Hello, not sure if this is the best place to seek answers but this forum popped up as an option when searching the net for info about Quatre Gain Cell Series Amplifiers. Want to know how to approach powering them up for the first time in probably 6-10 years. One is a DG250C and the other a GC500 the internals in both look fairly clean although showing signs of possible repairs or up-grades... etc, and both look like fairly substantial pieces of gear with one (GC500) having the most enormous power transformer I’ve ever seen on any piece of music gear to date period. A friend of mine got them out of a storage room in a club where they were once used as the house dance pa system and I don’t even know if they work or not. Given the nature of the situation it would seem reckless to simply load the speaker out’s and just plug it into the wall due to the size of the capacitors and the adjacent delicate looking pc boards with small chips standing off the board.
I’m hoping that I could use these (or one of them) for an alternative s-state system in my home as I do enjoy the clarity and POWER of a good s-state amp as an alternative to several tube amp sound systems that I currently own and rotate periodically. I had to sell my last good s-state power amp about a year ago due to relocation cost and I miss it. It was a JBL/Urei 6260 power amp and I used it mostly to power my Altec Valencia’s that also had to go about a year prior. Anyway… enough sob story telling. Any advice on these amps? Things I should know? Like, how to control the levels as there aren’t any on the amps themselves?? And the safest way to test power them up would be greatly appreciated. Again i have 2 amplifiers… Quatre Gain Cell Series DG250C QMI and GC500 QMI.
Also: I'm a diy-er that probably should have been on this forum a long time ago and looking forward to sharing ideas and learning more about how to tweak, mod and make usable circuits.
Thanks!
I’m hoping that I could use these (or one of them) for an alternative s-state system in my home as I do enjoy the clarity and POWER of a good s-state amp as an alternative to several tube amp sound systems that I currently own and rotate periodically. I had to sell my last good s-state power amp about a year ago due to relocation cost and I miss it. It was a JBL/Urei 6260 power amp and I used it mostly to power my Altec Valencia’s that also had to go about a year prior. Anyway… enough sob story telling. Any advice on these amps? Things I should know? Like, how to control the levels as there aren’t any on the amps themselves?? And the safest way to test power them up would be greatly appreciated. Again i have 2 amplifiers… Quatre Gain Cell Series DG250C QMI and GC500 QMI.
Also: I'm a diy-er that probably should have been on this forum a long time ago and looking forward to sharing ideas and learning more about how to tweak, mod and make usable circuits.
Thanks!
wellp... i've read most of the previous threads about the Quatre qmi amps since my first post and have the most important question answered being these are basically "lemons" which means (to me anyway) not much threat in powering them up to see if they're working. Haven’t yet decided what to do if they seem to function ok.. maybe use them or sell them, i like the idea (read from some of the post regarding these amps)of recycling them for parts if they don't work. Also enjoyed reading the link to the electronic attenuator patents posted on one of the threads. personally why bother? Seems much more simple and reliable to have the control at your finger tips. i see that some did read my post so thanks for that anyway and a belated thanks for the info already provided in past discussions.
the DG250C works great! although it's high-mids seem a little too strong for my taste had to back the "presence" way off on the decade 36's, but i still can't tell if it's just my own not being use to a good powerful amp or if the amp is distorting around those frequencies??
GC500 has a problem with the right channel...barely audible and distorted. going to replace 9 amp fuses for the right chan and see if it holds out. if the fuses blow again i'll bring to one of the techs at my work... if that proves failure than i'll sell parts. gonna have the dg250c checked out as well just for assurance
GC500 has a problem with the right channel...barely audible and distorted. going to replace 9 amp fuses for the right chan and see if it holds out. if the fuses blow again i'll bring to one of the techs at my work... if that proves failure than i'll sell parts. gonna have the dg250c checked out as well just for assurance
going to sell these amps. after considering what I've read about their general temperament being doubtful, i don't wanna hassle with them. going to sell them together for 100 bucks. not trying to spam out the forum here but Ive read the it's possible to cannibalize the chassis and power supplies for a complete reworking of another amplifier design ... a project way beyond my diy abilities. i'll post them on ebay as well as the marketplace on this forum and donate a percentage to the forum if the buyer is from here.
I had 2 of these Quatre gain cells years ago(1981)
The dealers had to refund the customers money because they could not keep them working. The dealer in Seattle Wa. had a stack of them. They oscillated and blew up. I removed the original circuitry, and replaced it with my first designs. I still have some of the driver boards, and have drawn the schematics. They were ahead of their time. The original engineer just didn't do enough testing. He did not follow through and finish the design. Anybody know the name of the engineer who designed them?
The dealers had to refund the customers money because they could not keep them working. The dealer in Seattle Wa. had a stack of them. They oscillated and blew up. I removed the original circuitry, and replaced it with my first designs. I still have some of the driver boards, and have drawn the schematics. They were ahead of their time. The original engineer just didn't do enough testing. He did not follow through and finish the design. Anybody know the name of the engineer who designed them?
Thank you. This is bringing back many memories of those days. I worked at Phase Linear and was into making audio equipment. Definitive Audio was a dealer in Seattle. I remember that there were two owners. Was Dave Gore one of the owners? They asked me if I could fix them. I took a look at them and decided that I could not. But I could now.
Back then, amp companies were trying to innovate. This amp had 2 differential transistor pairs. One for the input and main feedback. The other was connected across the emitter resistor of the voltage gain/level shifter stage. And there was a pot to adjust how much feedback. I would guess that he was trying to negate the nonlinearities in this stage. What do you think? Would you like a copy of the schematic?
Back then, amp companies were trying to innovate. This amp had 2 differential transistor pairs. One for the input and main feedback. The other was connected across the emitter resistor of the voltage gain/level shifter stage. And there was a pot to adjust how much feedback. I would guess that he was trying to negate the nonlinearities in this stage. What do you think? Would you like a copy of the schematic?
Wasn't he also the guy who sold those weird Chinese finger trap speakers? Cybele, if my memory serves.
I recently got three Quatre amplifiers that were headed to the dumpster. Not to duplicate posts, I repaired two out of three (one worked, the GC500). The DG250 had a bad MPSu60 and the GC250 one output. The DG250 is great sounding. The GC250 is next sound wise and the GC500 is a bit boomy.
Schematics? Please?
The DG250 has the RCA410 outputs, someone was curious if I remember.....
Schematics? Please?
The DG250 has the RCA410 outputs, someone was curious if I remember.....
More fun and games. My GC250C had an "upset this weekend (Sunday). It needed the MDS60 and the 2n6558 devices virtually in the middle of the upper PC board replaced along with a 1n4444 near the germanium protect device. I used a NTE375 and a NTE398 to replace them. I had to wonder as the MDS60 was listed as an NPN and it is really a PNP. Glad I use a variac. Another problem was in the lower board (good channel) was the tantalum input was dead shorted. I replaced both left and right input tantalums. This Quatre has rail fuses so I am not too worried about my Tympani 4 speakers. I under fuse it at 4 amps per rail. I know what some of you think about NTE but I have used this pair before in television repair and they are robust! So far, testing is good and it's playing in the back of my shop.