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The Single Power ES-1/2 repair and restoration thread - Page 6

post #76 of 157
Thread Starter 
Damn right!!
post #77 of 157
Tell me it isnt the all DHT monster ;p
post #78 of 157
Thread Starter 
That will come later on.
post #79 of 157
Not to thread crap at all, or poke at spritzer to finish his project... but I was setting up my system again, and I took the opportunity to take a new set of pictures of the inside of the Amp and PSU of my ES1.... just to add to the Body of knowledge growing about these amps.....

follow the link and take a look (you can see original size image my clicking on the zoom icon in the upper right when looking at an image).... It looks pretty good to me... I find a couple of soldering issues, but not much

Picasa Web Albums - mikma - 20090922 SP E...



Not very exciting, but thought that I would share.

Cheers,
post #80 of 157
This thread should be - using the basic circuit of the ES-1 plus the stock ES-1 case to make an entirely new ES-1, not restoring ES-1s. Restoring would indicate that only some of the innards are problematic.

I didn't know that Mikhail straight up charged for things that weren't in the case, how dumb does he think we are...I guess he had a rep for tightening up the case screws so that the case was unopenable...
post #81 of 157
Thread Starter 
Did you ever take off the top of the unit to see what transformers you have? Given Mikhail's transformer choices in some of his other amps I'd take a look just to be sure it isn't a 12V unit wired up backwards or some other crazy idea. The rest of the amp is the standard SP stuff, combined filament supply which will damage the tubes, bias supplies which are far from spec and tube bias which doesn't work so that all outputs are sitting at +100VDC severely limiting the output capabilities of the amp. One question though, do you run the amp with the XLR inputs normally and have you ever suffered channel imbalance from using the RCA inputs?

I've been trying to find time for the ES-1 but new projects are constantly cropping up. Those with the round Plitron transformers are lucky though since the transformers have a 40V/4VA bias tap which Mikhail never used. This can be used to properly bias the tubes and thus remove the offset. I plan on making a PCB which will fit in the case and carry a new headphone bias, tube bias and HV supplies of a single PCB but who knows when I'll get around to it...
post #82 of 157
Quote:
Originally Posted by spritzer View Post
I plan on making a PCB which will fit in the case and carry a new headphone bias, tube bias and HV supplies of a single PCB but who knows when I'll get around to it...
Slightly O/T and possibly not related to your intent with this comment, but I have had the thought that an effective, and somewhat evil way to prevent Mikhail scamming people any more with his amps would be to clone them (with fixes) and make at least the boards for them readily available.
post #83 of 157
Quote:
Originally Posted by Currawong View Post
Slightly O/T and possibly not related to your intent with this comment, but I have had the thought that an effective, and somewhat evil way to prevent Mikhail scamming people any more with his amps would be to clone them (with fixes) and make at least the boards for them readily available.

I think that's an incredible idea!
post #84 of 157
Thread Starter 
A clone of a clone? There will be a new version of this circuit available some day but I'm more concerned with helping the owners fix their broken amps.
post #85 of 157
New DIY circuit board soon. Solid state, or resistor current source.
10 turn finger pots for all critical adjustments.

Works with the fully regulated DIY T2 power supply board, partially
populated.
post #86 of 157
Quote:
Originally Posted by spritzer View Post
A clone of a clone? There will be a new version of this circuit available some day but I'm more concerned with helping the owners fix their broken amps.
Well, when you put it that way... the original amp that it was based on. I don't think most people realise that SP amps were clones. Maybe I should have said "without all the mistakes" instead of "with any fixes".

Anyway, I don't want to derail this thread, nor your efforts, just wanted to throw the idea out there.
post #87 of 157
Quote:
Originally Posted by spritzer View Post
Did you ever take off the top of the unit to see what transformers you have?
No... I thought about it last night... I could take a look tonight at one of them... The other has screws hidden under one of the boards (and I don't want to risk messing something up at this point.

Quote:
...The rest of the amp is the standard SP stuff, combined filament supply which will damage the tubes, bias supplies which are far from spec and tube bias which doesn't work so that all outputs are sitting at +100VDC severely limiting the output capabilities of the amp. One question though, do you run the amp with the XLR inputs normally and have you ever suffered channel imbalance from using the RCA inputs?
Well good to know I have just standard SP problems... not Big SP problems....

I run it with XLR the entire time. I first ran it with RCAs and it didn't give me the output level I wanted (just about max volume to get it up to power). But when I read that my Marantz had 5V output for XLR, I use that exclusivity. Half volume gives me a good level. I have never noticed a channel imbalance (RCA or XLR).

Should be able to take a peek at the transformer tonight.

Cheers,
post #88 of 157
Thread Starter 
It's probably a Hammond transformer of some kind so hopefully something which isn't underrated. No big SP problems that I can see... plenty of those to go around though.

If you switch to say a ECC83 in the first slot then you would get more gain (volume) but it's nice to hear that some units don't suffer the dreaded channel imbalance. Even my mini ES-1 (straight from the Stax schematic but with different tubes) had it so probably a gain issue I need to figure out.
post #89 of 157
I took the PSU back apart... but I discovered that the screws to take off the transformer cover were not accessible... so at this point I am leaving it a mystery...

Thanks again for the input...

I am fine with the gain right now with the XLR input... but probably will look for a little more punch in future tubes.

Cheers,
post #90 of 157
Thread Starter 
Rewire the output with new pots and a seperate 30VDC bias will give you plenty of slam.
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