New Aleph Mini PCB GB

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Retired diyAudio Moderator
Joined 2002
Here are my ideas for the group buy configuration:

PCB sets:
Mini-A stereo pcb set
- 2 amp boards
- 1 power supply board
- estimated price $15-20
Mini-A dual mono pcb set (for building monoblocks)
- 2 amp boards
- 2 power supply boards
- estimated price $20-25

As for kits, if Jason is willing to invest significant time with this, I could help him put together a parts list so that he can offer kits. I will not be doing any kits for this amp. I would estimate that the kits would take about 15 minutes each to kit together, as with my new LM3886 kits. It would be good if Jason could offer matched devices for this amp also, which shouldn't be too difficult. Alternately, a Digikey parts list will also be offered for those wishing to purchase their own parts.

If desired, output boards could also be created.

Proposed optional output boards (3 devices each)
- for using the amp board as a driver board
- estimated price: $15-20 for 4 boards (2 channels worth)
- abilility to be cascaded for 12 devices per board (Aleph 2)

These are just estimated prices, and will lower if the group buy gets substantial in size. This design is copyright of Nelson Pass, and this group buy will be run by Jason at close to non-profit (profits go to Jason in terms of free boards and a little beer money). I will just be helping Jason with the PCB layout. Once the board layout is finalized, I will do a prototype run with the board vendor to verify the design, and the cost of this is factored into my estimated pricing.

My proposed power supply board will consist of a bridge rectifier made with MUR860 diodes, heatsinked, and placement for 4 - 35mm snap-in caps (2 per rail). Digikey sells the Panasonic 35mm diameter caps in values up to 22,000uf. The power supply could be increased to allow for 3 of these caps per rail, but I feel that 2 should suffice. The A30 uses 3 of these caps, 10,000uf each, for each rail, per channel.

Approximated board dimensions:
Mini-A amp board: 2" x 2.9"
Power Supply board: 4" x 2.9"
Output boards: TBD if people want them

As for the color, one color needs to be choosed and stuck with. I am suggesting blue, to be different from my gainclone boards. :)

My intentions for this group buy are to help organize it, creating a complete pcb set, like I did for the gainclone kits. Once the design is finalized and Jason gets the boards, I will not be running any part of the group buy, or profiting from it in any way, except in the form of some free boards.

Any input/suggestions? I will be out of town from Saturday-Monday (unexpected family issues), and then Wednesday-Saturday (business trip for work), but once I get back, I can finalize the design with Jason. I can create a Wiki in the next couple of days to see if there is much interest for this project.

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Brian
 
Retired diyAudio Moderator
Joined 2002
Retired diyAudio Moderator
Joined 2002
Here is a revised layout. I made the board bigger. Here are the modifications:
- thicker voltage traces
- room for 7 output resistors (stacking), which is the highest number on all of the Aleph schematics I looked at.
- Cap size increased to allow for 12.5mm caps (220uf 35v elna cerafine will fit now)
- added spacing the silkscreen for terminal blocks for all connections
- added NPN compensation cap to Q5
- added C8 (10pf cap)
- added pads and increased size of R20 and R22 pads to allow for external parallel output devices. (will clarify the labelling later)

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


Any comments?

--
Brian
 
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