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DSP-Based Phono Preamp/ADC with Digital Out?

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#1
As the title asks, I’m trying to find a standalone phono stage that both uses a DSP to perform the RIAA eq and outputs digital in some form.

I’ve found phono stages that A/D to do RIAA EQ in DSP, then D/A right back to output, and I can find phono stages that have a digital output, but I can’t find confirmation of a phono stage that does both. I’m intrigued by the idea of using DSP to make a better preamp, but it seems more useful to use my system’s existing DAC to d/a the signal back rather than rely on what is built-in.
 

orangejello

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#2
I have the same question especially since it would allow me to use the headphone amp on my dac to listen to vinyl. I also want to see if it improves S/N. I think that my phono preamp RIAA is probably excellent, but I was also having some problems with power supply noise recently. Then realized that the rectifier tube in the power supply was about 15 years old and had many, many hours on it. Changed out the EZ80 and that problem is gone. But still would like to experiment with DSP RIAA and to make use of my headphone amp while listening to vinyl.
 

Frank Dernie

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#3
As the title asks, I’m trying to find a standalone phono stage that both uses a DSP to perform the RIAA eq and outputs digital in some form.

I’ve found phono stages that A/D to do RIAA EQ in DSP, then D/A right back to output, and I can find phono stages that have a digital output, but I can’t find confirmation of a phono stage that does both. I’m intrigued by the idea of using DSP to make a better preamp, but it seems more useful to use my system’s existing DAC to d/a the signal back rather than rely on what is built-in.
I believe the Parks audio Puffin is about to add a digital output, or at least has a DIY way to get one.
http://parksaudiollc.com
 

watchnerd

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#4
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splattened

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#5
I believe the Parks audio Puffin is about to add a digital output, or at least has a DIY way to get one.
http://parksaudiollc.com
Link describing the mod since I don't think it's linked on the front page: http://www.parksaudiollc.com/spdif/spdif.html

It is unfortunate and ironic that the Puffin digitizes the signal but then doesn't provide a digital out. It's not that I have an issue with the DAC (I don't), but it sure makes it a lot easier to integrate with a much wider variety of gear once that need for an analog input goes away.

Thankfully it doesn't seem like it'd be too hard of a mod, but I'm not versed in DIY electronics. And risking the destruction of what is now a $450 piece of equipment as my first project isn't too enticing to me. ;) On the other hand YOLO.

Edit: Also, here is the latest statement on digital out being a standard feature on the Puffin:
This is kind of a long term research project to see how folks will use a digital out. No plans to change the Puffin, but if this mod is successful over time then I just might offer it as a custom Puffin direct from me.
Source (see the comments on this post):
 
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BDWoody

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#7
As the title asks, I’m trying to find a standalone phono stage that both uses a DSP to perform the RIAA eq and outputs digital in some form.

I’ve found phono stages that A/D to do RIAA EQ in DSP, then D/A right back to output, and I can find phono stages that have a digital output, but I can’t find confirmation of a phono stage that does both. I’m intrigued by the idea of using DSP to make a better preamp, but it seems more useful to use my system’s existing DAC to d/a the signal back rather than rely on what is built-in.
Devialet offers a digital phono stage. Haven't played with one myself yet, but I understand they are quite nice...If not cheap.
 

Willem

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#8
I am still not quite sure what you want. My Pro-Ject phono E box Optical is a MM pre amp with optical and line outputs. I am not sure if the equalization is done in the analogue or digital domain but I don't particularly care.
 
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#9
Having something like a REW working with vinyl would be fantastic. One would need a REW generated frequency sweep pressed into LP and then a method of synchronizing REW to the LP - the correct RIAA curve would be a byproduct of an Eqed cartridge.
 

KozmoNaut

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#10
I am still not quite sure what you want. My Pro-Ject phono E box Optical is a MM pre amp with optical and line outputs. I am not sure if the equalization is done in the analogue or digital domain but I don't particularly care.
Pretty sure it's a normal Phono Box E with an ADC added. There's certainly enough free space in the case for it. It's a darn good preamp though, no matter how the EQ is done.
 

watchnerd

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#12
Having something like a REW working with vinyl would be fantastic. One would need a REW generated frequency sweep pressed into LP and then a method of synchronizing REW to the LP - the correct RIAA curve would be a byproduct of an Eqed cartridge.
That sounds inefficient and with zero benefit, IMHO, for putting the REW sweep on the LP.

REW is correcting for the room. There is nothing wrong with generating the signal digitally, per usual.

Then the process just becomes RIAA to restore flat EQ, then add REW.
 

BDWoody

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#13
Speaking as a user...yes to both. Very nice, not cheap, but it's an all-in-one proposition (integrated amp / DAC / phono / streaming end point).
Any regrets on the choice?

I appreciate nice things, that are actually nice things!
 

watchnerd

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#14
Any regrets on the choice?

I appreciate nice things, that are actually nice things!
None at all.

That's not to say I don't have a wishlist of things I wish it had (XLR inputs, a less fingerprint prone finish, a web UI for config instead of SD cards, and a few things still forthcoming for the new processor, like RAAT and room EQ).
 

scott wurcer

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#15
Having something like a REW working with vinyl would be fantastic. One would need a REW generated frequency sweep pressed into LP and then a method of synchronizing REW to the LP - the correct RIAA curve would be a byproduct of an Eqed cartridge.
Not sure what this would improve, there are numerous test LP's with frequency response sweeps both with and without RIAA. I'm afraid most people would be very disappointed in how bad many cartridges are, let alone the RIAA conformance of some of the test LP's.
 
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#16
Room EQ assumes that the signals entering the DSP are all of the same quality, so that the same EQ process is valid for all of them: the HDMI feed from an BD, an Apple TV..... That will not be correct for analog feeds that are ADed. The phono cartridge and the RIAA analog EQ generates a feed that may need different treatment. Plus there is a kind of reverse loudspeaker in the system - the phono cartridge.
 

watchnerd

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#17
Room EQ assumes that the signals entering the DSP are all of the same quality, so that the same EQ process is valid for all of them: the HDMI feed from an BD, an Apple TV..... That will not be correct for analog feeds that are ADed. The phono cartridge and the RIAA analog EQ generates a feed that may need different treatment. Plus there is a kind of reverse loudspeaker in the system - the phono cartridge.
There is no existing algorithm I'm aware for room EQ that handles the feedback loop of a cartridge resonating in sympathy with the speakers in real time.
 

Soniclife

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#18
Devialet offers a digital phono stage. Haven't played with one myself yet, but I understand they are quite nice...If not cheap.
You can not easily use one as a separate phono stage though, or apply room correction to the phono. The phono stage does output to the usb in parallel, so technically you could use a PC in real time, but it won't be elegant or make much sense.
 

Soniclife

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#19
There is no existing algorithm I'm aware for room EQ that handles the feedback loop of a cartridge resonating in sympathy with the speakers in real time.
Does anyone really want that? I'd of thought a cabinet or TT in the next room would be the best and simplest solution.
 

watchnerd

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#20
Does anyone really want that? I'd of thought a cabinet or TT in the next room would be the best and simplest solution.
I certainly don't want it.

I keep my TT in the same room as the speakers for the explicit purpose of inducing this effect.

If I want clean and pristine, I listen to digital.
 
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