Regular Audiophile Review readers know that I like older Stax headphones a lot. Some readers might think I like them entirely too much, but then they haven't heard my latest acquisition, a Stax SRM 007t vacuum tube output driver unit.
I bought it from a seller on EBAY. The description was light on details, but it did include a bunch of photographs of its exterior and interior. The seller wasn't well versed in electronics, being primarily into selling craft supplies. And the seller never actually tested the SRM-007t, but claimed it was in "excellent" condition. I submitted a "buy it now" offer that I felt would leave me some budget for possible repairs. It was a good thing that I did.
When the SRM-007t arrived I gave it a good look over and I didn't like what I saw. The first bad sign was that several of the screws that held on the outer case in place were missing. Missing screws are usually a sign that the unit was opened up by a less than fastidious repair-person (who was lame enough to loose screws.)
Too bad the next problem with my SRM-007t wasn't so easily remedied with additional screws. The amplifier flat out didn't work. The front lights came on when the unit was plugged in, as did the set of four internal LED warning lights, but nothing in the way of signal or sound came out of the unit.
Now, for most folks a DOA amplifier would be "game over." And kiss whatever was spent through EBAY as goodbye due to sunk costs, the money gone forever like "summer's wages," in the words of Ian Tyson. But I contacted Accutech, who are currently Stax's US distributors, and the authorized repair center for both Stax and Accuphase. I've been fortunate that Accutech has restored several vintage Accuphase units for me in the past, so I have a fairly long relationship with them. Accutech agreed to look at my SRM-007t, but with no promises. That was good enough for me. There was still hope. I sent Accutech my Stax.
After looking at my SRM-007t Accutech had some more discouraging news. My amplifier was missing parts. Specifically several zener diodes, transistors, and FETs had been removed from the circuit path and not replaced. Until the parts were put into the amplifier Accutech couldn't even begin to determine what was wrong with the unit and whether these missing parts had been responsible or whether some other parts had caused the missing parts to fail. It would be several weeks until the replacement parts could arrive from Japan, if these parts were still available. I agreed that ordering and installing the parts was the correct next step, even though that meant committing more money to what was still a very iffy outcome.
More than a month went by until I heard from Accutech again. Their email included an invoice and a list of replaced parts and the short comment, "Unit returned to factory specs." Hallelujah.
The repaired unit arrived yesterday and the best, most detailed description for the sound is, "WOW." Not only is the SRM-007t dead quiet so music comes out of an absolutely black background, but the soundstage is larger with greater specificity than the Stax SRM-1 Mk-2 that it is replacing.
Excuse me while I go back to listening to my Stax SR-X mark 3 headphones through this glorious sounding tube amplifier. Thank you Accutech. You've saved my bacon, yet again...