Simplistic NJFET RIAA

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#4,027
Merlin:

Single 1.2 makes it 90% near to two and since I use humble parts from my hobby stash in this 4 JFET, doubled up cascode test build with B1 tail and 22k RIAA, I am not nervous about perfection. Probably many things to tune before parts. Filter capacitors are 10mF-10R-10mF 63V Samwa CRC, nothing special at all, the RIAA caps are NP0 ceramics, the coupling caps are CCCP and no name China, cabling will be no name Italian RG-179 impersonator, the resistors are metal film from deep inland China probably. 😀

Massimo:

Yes, Italian enclosure, sides, front and back Alu, top & bottom ferromagnetic.
Will wire two pseudo balanced XLR parallel outputs to have easy interface to balanced gear without resorting to adapters.
 
#4,028
Salas said:
Merlin:

Single 1.2 makes it 90% near to two and since I use humble parts from my hobby stash in this 4 JFET, doubled up cascode test build with B1 tail and 22k RIAA, I am not nervous about perfection. Probably many things to tune before parts. Filter capacitors are 10mF-10R-10mF Samwa CRC, nothing special at all, the RIAA caps are NP0 ceramics, the coupling caps are CCCP and no name China, cabling will be no name Italian RG-179 impersonator, the resistors are metal film from deep inland China probably. 😀

Massimo:

Yes, Italian enclosure, sides, front and back Alu, top & bottom ferromagnetic.
Will wire two pseudo balanced XLR parallel outputs to have easy interface to balanced gear without resorting to adapters.
Click to expand...

OK now I understand it's a prototype, sorry seems too perfect to be a proto!!!😉

Only one TX?

How can do two pseudo balanced XLR parallel outputs?
 
#4,029
merlin el mago said:
If Mike can do the last favour to Salas can change the Alu cover for "corian"😉
Click to expand...

But corian isn't shielding the circuit.... Copper can be a very good material thanks to its electrical and mechanical proprieties. In that enclosure it can be used up to 4 mm thick, about 2.5-3 kgs each sheet.... expensive (nearly 10€/kg the raw material) !
But if Salas wants, I can have the sheet cut to measure easily 😉
 
#4,031
massimo said:
But corian isn't shielding the circuit.... Copper can be a very good material thanks to its electrical and mechanical proprieties. In that enclosure it can be used up to 4 mm thick, about 2.5-3 kgs each sheet.... expensive (nearly 10€/kg the raw material) !
But if Salas wants, I can have the sheet cut to measure easily 😉
Click to expand...

Thanks Massimo for your kind offer. This a test build. I will let you know when I will be making the final ''Midas'' version.🙂
 
#4,032
Salas said:
Merlin:

Single 1.2 makes it 90% near to two and since I use humble parts from my hobby stash in this 4 JFET, doubled up cascode test build with B1 tail and 22k RIAA, I am not nervous about perfection. Probably many things to tune before parts. Filter capacitors are 10mF-10R-10mF 63V Samwa CRC, nothing special at all, the RIAA caps are NP0 ceramics, the coupling caps are CCCP and no name China, cabling will be no name Italian RG-179 impersonator, the resistors are metal film from deep inland China probably. 😀

Massimo:

Yes, Italian enclosure, front and back Alu, top & bottom ferromagnetic.
Will wire two pseudo balanced XLR parallel outputs to have easy interface to balanced gear without resorting to adapters.
Click to expand...

massimo said:
But corian isn't shielding the circuit.... Copper can be a very good material thanks to its electrical and mechanical proprieties. In that enclosure it can be used up to 4 mm thick, about 2.5-3 kgs each sheet.... expensive (nearly 10€/kg the raw material) !
But if Salas wants, I can have the sheet cut to measure easily 😉
Click to expand...

Corian + shelf adhesive Mu-metal will be mine 1st choice less expensive & IMHO more effective.😀
 
#4,037

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