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Old 3rd December 2015, 04:53 PM   #1
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Default ACA Concept II

This is my second Amp Camp build. Like my first one, this will be a drawn-out affair. However, Iíve got it pretty well planned out and Iíve already made some progress in construction.

My primary motivation for this build was a pair of fan-cooled copper heat sinks I found at the local electronic salvage store a few months ago, which cost me $9 each. I knew I had to figure out some way to put them to good use. The fans are pretty quiet at low speeds, and I figured they would be good for a small ACA buildÖ so here we are.

Unlike my last build, this time Iím going to alter the circuit a little bit based on a suggestion made by Zen Mod in the official Amp Camp thread. Iíll be switching out the IRFP240 mosfets with IRFP150s, ďcrank[ing] up the voltage,Ē and halving the values of R1 - R4. That should produce an ďACA on steroidsĒ according to Zen Mod. Weíll see how that works out. If it doesnít, itíll be easy enough to swap in the standard components. My plans for this amp are to use it to drive moderately-sized subwoofers, using my current ACA mono blocks to drive a couple of small two-ways.

In order to fit my case design and to keep everything neat & tidy, Iíll be making my own 2-sided PCBs, something Iíve never done before. I laid out the board using Adobe Illustrator:

Click the image to open in full size.

Youíll note Iíve included circuitry for a mosfet-base fan controller. Iím not 100% sure Iíll be using that circuit, so that part of the board may change.

The heat sinks (with fans) will be connected with a piece of aluminum angle, and the PCB will mount to the heat sinks. Aside from the power jack, switches, LED, and in/out connectors, all the working parts of the amp will be included in this assembly:

Click the image to open in full size.

Click the image to open in full size.

The case framework will be made of welded steel. Wood at the front and perforated steel at the top and rear will complete the case:

Click the image to open in full size.

Click the image to open in full size.

In addition to the usual metal work and wood work, thereíll be some other fun stuff like etching and plating, so hopefully some of you will find this interesting. Stay tunedÖ



Edit: If you have Sketchup (and I suggest you download it if you don't), you can download my model here:ACA Concept to .skp model (zipped).
Attached Images
File Type: png ACA ver. 2a PCB.png (70.0 KB, 742 views)
File Type: png ACA ver. 2a innards front.png (67.4 KB, 728 views)
File Type: png ACA ver. 2a innards back.png (70.2 KB, 723 views)
File Type: png ACA ver. 2a front.png (307.8 KB, 732 views)
File Type: png ACA ver. 2a back.png (373.0 KB, 727 views)

Last edited by ChuckORWC; 3rd December 2015 at 06:01 PM. Reason: Added link to .skp file
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Old 3rd December 2015, 05:07 PM   #2
Zen Mod is offline Zen Mod  Serbia
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Fug

..... ly! should be added after completion


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Old 3rd December 2015, 05:11 PM   #3
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We'll see...

BTW, I'll be editing the original post with downloadable files as I go along...
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Old 3rd December 2015, 06:17 PM   #4
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With fan cooling you will want air filters before things get too gross.
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Old 3rd December 2015, 07:38 PM   #5
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Quote:
Originally Posted by Andersonix View Post
With fan cooling you will want air filters before things get too gross.
Good idea, Thanks.
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Old 3rd December 2015, 07:52 PM   #6
Zen Mod is offline Zen Mod  Serbia
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naah , with lazy flow - that's not pro amp with full blasting vents

blasting with some compressed air , once or twice per year , is enough
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Old 3rd December 2015, 08:18 PM   #7
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Default Construction begins...

Drilling the holes in the mounting bracket and heat sinks:

Click the image to open in full size.

Heat sinks attached to mounting bracket:

Click the image to open in full size.

Using printout of the PCB to locate holes for output devices mounting screws:

Click the image to open in full size.

Ready to drill!:

Click the image to open in full size.
Attached Images
File Type: jpg photo 1.jpg (48.7 KB, 667 views)
File Type: jpg photo 2.jpg (53.5 KB, 671 views)
File Type: jpg photo 3.jpg (51.3 KB, 663 views)
File Type: jpg photo 4.jpg (49.0 KB, 659 views)
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Old 4th December 2015, 04:21 PM   #8
AVWERK is offline AVWERK  United States
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I almost always use a fan but feel 4 of them will create too much noise
Even just above the turn on voltage and the slowest speed possible, this might still be too much
But it will defintely keep it cool and very nice work BTW

Regards
David
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Old 4th December 2015, 04:37 PM   #9
AVWERK is offline AVWERK  United States
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You might try Velcro instead of rigid mounting the fans to eliminate transmitting anything to the chassis. Rubber won't work as well as this stuff
Fans are light enough to handle Velcro without issue.
To eliminate a beat frequency of so many fans, you might just insert a diode to slow a couple down to spread out any noise contribution
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Old 8th December 2015, 02:41 PM   #10
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Rubber O Rings.
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