spritzer

No subs for the 6S4A's but the amp can be redesigned to fit some other tubes if supplies run out. They are even more oddball and nobody has any use for them... Tubes have to be matched pairs but ideally matched quads of the same identical construction. The biggest difference is GE or RCA manufacture but there are a few sub groups of the different tubes. While on the subject, the KGST power supply PCB's just arrived so I'll see when I'll have the time to stuff one and test it.

Doesn't even air this year...

There are some slightly different versions of Teflon so some might work better than others. Delrin would also work well... I honestly can't remember, it's been a while since I had a 4070 here. The walls are very thin and that shape is hard to make from wood. Could be some resin filled wood though. That shape is just so awesome though, somebody really knew their electrostatic dispersion theory.

Definitely switch to stock speed and see what happens. This is normally done in bios but some motherboards (all? I stopped doing this in 2002...) can do it in Windows. Could also be a failing capacitors somewhere. Most motherboards have stopped relying so heavily on electrolytics but the PSU still has them.

Hmmm my HE90 needs a new plug... No opening and the damping is a thicker type of wool than the one found in the Sigma. The real start here though is the housing, it took real skill to design something like that.

I had a pic of it somewhere but I can't find it. Basically it's a slot cut into the edge of the baffle on both sides that tapers off a few mm from the end. The pads then partially close it.

The main reason to swap to 10M90's is that they are cheap, easy to get (well if you are in the US) and can handle far more voltage. 2SA1156 won't work here due to voltage constraints so we'd need 2SA1968. Not everybody is sitting on a few hundred of those...

Indeed though the LL is based on the older SRM-1 Mk2. As for explaining that circuit, it's about as simple as it gets.

That's excellent, well done Tyll!!

We will probably start off at 20mA but it's also a simplified KGSSHV with the last stage removed. Pretty much a solid state KGST then.

The output capacitance is still a bit too high for most of these. This one makes me a bit happier... www.cree.com/~/media/Files/Cree/Power/Data%20Sheets/C2M1000170D.PDF Special SR-009 amp using these in the works. Price didn't pan out and I didn't want to drop 7k$ on transistors in one go. I haven't stopped looking though... I did manage to score a few thousand 2SC4686A's but they are all earmarked for KGSSHV production as I was running out of parts.

Do not plug the EL61 into a Blue Hawaii, neither party will like it very much... I just did some digging and they don't seem to like anything above 300V but the BHSE is 800V...

Wait for the all black KGST then... Too small to make any sense as it can only take GE tubes and not RCA's as the GE's are just a bit shorter...

Hey!!! I don't have a patent on wood...

Cryo is bullshit with some basis in reality. The crystalline structure of metal is a factor for some uses and for stuff like margarine and chocolate it is critical. How that would matter to tubes, cables, headphones etc. is beyond me though. Especially the tubes which will reach 150°C and undo what ever changes might happen when you cryo treat the metal. Utterly absurd stupidity. Plenty of DIY Stax amps but no commercial units this cheap.

I set it up after the idiots on HF made me an MOT.

Mp3's... really??? Stax requires a top end source (not expensive, just good) so any harshness could easily come from there. That and the mastering on most newer recordings is awful which doesn't help matters. What ever you do, don't buy ECC99's and stick it into the amp as it is now. It will destroy it.

It's more that Mikhail was insane to use caps that big.

I'd class both the 404 and 407 as harsh though the 404 less so. The stock tubes are probably fine but it's the tube type that is unfit for the role. Not much else out there though that can replace it. The ECC99 can be fitted with some mods.

The Kimik mod is a bad joke. Take some NOS tubes (not the good ones), a tube cooler which isn't needed and then it is "properly adjusted". Now the thing about the Stax amps is that their power supplies are completely unregulated so once the line voltage changes (which it will) those adjustments are no longer accurate. The distortion you are hearing when the amp is stressed is due to the amp design simply not being to swing enough voltage. The SRM-323 is better in this regard but it sounds a bit thin. Just the nature of the beast as Stax had to build it to a price. Tubes are high voltage, low current and low output capacitance. Electrostatics are high voltage, low current and low capacitance so the perfect pair.

Two caps wired back to back in an non-polar cap. Non polars aren't all that common with the Nichicon ES being one of the few good ones left.

One of my KGSSHV transformers melted so Richard replaced it. That replacement cost me about 300$ in customs fees as it was declared as if I had just bought them... The replacements seem to work just fine but I've only done brief tests.

I usually go for no more than 35°C above ambient. That's at max load which I'd never run a transformer at.

Well I do have a contact page now... Setting up the site was easy, finding time to add anything to it is trickier. Today I started work on three new amps instead of making so product pages. I'm seriously considering adding a thread in public area here and linking to it. I'm never going to accept orders for anything, just sell what I've already built, so having a thread for it makes sense. Ohh yeah, one of the amps I started on is a KGST...

We really should do that. Please address all requests for advise to [email protected]