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What will I expect to notice with a recap on a Stasis 3?

I recently purchased a completely original Threshold Stasis 3 amplifier. After blowing out the tremendous amounts of dust and visually inspecting, I hooked it up to my system. It still functions and sounds quite good. The bass is sloppy, female vocals are excellent and some mids get a little muddy at moderate volume. It is really pretty easy to listen to with minimal fatigue. Actually, sounds closer to my Conrad Johnson tube amp than the Krell. I expected a little more slam out of the Stasis but certain that some extra capacitance will help remedy that. If I were to recap, what improvements should I expect? Is this amp worthy of a rebuild? Is this amp a happy medium between an ultra analytical Krell and a gooey tube amp?
robbieshep
8 responses Add your response
georgehifi's avatar
georgehifi
10,312 posts
 
robbieshep
What will I expect to notice with a recap on a Stasis 3?
I expected a little more slam out of the Stasis but certain that some extra capacitance will help remedy that.
Yes a re-cap will improve everything, as those electrolytic caps are around 40 years old now, and don’t forget the smaller electrolytic ones on the boards also.
You will get a good improvement in the bass, but even a better if you replace those two slow release power supply ones for a a matrix of many smaller ones instead.
Something like this, with even more caps, use your own rectifiers if these aren’t rated high enough.
https://www.ebay.com/itm/HITACHI-12000UF63V-6-Capacitor-Welded-Schottky-Rectifier-Filter-Power-Supply/312720173080?hash=item48cf932818:g:sJIAAOSwh8VdQvQR

Cheers George
robbieshep OP
3 posts
 
George, Thanks for your reply. Do you have an idea of how much a recap would actually cost? I figure that the layout of the chassis will be a bit more labor intensive to remove the boards. I was figuring on $400 to $650 for a full replacement w/o the matrix.
georgehifi's avatar
georgehifi
10,312 posts
 
robbieshep OP


I’d say 2-3hrs labor at $120 pr/hr, boards are easy to take out. Parts about $150usd.
So around $600 odd to do the job just by a good technician, not a amplifier manufacturer or hifi shop, because they will charge like a wounded bull for both labor and parts.
Here is the circuit diagram should you need it, only stays up for a while, so save it. https://ibb.co/fdjZvFC

Cheers George
robbieshep OP
3 posts
 
George, you have been most helpful. A thousand thanks. I found a tech locally that is willing to do the work. I will be dropping the amp off this week. Really looking forward to seeing how this amp performs. Thanks again. Robb
georgehifi's avatar
georgehifi
10,312 posts
 

robbieshep OP

Pleasure, looks like there are 6 X smaller electrolytic caps on each channel to be replaced, and the 2 big power supply ones, use .47uf plastic by-pass across each of the big ones, or the many little ones I linked to if you go that way, which I think you should for better dynamics and bass tightness performance. I would get 2 of these and give them to your tech, that will be 72000uf per channel not bad. https://www.ebay.com/itm/HITACHI-12000UF63V-6-Capacitor-Welded-Schottky-Rectifier-Filter-Power-Supply/312720173080?hash=item48cf932818:g:sJIAAOSwh8VdQvQR


Plenty info here on the board ones, and Nelson chimes in also.
https://www.diyaudio.com/forums/pass-labs/297464-threshold-stasis-3-amplifier-capacitor-replacement.html
Also here
https://www.diyaudio.com/forums/pass-labs/182177-threshold-stasis-bias-thread.html
Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
Here are your checking and adjustment tables
https://ibb.co/W5xNhRR
robbieshep OP
3 posts
 
George, I appreciate all of the great info. On the adjustment table, aren’t the s/300 and sa/3 different amps from the Stasis 3? 
georgehifi's avatar
georgehifi
10,312 posts
 
Yes they’re all different amps, I believe the Stasis 3 (which isn’t on that table) is just a higher rail volt version (more Class-B 150w) of the all Class-A SA3. only 30 or 50watts?
And the Stasis S300 is later and different to both SA3 and Stasis 3.

Cheers George
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