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I have a well working BII/Legato fed by a Placid.
I have a slight hum. It's no big problem, but in hunt for perfection, it's.....
When touching the Muse's case (top), it's like touching the signal wire. It that normal ?
Before regging o'scope, I want to ask for an advice, pls.
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Sounds like a bad cap or a bad solder joint (on the cap).
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Touching either of the 4 results in "finger on the hot wire".
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Any hum would have to be a GND loop or possibly as Brian said a bad connection of some sort.
Are you using SE output from the Legato?
If so you may need to guard against EMI. Watch your high voltage AC etc.
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Yes, I'm running SE.
There's no gnd loops.
About touching the Muse's. Is it normal behaviour that the can of the cap has connection to signal wire.
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There are really only two ways I can see you getting a hum. EMI or a GND loop.
It is not unusual for touching a cap to have an influence on it.
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I've had some (very light) hum also, on a very powerfull amp, but I got that fixed with some 82.000uf caps on the placid power supply. (c1&c2, had those lying around from a old amp) Easy to try. Touching the output caps also introduces some hum in my setup. Totally quiet now. ( amp is connected differential and a sub connected to se outputs ) In a ideal world hum from the psu should be.... Emile Edited by user Friday, December 3, 2010 1:45:31 PM(UTC)
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Steamerzone wrote:In a ideal world hum from the psu should be.... ... absent or common mode and canceled by the balanced design?
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avr300 wrote:About touching the Muse's. Is it normal behaviour that the can of the cap has connection to signal wire. The metal can of electrolytic capacitors is typically connected to the negative lead. I learned this the hard way, when I brushed up against the negative rail reservoir capacitor of my electrostatic amp. The negative lead - and thus top - of that capacitor was sitting at -350VDC, and there was much swearing and cursing. In this case, you are just touching the ground.
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Ok, if that also applies to the non-polar Muse, then I'm touching signal hot wire when touching the can. I'm not touching GND. The cap is a coupling cap, not a decoupling one. It's connected serial in the signal path.
I'll check my mails routing, thought my clearance was ok.
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avr300 wrote:Ok, if that also applies to the non-polar Muse, then I'm touching signal hot wire when touching the can. I'm not touching GND. The cap is a coupling cap, not a decoupling one. It's connected serial in the signal path. Quite right, I'm getting confused. Still not recommended to touch it...... ;)
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