Here, not mine though: https://www.kleinanzeigen.de/s-anzeige/stax-srm-717-kopfhoererverstaerker/2750013661-172-1105

It can be switched internally only if the outside text on its back indicates multiple AC voltages

Never understood it took the US that long to introduce a PE (protective earth) wire on their AC power supply outlets and one way only fitting AC plugs; that’s long been a standard here in the EU.

yes, 100+117V as one of the rear pics show...

Google “Hysteresis” … (hint: causes low frequency distortions)

You have to use software like ETCHER to install that downloaded software to the SD-Card! ETCHER DOWNLOAD

...you want the resistors to blow first... Safety Resistors meant to blow...

Don't Zener Diodes add nonlinearities??

Put on the headphone the "wrong way" i.e. L-R reversed and see if it is then audible on the other ear. Then you know if it is your ear or the headphones! IF it is the headphones, then it would be good to send them in for revision or to a guy who knows how to repair them. I have a guy here who...

Actually when I bought STAX Set (a LNS + T1W amplifier) in the 80s, I was happy as can be - but there were no "forums" then, just friends to talk about it. Now however whatever you get or have is immediately "questioned" as there is always someone having an "opinion" of what is "better".... And...

...that you will be very happy with your set as the 009 is quite easy to drive!! ;)

That was NOT DONE by Mr Rauenbühler from what I know, he THEN sold Kits that DIYers could assemble themselves - and THIS IT WAS THEN!! He does not do that anymore since years, so this is NOT REPRESENTATIVE for his current series of Amplifiers for Stax headphones nor for the quality of his...

Don’t start a war here. Not worth it!

He’s not a competitor to Kevin Gilmore designs or what “Spritzer” or other known builders build…no worries, as he is mainly active on the German market :wink: And we all know how “crappy engineered” German producs are: BMW, Mercedes, Porsche… :LOL:

SIRRAH is an amplifier for STAX headphones made by Andreas Rauenbühler in Germany (high-amp.de) who is quite well known here. It is his least powerful amp, as he has much more powerful transistor (Polaris, Sirius, Elektra) and hybrid-amps (Alpha Centauri, Antares) - I own several of them and...