spritzer

That's a bit high but not massively so, I doubt that is the issue here. Intermittent issues are so hard to track down but do one thing, try to reseat the input BJT's (they are in the middle of the boards) and see if anything changes.

You can measure at the output connector or just directly behind it on the main PCB inside the chassis. Multimeter set to VDC and just a few millivolts should be present. You measure with regards to ground so the black probe goes onto the chassis or the middle pin on the volume control (either side) marked GND.

Well here is something odd, it's well known how much I "love" the SR-009 and I recently picked up a used one in Japan as a part of a larger bundle. I was just going to move it on as I already had one in my collection so after putting it off for a while, I sat down to test it in my main rig just to make sure it was ok. Now here is the odd part... this one sounds nothing like the other eight SR-009's I've had here over the years. It has a slight forward tilt to it but far better than any 009. It lacks that artificial "boxing in" of voices or the excessive brightness superimposed on everything. I dare to say they are pretty smooth and with proper bass response too. Thinking I was going nuts I grabbed the other set from my collection (which sounds like all the other 009's) and did a double blind test. I had my better half pick songs and hand me either of the two sets (plugged into the same Carbon CC) and this wasn't even close. With the regular 009, just the opening of a song was enough to give them away. That same feeling as with Tyll reviewing the Ultrasone ED10 if anybody remembers that... Now this set is never leaving my collection but why is it like this? It's not a super early one or a late one, I've had both (plus everything in the middle) and they all sound the same. In fact the other set I have here is one of the last ever made and it sounds the same as the very first set I got back in 2011. This set is in the SZ9-1200 range so this has to be a QC issue or something like that. I don't know the history of the set but no mention of it ever being serviced. Earpads feel like new and the whole set feels like new so yeah... not sure what is going on. I first tried tried them on Friday and I've probably logged 10 hours on them by now which is pretty unheard of for me with 009's. Hell, I had to force myself to try the Purrin Rock set which just arrived (those are weird) and now I'm back on the 009's.

No, never had this issue pop up but first thing to check would be the offset voltage. If something would fail, it could knock the servo out of kilter and damage the headphones.

I might do that and also fix that stupid cable entry and how the earpads are mounted. It's on the back burner though as I want to mull it over a bit.

Hehe not sure but I always like to take a basket case and make something useful out of it. I do have some plans for these 009's which might help with them all in the future...

Just don't do any of this, none of it is an improvement and just fucks up the sound for no good reason.

So I bought a lot of modified headphones on ebay, SR-Lambda Signature, SR-007Mk2 and SR-009. They looked to be in rough condition so I thought, worst case I'll tinker with them and have some more spare parts for my stock. Now... the first two units were bad... really bad but I fully rebuilt them from my stock of spare parts. Now I've been fixing up lost cause headphones for 20 years but still, these were the worst I've ever seen. Missing parts everywhere and utterly retarded ways of "improving" them by making everything worse. Now, I had left the 009's in their box until this morning and wow... just wow... So what are we looking at, these are the outside protection grills... taped to the outside of the housing with some rubber/butyl type tape. The earpads are fixed in place with it as well and it covers up the cable entry on both earcups. Now... this is after repairing two utter clusterfucks of incompetence and stupidity but yeah, not prepared for this one. Pull off the earpads and the tape around the cable entry and this is what greeted me. Just look at that soldering, the holes in the dust covers and well... the driver in backwards. These are dipoles like all Stax... it won't change anything to put it in backwards. There was nothing holding the earpads in except more of that glue and notice one missing screw on the driver. It gets worse though... Here is the driver removed and there is no dust cover at all. Yeah...nothing at all. Here is the other channel with just the tape over the cable entry removed. How this is supposed to improve performance is completely beyond me... Here is the housing with the driver removed and just look at all that adhesive residue. That ties into this, the earpads: Now they are utter trash at this point but look at the adhesive residue on them, that is hot glue! The most useless of adhesive which should only be used by kids in arts and bloody crafts! So end results is these headphones are completely fucked. The arc and housings can be used and the cable might be ok but the drivers are probably beyond hope. Add to this all the missing hardware and I'm not sure what I'll do with them. I might try to find a dead set of 009's with driver failure and make one good set out of the two or something creative. Final lesson, if somebody says they are modifying headphones and improving performance... odds are it is something like this.

They did suddenly show up in quantity at Mouser last time so it might happen again. I just found out about it as I had some on order and they suddenly shipped, way ahead of the set date.

Flights and hotel booked.

I'm thinking about it

So if it is anything like this: https://6moons.com/audioreviews/viva/4.html Yeah... this is utterly terrible. To make things worse, those are Rifa caps, known for one thing only... failing internally and presenting a dead short. Plus they are PSU caps, why they are used for coupling is beyond me. This does stink of SinglePower... Some more pics here: https://www.audioshark.org/amplifiers-8/amedeo-viva-visits-suncoast-audio-16591.html Look at this trash, 17k$ and all you get is an Alps RK27 for a volume control that costs less than 10$...

That's very cool. 🙂 The old ones were brass?

My schematic shows 8.2K for that position so not sure what schematic you have. Also check R44 and R45 if the voltages look a bit low.

I think Stax use the new Tung Sol GTB in the 700T so that is new production. Whether you can get them anymore... I'm not sure as they are made in Russia. As for the voltage, the GTB tops out at 450V so it's better than the regular version but still a long way from the 6S4A etc. There is also the 6BL7 but no new production that I know of.

It really doesn't matter, 5% is plenty good so just go with what ever fits.

If you want to use a 6SN7, I'd always use the 6SN7GTB's since they are higher voltage. I wouldn't touch the PSVANE tubes nor believe their specs though...

Check the resistors in the power supply, they are known to go bad.

For me the 007's are a clear step up in every way, much more controlled, actually layered sound stage (which so few headphones can do) and far more resolving. Once you get past a certain point the SR-Omega gets lost and confused. They are still great but yeah, 007's were a big improvement. I really don't agree about the X9000 bass compared to the 007's, it completely falls flat on its face. Apparent resolution vs. real resolution to me.

Price is always tricky, the 007's should be far more expensive based on the parts and their quality but the true cost has been amortized over the last 25 years. The CRBN without the forged carbon, CF headband and the fancy metal mesh could have been far cheaper. Then you have the issue of things being far too cheap so they aren't taken seriously. They way I see it is CRBN vs. Voce, both made in the US and similar enough in price these days. Voce is trash though...

This shit is just too retarded!! 😂 I for the record gave the entire 009 lineup another chance recently. Since they are so cheap now, for even like new used sets, I got a 009 and 009S... and they are still awful. This was actually one of the last 009's to be made and still sounds the same as my very early example. The 009S was also pretty new and yeah, still sounds the same sad mismatch of ideas. As for the X9000, it's not top of the line by any stretch of the imagination. Since I got a pretty much brand new SR-Omega for my birthday this summer I dragged out the X9000 for comparison and that lasted two songs... I couldn't get rid of the X9000 fast enough so it's back in the display case. Next comparison was SR-Omega vs. SR-007 nr. 35 of the production line... much closer but the 007 is easily better in every way.

I don't really give a shit what you think but my views/impressions are never for sale. The CRBN is flawed but still an excellent set of headphones with production quality rivaling Stax is many ways. In terms of sound, that is always subjective, but it's clear, based on the market, that people are not happy with where Stax are going. Used prices of 009's are now often below that of a used 007 (not even a rare Mk1) and the 009S's are headed that same way. Also notice how little talk there is about the X9000 from the long term Stax owners, those that did buy a set, quietly sold them off as they just aren't good.

Not sure, ones been sitting unsold in Japan for weeks for just over 3k$.

Nope, no way to do that and with roughly 40% failure rate, no way I'm ever touching one of them again.

This just makes the original Stax T2 sad... That hum's like there is no tomorrow.