Hi everyone,
My Crown IC-150 has a fairly loud hiss in the right channel. The white noise level or pitch is not affected by volume, balance, input, or panorama being adjusted. It does change pitch some when I adjust the bass or treble.
If I use the tape outs signal is good, no white noise but tape outs bypass almost the whole pre amp. I have cleaned and looked for problems but noise is still there.
I would love to get this going again, about to buy oscilloscope to try to trace. Other options or thoughts? I would greatly appreciate!
My Crown IC-150 has a fairly loud hiss in the right channel. The white noise level or pitch is not affected by volume, balance, input, or panorama being adjusted. It does change pitch some when I adjust the bass or treble.
If I use the tape outs signal is good, no white noise but tape outs bypass almost the whole pre amp. I have cleaned and looked for problems but noise is still there.
I would love to get this going again, about to buy oscilloscope to try to trace. Other options or thoughts? I would greatly appreciate!
Likely the line level opamp for that channel, there are no other semiconductors in the line level signal path.
Cheap and easy to change. no need to buy a scope to try that.
Maybe an open resistor or capacitor in the line stage on that channel as a second possibility.
still cheap to replace the parts without buying a scope if thats all you need it for.
for nostalgia it would be nice to fix it, but it likely needs a full recap and all the other parts are at least 40/50 years old. Many of the components are large value resistors which make for a high impedance circuit, also not good for noise. Its been acknowledged that even a recaped/updated the IC 150 isn't a good sounding preamp. If your going to do a full rebuild then its a good chassis to put something new and better sounding in. lots of DiyAudio circuits on the website.
Cheap and easy to change. no need to buy a scope to try that.
Maybe an open resistor or capacitor in the line stage on that channel as a second possibility.
still cheap to replace the parts without buying a scope if thats all you need it for.
for nostalgia it would be nice to fix it, but it likely needs a full recap and all the other parts are at least 40/50 years old. Many of the components are large value resistors which make for a high impedance circuit, also not good for noise. Its been acknowledged that even a recaped/updated the IC 150 isn't a good sounding preamp. If your going to do a full rebuild then its a good chassis to put something new and better sounding in. lots of DiyAudio circuits on the website.
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Thanks for the feedback, I have obviously been out of the hifi game for a while. I like the idea of keeping the chassis an upgrading the inside. I don't want my preamp to sound like anything... I hope my crown dc 300 is not also considered crappy equipment nowdays or I will have to rethink my plan. Thanks again!
First refresh the electrolytic capacitors and see if the hiss is gone.
If not, then look for bad solder joints. Only then consider replacing the op amp.
If not, then look for bad solder joints. Only then consider replacing the op amp.
I think my nephew is still using my old 150. All the volume balance panorama controls are before the 1 opamp per channel. There are no electronic buffers, transistors or ICs in the tape in out circuits. The Bass and Treble controls are in the feedback loop of the opamp that is why they effect the sound. The op amp in the 150 is an LM301. In the 150A I believe they used a different one.