Software for RIAA

[jonstanza]

Dear diyers

After the project (prototype preamplifier)
prototype preamplifier

I am developing a unit RIAA. I keep the same philosophy as the preamplifier, but with a higher gain.

The question is: what software-pro is most accurate for this purpose. Send a picture of the type of filter I want.The amplification has correction RIAA active and passive

I think the phono unit Spectral DMC-20 (or even the DMC-12!) has this philosophy.

Thank you very much
jon

[Leon08]

I know only this site.hifi
Hopefully it helps you.

[Bonsai]

Hello Jon, there is a write up in the link below in RIAA and a calculator as well based on the Lipshitz equations. The circuit you show above is the Baxandall circuit. In the RIAA writeup below, a design example for your circuit is given as well - you can take the values directly from the write up.

RIAA Phono Equalizer, phono amplifier | hifisonix.com

Good luck with your project!

[AndrewT]

The RC on the output works to the formula if loaded by infinite impedance at all relevant frequencies.
If you load it with a leaky capacitor or a typical Zin of the Receiver then the component values must be corrected for that extra current that flows.
It would be sensible to remove the effect of Zin from that and add a buffer of known Zin that can then be used to compensate that last RC to reasonable accuracy.

Your schematic falls into the usual trap of showing common Ground symbols for all the different Return currents.
Draw it properly and then your "as built" will have a reasonable chance of performing to the predicted results.

PS.
I had not looked at this Thread earlier, because the title led me to wrongly assume you were looking for software to perform the RIAA filtering.

[Bonsai]

Yes,

Andrew's comments are correct - you should buffer the Baxandall circuit for consistent results. When I get around to doing part 2 of the article on my site, I will add this note.

[jonstanza]

AndrewT and Bonsai.
Thanks for your help. I'm doing a study on this subject. is likely to adopt the passive filter.
note: Bonsai, thanks for the link, very good.

Capacitors for riaa of clartyCap, anyone know how they sound these elements
http://www.partsconnexion.com/capaci...itycap_mr.html

best regards
jon

[Bonsai]

Jon, these don't look like they are best suited for RIAA - for one thing the tolerance is quoted at 3% - means you will have to buy a bunch and sort them, or alternatively recalculate your R values to ensure a tight enough RIAA fit.

Best thing to do is to look at Wima. You need to focus on polypropelyne & polycarbonate types. You want 1% 50 to 100V caps for the RIAA. Also, in the interests of noise pick-up, there is a strong case for keeping the cap sizes small -no need for physically big caps. Panasonic also do some nice caps - take a look in Digikey. For Wima- I believe Mouser carry those.

[Joachim Gerhard]

I use KP1830. That is a 1% film and foil PP from Vishey-Roederstein.

[Bonsai]

Jon, try this link for some in-depth information

Picking Capacitors - Walter G. Jung and Richard Marsh

JG - thanks for your input - I guess you have a lot of practical experience here. I forgot about the Vishay parts - they are also very good (and defintiely avaiable from Mouser)

[jonstanza]

Hello "diyers"
after several tests with capacitors, I chose dynamicap (very musical and a price acceptable). The RIAA correction is passive . With various attempts I abandoned the RIAA active, I never liked the sound.

I send the first pictures of the boards, I'm waiting the aluminum box that I ordered to build.
later I sending more photos. The motherboard bus power is 6N copper mono-crystal
The pictures 1-board power suplly, 2- power suplly (lack the power transistors), 3-capacitor dynamicap for RIAA and filter 220v~, 4-SW gain input MC-low,MC or MM, 5-sw input impedance, and 6- mother board wiht module RIAA one channel

best regards