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Juma's LSK Preamp - through hole version

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T

tinitus

Ex-Moderator R.I.P.
Joined 2005
Hi
I see you have added me to GB spread sheet ... thanks

I will tell you the details when the final boards are presented

cheers :up:

btw, the optional feature to 'steal' the signal between input pre and output buffer may offer several interesting alternative uses

might be used for signal splitting, but maybe also for summing/mixing a signal :scratch2:
 
J

jameshillj

Member
Joined 2005
Thanks Prasimix, it looks pretty complete now.

I think we'd better look for a different supplier of those caps as Farnell prices for these are pretty high, particularly the Au$18 asked for the 10uF ones and the Au$13 for the 0.1uF MKT1837s (good caps tho) - the Welwyn resistors look good

I think I can squeeze the slightly larger Nichicon KZ electros into the spaces - the 100uFs are 12.5mm dia (designed Pana Fc's are 10mm dia @ 5cc) - similar with the 47uFs where the KZs are 10mm dia @ 5 cct (designed Pana FC are 7mm dia @ 2.5 cc) - can raise them up a bit with a rubber standoff, I guess or maybe on their sides on the bottom of the boards with taller support posts - similar thing with larger sized C7 options.

Thanks for the changes
 
prasimix

prasimix

Member
Joined 2009
jameshillj said:
Thanks Prasimix, it looks pretty complete now.

I think we'd better look for a different supplier of those caps as Farnell prices for these are pretty high, particularly the Au$18 asked for the 10uF ones and the Au$13 for the 0.1uF MKT1837s (good caps tho) - the Welwyn resistors look good

I think I can squeeze the slightly larger Nichicon KZ electros into the spaces - the 100uFs are 12.5mm dia (designed Pana Fc's are 10mm dia @ 5cc) - similar with the 47uFs where the KZs are 10mm dia @ 5 cct (designed Pana FC are 7mm dia @ 2.5 cc) - can raise them up a bit with a rubber standoff, I guess or maybe on their sides on the bottom of the boards with taller support posts - similar thing with larger sized C7 options.

Thanks for the changes
Click to expand...

10uF film is not mandatory, that was my idea since I have it :). Originally this was elco. I also put Panasonic FC's from Farnell as an example more to have better idea about size in accordance with working voltage then as a right (or only) choice for this project. I believe that shouldn't be a problem finding many other types from other brands which follow selected dimensions.
If something really missing on existing BOMs is a lack of reliable source for JFETs. Someone mentioned FETaudio, and maybe is a time for me to check with Spencer what he can offer.
 
prasimix

prasimix

Member
Joined 2009
Here is I hope final version of dual channel PCB and PS for powering single channel PCBs.

Please if someone can make a double check of all jfets pinouts.

New BOM is now broken into sections and include all variations on one place.
 

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  • Juma preamp rev.2.5 PS schematic.png
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K

koja

Member
Joined 2009
update

I see a lot happened over the weekend :).
Prasimix,
Thanks for adding CCSs, they are an upgrade over a single resistor.
I also wanted to update your list but was not able to open it. Would you please change my order to three (3) stereo boards (with PS section on it). Thank you!

> re: BOM: it would help if you could please call out the pitch dimension for each component. we in North America are likely to order parts from Digikey, Mouser, etc. and we will be substituting. It takes time to look through every spec sheet for the Farnell component, so it would help if you just called out the spacing between the holes. Thanks again.

> re: SK170/SJ74: Juma used BL grade parts with a few of the other components recalculated. I will be using those since i have them matched. you may also want to consider buying those matched from Spencer. This is, of course, unless somebody wants to take on the GB of a quantity of V-grade ones from DIYaudio store and matching them for the rest of us. do I hear a volunteer? :devily:
 
J

jameshillj

Member
Joined 2005
That's about it, Prasimix - I can play around with pcb design forever as I find it 'kind of' relaxing in a way!

For people that are a bit 'anal' about ground tracks (like me!), we can easily cut the grnd tracks next to C19 and C26 and just link this point directly to the J8 terminal - an easy option.

Also, could you upgrade my listing on the GB for 2 X single ch, 2 x single p/supply for them, plus one dual ch version, if you wouldn't mind - I'm out here in Australia by the way, I the middle of a hot spell!

Thanks for all your work - it's much appreciated
 
prasimix

prasimix

Member
Joined 2009
jameshillj said:
That's about it, Prasimix - I can play around with pcb design forever as I find it 'kind of' relaxing in a way!

For people that are a bit 'anal' about ground tracks (like me!), we can easily cut the grnd tracks next to C19 and C26 and just link this point directly to the J8 terminal - an easy option.

Also, could you upgrade my listing on the GB for 2 X single ch, 2 x single p/supply for them, plus one dual ch version, if you wouldn't mind - I'm out here in Australia by the way, I the middle of a hot spell!

Thanks for all your work - it's much appreciated
Click to expand...

Huh, that was mine intention, but for some reason it disappeared in the meantime. Don't worry, it's already included in rev.2.6 together with some other minor improvements and corrections.
 
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