The Stax thread (New)
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Jul 17, 2013 at 7:29 PM Post #23,626 of 24,807
Someone is selling a High-Amp.de amp, pretty nice alternative to the KGSS.
 
http://www.ebay.de/itm/Kopfhorerverstarker-fur-STAX-Elektrostaten-Selbstbau-Rohre-FET-Hybrid-/171077600414?pt=Kopfh%C3%B6rer&hash=item27d505049e
 
Jul 17, 2013 at 8:11 PM Post #23,627 of 24,807
Was looking at that this morning.
 
Anyway, got the resistor from RS this morning, soldered the bitch in. Powered on amp without source or my SR-5, measured all major points across the transistors again, staying at the same steady 620-625vdc. Then I flipped the amp over and tried measuring one of the bolts securing an end of the 2SC1828  and bam, an arc, killed my el cheapo Jaycar multimeter too.
 
Plugged in SR-5 and source. Still no sound on the left channel. I've searched around from the MK2 rebuild logs and normally I would just go check the wires for output to see if they are fine, but it's no use since the Left-Input solder pad on the circuit don't even produce sound when I have RCA wire connected to it.
 
Calling for KG's and Birgir's help on this one. It would suck to let this amp go as it sounds extremely good with my SR-5's. 
 
Jul 17, 2013 at 9:04 PM Post #23,628 of 24,807
Quote:
 
 
Thanks for the tip. So he found one for a good price at Japan, he's going to go ahead with it... but about the 120v American wallwart PS to purchase separately, does anyone have a good link to one to be used with a 100v unit of SRM-252?    They seem common enough to find, but what I'm concerned with is something with power jack polarity and how the Japanese versions are reverse of what is typically used here? I'm clueless to all this electronic stuff, but I'm guessing that's not a good thing to use for them. If anyone can post a link with the one with the proper polarity for the 100v unit to be used with the 120v outlets that'd be awesome.

This link would definitely be helpful to many of us :)
 
Jul 18, 2013 at 12:57 AM Post #23,629 of 24,807
Just plug in the Japanese transformer into your American wall outlet and be happy with it :)
 
Jul 18, 2013 at 4:03 AM Post #23,630 of 24,807
How is the Stax Lambda normal bias +SRD 7/SB combo?
 
Should I get it if I have a 2050 set?/ what differences would I find?
 
Jul 18, 2013 at 10:25 AM Post #23,633 of 24,807
Quote:
Was looking at that this morning.
 
Anyway, got the resistor from RS this morning, soldered the bitch in. Powered on amp without source or my SR-5, measured all major points across the transistors again, staying at the same steady 620-625vdc. Then I flipped the amp over and tried measuring one of the bolts securing an end of the 2SC1828  and bam, an arc, killed my el cheapo Jaycar multimeter too.
 
Plugged in SR-5 and source. Still no sound on the left channel. I've searched around from the MK2 rebuild logs and normally I would just go check the wires for output to see if they are fine, but it's no use since the Left-Input solder pad on the circuit don't even produce sound when I have RCA wire connected to it.
 
Calling for KG's and Birgir's help on this one. It would suck to let this amp go as it sounds extremely good with my SR-5's. 

 
Do a diode test on the transistors as I'm pretty sure some of them are fubar.  You can also measure voltages between the channels, especially before the output caps.  If they aren't close to each other then something is very wrong. 
 
No chance in hell to find any replacement sand though. 
 
Jul 18, 2013 at 12:20 PM Post #23,635 of 24,807
Quote:
Quote:
Just plug in the Japanese transformer into your American wall outlet and be happy with it :)

I wouldn't recommend this. 100v appliances on 117-120v mains AC is not a good idea especially with something so delicate such as the Stax amp, not to mention not regulated.

I actually talked to someone who's been using his Japanese transformer in America for at least a year and he said there are actually linear regulators that keep the voltage at 12V, even though the input voltage is greater than that.
 
Jul 18, 2013 at 12:20 PM Post #23,636 of 24,807
Quote:
How is the Stax Lambda normal bias +SRD 7/SB combo?
 
Should I get it if I have a 2050 set?/ what differences would I find?


I would suggest that the Lambda and SRD7 combo will work very well - if you get a good enough signal going into them - source and power amp. The quality of the source is the influence on the sound.
 
Jul 18, 2013 at 12:26 PM Post #23,637 of 24,807
I made the conversion, and it works!
 
Due to your photo, description form DefQon, Spritzer and a german forum, I clould now discover what was missing in my SRM-717.
 
STAX does obviously change this and that to confuse. In my case just two wire have been omitted (blue and purple from Jumperboard to Trafo).
 
I changed it now to 240V, bars 2 and 5 and changed the fuse to 0.8A, probably 0.63A would work as well.
 
I just wanted to attach the description with photos and a file which shows the current pathes for 100V, 120V, 220V, 240V.
 
Somehow I have no permission to do that.
 
If you want that , just PM me to send it via my email.
 
Jul 18, 2013 at 12:44 PM Post #23,638 of 24,807
Quote:
I actually talked to someone who's been using his Japanese transformer in America for at least a year and he said there are actually linear regulators that keep the voltage at 12V, even though the input voltage is greater than that.

 
If anyone with the knowledge of the inner parts of the Amp and the power supply of the 252s can confirm this then that would be great.  
 
I see that Elusive Disc's description of the 2170 specifically warn of doing this though, saying it can damage the amp and the headphones...
 
Jul 18, 2013 at 1:08 PM Post #23,639 of 24,807
SRM-717 voltage change
 
as I cannot upload a whole pdf, here the essential part:
 
here the schematic.
 
Regarding Voltage input to a 717 and 007t I can clarify that: (sited form earlier, and this is true, I verified it for SRM-717)

The power supply transformer has 7 tap on the input side which are
(0)Yellow= common (winding 1)
(1)White=same as yellow (winding 1)
(2)Green=100v tap (winding 1)
(3)Purple=120v tap (winding 1)
(4)Black=common (winding 2)
(5)Brown=100v (winding 2)
(6)Blue=120v (winding 2)

Jumpers
Six jumper bar for voltage change number 1 thru 6
For 100V you install one bar each for 1,3,6.
For 120V you install one bar each for 2,4,6.
For 220V you install one bar each 3,5.
For 240V you install one bar each 2,5.
 
What to do? 240V input
- PPL wire from Trafo to Jumperboard
- BLU wire from Trafo to Jumperboard
 
- Jumper in Position 2
- Jumper in Position 5
 
 
- Replace Fuse (250V, 750mA, or about 0.63A-0.8A)
   (Fuse was for 100V: 250V, 1.5A)


 
 
here below you do not see the missing purple and missing blue wires from Trafo to Jumperboard (on the board you see just the words BLU, PPL)

 
Jul 18, 2013 at 3:45 PM Post #23,640 of 24,807
Now that the Japanese Yen has crashed and likely will stay that way for some time, do you guys think Stax will lower the MSRP here in the U.S.? I only ask because Fostex just slashed the prices of the TH900 and TH600 significantly.
 
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