Simplistic NJFET RIAA

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Joined 2006
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First PSU mod completed... I just swaped the 25v tx by the block RK 30v one.

I am reading 40V in for 28vout in the shunts.

Major improvements in spatiality.... everything got bigger and more detailed (I also notice a reduction in noise ... maybe the block TX is more silent).

Of course there is much more heat inside the case so next I will try to reduce the voltage in 4 volts..... Hope this does not affect the soundstage size.
 
I need an help from you, guys.
Before ordering all the parts I need and designing a suitable RIAA pcb, I would like to ask Salas, Ricardo, Disco and others their findings about the right capacitors.

> C out (3.3uF): the suggested type seems to be Obbligato Premium copper or gold. Good sound, nice price I read.
Did anybody try Mundorf Supreme which is more or less in the same price category?

> C 4 (0.1uF): here a huge russian teflon cap (ft-2 or ft-3) seems mandatory. Not expensive and very transparent you reported.
Again, did anybody try an alternative? Obbligato, Mundorf, etc.? What about smaller polypropylene film & foil?
I have some nice old blue Ero KP 1838/63V 2.5% that might fit.

> RIAA Caps (47 & 16 nF) most of you suggest some bulky russian silver mica. Are those really different (read better) from the modern dipped ones? And what about polypropylene film & foil such as the tiny green Wima FKP2 or even Teflon? Not easy to find in the right value, but it's always possible to // them and get the desired values.
I have a lot of FKP2/63V 2.5%, but even some 1% capacitors branded "Madrigal" (most probably teflon) pulled out from and old ML No.25 cannibalized board.
As far as polystyrene, I don't like them too much. They are now cheap and unrealiable. Unfortunately the good silver axial ones manufactured by Philips are no longer available. Not to mention the ps film & copper foil caps manufactured by the Japanese company known for the Noble pots that Hiraga was using many years ago in his Kaneda preamp! Absolutely unobtainable nowadays.

Contibutions highly welcomed!
 
diyAudio Chief Moderator
Joined 2002
Paid Member
I need an help from you, guys.
Before ordering all the parts I need and designing a suitable RIAA pcb, I would like to ask Salas, Ricardo, Disco and others their findings about the right capacitors.

> C out (3.3uF): the suggested type seems to be Obbligato Premium copper or gold. Good sound, nice price I read.
Did anybody try Mundorf Supreme which is more or less in the same price category?

> C 4 (0.1uF): here a huge russian teflon cap (ft-2 or ft-3) seems mandatory. Not expensive and very transparent you reported.
Again, did anybody try an alternative? Obbligato, Mundorf, etc.? What about smaller polypropylene film & foil?
I have some nice old blue Ero KP 1838/63V 2.5% that might fit.

> RIAA Caps (47 & 16 nF) most of you suggest some bulky russian silver mica. Are those really different (read better) from the modern dipped ones? And what about polypropylene film & foil such as the tiny green Wima FKP2 or even Teflon? Not easy to find in the right value, but it's always possible to // them and get the desired values.
I have a lot of FKP2/63V 2.5%, but even some 1% capacitors branded "Madrigal" (most probably teflon) pulled out from and old ML No.25 cannibalized board.
As far as polystyrene, I don't like them too much. They are now cheap and unrealiable. Unfortunately the good silver axial ones manufactured by Philips are no longer available. Not to mention the ps film & copper foil caps manufactured by the Japanese company known for the Noble pots that Hiraga was using many years ago in his Kaneda preamp! Absolutely unobtainable nowadays.

Contibutions highly welcomed!

Teflon is superior in the interstage coupling position. I have tried polypropylene and stacked polysterene there also. PP film & foil I haven't tried.

Those huge micas are better than modern little micas. But if you can find modern pp film & foil its a good alternative. Has to work synergistically with the interstage. You cook. If small and good the layout gets tighter and that is a plus.

Polysterene old is good, modern I am not sure. What about RCL polysterene?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Lookie, lookie!

:) Got a DL 103R. Fortunately says 0.32mV on its individual spec sheet. Not 0.25mV as advertised. Even better. That is for 47k though. Does any body know where the audiophiles tend to usually load it? I would think that 150 Ohm is the minimum since it has 14 Ohm coils.
 

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