What about digital RIAA?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
I

iperv

Member
Joined 2008
Hi all.
I just ask myself why there is no standard high quality digital RIAA diy boards out there.
I think a simple 24/96 ADC paired with an i2s USB input, a software like jRiver and an USB DAC are enough.
What i missed?
My goal is to play vinyl in real time through PC and DAC I still use every day with my liquid files.
Of course a buffer/gain stage is needed to match gain and impedance of turntable.
I speak about digital RIAA via jRiver.
 
Last edited:
I

iperv

Member
Joined 2008
I mean:
i just use PC and DAC and, of corse, i'm a digital guy ;-)
Why i cannot simply put on my PC a digital real time audio file with no RIAA eq?
With jRiver (or similar) i can do an optimal RIAA eq, so i have only to implement an high quality ADC via usb, ro obtain an high quality cheap phono stage.

EDIT: sorry for t9, i'm mobile now.
 
SY

SY

Ex-Moderator
Joined 2002
SYclotron.com
MASantos said:
The extra amount of processing and equipment necessary doesn´t make much sense.
Click to expand...

Actually, it can, especially for those of us who work in the digital domain right up to the power amps. If you have a good ADC/DAC, you don't even need a preamp after it, simplifying things further.

Because the signal from cartridge is too small for good quality conversion.
Click to expand...

For MC, likely true, though one could use a step-up transformer. For MM, I'm not sure, the opamps used in good sound cards are pretty quiet.
 
scott wurcer

scott wurcer

R.I.P
Joined 2004
SY said:
For MC, likely true, though one could use a step-up transformer. For MM, I'm not sure, the opamps used in good sound cards are pretty quiet.
Click to expand...

The low level inputs on my external sound interfaces have typically 6K or so input resistance so I would recommend a proper cartridge termination and a buffer with gain like an SSM2019 or THAT1512. That way the cart could also be wired differential. Those parts would also do all but the low output MC's. The digital RIAA is well covered and a miniDSP would work as well as any number of other software or hardware solutions. A search for our member Jittipee's (I think I got that right) digital RIAA site has the correct coefficients for up to 192k. The set floating around the web has a trivial error (50.5Hz rather than 50.05Hz) as the low time constant.

I also think the phase errors quoted are overstated by a lot. In my simulations I found it mostly was an additional small processing delay. It also is MHO that the surface noise dithers a converter at 24bits so much that all the dynamic range arguments are moot.

EDIT - I'm speaking of IIR biquad version here.
 
I

iperv

Member
Joined 2008
neugruen said:
It can be done:
6moons.com - industry features: An Awesome 3some
www.behold.eu - Deutsch - Produkte - behold Classic - Andere Komponenten - MCA768
www.behold.eu - Deutsch - Produkte - behold Classic - Andere Komponenten - MCK768
www.behold.eu - Deutsch - Produkte - behold Classic - Audio Prozessor
Click to expand...

Very interesting.
Even if i don't think it's a cheap solution.

Anyway,
do you know of an hi-fi quality adc board?
24/96 or 24/192 or better?
With a digital output (USB, i2s, aes/ebu, s/pdif)?
Possibly cheap :cool: ?
 
billshurv

billshurv

Member
Joined 2014
Paid Member
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom