Threshold SA/1 monoblocks cap issues, perhaps?


Few weeks back I bought these monoblocks and added to my system consisting of Metrum Adagio, EAR 868L, Focal 1038BE and laptop working as a source which will be replaced with a custom made computer based transport in few weeks.

But these monoblocks seems to have few issues though the seller told me that everything was fine with these monsters.

1. There is big thump when I switch on these amps one by one and also within a second I hear a high frequency sound like "ptakk" from both sides. This sound is there while switching off the amp though less frequently and intensity IMO.

2. Initially I thought the sound is only while switching on and off but later I found that it is also there in between while the music is playing. This is more like "karr-karr" like.

3. One day I also heard it even when I switched off amp while rest of system was on. So I am thinking it might be due to leaky caps. All the caps look like in really good condition and seller told me that there is no need to chnage these as these have hardly been used. Even I use these for 20-30 min per day five times week.

4. Once I removed EAR868 from the chain and same issue was still there indicating EAR is not the criminal here. Adagi was working fine with Parasound Halo A21 which I had earlier before I added preamp and monoblocks.

I do not have much knowledge but I can learn quickly. Need the advise of experts as I really love the sound signatures of these monos.

rsjaurr
E36D101HPN333ME92M   33000uF/100V 76mm  In diameter about 4 inches long you need longer screws 10.32 US standard. These you can get at mouser they will ship to India $240 plus shipping. 
E36D101HPN333ME92M   33000uF/100V 76mm In diameter about 4 inches long you need longer screws 10.32 US standard. These you can get at mouser they will ship to India $240 plus shipping.
So in your opinion fault is with caps? 
Mallory electrolytic caps electrolytic Is dried up since the caps were made In 1984. There Is a Threshold SA/1 on eBay for sale he replaced the original Mallory 29000uF caps with Cornell Dubilier 37000uF caps the results.
The capacitor upgrade is a noticeable sonic improvement particularly with the lower bass notes, very deep and tight. In parallel with the new electrolytic capacitors.
E36D101HPN333ME92M   will do the job lower price than CDE.
While back I did sell 36000uF/100V AT 95C 8 capacitors for SA/1 made by United Chemicon.
E36D101HPN333ME92M 33000uF/100V 76mm In diameter about 4 inches long you need longer screws 10.32 US standard. These you can get at mouser they will ship to India $240 plus shipping.


Can you please send me the link for these longer screws 1032 US Stnd.?

I do not mind paying more for higher priced CDE caps if they are significantly better than the ones recommended by you.
The guy on eBay replaced the the original Mallory CGS293U080X6L3PH with 37000Uf 75V he lowered the voltage by 5 volts not a good idea. The cap was 29000uF 80V. The last number 3PH means 1/4 28 screws bigger screws not a problem USA caps uses 10.32 screws and 1/4 28 screws about 20 percent.
 You want CDE 39000uF/100V price $120 each.37000uF/75V is $80 each. 100 percent USA made. United Chemicon is USA and Japan both are made in USA. 
United Chemicon 
E36D101LPN303UEA5M   30000uF 100V and E36D101HPN333ME92M 33000uF 100V is a good replacement. CDE and United spec is about the same. CORNELL is 3 times more expensive. Cornell is the worlds most expensive used by McIntosh/Ayre/Lamm etc.