Thursday, March 28, 2013

Ampinstein... It's Alive! It's Alive!


I've always been partial to old Dynaco audio gear.  I built my first Dynakits back in the mid '60s (and the PAS3/Stereo70 tubed combo is still going strong, thanks to Van Alstine mods).   The company is long out of business (Panor Corp acquired the name and at one time produced some very good modern "Dynaco" gear, including a cool tubed CD player which I own to keep my Dynaco jones satisfied.  My completed mods and CD player are here).

Dynaco is mostly known for it's classic tube gear, like the Stereo 70, but Dynaco also produced some very good transistor gear.  The Stereo 120 was one of the first "quality" transistor amps, although, by today's standards, the circuits are woefully lacking.  A zillion years ago, I bought a nonworking Stereo 120 and repaired it.  But it soon was relegated to a storeroom, buried under years of accumulated crap.  I always thought someday I'd update the amp (again, Van Alstine has a cool MOSFET mod, but it always seemed too expensive).  Recently, a new company, Akitika, and its related Update My Dynaco, has produced a new series of modules for the Stereo 120 based on the LM3886 chip.  Now I'm more of a discrete guy, but the 3886 is considered a very cool chip and is used in a number of high quality amplifiers.  The Akitika cards (including a new regulated power supply card) are also very reasonably priced.

So out came the Stereo 120 cadaver, which I then gutted of its old organs and, after a little "grave robbing" at UpDateMyDynaco, I installed the new body parts.  After a hit of electricity, the new Stereo 120 was up and running...  Alive!  And it sounds great!  Here's a couple pics (I call it Ampinstein (Ampzilla was already used), because I kept thinking of the old Boris Karloff movie while I was doing  the construction...  well, maybe it was the brain surgery).




Here's a closeup of the 3886 chip and module.


Now I had to figure out how to use this amp.  I have so much stereo gear around, I have no obvious application for the Ampinstein.  And because it is a power amp, I also need a preamp to drive it, which I don't have.  Well, now in this new era of digital, computer based music, maybe I don't need a preamp.  Can I drive the Ampinstein directly from my MacBook Pro employing the cute little Dragonfly DAC I purchased a year ago? Will I get the control and drive I need for the amp?  So with a little hookup, and lowering every volume level I could find to protect the amp, I fired up both iTunes and alternately Decibel as music players.  I upped the levels and soon was playing beautiful music through the resurrected Stereo 120.


What a desktop system (well, if a little large overall).  Way cool, and I do say so myself.