Class D Amp Photo Gallery

Re: Re: Re: Re: On the way

classd4sure said:

*snip* about heat

What software did you use for working out that layout?

Ok, I'll make swiss cheese out of those hot plates. D***, I'm hungry now! ;) A rediculous number of strategically placed 3mm slots should do it, right?

What software I used? My head, it's pretty soft sometimes :) For visualizing it, I use UGS NX3, a pretty awesome piece of CAD/CAM software we use at my university.

classd4sure said:

I think I agree with Lucpes here. It's hard to tell by your drawing how you plan on mounting the supplies on that plate, looks like they're kind of integrated. You'd likely be better off isolating them from the divider, flipping the whole thing over, and going with the shortest possible runs for DC to the modules. The bulk storage caps on the modules arent' the biggest, so you really want that path as optimal as possible.

You can still do it and keep all the AC portion shielded from the modules if you work it out right.

Sorry, it just seams so easy when I explain it to myself :) The power supplies are only screwed onto the divider, as the vertical approach takes up less space and makes for shorter wires. The green cubes on either side of the PSU is where I connect the caps+amps, so if I go this way, the wire lengths will be cap length (70) + width through divider (10) + distance from divider up to connector (~10), which give us about 90mm wires. They won't be more than about 10mm shorter if I flip the divider over.

As you can see from the detail image, the caps' connectors are on the amp end, so I'll only have 10-20mm of wire from cap to amp.

The only way to get the wires considerably shorter, would be to stand the caps up, but in addition to the fact that I don't really have room for that, it would mean longer leads to the amp and a messier PSU layout.
 

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Don't worry, I'll spend time to put this in a better box (or I'll sell it "to be boxed" ;) ).

I plan to make a 5 channels amp based on Jan's AMP4 (and/or maybe AMP11) and the design will be in an aluminum box (Galaxy ?) and much more clean.

Or maybe based also on AMP6. It will depend on my future listening results comparing the 2 of them.

But there's one thing you said right : I'm enjoying (loving?) it even like that! :devilr:
 
Ok, I'll make swiss cheese out of those hot plates. D***, I'm hungry now! A rediculous number of strategically placed 3mm slots should do it, right?

Yep. If looks are important you can also just vent the bottom plate of the amp towards the PSU end of the modules, and put exhaust vents on the back plate towards the top. That should keep fresh air flowing around the heater and give you good circulation in the little compartments. You might also want some venting around your transformer as well (I would). Exhaust could then be on the sides.

Thanks for the CAD name, I knew it was no autocad. I shall acquire :devilr:
 
TOINO said:



Nothing special...

+80V/0/-80V supply in full-bridge. One Cycle Control modulator exactly as in the patent.
I have made it for sub-bass, but works fantastic at full range. Oscillation is about 300Khz.
After some unsuccessful attempts to transform it in BD modulation I decided to leave it as it is now.
My humble opinion is that OCC is a great and simple error correction technique.
Thank you Miss Smedley.:up:

What is the THD? One-cycle is basically a feed-forward control scheme.

And it's Professor Smedley, married.
 
Hi Koolkid

It is easy to see that my prototype has some EMI issues; they perturbate a lot my thd measurement instrument…
The last attempt I have made, is inconclusive, but the readings are always inferior to 0.5% -800W-8ohm.
Anyway this is not serious measurements as I have not special filters on the AP. Also I have no special interest in really know the thd…
It was my first and unique class-d amplifier, and for my great surprise it works…:D

koolkid731 said:


One-cycle is basically a feed-forward control scheme.


Here I strongly disagree…
The only thing that is feed-forward on OCC is part of frequency control scheme.
The remaining is tacked from the outputs before coils… this is feedback, right?
 
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Joined 2005
TOINO said:
Anyway this is not serious measurements as I have not special filters on the AP. Also I have no special interest in really know the thd…
It was my first and unique class-d amplifier, and for my great surprise it works…:D

Measurements are nice, but they don't ever include that subjective THD reducing factor you get from building it yourself :)
 
BWRX said:


Measurements are nice, but they don't ever include that subjective THD reducing factor you get from building it yourself :)


I love how everyone who prototypes a class d amp on a breadboard with no scope always say it's dead quiet. :bs:

Actually, if the bridge isn't switching right one of the mosfets can act as a constant current source .... and it really does quiet things right down.
 
Ok, I just have to show you the "beauty" I've had for a while now, while never getting my finger out to make a new case... ZAPpulse 2.3SE with dual mono power supplies, 500VA toroids, Schottky bridges, 2x 15000 uF RIFA PEH200 caps pr. rail, DACT CT-2 attenuator.

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


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


And yes, that is an electrician's drill bit I've use as a temporary volume control axle... Eventually, it'll be driven by a stepper motor and remote contcolled.