Wednesday, October 21, 2009

Circe! Circe!

In the summer, I use a separate stereo system geared for outdoor use. But when the cold drives me indoors, I turn back to my indoor system. For the past several years, that system has centered on 8 Watt Welborne Labs Laurel amplifiers driving a pair of Pi Speakers 4 Pi Studio loudspeakers.

For this winter, I thought it was time for a change: a little more power would be nice. I decided to hook up my old Parts Connection Assemblage ST-40 amp, the first amplifier I built from a kit, sometime in the late '90s. For those of you who don't know it, the ST-40 is a 40 Watt push-pull design built around EL34s, and it's one beautiful amp (if I do say so myself). I have not used it all that much in recent years, but every time I plug it in I'm amazed at how great it sounds.

Then, as I have documented in earlier posts, last winter the amp started blowing fuses. In a series of emails, Chris Johnson, the President of PartsConnexion (the unofficial successor to the old Parts Connection) diagnosed the problem as a shorted power transformer. I bought a new one, installed it (and cleaned up some sloppy wiring – remember, this amp had been my first effort), and Voila! Good as new!

So, last weekend I decided that my old, neglected but refurbished ST-40 should re-assume its rightful position. Right now it's paired with a Welborne Reveille preamp and drives the Pi Studio 4 speakers. Sources are a crappy CEC CD player (working on that) and a Rega 3 turntable (the latter accompanied by an Audio Electronic Supply phono preamp).

The ST-40 and the Studio 4s are a wonderful match. With 40 “tube Watts”, the ST-40 has plenty of power to begin with. Mated with the sensitive Pi Studio 4s (97 or 98 dB, if I recall correctly), the ST-40 can easily handle orchestral crescendos – or Eminem. After a long layoff, the ST-40 was grainy at first, but after a few hours it settled in and began displaying the clear, smooth lushness that makes it such a wonderful amp.

Firing up the system tonight, the first thing I noticed was that ST-40 is dead quiet. Even with the Reveille volume three-quarters of the way up (stepped attenuators!), when I put my ear to the Pi drivers I heard . . . nothing. Not even a trace of tube hiss. I must be a re-wiring genius!

Then I decided to put the amp to the acid test: Richard Strauss. First up, the second disc of the Rudolf Kempe Ariadne auf Naxos on EMI with Gundula Janowitz and James King. Both the glory and the difficulty of the recording is that it is miked very close. If your stereo is bad, you'll know it; but with a good system, the beauty of the voices makes the hair on the back of your head stand up – as mine is doing now.

Next up, the the third act of mono version of the Karajan Der Rosenkavalier, with Elizabeth Schwartzkopf, Christa Ludwig and Teresa Stich-Randall. You can quibble all you want about whether this is the finest version of the opera as a whole, but there's not a doubt in my mind that the trio is unsurpassed. And on the ST-40 it's spine-tingling. Sounds like its going to be a good winter!

The pictures were taken in low light and without flash to try to capture the tube glow, so forgive the fuzziness.

1 comment:

  1. I'm really glad to hear that your amp is working again. It's going to drive me to setup my amp and see if I can sort out its issues.


Related Posts with Thumbnails