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Group Buy for KG's Boards (2nd)


Lil Knight
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Great.  Thanks in advance if you come across an extra set.

Shouldn't be a problem with that.

 

Added late to list for HV on board if there are extras. Should I pay now or wait for confirmation.

 

Thanks

Just check your auto-calculated total, if it's correct, then you are good to go.

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Is there a square wave schematic?  I don't know much, or rather anything, about this amp.  If not, I can draw one from the PCB when it arrives.

 

The silk screen says +-15V, but PSU is going to put in about +-22V, without changes.  Should the PSU get tweaked or is the plan to run it at +-22V with a different opamp?  Also, does each board pair pull more current than the KSA5, since it comes with 2 PSU boards?  It doesn't look like it will from what I can make out.  What's the quiescent current draw of each board, or each balanced channel, or all 4?

Edited by holland
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Thanks, Birgir.  It's an interesting thread to say the least.

 

There are these 2 links, though the pdf schematic doesn't match the pcb shown in the jpg.  It's close enough, however, I'm not sure if either of those were the actual PCB.  The only differences that I can see is that the servo outputs to the bottom of the 49.9 resistor instead of tweaking the bias point of the NPN.  The 49.9 resistor is connected to a 4.7uf cap to float it.  It's also a RC filter if I'm not mistaken, to roll off some bandwidth.  The other is the diode string is replaced with an active circuit for adjustable bias.

 

http://gilmore.chem.northwestern.edu/squarewaveproduction.pdf

http://gilmore.chem.northwestern.edu/squarewave.jpg

 

I think I'll use +-15V @ 25VA for the balanced config with 1N4747 and 1N4745 in the supplied PSU boards.

Edited by holland
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http://gilmore.chem.northwestern.edu/squarewaveproduction.pdf

 

http://gilmore.chem.northwestern.edu/squarewave.jpg

 

this is the board lil-knight is producing

 

The nominal current with the 1.5 inch high heatsinks is 80ma

with the 2.5 inch high heatsinks you can go to 100ma

pot and 75k resistor are designed so that you can't over do it.

Edited by kevin gilmore
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