spritzer

Here is how I did the first one:

I haven't tried a new one in a few years but I might pickup a fresh set just to try out. Speaking of the 007's just see what Stax dropped on Youtube...

Not that I've heard but then again...they have so many issues (and noise) that it might just be lost in the haze.

I found these on the official Stax sale site so a bit more info: So...this is a 007t with inferior tubes (they can handle less power than the 6CG7) and the same 47k plate load. Not sure whey they fuse the B+ on each triode but that's clearly what's going on. Now for the SS: Not enough detail to see the VAS but this is clearly a take on the T8000 and 717 so resistor loaded VAS. You can spot the power resistors behind the VAS heatsink.

Could be. It is clearly a SMD part but most of these are also available in those packages but one wonders why... I doubt Stax are using any of these new fangled "non Japanese" parts as they just switched to On Semi out of necessity but yeah... who knows.

Clearly a jfet input but I didn't see the see any mention of a jfet VAS stage. If this is the same as all the pervious Stax amps (which I'm pretty sure it is), then that would be a 700V jfet...which doesn't exist.

These amps just make me sad... Same basic stuff as the 006t and 727 but at a much higher price. Resistor plate loads at 300kYen? Seriously?

Wrong primary wiring on the transformer? That would point to the high voltages...

The schematic I have is direct from Stax and I can't share it but a burned up resistor in the HV- line points to a short somewhere such as a shorted tube or a transistor. This would be shown somewhere as there should be burn marks somewhere.

The Pro Classic (Lambda Spirit in Japan and some other names in different markets) was the first "budget" Lambda and precursor to the L300 we have today. The new Lambdas will give you some improvements but over all it is just different and not a major step forward.

So he "improved" the design by taking out all the CCS stuff in the front end and replaced it with some resistors... which are way inferior... Yup...plus a shitty tube based PSU and I'm sure this is brilliant!!

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.