spritzer

The -430V is generated on the psu board by stacking a TL783 supply "underneath" the -400V supply. No need to cascode the 10M90's, single units per tube are just fine. Heaters can just be left floating or take a voltage divider from the B- line. Stax tied the heater directly to the B- line in the T2 so that would work here too. That chassis is similar to what I'm using for the small KGSSHV and they are nice to work with. The umbilical connector can be something like this: http://www.ebay.com/itm/1-Military-Gold-10-Pin-Twist-Male-Female-Connector-M10P-/300562711241?pt=LH_DefaultDomain_0&hash=item45faef02c9 Been using them for years and there is also a female version. You can also just generate the normal bias from the B+ inside the amp chassis via a voltage divider.

That's what I'm doing and why I might thin the Mk1 heard a bit.

My only problem is the cost...

Any Lambda would be a small incremental upgrade or a simple change of flavor but I'd hold out for a 007. Something I just found in storage, my modified KingSound M-10: Whole bass boost BS removed, RK27 installed instead, crap sand cast "plate" resistors replaced with Kiwame Carbon units, output caps upgraded and installed some heatsinks with some thermally conductive epoxy. Far better now but still not a good amplifier...

No need for that, just measure before the ballast resistor i.e. the resistor next to the bias output.

Happy Birthday!!!

Ditto what Kevin said and it is perfectly fine to have the amp "playing" when testing it.

Nope, no dummy load needed for any adjustment. PSU works just fine without any load and the voltages should stay the same with a load.

I'd rather say, crazy people do stupid shit... I can understand the need to change something in the WEE though as it is just garbage. Transformers not even remotely intended for this use and a bias supply which will kill the diaphragms. Pure win there...

This is exactly my problem too, nobody around to do any of this for me.

Kevin and I have been laughing about this post by eric65 today. The guy is the king of fucktards, clueless to boot and I hope it's clear that this shit doesn't actually work. If the amp had enough voltage swing for Stax, can you imagine how loud it would be with normal dynamics? That's assuming they would even survive the abuse for more than a few seconds. My favorite part is about the 'stat impedance being a constant. He can't read just one article about how electrostatics function?

Happy Birthday!!!

That silver one looks awesome!!!

What I'm really looking forward to is another one of these chassis that I have here. The reason is simple, the sinks on that one are huge so hello MOAR current. Even though the HV circuit is extremely linear with regards to output stage bias it doesn't hurt to run it far harder. That may remove some of that high end grain that is evidently very clear with the 007Mk1...

Dunno, I just come here for the bacon...

That's easy: http://www.moon-audio.com/stax-cable-mount-5-pin-din.html# Allied seems to be out of the male plugs.

Not sure to be honest. Haven't even fired up the boards yet.

We'll see how well the prototype runs and if I'm happy I'll probably make a few more as I have the PCB's. Nahh, just stick a 6.3A in there Single Power style...

Well there are some small issues. The KGSSHV logo is in the wrong spot so the screw is where the lower part of the K should be, one line is missing from the volume control bar and on the back the amp, the lines around the input section intersect with the screws a bit. I'll make another one though which will have this stuff fixed as this one has already found a home. I might get one of my Blue Hawaii's back then... Ordered some resin impregnated and fully shielded transformers so we'll see how that turns out. Ca. 110VA so plenty of current on tap.

Happy Birthday!!

Happy Birthday!!!

Just think about how much space I would have saved by simply sticking the boards on with some doubler sided tape. That's NorthWestern engineering style... A fully shielded transformer does fit in that space and I'm working on getting a slightly taller one that is less obstructive to internal airflow.

They are still being etched for me but it's close to my work and not terribly expensive. The black panels are just showing the natural aluminum underneath the anodizing but the silver panels are covered in some film and then exposed to the laser. This leaves the color residue on the panel and a nice textured feel. I can have this in pretty much any color so I might do a pink one... This shows just how tight a fit this is, roughly 180*100mm that's completely unobstructed. The PSU will have the fets connected to the bottom of the chassis for heatsinking but even so it's 108mm by 80mm. The area with the caps is a bit smaller so they should meet the 100mm limit. I've started to shop around for a transformer so we'll see if anybody is feeling brave and can make a shielded one for me. I can also fit one of my power boards to the back panel so easy AC wiring.

Speaking of offboards... As some of you might have spotted, I quite like to push the envelope in making smaller and smaller amps. Going with what Kerry did but in an off the shelf chassis and no SMD parts it is a challenge to shrink something this complicated. PSU isn't ready yet but it is version of the BH design so +/-400V max. That does mean more current though... The chassis is about 10mm wider than a SRM-727, similar height but much shorter. Ohh and far more power... Also, one should never do the chassis artwork 1 hour after they should have gone to bed...

Nope, the output transformers will be ditched and I'll use different output transformers which step up the voltage and acts as a phase splitter. Something like this...