Quartre Amplifier ???

[zenith26kc0]

Quatre schematic

Here is the schematic I use. The transistors marked with an X are prone to fail if the heatsinks get loose.

 

[Hennesy]

Thank you so much for sharing the schematic.

 

[rwscarne]

Here are the schematics for a Quatre GC-500 amplifier.

 

[frequency295]

Thank you!!

 

[ripper2860]

Hello Folks --

I am far from a DIY'er w. my one and only DIY being a Hafler DH 101 preamplifier built in my teens. Recently dusted off my Quatre DG250C and feeling in a rather vintagew mood, wanted to press it back into action. With great trepidation, I plugged it in and connected it to my 4 ohm ELAC speakers and lo' and behold, it sounded pretty good.

Based on my reading here and other places it seems that this amp is prone to packing it in giving up the ghost and taking speakers across rainbow bridge with it -- especially with 4 ohm speakers. So to my questions...

Was it all iterations of the DG250C or were there versions that corrected this propensity. Is there a S/N range that is considered OK? Below are pics of the boards in case that helps.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

I know this is an old thread, but I'm hoping you fine folks can assist.

Thanks in advance!!

Richard

 

[ripper2860]

OK. PICs do not seem to be loading via Google Drive, so let's try this again as attachments.

 

[lAMuDEtA]

My QMI GC-200

[Note: This is cross-posted in the "Quatre QMI Gain Cell Series Amps" thread.]

I know this is a long shot and I maybe shouldn't even be posting here, because to be honest I am not an audio DIYer. But you all seem very knowledgeable, so I'm hoping you'll be willing to help a noob.

Back in the early 1980's I was a wannabe audiophile and acquired the following:

• 
  GAS Thalia II pre-amp
  QMI GC-200 amp
  ace-BASS B2-50 sub-woofer
  KEF Corelli speakers
  Various input devices

I originally bought a GAS Son of Ampzilla, but due to a mix-up got the QMI instead. It was a great sounding system--clear mid's and high's with tight bass. It also suffered from the QMI bug and I toasted one set of output transistors and a speaker. I would hear a low AC hum that would get louder and then POP! But mostly I enjoyed it. ​Then life happened and I boxed it all up for a big move in 2000 where it all sat for 21 years.

Last week I unboxed it all and started hooking things up. I started with a tuner, pre-amp, amp and speakers. Lo and behold it worked! I then tried adding the sub-woofer between the pre-amp and amp and got silence. At one point I did hear the characteristic hum and managed to turn off the amp and pre-amp before hearing the pop. I do get sound when I plug headphones into the pre-amp. I get no sound from the sub-woofer when I connect it to the pre-amp. The speaker line fuses didn't blow and the speaker cones move freely. None of the amp's fuses blew.

So what to do? I'm a decent troubleshooter (40+ years as a network engineer) with a multimeter. I also have a Pioneer SP-SB32W sound bar with RCA inputs. Should I even try troubleshooting and, if so, what should the first steps be? Or is everything so old that it would need to be upgraded even if I wasn't having problems? I'm assuming the cost for that would be significant.

Thanks in advance for any advice.

Bob

 

[rayma]

I'd ebay the amp "as-is, needs repair", and get a better amp. It's not worth fixing.

The sub can probably be fixed since there are docs around.
Audio Pro B2-50 Subwoofer System Manual | HiFi Engine