Simple Cheap Compact IC-based High Performance Amp

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DeuceEFI
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by DeuceEFI »

KiCAD schematic has been updated as per the previous post.
https://github.com/DeuceEFI/Amplifier/c ... dc5d9e066d
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Thanks! :-) Back to me for more progress, then :-/
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Did some clearancing for the heatsink tonight. One more piece to cut/bend and i can look at fixing it down. Same goes for caps and bridges. It mostly sits where I want it now, so pretty soon I'll know how the boards need to look too.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

OK, heatsink is in place, though not bolted down, yet.

Boards should be wide, not long. up to 100mm wide, up to 50mm from heatsink to edge, smaller in either dimension == even better. But not at expense of crappy routing/placement.

A hole and empty bit in each heatsink corner for mounting brackets, please :-)

Like this, roughly:

Image

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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Power in and speaker out should attach near heatsink somewhere and input signal at the back of the board away from heatsink. I think I talked about that in an earlier post? Feel free to seek clarification and/or to tell me to eff off :-)
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Heatsink clearanced for tape deck mock parts, and mounted using three well aimed screws. The whole thing is stiffer as a result (ties back plastic to front steel).

Next up, power supply stuff, or maybe the TODO. I'll check that now and then edit this post.

viewtopic.php?f=37&t=1966&p=30972#p30972

Updated!

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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Power socket/switch/fuse holder installed. viewtopic.php?f=37&t=1966&p=30972#p30972

Will glue it in once it's wired up, and/or recess the clips so that they work. It's such a nice tight (hand cut!) fit, though, it barely needs it.

Pics later.

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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Only cap mounting and power distribution buses to go! viewtopic.php?f=37&t=1966&p=30972#p30972 Then it's down to the PCBs and IO wiring and fascia looks etc.

Time to get some progress made on the speakers now! :-)

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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Speakers are now semi usable, so I'm back to amp progress, but today, it's a different type ;-)

I've hijacked the amplifier module from those shitty Hama CS-482 PC speakers and am going to improve it a bit. Here's the baseline, or should I say bass-line, at 100 Hertz:

Image

And at 50 Hertz:

Image

Notice how the lower frequency signal has a much higher peak to peak? That's because it has a recovery time in between and gets recharged. You can watch the single-ended rail voltage sag during louder sections of music. Tomorrow I'll add 22000uF to the 2200uF that's in there, and retest with the scope. I bet it's louder, and possibly a bit clearer too.

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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Just quickly doing the math, looking at more than double the power output (4W vs 2W), under some circumstances. Should also give a more definite "too loud" point, rather than gradual muddying depending on signal material. Eg right now a transient following a bass note could be peaking at 2W but able to go to 4W if not preceded by a bass note. This will make it always be 4W, which is of course nothing compared to the ~50W it's going to be fed fairly soon :-)
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