I have an old Crest Audio V650 power amp. Everything is great except when I turn it on the fans sound like a turbine or helicopter.. I would like to know if it's possible to change the fan for one of those silent PC fans. Or would this cause any problem for the amp. Any suggestions or ideas will be appreciated.
If it sounds like a helicopter, the bearings are probably gone. It could also be misalignment causing the fins to hit the frame. You may try disengaging the rotor, cleaning the dust and old damaged grease and spraying a silicone-based "chain lube" into the bearing area. Alternatively, replace it with a fan of same voltage and RPM.
CPU fans are often speed-controlled while the ATX PSU fans are not.
CPU fans are often speed-controlled while the ATX PSU fans are not.
My Crest VS1100 amp had a 120mm 115V AC Sunon fan. It looks similar to what I see in pics of a V650 online. You can't just stick in a quiet DC computer fan without adding some kind of DC power supply for it. I replaced mine with a slower revving EBM Papst AC fan. It made some improvement to noise levels but AC fans are NEVER quiet enough for use in a hi-fi room. These are professional amps designed for rough and noisy environments. Your best bet might be to get something excellent like a 120mm Noctua fan and somehow safely install a 12V plug pack in there. You'd get a 3-wire fan and just use the red and black wires.
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Maybe I exaggerated. The fans are really loud like they are on high speed or something.I wonder if there is a speed dial inside that could control the fan. Or I wonder if I could replace the fans with something like this
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There's nothing inside the fan that you can change. Externally, it would be a chopper regulator for DC fan and a TRIAC phase control /dimmer for AC fans. For AC fans, you could also reduce the frequency but that would also require a proportional reduction in voltage, which is double the trouble.
"There's nothing inside the fan that you can change. Externally, it would be a chopper regulator for DC fan and a TRIAC phase control /dimmer for AC fans. For AC fans, you could also reduce the frequency but that would also require a proportional reduction in voltage, which is double the trouble."
I didn't mean if there is something inside the fan. I meant if there is something inside the amp that sends a signal to speed up or down the fan.
I didn't mean if there is something inside the fan. I meant if there is something inside the amp that sends a signal to speed up or down the fan.
The service manual doesn't seem to be freely available but this document says the fan is "two-speed", so it's likely to be a DC fan with the speed controlled by the drive circuit voltage.
And as mentioned above, the original fan label should have the make and model number on it, so it should be possible to find the specs.
Then you can search for a replacement with a lower noise spec, while having the same voltage and an equal or greater CFM spec.
It's also the possibile the fan is worn and noisier than it should be, or there could be something wrong with the drive circuit so the fan is running at high speed all the time.
I would start with a good cleaning inside the amp to make sure dust is not causing the problem.
And as mentioned above, the original fan label should have the make and model number on it, so it should be possible to find the specs.
Then you can search for a replacement with a lower noise spec, while having the same voltage and an equal or greater CFM spec.
It's also the possibile the fan is worn and noisier than it should be, or there could be something wrong with the drive circuit so the fan is running at high speed all the time.
I would start with a good cleaning inside the amp to make sure dust is not causing the problem.
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