spritzer

Sure looks like it...

The whole issue with measurement is indeed, how do you interpret the data. If THD+N is the holy grail...why do all the amps that suppress it completely sound like crap? Why do opamps with all the open loop gain in the world sound like turds? You can squash them down yet they still sound terrible. Why do certain circuits sound the way they do, what is going on really and why are some things which should be better...actually worse? As for the BH vs. 006t, well that is easy. If Stax were to test the amps at anything more than 100Vrms/1kHz then the difference would be starling. One amp can swing a lot of voltage without limitation while the other just can't.

Yeah, small size does add a lot of issues if you scale up power just a little bit.

Interesting input fets....

They are silistors actually and yeah, overload protection, and I remove them as they serve little to no purpose these days.

You can still get kits from Stax with the foam liner and the wool at least a couple of years ago. As always though, getting any parts from Stax is a pain....

The foam has no impact on the sound at all but the wool makes a lot of difference. I prefer to keep the wool in place as it makes them sound more balanced.

The 507 is the top tier Lambda in terms of build quality and comfort (though some don't like the new 009 style headband) but the sound is just so bloody thin. Compare them to the SR-404LE and the difference is startling, no substance to the sound.

Yup, the 507's are the biggest turd Stax have ever made. I don't think there is any other set which has just been truly bad like that. I'd take the 207's over them any day let alone the 307/407 which were the best from that generation.

Pure quality right there. Who needs full frequency response anyway...

The SRM-353X certainly superior to the SRM-1 Mk2 but it all comes down to value. The cost in parts of refurbishing the SRM-1 Mk2 is far lower and the difference between the two isn't all that big. I personally prefer the direct drive amps and with a transformer the cost is really high too due to the stepped attenuator.

A refurbished SRM-1 Mk2 does stand well up against the transformers. For me it is a toss up between the detail and accuracy of the amp vs. the raw power and voltage swing of the transformers.

A perfect transformer doesn't exist and they usually have a lot of capacitance which adds to the load and thus...loss. Bunch of other issues as well but for a budget setup, transformers work well and are easier than ever to use with all the excellent chip amps out there. Well not the Wee...all the ones I've seen have a shared negative which will blow up the amps...

It's the EIZZ 24 step attenuator.

https://www.head-fi.org/threads/the-stax-thread-iii.677809/page-1198#post-15108864 Ok, it's not often we see this level of shit... but holy fuck on a stick. So this is claimed to be an "improved Carbon" but the only improvement I can see is an added chance to burn your house down or give you a nasty shock. Seriously, this is apex level shit and how anybody would ship something like this out...is just beyond me. Also, gotta love "thinker" who consistently shows any possibility to do just that....

I've only talked to him once but he seemed like the nicest guy. Makes sense to do both panels at the same time. Might also be time for the bias supplies too.

I doubt anybody has a spare panel for these but Kent is at Electrostatic Solutions

The price of these has shot up recently so this will probably just get worse... As for the T8000, just get a 727 instead.

The balance and offset adjustments are the same as the for the Stax SRM-T1 so all the same applies. The pots are marked on the PCB so its easy to spot which is which.

On the ones I build that is not possible. Those dual split shaft pots are impossible to get outside of ordering thousands of them at a time.

Great write-up but one note, that is a regular KGSSHV and not a Carbon.

I like that one a lot!!

Let's just say I have a personal museum...

Yes, dual concentric volume control on this one and I'm pretty sure this was the first balanced Stax amp.

Now for something pretty rare... the ESP900... This is the closed back version of the ESP950 made for medical use such as MRI's etc. Not much is known about these and only a few sets have ever surfaced. I'll do a more indepth post about these when I modify them and dig into them a bit. Stock...well...they don't sound good. The earpads are unique to these so when you press them to the head...the sound gets better but it is no 4070...that's for sure.