BrianDonegan said:1 (the big one)): copper is much more expensive than aluminum
2) can't extrude copper, so fins would be soldered, fused (not as good as one piece), or machined (from big $$ chuck of copper).
3) You find one...
I am actualy using copper for a water cooled design. I use it for heat spreaders as well, both for small components on large heatsinks, and to bridge multiple aluminum heat sinks. Need to watch the copper to aluminum jundtions however, as they will corode like crazy.
Eperdicanus. (sp?) used to specifically stop metal to metal corrosion on alloys.
And any computer store carrys copper heat sinks and from what i see of these little ship amps, they could be flipped or mounted/modded for your purposes. its something like double the wattage dissapation to air is it not?
BrianDonegan said:1 (the big one)): copper is much more expensive than aluminum
2) can't extrude copper, so fins would be soldered, fused (not as good as one piece), or machined (from big $$ chuck of copper).
3) You find one...
I am actualy using copper for a water cooled design. I use it for heat spreaders as well, both for small components on large heatsinks, and to bridge multiple aluminum heat sinks. Need to watch the copper to aluminum jundtions however, as they will corode like crazy.
Re 2: Or Cast... Have you checked out the Zalman cpu coolers? I dunno if they are cast, soldered or or machined, but they are copper, and they are beautiful. Zalman 3100-Plus Mind you, I have no idea on an amp case design that would suit such a heatsink...
Re Water cooling: Didn't your mummy tell you that water and electricity don't mix?
Brian, do you get corrosion on your (air) heat spreaders?
Michael
I have a Zalman coler on my CPU. It's thin copper plates fused together in the center and then belt out into a round fan pattern. At the base, they are machined flat and polished to a mirror finish. They are quite beautiful.
I was thinking, among other things. of mounting an amp (not this one) to a copper plate (I have some 4" x .25" plate, about 36" long) about 8 inches long, then mounting two Zalman Cu-7700 coolers to it, and having them protrude slightly from the top of the amp case. Then regulate fan speed with a temp sensing circuit.
I don't plan on mixing them.
Well, not corrosion (yet anyway). But the copper, not being a good alloy like berylium, does patina quite readily. That is, it loses it's glossy shine and it reacts with oxygen forming a copper-oxide coating. This does reduce it's heat disapation to the air, but I am only using it to disapate heat to a heatsink. Copper has extremely good heat conductivity. It is also very reactive. Once the patina forms however, that's usually as far as it goes. Where things are mounted to it, and oxgen doesn;t touch it, it okay. Where the aluminum touches it there is a danger, but I haven't kept things together for long enough (DIY, you know).
So, when I was working as an elecrician's apprentice a long time ago (for my brothers), all aluminum wire needed to have this goop called NOALOX applied before connecting it to other aluminum or copper wires or fittings to prevent corrosion. Probably a brna dname for the stuff MadMaike mentioned. I should try using it on the heatsinks.... Hmm...
I haven't gotten around to building my amp yet but I have used a copper heat sink for another GC. That one was a pretty standard LM3875 NIGC with the latest iteration of power supply and snubbers along the guidelines that our own CarlosFM has been advocating. You can see some shots here:
http://www.diyaudio.com/forums/showthread.php?postid=681882#post681882
For the heatsink, I used a big chunk of copper (1"x 4" x 5") which I bought from online metals - http://www.onlinemetals.com/
Even without any channels or other techniques to increase surface area, I find that the copper barely gets warm.
I don't know how much the heat sink contributes to the sound, but this little amp has been impressing a lot of my friends and even holds its own when used against some expensive tube single ended amplifiers.
I'll report back when I get a chance to compare my version of Mauro's amp to the other GC. I'll start with the conventional amp that most other people seem to be building and depending on how it fares against the fully snubberized GC, then I'll decide if it needs upgrading.
---Gary
http://www.diyaudio.com/forums/showthread.php?postid=681882#post681882
For the heatsink, I used a big chunk of copper (1"x 4" x 5") which I bought from online metals - http://www.onlinemetals.com/
Even without any channels or other techniques to increase surface area, I find that the copper barely gets warm.
I don't know how much the heat sink contributes to the sound, but this little amp has been impressing a lot of my friends and even holds its own when used against some expensive tube single ended amplifiers.
I'll report back when I get a chance to compare my version of Mauro's amp to the other GC. I'll start with the conventional amp that most other people seem to be building and depending on how it fares against the fully snubberized GC, then I'll decide if it needs upgrading.
---Gary
BrianDonegan said:
The antenna guys (at least those who care or know what they're doing) use a type of silicone on the contacts, to prevent corrosion.
It never dries and it lasts for a lifetime.
The antenna falls with age and the contacts where the 75 ohm cable grimps are perfect, and full of silicone.
homer09 said:
Look here:
http://www.onlinemetals.com/merchant.cfm?id=253&step=2
and click on the size you want, for example 1" x 4".
Then go to the section where you can ask for a custom cut and you are done.
---Gary
I think I'm going to build some soon but I would just like to order from 3 places to minimize shipping.
I'm thinking getting everything from Mouser, Digikey, and PartsExpress .
So that means
220uF Radial 50V EL Capacitor Sanyo AX Bdent 63MV220AX
220uF Radial 50V lowESR EL Capacitor Sanyo FZ Bdent 50MV220FZ
10000uF 50V EL Caps Sanyo DAC Bdent 50PL10000DAC
22uF Radial 25V EL Capacitor Sanyo SAX Bdent 25MV22SAX
100uF Radial 25V EL Capacitor Sanyo AX Bdent 25MV100AX
will need to be replaced with something else as those parts houses don't carry them. Could someone help me choose good alternative parts that will fit the current PCB's?
Thanks,
Greg
I'm thinking getting everything from Mouser, Digikey, and PartsExpress .
So that means
220uF Radial 50V EL Capacitor Sanyo AX Bdent 63MV220AX
220uF Radial 50V lowESR EL Capacitor Sanyo FZ Bdent 50MV220FZ
10000uF 50V EL Caps Sanyo DAC Bdent 50PL10000DAC
22uF Radial 25V EL Capacitor Sanyo SAX Bdent 25MV22SAX
100uF Radial 25V EL Capacitor Sanyo AX Bdent 25MV100AX
will need to be replaced with something else as those parts houses don't carry them. Could someone help me choose good alternative parts that will fit the current PCB's?
Thanks,
Greg
Member
Joined 2003
Awesome, that new BOM is exactly what I was looking for.
Then for transformers I should be able to use 3 of these (one for each channel) of a 3 channel amp.
If I remember properly his Rev A design has 2 channels on a board, but they're actually seperate. So I'll build the amp with 2 RevA boards, fully populate one, and half populate the other.
Awesome, gonna order parts today, etch tomorrow, and build in a few days. Very cool.
Then for transformers I should be able to use 3 of these (one for each channel) of a 3 channel amp.
If I remember properly his Rev A design has 2 channels on a board, but they're actually seperate. So I'll build the amp with 2 RevA boards, fully populate one, and half populate the other.
Awesome, gonna order parts today, etch tomorrow, and build in a few days. Very cool.
Member
Joined 2003
