My Uber-PPA (Almost) (minor 56k warning)
Apr 27, 2004 at 5:11 PM Thread Starter Post #1 of 15

chosen1

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I finally finished my high-end PPA project.
amp_front.jpg

I had to source parts from 8 different places, and it took about a month to get them all.
Specs:
PPA amp board
STEPS board
Nichicon FG caps in C1 and C4
BC, Pana. FC, and Nichicon caps everywhere else
Vishay-Dale resistors throughout
OPA 627's on all three channels
Uncle Phil's diamond buffer
Cardas GRFA RCA's
Trimmer pots for R8 ala doobooloo
No bass-boost
Neutrik locking jack
Bulgin lighted power switch
All wire in signal path is teflon-insulated solid silver
Par-Metals 20-series case (completely clear-anodized)

Enough of that, here's the prOn:
amp_board.jpg

inside1.jpg

inside2.jpg


I mounted the Alps blue off-board to allow the installation of the stepped attenuator I will be recieving soon.
 
Apr 27, 2004 at 8:26 PM Post #3 of 15

rayofsi

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yes where did you find that bulgin? i have not been able to locate a ON/OFF bulgin anywhere, i am prepared to pay the uber expensive price on one!! well 2....
 
Apr 27, 2004 at 9:12 PM Post #4 of 15

till

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ufokillerz, Bulgin doesn't seem to manufacture a true on/off switch of this kind. You have to implement a small circuit that toggles a relais between on/off each time the switch is pressed. Which makes the switch non-applicable for a number of uses, like portable amps
frown.gif
 
Apr 28, 2004 at 5:23 AM Post #12 of 15

chosen1

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Thank you everyone for the nice comments.

I got the Bulgin switch from Newark. It is only a momentary contact so I used the same circuit that Wooderson used for his (thanks Wooderson BTW for the wall wart idea).

Quote:

how much did it cost you? component/time wise?


I have been afraid to add up all of the invoices, but I would guess somewhere around $500. As far as time ??? I kind-of lose track of time working on stuff like this, so I wouldn't even hazard a guess.

Wooderson, I wouldn't want to disapoint, so here:
The glow is intentionally pretty faint, so my camera had a little trouble really capturing it.
glow1.jpg


I wasn't originally going to go glowing, but my wife saw a pic of yours, and talked me into it.
 
Apr 29, 2004 at 4:26 AM Post #14 of 15

chosen1

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Quote:

You mean that other power supply next to the STEPS is just for the Bulgin switch and lights?


Not exactly. There is a power supply and a piece of protoboard. The power supply is an old ratshack wall-wart that I removed the casing and the prongs. The protoboard is the switch circuit and relay for the bulgin switch, The layout of the circuit takes up less than half of the board, but I decided to leave the board whole because it mounts easier.

The lights are actually powered by the led circuit on the STEPS board (the light in the switch), and the led circuit on the PPA board (the off-board LEDs).
 

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