I use 2003 Pioneer VSX-D912 receiver (analog chip power amp modules) as unbalanced pure analog line preamp, sum total purpose for gain and remote volume, nothing else.
Compared to RCA unbalanced preamp outputs, performance audibly improves employing speaker outputs through "bridging circuit" comprising 9k Ohm series resistor (source side) followed by 1k Ohm parallel (load side). The load is practically invisible/non-existent; the top remains cool at any level. Still though, the cooling fan operates past a certain volume threshold.
Adding large amounts of rope putty and two fishing weights significantly damped fan noise, but my room is dead quiet and fan noise is still audible for a few seconds when I pause music. Plus even though higher playback level masks fan noise, I presume fan noise masks some detail.
I removed the fan, which the 912 "sensed" was gone, and would not turn on.
Fan label: 24VDC, 0.11A.
Can I replace the fan with a dummy load, thus tricking the program into thinking the fan is present? Please specify appropriate load and how to wire it per the fan's three conductors. I have only standard DVM. I'll risk frying the 912 to test.
Thanks very much for your help. 🙂
Compared to RCA unbalanced preamp outputs, performance audibly improves employing speaker outputs through "bridging circuit" comprising 9k Ohm series resistor (source side) followed by 1k Ohm parallel (load side). The load is practically invisible/non-existent; the top remains cool at any level. Still though, the cooling fan operates past a certain volume threshold.
Adding large amounts of rope putty and two fishing weights significantly damped fan noise, but my room is dead quiet and fan noise is still audible for a few seconds when I pause music. Plus even though higher playback level masks fan noise, I presume fan noise masks some detail.
I removed the fan, which the 912 "sensed" was gone, and would not turn on.
Fan label: 24VDC, 0.11A.
Can I replace the fan with a dummy load, thus tricking the program into thinking the fan is present? Please specify appropriate load and how to wire it per the fan's three conductors. I have only standard DVM. I'll risk frying the 912 to test.
Thanks very much for your help. 🙂
Is the fan only 2 wires?
If Yes.......
Measure the DC resistance of the fan.
Try to find a resistor of that value that will handle at least 3W or so.
That's what I'd try.
If Yes.......
Measure the DC resistance of the fan.
Try to find a resistor of that value that will handle at least 3W or so.
That's what I'd try.
Thank you sirs!
Any ideas re. three wires to the fan? I will dis-assemble fan if necessary to confirm purpose of three conductors.
Any ideas re. three wires to the fan? I will dis-assemble fan if necessary to confirm purpose of three conductors.
3 wires means that there is either an RPM sense lead or PWM control over fan speed.
The 220Ω 5W resistor would go across the red and black wires generally, the standard color code is Red + Black - Yellow RPM.
If it does care that the fan is actually spinning then the 220Ω resistor might not work.
The 220Ω 5W resistor would go across the red and black wires generally, the standard color code is Red + Black - Yellow RPM.
If it does care that the fan is actually spinning then the 220Ω resistor might not work.
fan
Or just replace the fan with a quieter fan. There are many computer fans specifically designed to be very low db output. Available in most common fan sizes.
Or just replace the fan with a quieter fan. There are many computer fans specifically designed to be very low db output. Available in most common fan sizes.
Z - This is true but the system requires a 24V fan.
I suppose a 12V Zener on a nice quiet computer fan would be ok.
But as with servers if the RPM is out of a certain range then it will throw a fault.
At that point I suppose the best you could hope for is that the Receiver only senses that the fan is spinning & doesn't care the actual RPM.
I suppose a 12V Zener on a nice quiet computer fan would be ok.
But as with servers if the RPM is out of a certain range then it will throw a fault.
At that point I suppose the best you could hope for is that the Receiver only senses that the fan is spinning & doesn't care the actual RPM.
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On the one hand, too bad for the third wire. I'm hopeful it's irrelevant, as I never noticed RPM vary (good pitch sensitivity).
OTOH, this place is loaded with generous members! Thanks again. Will report results later.
OTOH, this place is loaded with generous members! Thanks again. Will report results later.
PCB stencil where the fan's three wires connect:
Red: "ON FAN +"
Black: "FAN -"
Yellow: "STOP"
266R shorts red/yellow.
There is only one fan speed (I'm intimately familiar with its pitch/speed). Within a certain range on the volume control, very slow variation and/or modulation causes the fan to quickly modulate on/off.
No 220R power resistor. I cut the Red/Black wires and shorted them across 600R. Power up, works fine even at maximum volume.
Beer's on me! Thanks, folks!
Red: "ON FAN +"
Black: "FAN -"
Yellow: "STOP"
266R shorts red/yellow.
There is only one fan speed (I'm intimately familiar with its pitch/speed). Within a certain range on the volume control, very slow variation and/or modulation causes the fan to quickly modulate on/off.
No 220R power resistor. I cut the Red/Black wires and shorted them across 600R. Power up, works fine even at maximum volume.
Beer's on me! Thanks, folks!
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OK, thanks again for your help. A different/related question. Sorry for the post length.
Power amps comprise two more 912 receivers, one each sited on the floor next to L/R speakers. The power amp fans are much less audible than the rack-mounted preamp, but now that "preamp" noise is gone I request comments reference the following proposal. Replacement 912s are only about $100, so I don't mind sacrificing one, even though unlikely.
Pioneer's 912 comprises sum total six power amp channels, three channels each (I presume) per proprietary PAC011A modules cemented to one aluminum heat sink, solid ribbed aluminum panel 4" x 8" x 1/8" with 10 double sided fins comprising one continuous bent 3mm aluminum sheet, each fin 4" tall x 1.5" deep.
Each 912 "power amp" drives two speakers per channel: one Main Speaker, one Effects Speaker based on Toole/LeJeune research and prior art.
Pioneer rates "Continuous Output Power (stereo)" 110Wpc, 20-20kHz, .2% THD, 8 Ohm only. Not even a measly 6 Ohm rating. Surround power rated only @ 1kHz.
Main Speaker is 12 Ohm, Effects Speaker 8 Ohm. I presume the channel driving the MS voltage limits while the channel driving the ES current limits. (This non-symmetrical load vastly upgrades performance vs. each receiver driving symmetrical load per channel.)
I used these 912s for several years. On the rarest occasion (count fingers on two hands) driving a prior much more difficult Dynaudio load, a 912 shut off, cooled down, then turned on a minute later no worse for wear.
So one 912 fan and heat sink is engineered for a typical HT load as follows: seven consumer HT speakers 6 Ohm nominal/possibly low 3 Ohm minimum (two rear surrounds wire in series), mid-high 80 dB, high-pass crossed 100-200 Hz for powered sub.
Above the bass range my loads are ruler flat 12 Ohm and 8 Ohm (10 Ohm/6 Ohm minimum respectively), low 90dB sensitivity.
I propose to disable both power amp fans. My hope is if either 912 over heats it would simply shut down then turn on a minute later as per prior experience.
If they shut down too often I install computer fan.
Power amps comprise two more 912 receivers, one each sited on the floor next to L/R speakers. The power amp fans are much less audible than the rack-mounted preamp, but now that "preamp" noise is gone I request comments reference the following proposal. Replacement 912s are only about $100, so I don't mind sacrificing one, even though unlikely.
Pioneer's 912 comprises sum total six power amp channels, three channels each (I presume) per proprietary PAC011A modules cemented to one aluminum heat sink, solid ribbed aluminum panel 4" x 8" x 1/8" with 10 double sided fins comprising one continuous bent 3mm aluminum sheet, each fin 4" tall x 1.5" deep.
Each 912 "power amp" drives two speakers per channel: one Main Speaker, one Effects Speaker based on Toole/LeJeune research and prior art.
Pioneer rates "Continuous Output Power (stereo)" 110Wpc, 20-20kHz, .2% THD, 8 Ohm only. Not even a measly 6 Ohm rating. Surround power rated only @ 1kHz.
Main Speaker is 12 Ohm, Effects Speaker 8 Ohm. I presume the channel driving the MS voltage limits while the channel driving the ES current limits. (This non-symmetrical load vastly upgrades performance vs. each receiver driving symmetrical load per channel.)
I used these 912s for several years. On the rarest occasion (count fingers on two hands) driving a prior much more difficult Dynaudio load, a 912 shut off, cooled down, then turned on a minute later no worse for wear.
So one 912 fan and heat sink is engineered for a typical HT load as follows: seven consumer HT speakers 6 Ohm nominal/possibly low 3 Ohm minimum (two rear surrounds wire in series), mid-high 80 dB, high-pass crossed 100-200 Hz for powered sub.
Above the bass range my loads are ruler flat 12 Ohm and 8 Ohm (10 Ohm/6 Ohm minimum respectively), low 90dB sensitivity.
I propose to disable both power amp fans. My hope is if either 912 over heats it would simply shut down then turn on a minute later as per prior experience.
If they shut down too often I install computer fan.
With fan installed and working normally: with much more difficult load (lower impedance, lower sensitivity), when stressed at high SPL for extended period, on rare occasion, this Pioneer receiver shut down, then I was able to turn it back on within about one minute.
I want to remove one fan and listen at high SPL. I use two or at most three of six power amp channels. With fan disabled, if the power amp stage overheats, do members presume the receiver will simply shut off again as before? Or rather is there reason to believe something worse might occur?
Even if one receiver self-destructs, I can live with that. I'm anxious to find out whether or not I can just remove the fan.
I want to remove one fan and listen at high SPL. I use two or at most three of six power amp channels. With fan disabled, if the power amp stage overheats, do members presume the receiver will simply shut off again as before? Or rather is there reason to believe something worse might occur?
Even if one receiver self-destructs, I can live with that. I'm anxious to find out whether or not I can just remove the fan.
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