I have heard various people talk about things such as picking up rf and other forms of noise, and had some questions about that.
First, what sorts of things should I do to keep that minimized. I do pick up radio sometimes, but very little.
I dont have hum like an obvious ground loop, but a very faint amount does exist. Nothing you can hear from the listening chair, or even a foot away from the speaker, but it does exist. Is this something you live with, or can little tweaking here and there fix that.
How about hiss, I have a bit of hiss. Again, not enough to be heard easily from my listening chair, and not enough to hear over the noise floor of most music I have, but it does exist. Can this be reduced, or is this also just a common issue with this design.
These amps are noisier than my modified acurus amps, and I dont believe the mods made the noise floor much lower, a little maybe.
First, what sorts of things should I do to keep that minimized. I do pick up radio sometimes, but very little.
I dont have hum like an obvious ground loop, but a very faint amount does exist. Nothing you can hear from the listening chair, or even a foot away from the speaker, but it does exist. Is this something you live with, or can little tweaking here and there fix that.
How about hiss, I have a bit of hiss. Again, not enough to be heard easily from my listening chair, and not enough to hear over the noise floor of most music I have, but it does exist. Can this be reduced, or is this also just a common issue with this design.
These amps are noisier than my modified acurus amps, and I dont believe the mods made the noise floor much lower, a little maybe.
RFI picked up on the input nodes is easily reduced by placing a 200pF cap across the Vin+ and Vin-. I have also used 150pF to ground on each pin in other amps.
you can also get RFI through the power supply if it is not properly decoupled AND your power supply can generate RFI through the junction capacitance of the rectifier diodes and inductance of the transformer secondary. (This is why I don't like those designs which put the diodes in close proximity to the amplifier chip.) This type of RFI can be in the tens of kHz to a few hundred kHz -- it is possible that it is a cause of unexplainable DC offset in some designs (you'll have to go to Analog Devices website for the explanation.)
you can also get RFI through the power supply if it is not properly decoupled AND your power supply can generate RFI through the junction capacitance of the rectifier diodes and inductance of the transformer secondary. (This is why I don't like those designs which put the diodes in close proximity to the amplifier chip.) This type of RFI can be in the tens of kHz to a few hundred kHz -- it is possible that it is a cause of unexplainable DC offset in some designs (you'll have to go to Analog Devices website for the explanation.)
all the opamp tests you'll ever need, the first one should help you out.
http://www.intersil.com/data/an/an551.pdf
http://www.intersil.com/data/an/an551.pdf
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