fan-based cooling for chipamp

oldfatbubba · 11th August 2007, 12:34 PM

I would like to share this cooling solution with the forum. It's simple, cheap and works damn well.

History: as initially built, my gainclone recieved comments in this forum about the inadequcy of it's heatsinks. I agreed. After driving it hard for a few hours, it's Pentium 4 heatsinks became way too hot.

So, an internet search, Mouser order later, and a weekend later, voila...

http://home.comcast.net/~eric.ericks...clone/Fans.JPG
fans mounted to sinks

http://home.comcast.net/~eric.ericks...e/Fanctrlr.JPG
controller

http://home.comcast.net/~eric.ericks...thermistor.JPG
thermistor

I used this controller circuit....
http://www.rason.org/Projects/fancont/fancont.htm
...replacing the 2n2907 with a TIP42 (read: overkill). I used two 10k thermistors in parallel, one mounted to each heatsink, so I had to change R2 to 5K. Also, I changed R3 to a 5K and R4 to a 5K trimmer.

Original Burnedfingers · 12th August 2007, 10:39 AM

Instead of using the Pentium 4 heatsinks why not re read the manufactures engineering data and size the heatsinks correctly?
This would eliminate running the chips at too high a temperature and eliminate the need for any special cooling circuits.

oldfatbubba · 13th August 2007, 01:59 AM

Cut me a little slack, burnedfinger.

I had no prior experience with heatsinks as this is my first non-tube project. I'll know better next time.

head_spaz · 13th August 2007, 04:47 PM

Check these out

troystg · 13th August 2007, 04:58 PM

Actually under "most" normal listening conditions those sinks would have been fine it the fins were vertically oriented and there were some vent holes beneath for convection flow. You may have even gotten away with chassis mounting the chips directly to the enclosure. It looks to be aluminum.

However, the fan controller circuit is WAY more interesting and I'm sure gave you a few hours of DIY fun...

BWRX · 13th August 2007, 05:01 PM

Quote:

Originally posted by troystg
However, the fan controller circuit is WAY more interesting and I'm sure gave you a few hours of DIY fun...

And it lets bubba use his current heat sinks! A job well done.

head_spaz · 13th August 2007, 07:04 PM

Brian,
Are lexdyxic or what?????
It's UNITE, not UNTIE.
Sheeeesh man. Get wtih the porgram!

bawang · 14th August 2007, 01:21 AM

Hi, oldfatbubba (nice choice for a name!)

The heatsinks are exactly the type that I am using for my PC based sound system in my office, again using LM3886s, except that I install them with the fins vertical and 5mm holes drilled on the bottom and top of the chassis. No overheating even when listening at LOUD levels, passive cooling. Now, if only I can get rid of the small residual hum.....

oldfatbubba · 15th August 2007, 04:30 PM

Quote:

Originally posted by bawang
Now, if only I can get rid of the small residual hum.....

Did you use a star ground? Are any wires carrying AC running near the inputs?

bawang · 16th August 2007, 01:20 AM

Grounding is done as per the recommendations of DIYaudio members. A star ground for all ground wires (except input signal ground, which is connected to the PCB input signal ground) and from here connected to earth (casing, connected to socket earth) through a 10 ohm resistor. It's OK, I know that grounding is witchcraft in itself, I'll sort it out someday. For now, the hum is not offensive, you can only hear it if your ears are within 3 or 4 inches of the loudspeaker..... BTW, this is an ESP P19.

11th August 2007, 12:34 PM	#1
oldfatbubba Account disabled at member's request Join Date: Jun 2006	fan-based cooling for chipamp I would like to share this cooling solution with the forum. It's simple, cheap and works damn well. History: as initially built, my gainclone recieved comments in this forum about the inadequcy of it's heatsinks. I agreed. After driving it hard for a few hours, it's Pentium 4 heatsinks became way too hot. So, an internet search, Mouser order later, and a weekend later, voila... http://home.comcast.net/~eric.ericks...clone/Fans.JPG fans mounted to sinks http://home.comcast.net/~eric.ericks...e/Fanctrlr.JPG controller http://home.comcast.net/~eric.ericks...thermistor.JPG thermistor I used this controller circuit.... http://www.rason.org/Projects/fancont/fancont.htm ...replacing the 2n2907 with a TIP42 (read: overkill). I used two 10k thermistors in parallel, one mounted to each heatsink, so I had to change R2 to 5K. Also, I changed R3 to a 5K and R4 to a 5K trimmer.

13th August 2007, 04:47 PM	#4
head_spaz diyAudio Member Join Date: Mar 2004 Location: Arkansas	Check these out __________________ Writing is good exercize for the texticles!

13th August 2007, 04:58 PM	#5
troystg diyAudio Member Join Date: Apr 2004 Location: Lousy Anna	Actually under "most" normal listening conditions those sinks would have been fine it the fins were vertically oriented and there were some vent holes beneath for convection flow. You may have even gotten away with chassis mounting the chips directly to the enclosure. It looks to be aluminum. However, the fan controller circuit is WAY more interesting and I'm sure gave you a few hours of DIY fun... __________________ Troy Thinking positive doesn't make things better, it makes you a better person.

13th August 2007, 07:04 PM	#7
head_spaz diyAudio Member Join Date: Mar 2004 Location: Arkansas	Brian, Are lexdyxic or what????? It's UNITE, not UNTIE. Sheeeesh man. Get wtih the porgram! __________________ Writing is good exercize for the texticles!

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12th August 2007, 10:39 AM	#2
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Instead of using the Pentium 4 heatsinks why not re read the manufactures engineering data and size the heatsinks correctly? This would eliminate running the chips at too high a temperature and eliminate the need for any special cooling circuits.

13th August 2007, 01:59 AM	#3
oldfatbubba Account disabled at member's request Join Date: Jun 2006	Cut me a little slack, burnedfinger. I had no prior experience with heatsinks as this is my first non-tube project. I'll know better next time.

14th August 2007, 01:21 AM	#8
bawang diyAudio Member Join Date: Oct 2001 Location: Malaysia	Hi, oldfatbubba (nice choice for a name!) The heatsinks are exactly the type that I am using for my PC based sound system in my office, again using LM3886s, except that I install them with the fins vertical and 5mm holes drilled on the bottom and top of the chassis. No overheating even when listening at LOUD levels, passive cooling. Now, if only I can get rid of the small residual hum.....

16th August 2007, 01:20 AM	#10
bawang diyAudio Member Join Date: Oct 2001 Location: Malaysia	Grounding is done as per the recommendations of DIYaudio members. A star ground for all ground wires (except input signal ground, which is connected to the PCB input signal ground) and from here connected to earth (casing, connected to socket earth) through a 10 ohm resistor. It's OK, I know that grounding is witchcraft in itself, I'll sort it out someday. For now, the hum is not offensive, you can only hear it if your ears are within 3 or 4 inches of the loudspeaker..... BTW, this is an ESP P19.

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