I've enjoyed this thread and have been thinking along similar lines for my JLH Class-A. But another thought is to look at something other than water for the transfer medium. I had not realised that liquids differed in their thermal characteristics until I read a book by Phil Irvine the great bike/car engine designer. He makes the point that oil absorbs thermal energy more quickly than water but also dissipates it more slowly. (This is probably why people poured boiling oil on their opponents when their castle was being attacted!) For our purposes this makes oil quite attractive. The thermal properties mean that it is better than water at drawing heat away from the relatively small confines of the area around the semi-conductor. On the other hand the slower dissipation rate will not be a great handicap. Most of us will be able to make the liquid to air heat exchanger as big as we like. There will not usually be space restrictions on a set up where the radiator is mounted outside the house and old car radiators are cheap etc.
Now I haven't done any further research on this but I have a couple of questions I wanted to chase up. One: the viscosity of oil may mean that a motor can't pump as much fluid through the pipes when compared to water. This reduced flow rate may negate some of the thermal advantage...... although the flow should improve as the system warms up the oil. I am guessing that it won't have corrosive problems and a gallon of olive oil could look attractive too.
Secondly, what does it sound like? What I'm really waiting for is for someone to do an A/B test and announce that the oil based design had smoother highs than the water cooled system!
Now I haven't done any further research on this but I have a couple of questions I wanted to chase up. One: the viscosity of oil may mean that a motor can't pump as much fluid through the pipes when compared to water. This reduced flow rate may negate some of the thermal advantage...... although the flow should improve as the system warms up the oil. I am guessing that it won't have corrosive problems and a gallon of olive oil could look attractive too.
Secondly, what does it sound like? What I'm really waiting for is for someone to do an A/B test and announce that the oil based design had smoother highs than the water cooled system!
From my sitting on the fence, pragmatist engineer POV, I fail to see why it's better, for the simple reason that the pump, fittings and heat exchanger (car radiator) are cheap, easily obtained and more than adequate for the task. Even with several Alephs a decent size radiator, sited well will dissipate more than enough heat. There is always a breeze up the side passageway of my house, which is where I'd place the radiator if I were going to do this (nearly did myself, but tubes sound better).Jonathan Bright said:
If you want to pick up more heat in the assembly with the semi's mounted on it, simply use a angled entry fitting, use a flange plate internally with a number of holes drilled in it, zigzag the tubing, or place a spring in the straight sections to make the water flow in there more turbulent to improve the heat transfer. Cheap, simple, not fancy, last forever. And as the absolute temperature in any well thought out system should be quite low, there are a lot of plastic fittings and adaptors that will allow you to use a 50/50 water/ethyl glycol mix and prevent oxydoreduction.
Grey, alaskanaudio, akira and Brian Donaldson have given a lot of good suggestions on how to do it. Another tip for bending the tube, plug the ends with a bit of scrap pine, fill the tube with fine sand and bend it around an object of approximately the correct radius. I've built car exhausts this way (with a bit of applied heat from an oxy) and everyone who saw them thought they'd been made with a mandrel.
I certainly have no problem with trying to improve something that needs it, but until you try water cooling and discover for yourself just how effective it is, I don't see the point to all these embellishments.
I'm sure that some of them would look cool, though.
You want to beat your head against the wall? Bend your will against the portability issue. Other than that, if it ain't broke, don't fix it.
Grey
I'm sure that some of them would look cool, though.
You want to beat your head against the wall? Bend your will against the portability issue. Other than that, if it ain't broke, don't fix it.
Grey
Are the transistors need tobe cold? I remember Mr.Pass said that mosfets likes it "HOT". So if it is a mosfet amplifier, class A (runs hot), and we use very effective cooling device, like water cooling, fans and radiator, will it change the sound?
I have encountered a commercial power amp that uses very thick aluminum block (not heatsink)+heatsink. I wonder if it is for adding weight or what.
Then I realize that the massive metal block is there to maintain "Thermal Inertia", so the temperature will be very stable.
There is a thread somewhere about "Thermal Memory Effect/Peufeu website". I know that this "thermal inertia" is opposite than that "thermal memory".
But which is more make sense and which is hoax?
I have encountered a commercial power amp that uses very thick aluminum block (not heatsink)+heatsink. I wonder if it is for adding weight or what.
Then I realize that the massive metal block is there to maintain "Thermal Inertia", so the temperature will be very stable.
There is a thread somewhere about "Thermal Memory Effect/Peufeu website". I know that this "thermal inertia" is opposite than that "thermal memory".
But which is more make sense and which is hoax?
try this
Its not very expensive nd looks good AND does the job!
http://www.quietpc.com/uk/watercooling.php
Its not very expensive nd looks good AND does the job!
http://www.quietpc.com/uk/watercooling.php
You can even do without the waterpump if the waterpipes are sufficiently large enough.
Warm water is lighter then cold water, so if you can place the radiator in the top of your house or outside you can use this characteristic of water for natural circulation.
you should place your amplifier as low as possible, and the pipes of the warm section of the sink should go straight up (a few decimeters horizontal will not harm if the diameter of the pipe is large enough).
If the amplifier warms up the water warms up allso.
This way the warm water will be lighter then the cold water and starts to flow to the top of the sink.
The cold water will take the place of the warm water, and so the natural circulation starts.
This is an old technique used in old central heating systems.
Edwin
Warm water is lighter then cold water, so if you can place the radiator in the top of your house or outside you can use this characteristic of water for natural circulation.
you should place your amplifier as low as possible, and the pipes of the warm section of the sink should go straight up (a few decimeters horizontal will not harm if the diameter of the pipe is large enough).
If the amplifier warms up the water warms up allso.
This way the warm water will be lighter then the cold water and starts to flow to the top of the sink.
The cold water will take the place of the warm water, and so the natural circulation starts.
This is an old technique used in old central heating systems.
Edwin
Grey,
You are right about the robustness of heatingsystems and tractors, but if your radiator is big enough and is capable to create a difference of more then 5 degrees celcius between the cold and warm waterpipes there will be no problem.
If the difference in temperature between the cold and warm pipes are bigger, the water will flow faster.
I agree it is much easier to implement a pump in the system
Natural circulation must be well calculated and therefore are more difficult to implement.
Edwin
You are right about the robustness of heatingsystems and tractors, but if your radiator is big enough and is capable to create a difference of more then 5 degrees celcius between the cold and warm waterpipes there will be no problem.
If the difference in temperature between the cold and warm pipes are bigger, the water will flow faster.
I agree it is much easier to implement a pump in the system
Natural circulation must be well calculated and therefore are more difficult to implement.
Edwin
I started a thread about this in the solid state forum, but since I am now planning on building a water cooled Aleph30 (possible 5 channel, depending on how well the water cooling works out), I'll jump on this thread.
I just bought a piece of copper 1/4" x 4" x 36" ($30) that I will chop up and use GRollins' method for the heatsink/spreader (1/2" copper pipe soldered to a 1" copper plate).
I will be using about 6' of copper/aluminum baseboard pipe for the radiator. This will be 6 - 1' pieces arranged in two layers of 3, all linked by 3/4" pipe fittings (the radiator pipe is 3/4"). The change from 1/2 to 3/4 should slow the flow rate while the water is disapating heat, then speed back up a bit as it reenters the 1/2 pipe. The pump and radiator will be mounted in a second case (that looks like my amp case hopefully), with fully vented top and bottom panels to allow for convection through the radiator.
For the pump, my brother asked his "pump guy" what to use. He did a quick analysis of the design volume and heat characteristics and came back with the Iwaki Walchem WMD-15RT. It's a magnetic drive pump, meaning that the impeller is driven magnetically by the motor, so there are no seals that can leak. Supposedly very very quiet. It has the proper flow, head and heat resistance to last a long, long time. My brother can get one for $80USD, but that's a good deal. Need to think about it as it's more than I wanted to spend.
A few other comments on other posts I saw:
Using straight anitfreeze is a really bad idea. Antifreeze is not a very good coolant. It is added to cars primarily to keep the water in the cooling system from freezing. It also has some additives to prevent corrosion. If you add straight antifreeze to your car with no water, your car will overheat. Ideal mixture is said to be 50/50. My system will be copper/poly (no aluminum contact) so I will use straight water. Race cars use straight water, then empty it out after each race.
Water is a better cooling medium for this type of cooling project. Oil is better if temps will exceed the boiling point of water. Oil is better in open systems, where pressure is not such a big deal. Remember, oil expands when heated. Water contracts when heated, until it boils, then it expands a lot. In a sealed low temp system, water is the way to go. The fact that oil disappates heat more slowly will be a problem unless you have active cooling on your radiator, or a really really big radiator. Similar to using cast iron for a heat sink. It takes a long time to heat up its large mass, but stays hot for a long time. I think we want this to cool very quickly. Machinists use oil for cooling metal during machining, but it's a full-loss system, constantly pumping fresh cool oil.
I just bought a piece of copper 1/4" x 4" x 36" ($30) that I will chop up and use GRollins' method for the heatsink/spreader (1/2" copper pipe soldered to a 1" copper plate).
I will be using about 6' of copper/aluminum baseboard pipe for the radiator. This will be 6 - 1' pieces arranged in two layers of 3, all linked by 3/4" pipe fittings (the radiator pipe is 3/4"). The change from 1/2 to 3/4 should slow the flow rate while the water is disapating heat, then speed back up a bit as it reenters the 1/2 pipe. The pump and radiator will be mounted in a second case (that looks like my amp case hopefully), with fully vented top and bottom panels to allow for convection through the radiator.
For the pump, my brother asked his "pump guy" what to use. He did a quick analysis of the design volume and heat characteristics and came back with the Iwaki Walchem WMD-15RT. It's a magnetic drive pump, meaning that the impeller is driven magnetically by the motor, so there are no seals that can leak. Supposedly very very quiet. It has the proper flow, head and heat resistance to last a long, long time. My brother can get one for $80USD, but that's a good deal. Need to think about it as it's more than I wanted to spend.
A few other comments on other posts I saw:
Using straight anitfreeze is a really bad idea. Antifreeze is not a very good coolant. It is added to cars primarily to keep the water in the cooling system from freezing. It also has some additives to prevent corrosion. If you add straight antifreeze to your car with no water, your car will overheat. Ideal mixture is said to be 50/50. My system will be copper/poly (no aluminum contact) so I will use straight water. Race cars use straight water, then empty it out after each race.
Water is a better cooling medium for this type of cooling project. Oil is better if temps will exceed the boiling point of water. Oil is better in open systems, where pressure is not such a big deal. Remember, oil expands when heated. Water contracts when heated, until it boils, then it expands a lot. In a sealed low temp system, water is the way to go. The fact that oil disappates heat more slowly will be a problem unless you have active cooling on your radiator, or a really really big radiator. Similar to using cast iron for a heat sink. It takes a long time to heat up its large mass, but stays hot for a long time. I think we want this to cool very quickly. Machinists use oil for cooling metal during machining, but it's a full-loss system, constantly pumping fresh cool oil.
WorkingAtHome,
You are not correct about water contracting when heated.
Water has its highest density at 4 degrees celcius.
When water is heated above, and cooled below this temperature it will expand.
If your water cooled system contains a large amount of water the pressure in the system will rise.
A solution to this is a damper ( i don't know the correct word) used in watersystems to absorb the expanded water.
Edwin
You are not correct about water contracting when heated.
Water has its highest density at 4 degrees celcius.
When water is heated above, and cooled below this temperature it will expand.
If your water cooled system contains a large amount of water the pressure in the system will rise.
A solution to this is a damper ( i don't know the correct word) used in watersystems to absorb the expanded water.
Edwin
WorkingAtHome.
If i understand it correctly you will make your own radiator out of tubes.
You have to consider that tubes has verry little surface area.
If you make your radiator out of tubes he must be verry big.
I advise you to search for an old airconditioner and use its radiator, or an old waterchilled cooler used in offices like i found recently.
The last one has a fan to suck air thrue the radiator, and can dissipate a lot of heat.
Maybe you can do without a fan with the above mentioned radiators if the case which houses the radiator is high enough.
This way you create a chimney with more volume of warm air.
And becouse of the mass differences between warm and cold air the air will flow faster thrue the radiator.
Hey this sounds again like natural circulation.
Another thing you have to think about is the speed of water thru the tubes.
In drinkingwater systems with a central boiler, the warm watersystem has a circulation system with pump.
The speed of water thrue this system is not allowed to go beyond 0.7 meters per second maximum, preferably 0.5 meters per second.
If the speed of water goes beyond this point the tubes will wear becouse of erosion.
In our amplifiers this may be a lesser problem as they are not working 24 ours a day.
Edwin
If i understand it correctly you will make your own radiator out of tubes.
You have to consider that tubes has verry little surface area.
If you make your radiator out of tubes he must be verry big.
I advise you to search for an old airconditioner and use its radiator, or an old waterchilled cooler used in offices like i found recently.
The last one has a fan to suck air thrue the radiator, and can dissipate a lot of heat.
Maybe you can do without a fan with the above mentioned radiators if the case which houses the radiator is high enough.
This way you create a chimney with more volume of warm air.
And becouse of the mass differences between warm and cold air the air will flow faster thrue the radiator.
Hey this sounds again like natural circulation.
Another thing you have to think about is the speed of water thru the tubes.
In drinkingwater systems with a central boiler, the warm watersystem has a circulation system with pump.
The speed of water thrue this system is not allowed to go beyond 0.7 meters per second maximum, preferably 0.5 meters per second.
If the speed of water goes beyond this point the tubes will wear becouse of erosion.
In our amplifiers this may be a lesser problem as they are not working 24 ours a day.
Edwin
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.