Influence of RIAA impedance value on sound

[Uchi Deshi]

I'm going to build RIAA preamp. Do you think that RIAA EQ impedance value influence on sound or perhaps you have got any expirience?

[ingrast]

If you are talking about eq. input impedance, and your eq. is active, you have to make sure it matches the pickup specified load, usually 47 K.

Rodolfo

[Uchi Deshi]

I haven't meant input impedance, but RIAA EQ circuit impedance.

[ingrast]

Right, I meant RIAA equalizer input impedance (as seen from the pickup as a load). Above said holds.

Rodolfo

[phn]

Speaking as a non-engineer, I think impedance should make a difference just as the choice of values (low or high) for the caps and resistors in the RIAA network will.

You could try them thar low-impedance SMTs

Everywhere an engineer looks he sees objects. He sees problems to be solved. Don't. See it as options.

[EC8010]

Originally posted by phn
Everywhere an engineer looks he sees objects. He sees problems to be solved. Don't. See it as options.

No, no. We see them as "options" to be optimised.

Broadly speaking, a lower impedance RIAA network will be lower noise but its loading may cause the driving stage to distort more and any stage that sinks grid current into it to distort less.

Ultimately, the impedance of the RIAA network is determined by the capacitor (or inductor) values available in the designer's parts bin.

[peranders]

Originally posted by phn
Everywhere an engineer looks he sees objects. He sees problems to be solved. Don't. See it as options.

I would use the word "properties" instead of problems.

[peranders]

Originally posted by Uchi Deshi
I'm going to build RIAA preamp. Do you think that RIAA EQ impedance value influence on sound or perhaps you have got any expirience?

Possibly yes but first you must deside how the topology of the correction should look like.

1 non-inverting, active correction (feedback), most common

2 non-inverting, two stages and passive correction

3 non-inverting preamp and inverting active correction.

4 multiple stage correction

When you have desided which type you are going to use you also know in which value range you can build the RIAA correction network of.

Check Walt Jung, page 6.14, good stuff about RIAA amps.
http://www.analog.com/library/analog...h6_final_I.pdf

[phn]

I have three words for you engineers:

Yeah, yeah, yeah