Simplistic NJFET RIAA

Hi guys. I finally did a board for the 24v salas shunt reg, if anyone's interested.

I haven't tested yet, but I will tomorrow (so there may be errors).

I have put the fets on the outer edge to make mounting on heatsinks easier. Mine will be screwed onto the inside edge of my case as it's 6mm aluminium plate.

Should look and sound great mounted inside my preamp case alongside a Pedja Rogic buffer.

Cheers, Lee.
 

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He means better not standing upright on the pcb.

As for the heat proximity to elcaps, this is right. But in our case at the currents involved, I have experienced just warmth not heat.
If you revise that, (better for someone who may try more current), allow for a 0.1 uf filmcap bypass next to the Cout too, so someone without a special quality cap can bypass some of its esr.
 
massimo said:
Thomo, just to give a better idea, I've drawn in 5 min. a pcb based on your design. I didn't check the circuit anyway.

P.S. It can be improved, of course!

Darn, you threw it together in 5 minutes ? And here i am, struggling to make a useful pcb :confused:

To be honest, it looks great to me. Maybe C4 is a little small in that footprint ?

Cheers
Ebbe
 
es44 said:


Darn, you threw it together in 5 minutes ? And here i am, struggling to make a useful pcb :confused:

To be honest, it looks great to me. Maybe C4 is a little small in that footprint ?

Cheers
Ebbe

I simply copied Thomo's design without checking El cap dimensions and layout. That's why I added later "it can be improved". I must say, then, "to be improved" (maybe with a better gnd arrangement as well).
 
Salas,
The 58db RIAA version is up and running...sounds great! I have not yet tried the LED mod to the Shunt reg, is it worth doing? Are the posted Shunt Reg boards designed with the LEDs? It's been a long time since I had sand in my system, but with the LO MC, it is the only way to fly. Thank you.
 
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cygnus x1 said:
Salas,
The 58db RIAA version is up and running...sounds great! I have not yet tried the LED mod to the Shunt reg, is it worth doing? Are the posted Shunt Reg boards designed with the LEDs? It's been a long time since I had sand in my system, but with the LO MC, it is the only way to fly. Thank you.

Great Cygnus! Is the gain I calculated for you adequate in the end?
I did not have the chance to compare the Vbe & LED head to head, because one is in Michael's house with different gain setting and cart and the other with me. I heard the same basic thing, and the Vbe is standard to make, when LEDS need individual care. I had the feeling that maybe the LED ''Kitsch Shunt'' was a bit more open in the highs but not sure. Better mod your Vbe one to LED if you are not in lazy mood at a point, and compare with fresh aural memory in your system, and let us know. I mainly made the Led one just for fun!:D Had no complains with the Vbe one. Also tell us more details about your sound now VS the hybrid tube circuit you used.

P.S. A problem in your case is that the LED version will kill the left hand 2SK170 with excess Vd and dissipation. Your B+ is high. You must replace the Led CCS function it does with a ring of two 60V BJTs of 10mA current at Led string's tail.

Regards
 
Yea, it was hard for an old "tube head" to go back to sand, but if the shoe fits (or the fat lady sings) then...? The sound compaired to the NJFet/tube and old tube Phono stage (Siren Song) is the NJFet is more focused, and transparent, easier to pick out instruments and placement with faster transents, way better bass. The tube stage was just to noisey for the LO MC.
One thing I'm wondering about, is if I'm pushing the ShuntReg to hard, I've got it set for 45V out, with over 50V in? Also if I use a buffer on the RIAA, what should the resistors be? Currently 1.6K and 680 ohm (when I had it set up for 36V).
 
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Here for the Led shunt.
 

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