Laowei

Just wondering if you noticed a change in SQ when using the Stax extention.

http://www.mouser.com/Search/ProductDetail.aspx?R=T93YA105KT20virtualkey61330000virtualkey72-T93YA-1M T93YA is what you need. Trim screw on top, and pins in a row on the bottom.

Built it to 350V like you did. It settles in at +349 and -358. The non symmetry does not bother me as the tubes cathodes are sitting around 23V off the negative rail anyway.

ATM long term temperature monitoring mine while listening. The heatsinks opposite side of the CCS are running 130-134F. I'll probably go with a cutout in the top plate and screen mesh insert above the tubes and heatsinks and see how that works out. Agree that the KGST is a very special amp. Can't turn it off if I start listening. Many thanks again to Kevin and Birgir for the original design and development. And to Geoff for the PCB group buy.

Congrats on the nice build, Insanity!

Please post a link here.

Try Mouser. http://www.mouser.com/ProductDetail/Kycon/KUSBX-BP-KIT-SC/?qs=sGAEpiMZZMulM8LPOQ%252bykzAp4yt8IxVbGCTGRemOe8Q%3d

Then I must have a pumpkin head. On my recently purchased 009s, over several days I had to bend the fuck out of the arc to get them to do proper bass. They now are sitting very light on my head and ears, especially since I am coming from LCD-3s. The 009s are playing wonderfully with my KGST now.

Yeah, just give them a Spritzer Thump.

Try Mangler here or on that other site. Last I heard he had a set for sale for $30 +S/H.

Nice build.

Actually not. Shuguang in Tianjin north China, first started with their premium Treasure tube line a few years ago. A number of the engineers that were responsible subsequently left and started their own Psvane company originally in Guangzhou south China. I believe they may have since moved to Tianjin.

^ Can't argue with doing it right.

What I did with my 8mm thick front panel: >Drilled 9mm diameter thru. >Counterbored 19mm diameter minimum x 3mm deep (leaving a 5mm length of the 9mm hole). This is for socket clearance to tighten the installed washer and nut. And modified the Alpha pot by taking a wire cutter to the little piece that sticks up from the mating face. It is there to go in a matching hole in the front panel to stop the pot from rotating. Not really needed if you tighten the nut securely.

FWIW, another data point to add: Got my new SR.-009 last week. Also purchased from PriceJapan. Also no channel imbalance.

Thinking this thru, the 24V Zener clamps the voltage across the grid and source of the FQPF 8N80C. The grid will only draw minor current if the zener's breakdown voltage is exceeded. On second thought 1 watt should be fine.

Took me a while to troubleshoot my latest problem. I found the 24V 3W Zener on the output mosfet failed, shorting out the +350VDC supply. Symptoms were a slow ramp up of B+ voltage with the PS disconnected to the channels, and no B+ when one or two channels connected. B- was unaffected. The 3AT fuse did not blow, as the CCS regulated the current to the short. Looking now to replace the Zener. Locally, I've found 1watt and the physically larger sized 5 watt. Will 1watt be adequate, or should I order a 3watt from Mouser and wait a week for delivery?

Thx.

How do the Stax electrostatic headphones scale with voltage? For instance, a model's sensitivity is rated at 101dB@100VRMS at 1khz, if the voltage is doubled is there a 6dB increase of SPL?

Oh my!

Nice! A real mini BHSE.

WOW! Super nice work!

Measure the voltage across each zener in the string with the power on. Turn it off and let the HV capacitors settle. Replace the highest measured 100V zener in the string with a 91V zenner. Power up and remeasure for 350VDC output. Repeat replacing the 91V zener as necessary to get desired PS output voltage.

I have a balanced Schiit Gungnir DAC in my main system and will hook it up soon and listen to 96/24 downloads. Even now, the KGST and SR-207 in mono via iPod sounds very promising. Surprisingly in mono, it sounds more open with low level detail than my current LCD-3F. Guess you could say I'm liking it. More to come as I get both channels up, get the upcoming Schiit statement DAC and more a more high end Stax set. Thanks again to Kevin and Birgir for all the work this design, and Headinclouds for putting on the GB. I am enjoying building this amp and exploring the new for me Stax universe.

Listened to one channel of my KGST last night. First time I ever heard a Stax, even if only a lowly SR-207. Source was an iPod Touch with its crappy digital attenuation playing MP-3 compressed files. It sounded pretty good actually, which I attribute mainly to the KGST. Originally I wired up one channel, and dialed in the balance and offset. Warmed up for a half hour and reset the trim pots. Powered down and hooked up the iPod, powered up and listened. Nice and quiet. Then I powered down and wired up the other channel. Could not get either to balance or get to zero offset. Tracing voltages, one of the first channel's CCS plate loads was acting up -could not get a stable voltage. Powered down and using my Fluke as a diode tester, found a problem with that one IC, compared to the other 5 in the amp. Unwired the first channel, and the second channel was able to balance and zero offset. Listened to that channel, and everything was nice and quiet there too. Listened for about an hour to mono..... Ordered some more 10m90s and other parts from Mouser this morning.