Simplistic NJFET RIAA

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skouliki

skouliki

Member
Joined 2010
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Both are good. Just get the better ppm one that he dimensions fit. Check that, don't force a big one that is bad for the layout, does worse than the ppm thing which at 100 and under is good enough.

50K won't matter VS 47K. Many Japanese classic integrated amps etc had 50K for mm.
 
Q

quan

Member
Joined 2007
Hi Salas, how important are the resistors for the 2sk369bl? . I am gathering parts for the build currently. With regard to those resistors, can i use carbon resistors ( 5 percent tolerance)? . I looked at my local supplier either they don't have it or charging 30 dollars plus as it is a small order.
Quan
 
vgeorge

vgeorge

Member
Joined 2004
goldenview.gr
Some progress, still collecting parts. Not much are soldered as I will probably make some part substitutions.
 

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lohk

lohk

Member
Joined 2001
Salas said:
No you can't use 1.2k with just one FET. 56dB won't be dynamic on 0.4mV also. You better get a couple more FETs. If not same idss to the pair you now got, combine them between channels so the same total current runs through the 1k2 resistors. R2 & R3 can help equalize the current between each pair. If say 1mA different FETs, use next value up under the stronger one.
Click to expand...

Thank you, Salas, for the quick and comprehensive answer.
But I am lucky, Mike will provide me a perfectly matched pair for a good quadruple.

I have an unused Goldring Eroica Lo Output left over from older days. Does anybody have experience with those?
 
lohk

lohk

Member
Joined 2001
It may have been a topic already, but since the FSP is an unsymmetric circuit and the output cap is DC biased, would it not make sense to try a high quality electrolytic capacitor for C4?
I do not want to start a heretic or controversial discussion since high quality foil caps are considered to be superior in any way. But I have quite good experience with elcaps in similar situations, even non-bypassed. And I have also experience that foil caps in DC biased situations can sound more "distorted" than high quality elcaps. Any opinions?
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
vgeorge said:
Some progress, still collecting parts. Not much are soldered as I will probably make some part substitutions.
Click to expand...

Looking good. NOS USA Teflon even... Do those sinks have the needed mass for the output MOSFETs though? They are tall nonetheless.

P.S. See not to short any pads with the metal can C3s. Keep their barrels 1mm above board level.
 
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