Vacuum State of the Art Conference 1998
You didn't make it to the VSAC 98 show!? Boy, did you miss out! Here's some of the things that happened ...
Tim Lollar and Paul Joppa presented a "Tube Tasting," a sonic evaluation of no less than 16 preamp tubes ... in a blind test, no peeking allowed. 12AX7's, 12AU7's, 5687's, 5670, 5965, 6DJ8's, 6SN7, 6J5, and a real old-timer, a 201 direct-heated triode. The drawing shows Tim's circuit, with the tube-under-test driving a direct-coupled cathode follower; the plate-load resistor is set to Rp x 4, and the fixed bias is set by a separate adjustable DC supply.
(Paul is resting his elbow on an Exemplar, the horn-loaded high-efficiency speakers that made such a favorable impression at the show.)
After the crowd heard all 16 tubes, Tim and Paul lifted the veil and let us know which ones we'd been hearing. Then they cued up the CD player and we heard all 16 again with a different musical selection. The VSAC favorites? Well, you had to be there ...
Here's Ron Welborne, looking like the cat that ate the canary. I think he's pleased (with good reason) about the sound of the new KR Labs mono-plate 2A3.
Here's the reason for the smiles ... the Moondog 2A3 amplifier. The tube at the back with the black base is the new KR Labs 2A3.
The Eire speakers from Shamrock Audio. Despite Mike McCall's extremely conservative rating of 85dB/metre, they played quite well with the 3 watt Moondog, and were a great match with Ron Welborne's new KR52B 25-watt amplifier (shown on the left). The dynamic qualities of the KR52B are reminiscent of the KR Vacuum Transistor I heard at the CES; they sound considerably more powerful than the wattage rating would indicate. According to Ron, the secret to getting real dynamics from the larger KR tubes is a power supply with peak currents that match the capability of the KR tubes.
Tony Glynn of Lowther USA enjoying the sound of (what else?) Lowthers. Note the beautiful cherry-stained birch cabinets crafted by Jeannie Hopkins.
Those of you who are familiar with Lowthers know how nice they sound with 2A3 amplification, and that's what we were listening to at the show ... the KR Labs 2A3 were making sweet music in many rooms at the VSAC98 show. (I wish I could say the same thing about the sonics of the CES!)
Moving from 3 watts to 20 watts, here's a photo of Jack Strayer's 1950's cinema-style push-pull 845 amplifier. (Do you think the bias meters are big enough?) In a concession to modernity, he uses Svetlana SV572's instead of costly NOS 845's. No tweak parts or fancy cable, just beautiful Class A direct-heated triode sound in a classic Williamson circuit. One of my favorites at the show.
Here's the eXtreme Audio (shortly to be renamed Ultra-Fi Dream Team) room, featuring Exemplar horn speakers, the eXcite parallel-feed 45 amplifier, and the Electronic Tonalties 2A3 Paraglow. Anyone doubting the dynamics of a 3 watt amplifier had to hear this one. If all you've heard of horn speakers is Altec A7's driven by a Crown DC300 PA system, well, you haven't heard horn speakers yet.
Welcome to the Craftsman's Room