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 http://www.webalice.it/mauro.penasa/Archivio_Progetti_audio.html. 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 http://www.diyaudio.com/forums/showthread.php?s=&threadid=54571 if you wish to learn more.
Peter & Uriah
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 http://www.webalice.it/mauro.penasa/Archivio_Progetti_audio.html. 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 http://www.diyaudio.com/forums/showthread.php?s=&threadid=54571 if you wish to learn more.
Peter & Uriah
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
Uriah
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
Uriah
So for $65 you can get "most" of the parts and PCB's for an amp that COMPETELY crushes the typical gainclone. 
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.
I'm still in....
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.
I'm still in....
Guys we now have a dozen interested people. Thats 24 boards and we are 1/4 of the way there. Who knows, maybe we can get even more than 100 boards requested and drop the price a bit more.
Maybe one of you would like to start a heatsink or toroid group buy. If you want to do a toroid group buy I know that the guy at Antek has worked with DIYers in the past. From what I recall he would take one single order from one guy for several toroids and then ship them out separately. This is just something I read in passing and didnt care about at the time so my memory may not serve me in this case, but its worth a shot if one of you wants to work on that. Heatsinks can be ordered in 6ft sections from most heatsink manufacturers and then cut up with an ferrous cutting blade on a table saw. This is a LM3886. It doesnt need a lot of sink to start with, but its a money saver.
Uriah
AS OF RIGHT NOW I HAVE
bacood_2000 x2
warp_foo x2
Coreyk78 x2
SRMcGee x2
troystg x2
samsagaz x2
widman x2
billyk x2
korben69 x2
tube-arama x2
bandol83 x2
erikdebier x2
Maybe one of you would like to start a heatsink or toroid group buy. If you want to do a toroid group buy I know that the guy at Antek has worked with DIYers in the past. From what I recall he would take one single order from one guy for several toroids and then ship them out separately. This is just something I read in passing and didnt care about at the time so my memory may not serve me in this case, but its worth a shot if one of you wants to work on that. Heatsinks can be ordered in 6ft sections from most heatsink manufacturers and then cut up with an ferrous cutting blade on a table saw. This is a LM3886. It doesnt need a lot of sink to start with, but its a money saver.
Uriah
AS OF RIGHT NOW I HAVE
bacood_2000 x2
warp_foo x2
Coreyk78 x2
SRMcGee x2
troystg x2
samsagaz x2
widman x2
billyk x2
korben69 x2
tube-arama x2
bandol83 x2
erikdebier x2
If your building monoblocs then these will work fine.
http://www.apexjr.com/images/AdireToroid.JPG
Part # XFM-D0012 from here:
http://www.apexjr.com/miscellaneous.html
http://www.apexjr.com/images/AdireToroid.JPG
Part # XFM-D0012 from here:
http://www.apexjr.com/miscellaneous.html
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