Shouldn't a Phono Stage Be Like a DAC? Why so expensive?

[Don Hills]

... staggered releases could keep some albums in the charts longer as well, without needing to gouge the customer.

I don't think they'll pass up the opportunity to gouge the customer.

 

[watchnerd]

I think the Devialet does the same as well.

Have you tried a Devialet with your 4367's?

High bandwidth, super low-distortion integrated amp plus wide dynamic range, low distortion speakers sounds appealing to me.

 

[March Audio]

Yes, I may be looking for problems that aren't there...



However, it's evident that digital data engineers didn't consider XLR when they made connector standards. Why is that? Are their choices relevant for analog applications as well?

Sorry for asking stupid questions. It's a bad habit of mine

Yes that is correct. Xlr is not suitable for RF. However it is perfectly suitable for low audio frequencies.

I will try and find some explanatory links but RF and high frequency transmission is a completely different game. You have issues of reflections, standing waves, loss, impedance, propagation delay etc. You are into transmission line theory. RF connectors have to be very carefully designed and made. Behaviour of cables and connectors are very differentvat 250 MHz than they are at 20kHz.

None of this is relevant at audio frequencies.

Some google hits.

https://www.google.com/url?sa=t&sou...gglMAA&usg=AFQjCNGROfz4FyyCvAGz5WftRSIi04PVpA

Note the statement on page 12.

 

[dallasjustice]

I'd love to. I talked to Nyal and he offered to let me demo. Alas, the DSP capabilities inside Devialet are only IIR; no FIR. I'm not a believer in IIR when trying to use opposing wall subs to cancel modes because of the crossover. It probably wouldn't work as well as FIR. I'm sure there's limited CPU power inside the Devialet.

Have you tried a Devialet with your 4367's?

High bandwidth, super low-distortion integrated amp plus wide dynamic range, low distortion speakers sounds appealing to me.

 

[watchnerd]

Is there something akin to a preamp version of the Devialet made by anybody?

In other words, a software defined DSP based RIAA stage with full config customization and digital out?

 

[Frank Dernie]

I'd love to. I talked to Nyal and he offered to let me demo. Alas, the DSP capabilities inside Devialet are only IIR; no FIR. I'm not a believer in IIR when trying to use opposing wall subs to cancel modes because of the crossover. It probably wouldn't work as well as FIR. I'm sure there's limited CPU power inside the Devialet.

There is no room compensation software available from Devialet. It is a much requested feature for a future update, but so far no response.

 

[watchnerd]

There is no room compensation software available from Devialet. It is a much requested feature for a future update, but so far no response.

The look-a-like Micromega M One 150 does have room eq, though.

 

[Frank Dernie]

Is there something akin to a preamp version of the Devialet made by anybody?

In other words, a software defined DSP based RIAA stage with full config customization and digital out?

My Metric Halo recorder ULN2 can be used like this, the RIAA curve is one of the supplied plug ins, but there is no ability to adjust input loading and it is firewire/Mac. Given that they make this available maybe other ADC/DAC suppliers do too???

 

[svart-hvitt]

Is there something akin to a preamp version of the Devialet made by anybody?

In other words, a software defined DSP based RIAA stage with full config customization and digital out?

I haven't seen such a one-in-all package.

The problem with phono signals is the extremely low voltage and impedance. So what you'd need, is a preamp that magnifies the incoming signal to a level that off-the shelf analog to digital converters handle.

There are some flat amplifiers for use with the tiny phono signals, for example Channel D and the aforementioned Violectric PPA V600. The flat signal can be manipulated after AD conversion.

I think this is the ideal chain:

Cartridge => flat preamp => AD converter => digital RIAA and DSP => DAC

This electric chain should, I guess, be of low noise in order for the DSP to be specifically targeted at correcting noise from the vinyl disc instead of trying to correct chain induced noise.

 

[Frank Dernie]

The look-a-like Micromega M One 150 does have room eq, though.

Slightly similar styling, completely different design and engineering. Up/Down push buttons for volume on the remote would rule it out for me

 

[Frank Dernie]

I haven't seen such a one-in-all package.

The problem with phono signals is the extremely low voltage and impedance. So what you'd need, is a preamp that magnifies the incoming signal to a level that off-the shelf analog to digital converters handle.

There are some flat amplifiers for use with the tiny phono signals, for example Channel D and the aforementioned Violectric PPA V600. The flat signal can be manipulated after AD conversion.

I think this is the ideal chain:

Cartridge => flat preamp => AD converter => digital RIAA and DSP => DAC

This electric chain should, I guess, be of low noise in order for the DSP to be specifically targeted at correcting noise from the vinyl disc instead of trying to correct chain induced noise.

AFAIK one attraction Devialet felt to a digital RIAA input was it did not need amplifying before ADC, just loading correctly.

 

[Purité Audio]

Illusonic processors are I suppose like. Devialet preamp only much more comprehensive.
Keith

 

[Soniclife]

Is there something akin to a preamp version of the Devialet made by anybody?

In other words, a software defined DSP based RIAA stage with full config customization and digital out?

http://www.psaudio.com/nuwave-phono-converter/ ?

 

[DonH56]

Not sure why a flat preamp into an ADC is better than one that performs RIAA compensation... The RIAA curve is what, about 40 dB gain difference from low to high frequencies? So you have to have 40 dB (a little over six bits) of dynamic range in the ADC just to handle the compensation. I'd have to analyze the gain structure for noise and distortion, given the parameters of the preamp and ADC, to see which "wins" for optimum dynamic range in a particular test case. But, not worth it to me, TT's in storage and not inclined to dig it out.

 

[Soniclife]

AFAIK one attraction Devialet felt to a digital RIAA input was it did not need amplifying before ADC, just loading correctly.

I'm not quite sure what you're saying, but the line stage has adjustable gain, before the ADC.

 

[svart-hvitt]

Not sure why a flat preamp into an ADC is better than one that performs RIAA compensation... The RIAA curve is what, about 40 dB gain difference from low to high frequencies? So you have to have 40 dB (a little over six bits) of dynamic range in the ADC just to handle the compensation. I'd have to analyze the gain structure for noise and distortion, given the parameters of the preamp and ADC, to see which "wins" for optimum dynamic range in a particular test case. But, not worth it to me, TT's in storage and not inclined to dig it out.

I guess the answer to "why digital phono curve correction" is flexibility and accuracy. RIAA is just one of many phono correction curves. It's cleaner to do as much conversion and processing in the digital domain. And lastly: It's possibly easier to amplify an uncorrcted curve than a corrected curve?

 

[DonH56]

AFAIK one attraction Devialet felt to a digital RIAA input was it did not need amplifying before ADC, just loading correctly.

I'm pretty sure it needs amplification before digitization but you could forego equalization if it is a better trade to give up the dynamic range in the ADC for RIAA (or whatever) compensation. That is a trade I do not claim to know for their system.

 

[DonH56]

I guess the answer to "why digital phono curve correction" is flexibility and accuracy. RIAA is just one of many phono correction curves. It's cleaner to do as much conversion and processing in the digital domain. And lastly: It's possibly easier to amplify an uncorrcted curve than a corrected curve?

Flexibility, accuracy, stability, etc. are all benefits of digital filtering, all true. As for easier to amplify without including EQ in the preamp, there are a lot of factors that go into that. Without including EQ you need a lot more dynamic range in the preamp so it is not clear to me it is always a win for dynamic range (SFDR, SNR, THD, IMD, all that jazz).

As for multiple curves; yes, there are many, but many of them are fairly similar, and how many folk really need them let alone have access to such a plethora of non-RIAA recordings? Collectors, libraries and museums, but how many common folk? Perhaps I am just too common... Before dumping most of my collection of 3000+ records I had only a few that employed other than RIAA emphasis, and most of those were older recordings given to me by my grandparents. Had to get a 78 rpm player for many of them, but there were some gems. My cheapo ARC SP3a1a only had RIAA so I tweaked the tone controls as needed.

I need to stay out of this one, there's never much point in trying to win a religious debate.

 

[svart-hvitt]

Flexibility, accuracy, stability, etc. are all benefits of digital filtering, all true. As for easier to amplify without including EQ in the preamp, there are a lot of factors that go into that. Without including EQ you need a lot more dynamic range in the preamp so it is not clear to me it is always a win for dynamic range (SFDR, SNR, THD, IMD, all that jazz).

As for multiple curves; yes, there are many, but many of them are fairly similar, and how many folk really need them let alone have access to such a plethora of non-RIAA recordings? Collectors, libraries and museums, but how many common folk? Perhaps I am just too common... Before dumping most of my collection of 3000+ records I had only a few that employed other than RIAA emphasis, and most of those were older recordings given to me by my grandparents. Had to get a 78 rpm player for many of them, but there were some gems. My cheapo ARC SP3a1a only had RIAA so I tweaked the tone controls as needed.

I need to stay out of this one, there's never much point in trying to win a religious debate.

Why do you call vinyl a religious debate?

The debate has been about specs, facts and things that tolerate scientific scrutiny.

Vinyl is, true, an inferior to digital distribution format. Still, it's possible to use technical insights in discussing how to optimize this ancient format?

 

[dallasjustice]

That's right. I am pretty sure my prism Titan has the same. Either of those converters are excellent.

My Metric Halo recorder ULN2 can be used like this, the RIAA curve is one of the supplied plug ins, but there is no ability to adjust input loading and it is firewire/Mac. Given that they make this available maybe other ADC/DAC suppliers do too???