Premier 11 Just started buzzing

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MatthewScott
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Premier 11 Just started buzzing

Post by MatthewScott »

Hi - I am new to this forum. Glad I found it! My Preamp and Amp are both CJ. The AMp I have is a Premier 11. I listened to it fine this morning. Now this afternoon, when I turned it on, it is buzzing/humming...NOT from the speakers but from the amp itself. It's rather loud (vs a softer hum/buzz) Anybody know what that might be? Thanks.
CJ PV10, CJ Premier 11, Klipsch Forte IV's, Rega RP6 (with RB3000 tonearm, Groovetracer sub, Tango Spinner double pulley, linear power supply, Dynavector 10x5 Mk2 cart), Cardas Clear interconnects
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Re: Premier 11 Just started buzzing

Post by admin »

Welcome to CJO, nice to have you with us.

As for your issue, I think I would start with some basic trouble shooting. 1) Check/role the tubes, 2) open up the unit to look for visual signs of defective components (ie bulging caps, burn marks, etc), 3) check the power supply. As you describe the humming coming from the amp and not the speakers, this seems to indicate that something is actually moving (vibrating) in the amp, so I would try to touch components with a non-conductive item (like a pencil eraser) to see if you can identify the actual component that is making the "humming sound."

If nothing is obvious, you will have to go to the schematics and do some more heavy duty detective work. Let us know what you find.
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Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
MatthewScott
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Re: Premier 11 Just started buzzing

Post by MatthewScott »

Thanks. Will do. I'm an amateur but I'd like to know how to trouble shoot this thing. I've figured out other things that were going on with it, so hey!
CJ PV10, CJ Premier 11, Klipsch Forte IV's, Rega RP6 (with RB3000 tonearm, Groovetracer sub, Tango Spinner double pulley, linear power supply, Dynavector 10x5 Mk2 cart), Cardas Clear interconnects
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Re: Premier 11 Just started buzzing

Post by roberto »

Hola. It looks that you might have a loose screws securing the power transformer. Be careful because inside are letal voltages. Just disconnect the mains AC from the wall or from the power line conditioner and wait at least five minutes before opening the cover. Then go direct to the power transformer and with the aid of a screw driver and and pliers, usually its a point NO. 2 Philips type, secure all four screws that are securing the power transformer. They must be very tightened.

The transformer has a lot of thin metal sheets, that could vibrate with the 60 Hz line frequency, if they are loose.

I hope this is your problem and a very easy task to solve the humming and odd noise.

Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: Premier 11 Just started buzzing

Post by MatthewScott »

Just an update. Curiously the buzzing stopped the next day. That hasn't come back, yet, after a couple of weeks. Oddly, an output fuse blew yesterday. I replaced it and it sounds fine. The output tubes don't "appear" to be doing anything that would indicate a problem tube. Two of the output tubes are on the older side, so it's time to order more tubes. Is that related? Who knows. For now, the amp is playing fine. Thanks for the help, CJ owners. If anything further happens, I'm sure you'll hear about it! :) - Matt
CJ PV10, CJ Premier 11, Klipsch Forte IV's, Rega RP6 (with RB3000 tonearm, Groovetracer sub, Tango Spinner double pulley, linear power supply, Dynavector 10x5 Mk2 cart), Cardas Clear interconnects
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Re: Premier 11 Just started buzzing

Post by roberto »

Keep your fingers crossed. On the other hand, its a good idea to change the old tubes. You will be having back the great Conrad Johnson sound, with new output tubes, effortless. Happy listening!
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: Premier 11 Just started buzzing

Post by Big Dog RJ »

Yes, definite good advice.

If your changing tubes, and specially output tubes, might as well change all 4 on the Prem 11. If you order through CJ, they also do matching tubes in batches, which have been run in / burned in a controlled process, hence all 4 tubes have been burned in equally. CJ tries its best to offer the best possible sound for the money spent. Therefore, whenever I have ordered tubes directly from CJ, I've noticed straight away an equal sort of sonic performance across all output tubes. Plus they're easier to bias, compared to using different tubes having different life spans on them.

When I used Manley amps, each monoblock had nearly 16 tubes (400 watt mono amps) and ordering in batches was very expensive, especially KT90's. CJ was more manageable thereafter since I used only 4 output tubes per channel and intended to keep it that way. With their 60w to 70w rated amps, such as the Prem 11, MV60, LP66s, LP70s, Classic 60 and so on, the beauty of these amplifiers were that for the money spent, they deliver superb sound with minimal tube maintenance, and this is the main reason why I gave up on monoblocks.

If you were to re-order a tube set from CJ (if finances permit) then I would go ahead and re-order the entire tube set, including the smaller input & driver tubes, after all there are only 4 of these small buggers, and they don't cost much either. Ordering the output tubes in quad batches (of 4) makes more sense when you have an amp such as the Prem 11.

Fresh tubes will give you a very "rich sound" and remember to keep an eye on the bias. Once installed and biased properly, this should last a good while.
I would not fiddle with somewhat new tubes and old tubes and mix channels, although these designs have individual biasing, the life span factor is varied causing other anomalies, which I have found to be very annoying.

Hope my 50cts helps; cheers,
RJ
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