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Juma's LSK Preamp - through hole version

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prasimix

prasimix

Member
Joined 2009
Ok, I remove PS from single channel preamp and add transformer (two primary to address both 115V and 230V regions). I'm not very satisfied with open jumpers for selecting AC voltage so if someone have better idea, please let me know. This layout make obsolete previous single channel version. Dual channel version with PS (without transformer is still actual).
 

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BigE

BigE

Member
Joined 2008
Thank you!

Will the single jfet preamp board be available seperately?

Would it be possible to turn IC2 and Q19, Q20 around to allow them to be screwed to the chassis -- or onto a heatsink "power amp style"? Is IC1 close enough to the side of the board to allow such mounting?
 
prasimix

prasimix

Member
Joined 2009
BigE said:
Thank you!

Will the single jfet preamp board be available seperately?
Click to expand...

Yes, that's idea, but in pairs.

BigE said:
Would it be possible to turn IC2 and Q19, Q20 around to allow them to be screwed to the chassis -- or onto a heatsink "power amp style"? Is IC1 close enough to the side of the board to allow such mounting?
Click to expand...

Hm, hardly possible without introducing jumpers. From other side that heatsinks is not mandatory, Juma said that he do not use it.
 
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
prasimix said:
Yes and no, what if someone still want one PS per channel?
Click to expand...

I meant seperate stereo preamp curcuit only, without power supply
but maybe I should have said 2x mono

which reminds me
mono power supply boards could also be 'dual', side by side, and breakable
and if some one only want one supply board, you just break one before delivery

but not sure how much different they calculate prices when breakable

so basicly, what I suggest is one preamp board with 2 channels(without power supply)
and one breakable power supply board, with dual mono power supply
 
prasimix

prasimix

Member
Joined 2009
WALTER BURKHARD said:
In the BOM list you recommended pacificsemi.com to order Toshiba 2SJ74V or 2SK170V TO92-FET. I can tell you there can only selling fakes! I order 2 years ago big QTY all are BJTs , i guess there learn Aaf :) and some guys still remember him?
Click to expand...

Huh, this does not sound good :headbash:
Yes, I put pacificsemi since I found there required jfet. Do you have any other source to recommend?
 
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