FaxData
New Head-Fier
- Joined
- Apr 27, 2007
- Posts
- 7
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- 0
Hi, nice to meet you all.
I wish my first post was something besides a call for help...
I've put together my first CMOY based on the plans over at tangentsoft, with the standard radioshack board, metal film resistors from radioshack and the rest of the parts from digikey. Using test cables with alligator clips, I hear soft (but pretty loud) noise, equal in both channels. The noise is there with or without a source, and it does not get louder with a source attached. I don't notice any distortion in the source when I have my ipod hooked up.
The power supply part seems to give a stable voltage, +/- 9.54v (two new batteries), measured between ground and the two power pins on the opamp. All the resistances seem to be correct from the opamp pins to the ground as well. There's no DC to the left channel output, and there's 4mV to the rigth channel. I've checked all the different solder pads for shorts and I can't find one. The amp does not heat up, and there's no buzzing or hissing.
R2 is 100k, R3 is 2.2k and R4 is 10k. The opamp is OPA2132PA. Other than the gain of 5.5, everything is pretty much by tangentsoft's default design. I tried adding 10 ohms to R5 on one side, and I couldn't tell any difference at all, so I changed it back to a jumper. I thought I might have burnt the opamp, but switching it out with a spare didn't seem to change anything at all.
The Front The Back
I've searched but haven't really found how to fix my problem... I don't even know where to start in diagnosing this.
Any advice?
I've put together my first CMOY based on the plans over at tangentsoft, with the standard radioshack board, metal film resistors from radioshack and the rest of the parts from digikey. Using test cables with alligator clips, I hear soft (but pretty loud) noise, equal in both channels. The noise is there with or without a source, and it does not get louder with a source attached. I don't notice any distortion in the source when I have my ipod hooked up.
The power supply part seems to give a stable voltage, +/- 9.54v (two new batteries), measured between ground and the two power pins on the opamp. All the resistances seem to be correct from the opamp pins to the ground as well. There's no DC to the left channel output, and there's 4mV to the rigth channel. I've checked all the different solder pads for shorts and I can't find one. The amp does not heat up, and there's no buzzing or hissing.
R2 is 100k, R3 is 2.2k and R4 is 10k. The opamp is OPA2132PA. Other than the gain of 5.5, everything is pretty much by tangentsoft's default design. I tried adding 10 ohms to R5 on one side, and I couldn't tell any difference at all, so I changed it back to a jumper. I thought I might have burnt the opamp, but switching it out with a spare didn't seem to change anything at all.
The Front The Back
I've searched but haven't really found how to fix my problem... I don't even know where to start in diagnosing this.