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The blue boards are (expensive) fibre glass prototype boards.
I could not justify the cost of PCBs, so I used these for the Amps.
The smaller board is the othere supply module, and the small brown
veroboard is the anti-thump and speaker protection board. The handles on
the top are nice stainless steel (from an old kitchen) and go over the
two fan vents. The fan vents came from an old DEC PDP11 psu. The reason
the handles are here apart from looking good, is to make sure that a glass
(of Beer) cannot be stood on top of the amp (BANG!)
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On the left you can see the pre-amp and input selectors.
The board in the middle carries two bargraph driver chips
and the ten leds (for each side) that indicate power output.
You can also see the relays that switch
the speakers in (recovered from and old Jaguar XJ40).
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In the middle is a very big toroidal transformer that powers the beast.
It should have cost well over £100, but by a real stroke of luck, I
picked it up on Ebay for £12.00. Thhe bank of smoothing caps behind it
cost more than that! The shield over the transformer helps to reduce mains
hum, and in fact, there is none.
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Two fans, recovered from two dead PC power supplies. I picked up some hefty
heatsinks on Ebay for £7.00, upon which the power transistors are mounted. The
fuses are the plus and minus 70v lines to each side, with leds to indicate
that the fuse has not blown. The RCA panel is just a useful addition - Left and Right
in, then straight out again. The reason I added it was that I may take a cable
from here to my lighting controller.
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Here it is then, 500W rms per channel (Stereo), two input channels,
each with volume,treble,bass. Switchable EQ and Mono/Stereo on
each channel. Led bargraph power display (behind the smoked window).
