spritzer

Indeed good sir.

Any normal amp would run the outputs in series (as in the amp outputs are the same) and only the bias supplies are different. Now the A-10 is a steaming pile of fail and Ray is a half-wit so anything could happen. If the headphones work on the BHSE then the A-10 would be my first place to look for faults, same with any other amp/headphone fault situation.

Not sure. This was all in the early 90's but somebody might have posted the documents somewhere.

...and then get sued by Magneplanar just like Apogee...

Some updates to the Stax DIY amps. As soon as I get the SRM-727 here then I'll post a guide how one goes about altering the feedback loop but for now we'll have to settle for something less fun. SRM-Xs These are pretty uncommon as they were only sold with the SR-80Gold headset and being electret units, have no bias supply. Now this being Stax it doesn't mean there isn't a space for one or two on the board. Now this design is very different from the SRM-Xh I modified above even though they share the same chassis and there were even some SRM-Xh's which used this PCB. Just take a look at these pics: The core design is similar but very different layout and same goes for the output devices. The Xs is a bit unique as it uses Mosfets for output devices, 2SK216's to be exact which can be found in the Blue Hawaii as well. Now the whole point of me writing this was lack of a bias supply in the SRM-Xs. In the pic above it should be between the large blue caps and the transformer. The spaces are for 3 caps (10mm pitch), two diodes and one resistor plus the terminal for the connecting wire. For the caps I just used what I had at hand, 10nf Wima caps rated at 630V as the exact value of the caps isn't important. You can also leave out the one next to the resistor as it isn't really needed. Now for diodes I used UF4007 (1N4007 would also do just fine) and the resistor is the standard Stax 4.7M (I used 5M). This is just a voltage doubler off the B+ so the bias isn't exactly correct but it works just fine into my SR-404. Here is also a teaser for something I'm working on, converting a SRM-1 Mk2 to balanced operation. I found this upgraded PP unit in Japan and it was missing the main heatsink/output transistors and in a pretty sorry state inside. These will be replaced but the main attraction is that these amps sound great, are fully DC-coupled and are a doddle to convert to balanced operation. Just replace one resistor on the board (910K) and add one resistor beneath the board (1K) and you instantly double the voltage swing of this thing.

Yup...

Stax did experiment a lot with the bias supplies and they still vary a lot from amp to amp. I can't say I'm a fan of having a cap after the ballast resistor though... As for output caps, the Woo Audio GES (which is the all triode amp Dr. Gilmore designed and can be found on Headcase) has 2.2uf/630V output caps but Stax have always used smaller caps in their amps. Their latest capacitor coupled amp (the recently discontinued SRM-300/310) used 100nf. Now I know Woo has been playing with the 2,2uf value as at least one amp had 3.3uf which is also the value used in the larger WES. I do like the Spritzer constant. It says a bit about that I just got a large shipment of Stax stuff from Japan and I had no recollection of buying some of the equipment. Still it's not bad to find a mint SR-Lambda I never knew I had...

Look what I just got, pulled SR-007 Mk1 drivers... I haven't tested them yet but odds are that they are just fine. Also got an SRM-T1 which will be converted to accept ECC99's. The damn thing looks like new too boot...

Truly, stunningly beautiful.

I have the parts sorted but haven't found the time to assemble it yet. It will probably sound horrible but well worth it for the crazy idea alone...

Yup, should only take a few minutes thanks for the ever so helpful Stax engineers who left most of the feedback loop in place. My take on this particular design is that they wanted to try something different and it simply failed. As KG said on HF, you need a lot more power going through this thing to behave without feedback and all the sims confirm it. We'll see soon enough.

ALO Rx FTMFW!!! (says a "proud" owner)

I for one don't doubt it is a good sounding amp, in fact I've been looking for a cheap one. I always liked the old hybrid model, the SRA-3S.

Well the push-pull nature of the planars should make it less important but the large diaphragms do need a lot of damping so lets just say damping factor is important.

He probably meant a CCS, constant current source. Edit: Indeed it was. Ohh and I'd love to see the schematics.

Yeah, low output impedance and high damping factor are a must with any planar driver. Just don't try to tell that to the idiotic fanboys...

What an oversized Cmoy with no internal charging circuit for 600$ isn't a good deal?

Nah, that's just the desktop rig but I somehow floated by the whole "amp wars" without too much trouble. I guess I was too focused on buying all those electrostatics to notice the shit storm going on... Pretty much every thread where somebody opens up a RSA, Single Power or Rudistor amp is both funny and sad at the same time...

Ahh reading the archives, what a great idea. Fire up the KGSS, put on the Omega 2's and read about all the drama I somehow completely missed by sticking to electrostatics.

Awww.... Good show, Steve!!

Single color is cheaper, simple as that. Personally I'd be more worried about the crap inside rather then the appearance. Ohh and it isn't sovkiller here, it's sovshiller. One of the biggest fucknuts around and the reason why we have a limited edit window...

In other Stax news, KG has tracked down the reason why the 727 sucks so badly compared to the 717. This has already been posted elsewhere but I figured it should be here as well. The 727 is in many regards a KGSSHV but with the output stage outside of the feedback loop. So while they added the CCS for the third stage they fucked up the output stage for no good reason. Help is at hand though as Stax were ever so kind to leave most of the feedback traces in place so there is no need to run wires from the plug in cards to the motherboard. Here is a picture of the mods (taken by Kevin so it is huge) needed to be done which I will do as soon as Kevin is done playing with the amp. I also bought a SRM-300 for Kevin to take apart and here are some internal pics, front and back of the PCB. What we have here is an enlarged version of the SRM-001, capacitor coupled and running off a regulated PSU, complete with the rather nasty Alps RK097 volume pot. Due to that there is a rather unique balance function on the back panel, a fixed resistor for one channel and a cheap PCB mounted pot for the other...

Nope, they don't have the midrange shout of the other models which makes all the difference to me. The 303/404 have better bass and treble but that damn shout just kills it for me. I had a 404LE here at the same time with my last 202 and they were rather similar but the LE was more refined. That said I do have a bong standard 404 here which doesn't have the midrange coloration. Now this could be a SR-SC1 which is simply missing the sticker on the plug but I doubt it. I don't want to mess with them either as they are my test/loaner phones.

It's quite good actually. The SR-202 is far better over all than the 303/404 and the SRM-212 is a nice, low power version of the old SRM-1 Mk2.

He didn't abuse them, he just unlocked a hidden feature...