OEM fan is 80mm 24V single-speed w/on-off sensor. Toward less noise I consider replacing with THIS 92mm 12V 3-speed.
I presume the 12V runs OK but at slower RPM, plus its 15% larger size and highest speed setting provide adequate airflow. (Receiver has thermal protection circuit.)
Please advise.
Also, prior to above fan swap: I fist desire to install THIS zener diode to slow OEM fan speed for less noise. Mouser has MOQ of 1000. Who sells that part or similar functioning part in small numbers?
I presume the 12V runs OK but at slower RPM, plus its 15% larger size and highest speed setting provide adequate airflow. (Receiver has thermal protection circuit.)
Please advise.
Also, prior to above fan swap: I fist desire to install THIS zener diode to slow OEM fan speed for less noise. Mouser has MOQ of 1000. Who sells that part or similar functioning part in small numbers?
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Sorry I got it backward. I see now the 12V fan runs at twice its speed at 24V with corresponding quick burn out (not slower speed as in the OP).
Someone posted a "12V zener" is appropriate to drop 24V to 12V. I'd much appreciate a link to the correct part.
Someone posted a "12V zener" is appropriate to drop 24V to 12V. I'd much appreciate a link to the correct part.
I had a need for a 24volt fan and had 2 12volt units on hand....stacked them up and ran them in series....seems OK.
zener would be good w/ a dropping resistor.
or the other technique, use regulator.
please mind the power dissipation of the fan.you might want a big resistor wattage like i did (now using regulator as 10W resistor getting pretty hot)
or the other technique, use regulator.
please mind the power dissipation of the fan.you might want a big resistor wattage like i did (now using regulator as 10W resistor getting pretty hot)
Another option...make a ccs circuit using a transistor. Saves the fan from high currents also.
Gajanan Phadte
Gajanan Phadte
Google is your friend - there is a ton of info sitting on the web and ready to go.
This is as simple as it gets: 24V 12V DC DC Converter - Storage
Note that it may be assumed that experimenters know these regulators require a TO220 size heatsink.
This is as simple as it gets: 24V 12V DC DC Converter - Storage
Note that it may be assumed that experimenters know these regulators require a TO220 size heatsink.
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😀, linear regulator can get very hot. I use series resistor with fan, and then place 12v zener over fan, to steady voltage, so it doesn't creep up.
I don't care how hot resistor gets, no runaway effect here.
Knowing 12V fan, current draw makes calculating (guessing) resistor easy
Regards
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You might find that the lower voltage fan pulls more current and requires its switching/drive circuit within the amplifier to be uprated.
You will need a very high wattage dropper resistor.
I use multiple resistors in series.
Make sure the resistors are kept well apart to aid getting rid of heat.
I use multiple resistors in series.
Make sure the resistors are kept well apart to aid getting rid of heat.
If the load fan is less than 1 amp then take a look at these:
Digi-Key
data sheet:
http://www.cui.com/product/resource/v78-1000.pdf
Add a couple of caps and you're done.
🙂
Digi-Key
data sheet:
http://www.cui.com/product/resource/v78-1000.pdf
Add a couple of caps and you're done.
🙂
Thanks for all the help.
Over the weekend I found a passive unintentional fix for the fan noise. First, I employ three matched receivers, all with the aforementioned fan. One receiver functions as preamp only (front wall, off-center in rack), the other two receivers act as 2-ch power amps (on floor next to speakers).
I am most sensitive to fan noise from the "preamp" receiver because it's elevated in a metal rack. Sensitivity to the power amp fans is far less and not objectionable.
Multiple parameters determine fan-on-off status, one being SPL threshold even if receiver functions only as preamp (power amps unused). I advanced gain 8 dB on the power amp receivers, thus lowering the SPL range for the preamp by the same margin (8 dB). This causes the preamp fan to stay below the fan-on threshold, thus it stays off at even the highest SPL. Level control is ultra-high linear ladder resistor in analog chip. Sound quality stays constant at all SPL settings.
Power amp fans: Each receiver has six power amp channels, three channels each per two pure analog chip modules. Rear module = Front LCR, front module = Surrounds Left/Back/Right. Previously I employed two front channels from the front module only. I switched input/output so now I employ one channel from the front module/one channel from the rear module.
Current increased, voltage increased, heat sink at least doubled, distortion is lower, etc, etc. SPL threshold increased for fan to switch on, and I am less sensitive to these fans vs. the preamp fan.
It's nice for the fan noise to have worked itself out indirectly.
Over the weekend I found a passive unintentional fix for the fan noise. First, I employ three matched receivers, all with the aforementioned fan. One receiver functions as preamp only (front wall, off-center in rack), the other two receivers act as 2-ch power amps (on floor next to speakers).
I am most sensitive to fan noise from the "preamp" receiver because it's elevated in a metal rack. Sensitivity to the power amp fans is far less and not objectionable.
Multiple parameters determine fan-on-off status, one being SPL threshold even if receiver functions only as preamp (power amps unused). I advanced gain 8 dB on the power amp receivers, thus lowering the SPL range for the preamp by the same margin (8 dB). This causes the preamp fan to stay below the fan-on threshold, thus it stays off at even the highest SPL. Level control is ultra-high linear ladder resistor in analog chip. Sound quality stays constant at all SPL settings.
Power amp fans: Each receiver has six power amp channels, three channels each per two pure analog chip modules. Rear module = Front LCR, front module = Surrounds Left/Back/Right. Previously I employed two front channels from the front module only. I switched input/output so now I employ one channel from the front module/one channel from the rear module.
Current increased, voltage increased, heat sink at least doubled, distortion is lower, etc, etc. SPL threshold increased for fan to switch on, and I am less sensitive to these fans vs. the preamp fan.
It's nice for the fan noise to have worked itself out indirectly.
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