Convection cooling in a GC amp

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Peter Daniel

Peter Daniel

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Joined 2002
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#1
Never mind the hype, here's the New Amp

Acting on a hint from a custom order and motivated by the discussion on AA forum, I came here with a new design for an integrated GC amp. This time the chassis is made out of wood (of course maple😉)
 

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#3
The bottom is containing the circuitry. I also used the ideas from the other thread (waterproof chip) and integrated revolutionary design for heat sinking😉. The 1" copper pipes are located in ea. corner and using convection method release the heat . The chip itself is mounted to 1/8" copper plate, which is soldered to the pipes. The rest is pretty conventional: BG caps, MUR860 diodes and Nobel pot.
 

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#8
The transformer is mounted in a top compartment. There is no bolt used here, but the whole space is filled with expandable foam (door and window type). I was hoping that this would reduce possible vibrations. There are 3 acrylic plates between the two maple frames. The pipes are tight fitted in the openings. I used mu-metal shielding under transformer to reduce any intererence.
 

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#9
Here's how it looks when the transformer space is closed. You can notice the small suspended board holding the diodes. It is placed conveniently right above the secondaries wires. You also see solder residue on pipes😉 While soldering, the acrylic didn't really suffer much.
 

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#11
The copper pipes go through the whole height of the amp, so you can see through them. I kinda like that effect. This amp is also kinda similar to first Aleph 0 from Pass Labs, but I hope that this time I won't be blamed for that😉

While the top box is closed tightly with the bolts, the bottom one is floating freely and is only protected by two screws (with rubber grommets) from falling off. The feet rest on bottom frame.
 

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#12
Very good peter. The convection system is very near mine but i installed tight fitting springs inside the pipe. That makes it an augmented convection, you see when the hot air rises the shape of the springs causes a vortex action, which circuates the air to the inner walls of the pipe making a greater transfer of heat energy.Otherwise the flowing air current mainly stays in the center of the pipe and dosent transfer the heat from rising air currents as well.
Cool looking cab BTW. How did you get away with a single volume control?I havent given up on the motorized controls just trying to find the right combo of stepper/pot.
ron
BTW where are you getting the maple?
 
#14
cool

here's a question (hope it's not been asked b4)

what do you use as PS wires ie. from diodes to caps or tx to diodes ?
is it better to have short leads from diodes to tx or from diodes to caps + opamp ?
finally, how is the diode bridge assembled (picture ? 🙂 ) ? do the diodes ever need heatsinking at all (it gets up to 45C in the summer in my house)

ok that was more than one question I guess.. take your pick 🙂

regards

Stelios
 
#16
stelios said:
cool

here's a question (hope it's not been asked b4)

what do you use as PS wires ie. from diodes to caps or tx to diodes ?
is it better to have short leads from diodes to tx or from diodes to caps + opamp ?
finally, how is the diode bridge assembled (picture ? 🙂 ) ? do the diodes ever need heatsinking at all (it gets up to 45C in the summer in my house)

ok that was more than one question I guess.. take your pick 🙂

regards

Stelios
Click to expand...

From TX to diodes I use whatever is supplied with a transformer. From diodes to caps I use either Kimber or Cardas 19ga wire. This time I used Kimber as the wiring was pretty complicated and Cardas requires soldering pot. As to the lengh of the leads between those, it doesn't really matter to me, I do whateb=ver is convenient from construction POV. Probably diodes closer to transformer might be better choice. The diodes get pretty hot on certain type of music (and volume), but I never heatsinked 'em and didn'e experience any problem so far.

Here's the pick of the diodes board. I believe that this is the most comact layout for double bridge. I used only the components leads and solder everything p2p. The four bigger holes are for AC from TX. 8 diodes provide 4 common points for positive, negative, and two grounds. From ea. point two wires (8 total) run to the caps.
 

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#19
well, that looks very nice 🙂

would you believe, I did exactly the same thing but it looks like a pile of %"^!£$%

actually those holes for the tx leads are a good idea
I did sth different which wasn't as good

I also used a veroboard (?) without the soldered thru holes and I guess from looking at yours it makes a big difference on how tidy it looks

I guess I'll have to figure out a way to use heatsinking then.
Funny how it gets hotter with different music - I think we observed the same thing in our gc.

cheers

s
 
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