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schro20 15th November 2008 11:47 PM

my_ref revC group buy (Mauro Penasa LM3886 design)
Summary: we (schro20 and udailey) are looking for a show of hands from people interested in a group buy of my_ref/revC kits (board + parts approx. 65$ for dual mono).

Details: We are putting together a group buy (assuming enough interest) for the my_ref/revC design of Mauro Penasa's (thanks, Mauro, for giving permission to use your design!). The board will be the same board as was last produced by the TwistedPear guys (thanks to Russ for the layout and Brian for some parts donations!). The (almost final) circuit diagram can be found at For the power section take a look at the revA documents. For the amp section take a look at the revC documents. Each board contains a mono stage with its own power section and speaker protection relay. The only difference from Mauro's diagram are additional 220nF by pass caps parallel to the 100uF caps C6, C11, C9, C18, C19, and C20 (this corresponds to rev 1.2 of the layout Russ made).

To avoid bugs we will not make any changes to this design. In effect we are making a clone of the TwistedPear kits.

If we can get together orders for 100 mono kits (50 dual mono pairs for a stereo amp) we can make the economics work so that a pair of mono boards with all the parts will cost 65$ + shipping (a single mono kit will be 35$ + shipping). To make a complete amp you will need to add a transformer, heatsink, connectors, power switch, fuse, and a case. We will not be offering any of these latter parts.

This cost ESTIMATE is APPROXIMATE at this time (though it is based on actual bids; we just haven't pulled the trigger).

If you are interested (no commitment at this moment, but please be serious) in purchasing kits at this price please PM schro20 or udailey and let us know the number of mono kits (2 of those make one stereo amp) you would be interested in. We will wait 10 days to make a go-nogo decision.

There is an entire thread devoted to this circuit at if you wish to learn more.

Peter & Uriah

troystg 16th November 2008 02:19 AM

Unfortunately I sold my original when I moved due to space restrictions. I still wish I would have been able to keep it.

I would LOVE to get another. I'm in!

udailey 17th November 2008 03:23 AM

Peter and I are looking forward to a successful group buy. All parts are the same as the original Twisted Pear buy as well as the PCB design. Hope we have several interested parties.
Let us know guys!

SRMcGee 17th November 2008 12:04 PM


I'd be interested in a stereo set. Do you happen to know the dimensions of the pcbs and their height when populated?


udailey 17th November 2008 12:10 PM

Boards are about 4.3x3.2" and the height is determined by the on board power caps which are about 2" tall so maybe give it 2.25" to be safe.
Thanks for your interest and I hope we can put together a group buy for you and everyone else. Its as good as done if we get enough orders :)

bacood_2000 17th November 2008 10:00 PM

I'm interested in a dual mono, thanks.

samsagaz 18th November 2008 06:19 AM

i want 2 Mono BLocks :)

widman 18th November 2008 01:56 PM

I'm in for a dual mono kit.


udailey 18th November 2008 02:42 PM

Great. Thanks for showing some interest guys. We now have ...
bacood_2000 x2
warp_foo x2
Coreyk78 x2
SRMcGee x2
troystg x2
samsagaz x2
widman x2

If we can keep getting about 3-5 guys a day then I would say in two weeks we will have a full order. The reason 100 boards is so important is that so many price breaks occur at QTY100.
Spread the word :)

troystg 18th November 2008 03:01 PM

So for $65 you can get "most" of the parts and PCB's for an amp that COMPETELY crushes the typical gainclone. :smash:

I don't think there will be an issue with getting enough people together.

The generic gainclone kits are over $50 and they are no where near as good as Mauro's creation. :bigeyes:

I'm still in....

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