Simplistic NJFET RIAA

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urbano63

Member
Joined 2005
Hi Salas,
after the RIAA there is a JC-2 preamp kit that tubeshunter is selling on eBay.
I have no hum after your help, and i like how the RIAA sound.
Now perhaps because of long coaxial cable and/or because the JC-2 i lost a little bit of detail.
I tested the RIAA connected directly at my headphone amp before.

Ricardo your work is very good

Ciao nicoch,
how many Km of internal signal wire ? :D if i measure all the cable some meters. There is about 50 cm for the phono in, and less for each of the other 4 input.
But there is about 1 mt of coax cable between the pot and pre input.
This is a first test ... Yes i doubt and I can optimize the layout.
The cable capacitance used is about 280 pF/mt
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
urbano63 said:
Hi Salas,
after the RIAA there is a JC-2 preamp kit that tubeshunter is selling on eBay.
I have no hum after your help, and i like how the RIAA sound.
Now perhaps because of long coaxial cable and/or because the JC-2 i lost a little bit of detail.
I tested the RIAA connected directly at my headphone amp before.
Click to expand...

Very well. Headphones is a very revealing test. Keep it as a benchmark, and try to reach the detail level against it the more you can. I am glad that you liked it. Happy listening!

P.S. Remind me, what is your TT comprised off?
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
RCruz said:
The offending zener was replaced and now there is no more "woosh"... both channels sound the same with a very low ripple at full volume... :)
Click to expand...

That was an easy one, the usual suspect did it.:p

I wonder why nobody can get TC compensated zeners in stock. Microsemi has some of the best. Keep it up with 1000uF good zener filter caps guys, its safer, and try to always get the glass encapsulated ones (usually red with a black stripe) even if 500mW. The black plastic ones suck. Very erratic.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
We do that if needed (if with crap zeners at hand only) but a tempco zener would be low impedance too. If you remember there was a guy in the low voltage regulator thread that had access to some ESA lab tempco zeners and informed us that they are down to one led noise. Now to reach 36V with leds you will need 17-20. The resistor can be a good compromise, but it will be in the kOhm range. A good enough zener and a good 1000-2200uF cap can do enough of a decent job at least.
 
nicoch58

nicoch58

Member
Joined 2004
Wow very great TT !!! put an MC on the baby:)



I see that there are some crazy boys ,and report that AM aircap (pf range) sound better than styrene :scratch:
look
 

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