Retro Hi End Trivia Question

I AM SITTING HERE WITH ONE HOOKED TO A NAKAMICHI 630 AND
SOME JBL'S IT PLAYS AND SOUNDS GREAT ITS NEVER FAILED ME
AS OF YET AND THE BASE POUNDS!!!!!.

I pulled a Quatre DG-250 out of a dumpster in Jan '01. It had three dated repair tags on it, the latest from '93. Figuring that it had been tossed because of internal meltdown, I powered it up by slowly applying mains voltage through a Variac and measured reasonable DC across the Foster's beer-can-sized filter caps. No DC on the outputs. Much better than I expected from a dumpster dive. In a fit of bravado, I hooked it up to my Snell C-1s and my SS preamp and listened for about 5 minutes before grit-induced fatigue set in. It turned out that at some point the output transistors and half of the driver transistors in one channel had been replaced, and the output stage bias current was set very low. Bringing the bias up to about 100mA got rid of most of the grit. Bass was firm but midrange seemed congested and treble was brittle. I much prefer my Audionics CC-2 modified for inverting input. Considering the outlay in time and money, the Quatre is OK, my guess is that the quasi-complimentary output stage holds it back and stability under load is questionable.

I use to work at the factory! I was the sales manager for about a year - selling amps direct, advertising in the classified section of the LA Times. When I was selling amps - which was highly rated and cutted edge and inexpensive (and gorgeous) - other high dealers were selling anything but amps.

The gain cell circuit allowed the amp to clip with even-ordered harmonics, which was one of the reasons it had a "liquid" (tube) like sound. The bass was simply the best there was at the time. Still pretty good. Bought one on eBay for sentimental purposes and was suprised how good it sounded - so dynamic. Kinda like my Creek 4340SE. If I can find the time I might compare the two.

I have a Dunlap-Clarke Dreadnaught 1000, and it's still in daily use after 28 years! It's built like a tank, and I use it to drive the woofers on my Infinity RS1s.
The sound is comparable to other '70s solid state amps in this genre; very similar to the Marantz 500.
Whoever these guys were that engineered it built it to last -- it's one of my favorite vintage components.

The Quatre Gain Cell, ah...yes. I remember all the horror stories about how unstable they were, and the loud transformer hum. I was always curious about that amp until one day, at a local flea market, I spotted one. It had a silver face plate with one of the top corners bent over backward on the faceplate. I took it home for $10.00.

Totally fearless, I put it into my system (Dayton Wright SPS mk3 preamp, Rega Planar II turntable with Grace 707 tonearm and Grace F9L cartridge, CM Labs 912a power amp, JSE's "infinite slope" top of the line monster size speakers on casters.

The amp powered up instsntly and sounded much better than my CM Labs 912a (but that 912a was a drop dead gorgeous amp with that bronze faceplate and those huge backlit meters, and the oak side panels).

There was a midrange airiness with the Quatre that I hadn't heard from any transistor amps. The openness and transparency was absolutely intoxicating - along with the loud hum I noticed when the music stopped playing.

I opened the amp up and couldn't believe how little was inside. The transformer was huge - and loose. I cut some rubber pads and was able to wedge them under the transformer, then retighten the bolts which were under the amp on the bottom plate. It cut the hum to at least 3/4 of what it was. I also decided to glue cut up rubber computer pads on the inside of the amp at strategically loacated places along the sides and underneath the top cover plate. That reduced the hum to where it was now mostly inaudible, even with the ear placed close up to the amp.

I eventually sold it, but still remember to this day how incredibly transparent and open that amp sounded - along with bass that pounded your chest.

Too bad the company couldn't overcome the early reputation for them being unstable.

Anyone know with what serial number they overcame the instability problem?