spritzer

You are supposed to bend the arcs on the 007 to get the perfect fit so perhaps that is the issue or they are a bit loose? Please don't use anything but JIS screwdrivers on these or you will utterly destroy the screws.

Did anybody try these at the NYC meet? https://apos.audio/products/sjy-electrostatic-headphones

If they can fix the QC issues everybody is talking about, then I'm hyped. I never had issues with my sets but then again... I don't use them all that much.

The diode bridge could be shorted or something down the line is making it pull a lot of current.

The L500 pads are virtually the same, a bit thicker but it won't change much. Same for the L700 pads but they will both also melt away. I always use the all leather pads from China now, cheaper and much better quality but you need to get them onto the plastic mounting plate from the original pads... which is a bit of a pain

2 and 5 is what I'd set it to and that is also likely not the cause, fuses blow for a reason so check for any failed parts. These amps are almost 30 years old at this point so they need to be refurbished.

If the fuses are blowing, then something is wrong somewhere. Never use fast blow fuses, let alone 30A. If the fuse manages to hold and something is shorted, do you want to dump 2.4kW into the amp? No...

That's excellent news as I liked the latest version I heard, V3.0 I believe. The amps are pretty poor though but better than the first version

Sorry, the links I used to buy them are dead but they are floating around on goofish

Multiple on both accounts... I might have a bit of a hoarding issue...

It could be the 20AWG wire but going by the price... I doubt it. Maybe some Chinese clone

Yeah, this is shockingly bad. Why they didn't just adapt the many headbands on the market in China is beyond me. The CD3000/R10 units are very well made from the right supplier.

When I've had time recently I've assembled a few more DIY electrostatic headphones: First off, the last of the Superex chassis I had in stock so I designed a new stator design for them: This has been a long running project to to make drivers and test the various aspects in a controlled housing. They are not ideal as they are mostly closed but I got a bunch of them for next to nothing years ago. New stators with some minor tweaks and a protective grill too: These are not really built for sound quality but to test different coatings, distortion tests on drivers and all that jive but still fun to have a pile of these here. Since the Superex is just a Beyerdynamic clone, I found some DT880's with blown drivers that could also work: The need to be modified internally a bit to open up the back but nothing major. Different stators on this one and the drivers have to be at a 45° angle to get it all to fit (not that it matters at all) but same basic idea as above Round them off with some nice leather pads, silicone 6 core cable and my new Stax plugs that I've been refining recently. These do sound better than the Superex shell as the backwave is more open. Finally, the second of those Kiwi Ears headphones was fitted with drivers: No major changes here except I didn't use the bayonet plate to fix the earpads, I rather slipped the stock pads over the lip of the housing which helped a lot Also some simple tweaks to ensure better baffle seal: Thick cloth tape here and it works nicely. These are okey sounding headphones for next to no money at all.

In other news from China, here we have the fake SR-X1: I've known about these for a while and I finally bought a set as they are so cheap... and very, very rough. They didn't arrive with any earpads but the knockoff leather X1 pads you can find in Asia do work nicely. They are clearly not a 1:1 clone and that headband is something really special in terms of being pure and utter garboleum but it was stupid cheap to add it to them. Housing is 3D printed and quite badly done but look at that cable... to make the 3D print soft and pliable it looks like an absolute mess. Same on this end but the actual plug is nice quality. Nothing wrong with those pins and the spacing seems just fine. Better look at the actual cable used, it is pretty stiff and unwieldy but at least it is 6 parallel cores so the capacitance shouldn't be too bad. It's too short though at 1.5M or so and who knows what the voltage rating is on that thing. I did order a couple of extra ones (and some extra housings too) so I'll zap it with some high voltage and see how it holds up. Anything that can't withstand 1kV AC over an extended time isn't really suitable for this role. Better shot if the actual plug, nothing wrong with those pins and it even has the cutout relief for the bias pin which I always skip on my own plugs. The driver face and the electrodes are etched aluminum or stainless steel. Not sure which as I haven't taken them apart yet. This headband was clearly an afterthought and that metal bends if you look at the wrong way but it does function... kinda. Here we can see the assembly "quality"... or very much lack there of. The housing does not fit correctly together and you might ask... why was this printed in white and the painted? Well I paid extra for the paint... but whey when there are excellent black filaments. Dunno and why not resin print this? Done right and that is superior to injection molding. More of this ace paintjob and the headphones falling apart but nice gold pins there as well. As for how they sound... well sound is produced but something is very wrong inside those drivers. They are far more inefficient than a stock unit and there is audible distortion... quite a bit of it actually. It gets worse and worse as you push the volume to normal levels for me so I'll have to take them apart and see if the drivers are misaligned. They are balanced between the channels though and at low level listening... these are not the worst ever. Now all of this is pretty terrible but clearly a work in progress and not done by some estat fanatics as one would suspect. The drivers don't really work (well they do produce some sound) and the quality is downright atrocious but funny enough, that crap cable does have strain reliefs on both ends which the aftermarket Stax cables do not have. Needless to say, best to stay away from crap too...

I'd rather not say but I'm missing 3-4 units at this point unless something super, super rare pops up.

Since I just got these, might be time to talk about possibly the rarest stuff Stax ever made. Let me introduce the SRM-Monitor Mk2 and the SR-Lambda Pro New: I've only seen a couple of these for sale over the years so very rare indeed. The headphones are basically the modern version of the Lambda Pro's but not the Spirit/Pro Classic, made later than that. The SRM-Monitor has been called the Mk2 but the changes are mostly to the chassis. Inside there is still a SRM-1 Mk2 and the ED-1 but with different parts. They are all Pro bias only and notice the extra output on the back. The volume knob is also similar to the SRM-T1S/W knob and not the SRM-1 Mk2 unit found of the original Monitors. I have no idea when these were made but I've heard late 90's and for special customers which wanted to replace their older Lambda Pro sets and SRM-Monitors. With these here the Lambda collection is almost complete...

That doesn't look like a stock unit to me but SRPP off a common heater supply...that's such a terrible idea. I do find it funny though that the High-amp circuits seem to be regressing, getting worse and worse over the years while still being filled with parts that are long out of production.

Better yet... Single Power ES-1 board!! Seriously though, as fucked as the ES-1 and ES-2 were... there was less wrong with the actual circuit than this pile of fail. Let's put build quality aside, the permanent 100V offset, non floating heaters chewing up tubes and some other "minor" issues... they did produce enough volume for a normal listening session.

Given the number of windings there, it has to be at least a couple of transformers. That is also clearly a Toroidy transformer, based on the color of the wires, and they never do tall transformers, they always just get larger and larger in diameter. That means it could just be transformers in there.

Yeah I agree but one possible major, major issue... one filament supply per channel for a balanced amp. These are no indirectly heated tubes... the filament supply is the bloody cathode.

They are very different headphones and the ES-2a easily beats in terms of price but I'd lean more towards the 009D in terms of raw performance. The 009D is really growing on me and what amazes me is how Stax can release crap like the X9000 and the 007S and then this... Both the X9000 and 007S are headphones I'd never listen to for fun while I've been logging a lot of hours on the 009D.

Look like 1544's to me too and that's not good given the gain is a quarter of what it should be. It is just me or are the output tubes AC heated? Those wires seem to run right to the transformer...

There is not enough detail to retrace anything or know what is on the heatsinks but from a build quality standpoint... this is very dire. One thing springs to mind... where is the power supply? Seriously, where is it? Also signal wires make no sense, that bias supply has be scratching my head, that's not how you do point to point wiring and servicing this would be an absolute nightmare. Does anybody see 20k€ here?

I've going over my collection, filling in any items I'm missing, I felt I really should have a modernized version of the Sigma. I came across a rather abused normal bias set which needed new drivers but wanted to try something different... so here is the SR-Sigma 507: The housing was very discolored so I wanted to try my hand at painting it. The frame was primed and painted satin black but I left all of the other parts in the primer color. The plan was to make them gloss white but this looked too cool so this is how they stayed. The drivers and cable are from a 507 so it took a lot of work to get this right. The drivers are in the cage that Stax introduced with the x07 series so I glued the drivers and fitted spare metal grills to them. In terms of sound, this is the best Sigma I've ever heard. The bass is overblown, as is always the case with Sigma's, but it has some real power to it and is more controlled than every other I've heard. The top end is nice and clean and the midrange is just sublime. A fun addition to the collection.

Figured I'd post this picture here as well as in the Stax thread, MA-009 vs SR-009D I've just been on holiday so no work on this project but I'll probably make some new diaphragms for the MA-009 soon. The ones in there are just too unstable, any major airpressure and they just stick to the stators.