Simplistic NJFET RIAA

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luxury54

Member
Joined 2008
sorry for bumping in this thread with my question but I downloaded the schematic of the RIAA stage and seems to me very tempting to try out;
however, I would also like to try it with my R2R tape deck as a play preamp and since I heard that the RIAA filter stage doesn't differ too much from the NAB filter stage used for 19cm/s tapes, I wonder if someone would know how to change the filter values of the RIAA equalization so that I'll be able to use it as a repro preamp also using NAB equalization standard?

Thanks
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
luxury54 said:
sorry for bumping in this thread with my question but I downloaded the schematic of the RIAA stage and seems to me very tempting to try out;
however, I would also like to try it with my R2R tape deck as a play preamp and since I heard that the RIAA filter stage doesn't differ too much from the NAB filter stage used for 19cm/s tapes, I wonder if someone would know how to change the filter values of the RIAA equalization so that I'll be able to use it as a repro preamp also using NAB equalization standard?

Thanks
Click to expand...

http://www.diyaudio.com/forums/analogue-source/222113-preamp-reel-reel.html
 
The Space Egg Corp

The Space Egg Corp

Member
Joined 2010
Hi Salas

I had an 'old' schematic from before the PDF.
I am though, working from the PDF, on both the Shunt & NJFET.
I just have 100n interstage, NOT the 47n as the PDF.

You just answered in part my question, a couple of posts back...
...I was wondering how much of the VVVLF 'filter' came from the 'interstage cap'...
...and how much comes from the 2.2uF 'output cap'.
I have some 'un-authorised !' 6uF 'output caps' I would like to try.

I obviously have to wait to test Toshiba's to get an idea of 'gain'.
Also I still don't exactly know what cartridge I will end up with.
Although I am working from the PDF 'hi-mc' eg. DL-160 schematic.

Just drew a MKI & MKII board layout yesterday.
MKII looks OK, we get it 'perfect' for MKIII !!!

I am thinking that having a 'permanent pot' for 1st stage gain would be an advantage for me.
Perhaps a fraction of the total value leading to 1st stage, say 100, 200 or 500R ?
A small amount of adjustment would make setup much easier.
I'm sure a decent 3/4 Watt 20-turn would be OK left in-circuit.
Any 'authorised' standards here ?

Cheers

Si.

Anyway...
...this is FUN !
We scribble some Shunt-Reg board layouts tomorrow !
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Doing a portion of the 1st stage's loading does things to the Riaa. Better do its source resistor. The output cap does whatever portion it does with your amp's Rin in line level. Rest is what 47n or 100n do to 1 meg. See, combine, decide, listen, tweak. Do bib 1.1 for reg.
 
The Space Egg Corp

The Space Egg Corp

Member
Joined 2010
My friend tells me Denon have discontinued the DL-160.
I thought it was a popular, well spoken of product.
I think the DL-110 ( nearly the same ? ) is still being produced.

Anyone know why Denon pulled the DL-160 ?

Si.

I have a 'cartridge grave-yard' here !!!
Might have a rumage through, see what junk I can come up with to 'bolt-on' to the SME...
...at least for a laugh !!!

How annoying is it that some carts don't have 'holes' all the way through ( ie. Denon )...
...AAArrrggghhh!!!
 
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