Simplistic NJFET RIAA

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guglielmope

Member
Joined 2004
Hello Salas,
I'm interested to build this RIAA but I'm very slow in my works.
But It's in my ideas for hte next months.
In my system I've a lot of tube but I like your design and in the future I'd like to compare with this:
http://www.troelsgravesen.dk/TranscendentRIAA.htm
I'd like to clone this projec but using as second stage an Aikido for better output impedence and linearity.
I'll use Optivol as Volume control. It 's input impedence is about 10kohm, I think a bit low also for your Riaa.
Thanks for your Super work.
I'm a fan of your circuits (also regulators)
Ciao
Guglielmo
 
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urbano63

Member
Joined 2005
guglielmope said:
Anyone have tested this mica caps that are available with the exacts values on Ebay?
See this link:
http://shop.ebay.it/merchant/e7mkg?_nkw=mica&_nd1=0&_trksid=p3911.m270.l1313&_odkw=&_osacat=0

Ciao
Guglielmo
Click to expand...

Ciao Guglielmo,
I have used them. I don't know if the Russians mica caps with metal case sound better. I can tell you that I really like the sound of this phono. Salas phono:D.
If you buy the caps from e7mkg just got more than 2 per value. I bought a pair of 0.016uF and when I measured them one was 16200pF the other 16nF. The same with the 0.047uF. One was 47nF the other 46800pF. I solved by adding a parallel silver mica caps of 180pF . And for the 100nF cap. i used FT2, Cout is a K73-16 (3.9uF//100nF FT2).
Ciao. Luca

PS
Salas wrote: OUTPUT CAPACITOR: For driving 100k is 0.68uF, 1.5uF for 50k, 3.3uF for 20k and 6.8uF for 10k.
 
Last edited:
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Hi Gugliemo,

The simplistic has 30 Ohm output impedance and about 8mA drive capability. Just make your output cap as big as needed (6u8).

Thanks for your kind words.
Feel confident about comparing the simplistic phono with any tube circuit BTW.
I had made 7 tubed ones.:)

Regards
 
disco

disco

Member
Joined 2006
urbano63 said:
Ciao Guglielmo,
I have used them. I don't know if the Russians mica caps with metal case sound better. I can tell you that I really like the sound of this phono. Salas phono:D.
If you buy the caps from e7mkg just got more than 2 per value. I bought a pair of 0.016uF and when I measured them one was 16200pF the other 16nF. The same with the 0.047uF. One was 47nF the other 46800pF. I solved by adding a parallel silver mica caps of 180pF . And for the 100nF cap. i used FT2, Cout is a K73-16 (3.9uF//100nF FT2).
Ciao. Luca
Click to expand...

http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&item=390095341362
 
RCruz

RCruz

Member
Joined 2006
Paid Member
I get this message in the link:

Error
This file is neither allocated to a Premium Account, or a Collector's Account, and can therefore only be downloaded 10 times.

This limit is reached.

To download this file, the uploader either needs to transfer this file into his/her Collector's Account, or upload the file again. The file can later be moved to a Collector's Account. The uploader just needs to click the delete link of the file to get further information.
 
RCruz

RCruz

Member
Joined 2006
Paid Member
Nice pdf !

Just want to report what I found relative to the 1000u Cap over the voltage reference zener in the shunt:

My first experiment was 220u Ruby ZL that produced quite fast and detailed bass if a little light.

Second attempt with 2200u Ruby ZLH produced full bass but a little mudled.

Third option was 470u Ruby ZA and this gave a good compromise between full bass retaining detail and "snap".

Last option was 470u BG FK... this is the best option so far.

Ricardo
 
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