Comments for Precision Services

Comment on Upgrading the Stax SRM-252S by JohnB

JohnB — Sat, 15 Feb 2025 16:23:15 +0000

In reply to Daniel. You're welcome, and thanks for the heads-up, it's corrected. Web hosting was recently changed...

Comment on Upgrading the Stax SRM-252S by Daniel

Daniel — Mon, 10 Feb 2025 23:09:41 +0000

Hello, BOM link seems to be dead, can you pls reupload? Many thx for your great work!

Comment on Upgrading the Stax SRM-252S by JohnB

JohnB — Fri, 31 Jan 2025 03:32:14 +0000

In reply to Henry Young. Glad you found it, Henry. Take your time and get the details right! I love your story... if only we were all blessed enuf to have 230V straddling our skull! :) Cheers.

Comment on Upgrading the Stax SRM-252S by Henry Young

Henry Young — Wed, 29 Jan 2025 13:32:27 +0000

Dear John,
Amazing write detail on the SRM-252S projects.
I just discovered your Precision Services website & viewing your “Audio Stuff”, I have totally lucked out. Recently acquired a SR-L300 & SRM-252S, I plan to mod the amp following your description. My units main board is the exact one you mod. Very excite to see the jump in SQ after the project. May take some time, as I spread my time with 6 grandkids in 3 different states. Anyway, I see you have the SRD-7.
Ha-ha. I owned the SR-Lambda / SRD-7 back in 1980. Loved the sound, but sold them. Some audio buddy frightened me into selling, something 230vdc between my skull. Regrets, the replacing Beyerdynamic DT880 a totally short on all SQ features. John, thanks for letting me bend your ears.
Cheers, Henry
Cary, North Carolina.

Comment on Upgrading the Stax SRM-252S by JohnB

JohnB — Thu, 23 Jan 2025 17:21:22 +0000

In reply to donald troise. Thanks for your comments, Don. And good on you for your persistence and getting all of the details right. It pays off in the end!

Comment on Upgrading the Stax SRM-252S by donald troise

donald troise — Fri, 10 Jan 2025 17:02:46 +0000

I had given up on this amp before finding John’s mods. These are not simply upgrades of components; this is an engineering rework.
I implemented the mods one at a time, and each one provided an audible, easily recognized difference. The last one that I implemented was the optimum filter and by far the most impressive although they are all necessary parts of the whole. This should be considered a new amp because it is nothing like the stock amp, the soundstage is wider and deeper with more air around the instruments, and the singer is dead center with the instruments at the top left and right and the bass at the bottom rear where it belongs.
There is full control of the volume control w/o any distortion from excess gain and the organic warmth in the mid-range is to die for.
I would have never believed that I would be in love with a transistor amp being a tube guy. I cannot quit listening and there is no fatigue at all.
Thanks to John for this remarkable engineering rework as he has saved me a lot of money, as there is no desire to find something better.

Donald Troise