Hi
I just assembled a preamp from an eBay NE5532 board (with onboard 12Vdc power supply) and a recycled phono preamp case.
I tested the board and the frequency response was quite flat through 20-20K (rough test) so I thought I would put it in a case. I replaced the front panel with clear acrylic. I wanted an amp to boost my digital audio players signal and see what effect it would have on the LM1875 integrated stereo amp I recently built.
One channel drops out earlier than the other when the volume dial is turned to zero. I checked the no-brand 10K taper pot before assembly and there was a channel to channel difference in resistance at the off and fully open positions, maybe a 100-200 ohms.
Can anyone suggest a pot in the same dimensions that would have better matched channels. Or could I just use a series resistor on one channel?
Cheers
I just assembled a preamp from an eBay NE5532 board (with onboard 12Vdc power supply) and a recycled phono preamp case.
I tested the board and the frequency response was quite flat through 20-20K (rough test) so I thought I would put it in a case. I replaced the front panel with clear acrylic. I wanted an amp to boost my digital audio players signal and see what effect it would have on the LM1875 integrated stereo amp I recently built.
One channel drops out earlier than the other when the volume dial is turned to zero. I checked the no-brand 10K taper pot before assembly and there was a channel to channel difference in resistance at the off and fully open positions, maybe a 100-200 ohms.
Can anyone suggest a pot in the same dimensions that would have better matched channels. Or could I just use a series resistor on one channel?
Cheers
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Alps make potentiometer in the same footprint which might be more accurately matched (even then, they're not usually "perfect" especially at lower volumes), but IMO a small difference near zero isn't a huge problem in general use, the main thing is the volume tracks pretty close in the useful range (around 9 o clock through 3 o clock)
OK , just fixed it. This board came with white wires going to RIGHT channel - throws me off every time. I have to swap the pins on the plugs otherwise I can go round in circles with pot wiring.
I will now have three devices connected each with its own volume control (my amp has volume pot). I just erased a paragraph explaining how I might set the volumes but the logic was doing my head in - solving a three variable equation
What are people doing in this case, just going by feel and trying to get cleanest signal at each stage?
Job done!
I will now have three devices connected each with its own volume control (my amp has volume pot). I just erased a paragraph explaining how I might set the volumes but the logic was doing my head in - solving a three variable equation
What are people doing in this case, just going by feel and trying to get cleanest signal at each stage?
Job done!
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