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The Single Power ES-1/2 repair and restoration thread - Page 5

post #61 of 157
mine also occurs on the left channel.. Interesting.. the two units sound similar even though the innards appear different. One actually has audio note caps in it, but it still has the orange drop bypass caps. The "newer" version uses 50W NI power resistors instead of a bunch of 5W? resistors. I'll confirm once I retake some photos.

I've not compared the two side by side extensively as they have been in two different locations (home and office), up until now...
post #62 of 157
Quote:
Originally Posted by pabbi1 View Post
Maybe because he planned it this way?

Oh, and the tube business has been sold.
I doubt its been sold. The phone number still goes to Singlepowers voice mail.
Where did you hear its been sold?
post #63 of 157
Quote:
Originally Posted by shokunin View Post

I've sent a link to Kevin that has the high-res photos of the Power supplies, after lunch I'll try and photo the amp sections.
OH my. typical mikhail. On the hand wired supply there are actually
2 seperate filament supplies. Except that one of them was never
wired up. So the one transformer is running significantly over power
to run the filaments of all 8 tubes.


FINALLY !!! Someone with a decent camera. YEAH.

So one of your units has goldpoint attenuators, no black gate cathode caps, and 1200 volt orange drops,
chassis mount plate resistors and 4 pot bias.

and the other has

shalco attenuators, black gate cathode caps and audio note copper foil 630 volt caps in SERIES with 1200 volt orange drops.
Dale plate resistors, two pot bias and two large pots hooked to nowhere. And a bread tie to hold the wires together.
post #64 of 157
I noticed that one bridge has no output on it ???
post #65 of 157
Quote:
Originally Posted by kevin gilmore View Post
OH my. typical mikhail. On the hand wired supply there are actually
2 seperate filament supplies. Except that one of them was never
wired up. So the one transformer is running significantly over power
to run the filaments of all 8 tubes.


FINALLY !!! Someone with a decent camera. YEAH.

So one of your units has goldpoint attenuators, no black gate cathode caps, and 1200 volt orange drops,
chassis mount plate resistors and 4 pot bias.

and the other has

shalco attenuators, black gate cathode caps and audio note copper foil 630 volt caps in SERIES with 1200 volt orange drops.
Dale plate resistors, two pot bias and two large pots hooked to nowhere. And a bread tie to hold the wires together.
Yup, I have no idea why the larger pots in the Shallco version had the wires cut and doing nothing... I have no idea what the deal is with the Audio note caps AND the orange drops. I'm no EE, but there are things in there that makes me go Hmmmmmm....?
post #66 of 157
Quote:
Originally Posted by kevin gilmore View Post
...and audio note copper foil 630 volt caps in SERIES with 1200 volt orange drops....
what the helll is mikhail thinking????? i can't imagine anyone doing this
intentionally...
post #67 of 157
Did i just imagine that there was some pics of the 2 power supplies on this thread, as I can't see them now?
post #68 of 157
Thread Starter 
It is strange that we are both experiencing channel imbalance and in the same channel. I've bypassed the attenuators so they aren't to blame and even redone most of the solder joints in the left channel.

Quote:
Originally Posted by takezo View Post
what the helll is mikhail thinking????? i can't imagine anyone doing this
intentionally...
This is the sixth amp that I've seen like this and that shows clear intent. Why he did it I have no idea except trying to meet the 0.05 value used in the original Stax design. I'm using 0.33uf caps in my unit and it's safe to go even higher...
post #69 of 157
Quote:
Originally Posted by spritzer View Post
It is strange that we are both experiencing channel imbalance and in the same channel. I've bypassed the attenuators so they aren't to blame and even redone most of the solder joints in the left channel.
I will add that my ES-1 Concerto also has an occasional electronic buzzing sound in the left channel. It's not an imbalance -- just a strange brief electronic sound. My friend who repairs guitar amps said it's probably a bad resistor somewhere, or possibly a cold solder joint or tube contact. It's noticibility is greatly dependent on the tubes being used - and with my current tubes I hardly ever notice it. I never notice the problem in the dynamic output.

Any chance you'll become an ES-1 tech (for hire of course) so that we could send you ours in order to upgrade the circuits if necessary?
post #70 of 157
Thread Starter 
A cold joint, bad resistor or contact issues can all be a candidate since the soldering in all SP products is beyond sub par, nearly all resistors used on the limit and the tube sockets the cheapest ones you can find.

As for being a ES-1 tech, that isn't going to happen. I don't have the time to spare for such a massive undertaking. My goal is to fix up my amp, document the process and thus provide a guide for any tech to work from.
post #71 of 157
By "fixing up the amp", do you mean "ripping everything out and rewiring from scratch, replacing all sub-par components"?
post #72 of 157
Thread Starter 
I will completely gut the amp/psu chassis, have them repainted and then start from scratch. Most of the parts will be thrown out except for the HE90 sockets and the attenuators. Even the transformers may be scrapped for smaller units but I'm not sure about that yet. Then I'll put in some teflon tube sockets, teflon terminal strips and rebuild the amp properly with signal- and power lines well away from each other, wires properly secured and the filament wires well out of the way. I may even add some ventilation holes while I'm at it...
post #73 of 157
Any updates?
post #74 of 157
Thread Starter 
No major updates to report on but I do have some alterations to do ASAP which should fix the channel imbalance. Then I have install one more pot and the amp section is pretty much finished with full output voltage swing and much lower distortion then it ever had. I'm juggling a lot of projects right now (about 10 different electrostatic amps with a Blue Hawaii the closest to completion) so it may take a while to get to this.
post #75 of 157
And wait till you see spritzer's project number 11.
Gonna be huge.
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