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EQUIPMENT FORUMS >> SE34I.6 >> Bouncing meters
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Message started by hifitubes on 10/26/13 at 21:16:47

Title: Bouncing meters
Post by hifitubes on 10/26/13 at 21:16:47

What does it mean with the meters moving slightly, but you have no signal passing into the amp.

Is the transformer getting saturated by DC on the line? The transformer hums a fair amount.

Title: Re: Bouncing meters
Post by marky on 10/27/13 at 00:30:46

Piecing it together this is your other new Rachael which is sensitive to your dishwasher ? This problem also shows up in the transformer which causes the powers tubes to draw more and less current when idle. Could be as you suspect, an earth going live somehow. It shouldn`t be as drastic as wrong wiring, more likely induced by screening or close proximity to a field, such as when you pass your hand over a suspect tube to hear a hum. If I still couldn`t find the prob after going through all the earthing, isolating and cable choices I guess I`d have the back off of both amps and compare wiring. Theres also `tube jiggling` to make sure a dodgy connection isn`t doing it.

Thats probably my fix it solution for everything :)
Good luck though...

ps the` floating earth` or is it `floating bridge` is how Steve makes the 2 amps stay in perfect sync without smearing. I don`t fully get it but it must be to do with balance and the chassis holding the earth onboard. If the outputs are earthed through the mains there must be a signal path in the outputs so.......

Title: Re: Bouncing meters
Post by hifitubes on 10/27/13 at 06:37:38

Thanks, I've been overloading myself with reading lately but not really learning a lot.

Between the dishwasher issue (only when it's on), bouncing meters, tranny seeming hotter than before, and a little more hum than before, I suspect the power scheme first.

I should try different rectifier and EL34 tubes. I swap input tubes often.

I have some hum on speakers but I can't hear it from listening position, but I think it could be quieter.

I'll do more testing tonight but thanks for your input.

Title: Re: Bouncing meters
Post by hifitubes on 10/27/13 at 11:11:14

My system is one Rachel right now, not bridged, but I do have a subwoofer with plate amp connected to terminals as well. I should check it's phase switch too.

The DAC, sub, and amp are in plugged into a basic Furman power strip. I used to run amps through an Audience AR2P which had an Auricap inside. I wonder if it blocked DC?

Title: Re: Bouncing meters
Post by Rivieraranch on 10/27/13 at 13:54:58

You could try washing your dishes by hand. . . .

Title: Re: Bouncing meters
Post by Lon on 10/27/13 at 13:58:47

LOL!

Title: Re: Bouncing meters
Post by hifitubes on 10/27/13 at 17:45:25

I'm worried someone is going to get hurt or the amp will be damaged.

Today I put a cheater plug on the Rachel, hooked it up to an AC regenerator, and turned on the dishwasher.

A loud buzz comes out of the speakers when dishwasher is running.

I measured 20V AC across chassis of DAC to + Rachel binding post, 30V AC across AC Regenerator chassis to + Rachel binding post, and 3v from chassis of Rachel to + Rachel binding post. If I tried to measure DC it just kept climbing.

I wonder if neutral and ground are tied at dishwasher?