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Juma's LSK Preamp - through hole version

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K

koja

Member
Joined 2009
an added note

Prasimix,
since you know I will use the board to bridge amps I wanted to throw in an added explanation: I will likely use one LSK channel as the phase splitter, then take Out+ and Out- signals each to its own buffer (so one LSK channel followed by two buffers). Can you please check if the board provides for a reasonably neat way to make this connection? thanks.

p.s.> btw I am likely to take 5 dual channel (stereo version) boards. Thanks. (this is up from 3 which i said last time :).
 
prasimix

prasimix

Member
Joined 2009
koja said:
Prasimix,
since you know I will use the board to bridge amps I wanted to throw in an added explanation: I will likely use one LSK channel as the phase splitter, then take Out+ and Out- signals each to its own buffer (so one LSK channel followed by two buffers). Can you please check if the board provides for a reasonably neat way to make this connection? thanks.

p.s.> btw I am likely to take 5 dual channel (stereo version) boards. Thanks. (this is up from 3 which i said last time :).
Click to expand...

I think that could be a very simple task. Let's assume that you'll use "upper" channel from your dual channel PCB as phase splitter (schematic in post #89). "Upper" buffer is already connected to one half of the splitter. Another half you can bring to other buffer from OUT2A pin #1 to OUT2B pin #2. That's all.

EDIT: On existing dual channel PCB it's possible to introduce one optional jumper to make above mentioned connection.
 
Last edited:
prasimix

prasimix

Member
Joined 2009
Here is I hope the final layouts of all three PCBs. I'll leave then for couple of days and if nothing new is popped up, I think that's the time for send it to the production.

GB list is pretty on target, and I can assume it closed, thanks everyone for make it happen. I still need destination country from some of you, that I can calculate total cost.
 

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  • Juma preamp rev.2.6 BOM.pdf
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J

jameshillj

Member
Joined 2005
I was curious to see that you have sorted out the sizes of the pcbs so that 2 of the gain stage pcbs can fit on top/below the single power supply board - might need a bit of a bracket for the mounting holes near the vertical IRF610/9610 heatsinks, but not very difficult - very neat bit of design.

I know it's a bit late in the day for any more mods but perhaps, as there is mains power on the board anyway, that perhaps it could be possible to extend the end of the board to include a series NTC in the mains input active line - keeps things a lot simpler for mains wiring.

I won't say anything more about extras but the inclusion of a mains dc trap comes to mind altho the primary winding impedance makes it nearly unnecessary (again, IMO).
 
prasimix

prasimix

Member
Joined 2009
jameshillj said:
I was curious to see that you have sorted out the sizes of the pcbs so that 2 of the gain stage pcbs can fit on top/below the single power supply board - might need a bit of a bracket for the mounting holes near the vertical IRF610/9610 heatsinks, but not very difficult - very neat bit of design.

I know it's a bit late in the day for any more mods but perhaps, as there is mains power on the board anyway, that perhaps it could be possible to extend the end of the board to include a series NTC in the mains input active line - keeps things a lot simpler for mains wiring.

I won't say anything more about extras but the inclusion of a mains dc trap comes to mind altho the primary winding impedance makes it nearly unnecessary (again, IMO).
Click to expand...

Tried to add it but there is simply no more space for it, sorry.
 
SRMcGee

SRMcGee

Member
Joined 2004
Paid Member
prasimix:

Can you confirm that the BOM has not changed since your version 2.5 (2014-01-19)? I need to identify the corresponding part numbers for Mouser or Digikey and don't want to generate a bad list.

In fact, to make things a little easier, could you post the Excel spreadsheet as opposed to a .pdf? That would simplify adding entries and prices.

Regards,
Scott
 
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