Water cooling, practical matters.

[powerbecker]

snip Eva
That's lovely, do you have more pictures or the entire article?

Hi Eva,
1980 one of my friends put this 80kg monster for "testing" to the german hifi-magazine HiFi-Exklusiv, they done some measurings, the thd was not so famous : At this time a had no meter
Btw, I think this was the last time for technical tests....other mags started only with hearing-"tests"
The article is german written, it is scanned, but for details the pics are too big to put it here.
Regards
Heinz!

 

[lineup]

Has anybody experiemented with water cooling. I'm especially interested in making it as socially accpetable as possible (i.e. as invisible and unnoticed as possible)

Once upon a time......

in 1979 I build a 2channel poweramp with 80 workinghorses in two half-bridges.......

.....further components :

1 EI-transformer 4kVA
2 heat-cooler from Fiat124S
3 7l transformer oil

..the expansion vessel was in the container at the top, together with the 2N3055´s. It was made from a folded Perbunan skin also the the tubes must use this material, because the hot oil solves plastics..

Amazing. 30 years ago.

Heat-cooler from Fiat 124S

One amplifier with the power of cars. Like

 

[ostripper]

As I put this on the other watercooled thread ,Ill put it
here:

Totally fanless convection.....
All you do is mate this up with a quality (not a cheap thermaltake)
pump, thermal and electrical failsafes wired to the amps
AC (my class AB trips the soft start for thermal).

It's scalable too, you can buy as many of these passive
extrusions as necessary from..

http://www.pc-water-cooling.com

From ASKA:
In the last ten years a huge variety of quiet fans have become available. These are outstanding, particularly the larger 120 x 120mm DC versions with low speed (typically 1800 rpm). Papst make temperature controlled fans which are around 21dBa, and with careful mounting, and use of a plenum chamber, it's possible to bring fan noise to below room ambient.

I agree ,forced air cooling is very effective for AB. I use a
single 80mm panaflow for 2 150W amps and with just
2 -160 x 60mm heatsinks face to face I can't get 20C
over ambient.
Many commercial offerings use REALLY small
heatsinks and get away with it by stuffing a 60mm in
the chassis.(large STK-XXX chip amps)

 

[AKSA]

Just to further illustrate the range of fans now available, here's a 120x120 using a Sony bearing developed for low noise and long life.

This fan costs around $15, gives 33.5 cfm at just 800rpm, with 100mA current draw at 12V. It emits just 8.7dbA of noise, which is actually extraordinary..... you would not hear it with your ear more than about a foot from the outlet.

With the appropriate heatsink, forced air circulation at this rate would roughly triple the thermal capacity over simple convection and considerably reduce the size of the heatsink. With two back to back MF18-200 heatsinks from Conrad (which present 120x120 frontal area), this would do 350 watts of heat between them at 27C above ambient. This rating is based on an actual test I did some years ago with these heatsinks and around 35 cfm.

Directron

It would seem that water cooling is not really needed these days for a high dissipation Class A amplifier, providing you have the right heatsink and fan combo.

Hugh

 

[lineup]

Interesting.
Such very silent 120x120 mm fans.

But I am not surprised.
The call for very quiet PC systems have increased, constantly.
For 2 equal PCs, you take the most silent one.
So, for PC makers, it is one competitive factor: sound level.

Why this low sound issue has become important
is that many of us have 24/7 broadband IP-connection.
PC will run all the time in our living rooms.

It wasnt like this when we used (very) Slow Modem via telephone lines.
Cost would be proportional to hours online.

 

[lineup]

Totally fanless convection.....
All you do is mate this up with a quality (not a cheap thermaltake)
pump

http://www.pc-water-cooling.com/media/konvpro21_150.jpg

ostripper,
can you tell shortly about such pumps

The only pumps I have used, was that air pump
I used when I had fishes in my aquarium.
To put air, oxygene into the water.

 

[ostripper]

In response to both ASKA and Lineup in regards to fan noise,
a Pulse Width Modulation circuit -

An externally hosted image should be here but it was not working when we last tested it.

is the most elegant solution . A class AB amp will
not create much heat at idle so the fan is off at this point (0 DB)
while amplifier abuse is in progress the fan will
scale all the way to max (2500 + RPM) . The good thing about
using this little circuit is you can use any junkbox fan (60-120mm),
the drawback is a little noise from the PWM oscillator, which
can be solved with a shielded cable run to the fan motor.

If I was to use watercooling ,I'd also use this circuit for
fan cooling a smaller heat exchanger as this would reduce size
and expense.

Here's your pump ,Lineup...

http://www.pc-water-cooling.com/home.html
Pumps are at left ..OS

 

[lineup]

good
there we have 2 working systems for cooling amplifiers

 

[neil_kaye]

Here is a new CPU cooler that uses a refrigerant:

http://gizmodo.com/5053065/thermaltakes-xpressar-pc-case-uses-actual-fridge-compressor-for-cooling

 

[lineup]

thanks, neil_kaye

here is how it works

An externally hosted image should be here but it was not working when we last tested it.

 

[ostripper]

Looks like a standard AC unit for PC use. It could be very compact,
but would be overly complicated for audio use.

Also, 1. the compressor would create heat as well ,making the unit only useable as an external assembly...
2. The "cold' side (at the OP devices) would create
condensation as the system would be far below ambient.

 

[lineup]

yes, in fact was one comment at that site
about condensation = water