about 45-50 deg C.

22nd December 2006, 05:13 AM	#3
steenoe diyAudio Member Join Date: Mar 2004	Hi Don Install new electrolytics on the amplifier-boards(only) at first. As far as I recall there is 3 electrolytics in each channel. A friend of mine has a Stasis 2 that started to act strange, playing louder in 1 channel and running hotter also in 1 channel. After changing the 6 small electrolytics, all problems was solved and it was back in duty Its ofcourse a good idea to adjust the amp when you are done. Steen