You Know What I'd Like?

[Cressy Snr]

A phono stage that would take a turntable input, convert the cartridge signal to digital, carry out the eq, then output this signal,to my DAC, where it could then be converted back to analogue and fed out balanced to my amp.
And no I don't mean those things that are supposed to digitise your LPs so you can put them via Audacity into your PC.
I want something that simply plays your records into and out of your favourite DAC; no computers involved.

[pre65]

Surely, if you "digitise" a record, then the rest is easy, and you won't wear the original out by repeated playing.

Has anyone here digitised vinyl and got excellent results ? It's something on my (long) list of things to try.

If you don't want to try that Steve what are your objections ?

[Cressy Snr]

My objections to digitising LPs are that it has to be done in real time, then you have to set up and number the tracks.
I can't be arsed with that malarkey. The days of me carefully spending two hours to record a C90 compilation are long since gone; life's too short.

I want to just put a record on, listen to it, turn it over and listen to the other side.
I don't want to be forking out vast sums on phono stages when with a simple ADC to digital RIAA setup, you can go straight into your power amp from the analogue output of your DAC.
The DAC simply acts as a digital line stage/source selector.
I also can't see why the ADC/RIAA couldn't operate with switchable sampling levels from 16/44 to 24/192
It can't be that hard.

[pre65]

I shall watch this topic with interest.

[Nick]

It can't be that hard.

Just remember while you are doing this, that the dynamic range of the ADC needs to

1. Include the 40dB range from 20Hz to 20kHz that the eq requires, more if you want to go above 20kHz
2. Has sufficient overload margin for scratches and pops, maybe another 30dB
3. Has enough dynamic range to capture the audio. Say 70dB

So add that all up and you find you need a ADC with a S/N ratio of at least 140dB, all of a sudden not so simple when you are dealing with a input signal in the < 1mv range.

Not impossible, but not simple to do well. I have spent time thinking about it.

[Cressy Snr]

Bah! Never mind.
Could the signal go through a mic preamp, prior to the ADC/digital eq. The thing would probably have to be MM only.
It'd be difficult to make it cope with an MC cart.

[pre65]

I found this article, and somewhere in it (could not see it myself) it says that " Another 24 bit delta sigma ADC I know yields an SNR of 140 dB"

http://www.beis.de/Elektronik/DeltaSigm ... Sigma.html

And

http://datasheets.maximintegrated.com/e ... X11214.pdf

[Nick]

Yes, you would need something like a mic preamp to bring it to the level the ADC needs, that would work for MC and MM, but as always you are adding up your noise floor. It could be done, especially if you can live with trimming any of those ratio's a bit. But my point was doing it digitally doesnt make all the problems go away.

I suspect a £100 phono stage + ADC that output spdiff would do what you wanted, but I dont think it would automagically sound better that a dedicated analogue solution.

Talk to Andrew L, just about everything Keysight (nee Agilent, nee HP) make now consists of low noise analogue wonder with the required bandwidth and S/N connected to an ADC with the require sample rate and bit depth connected to a computer. (or the other way round for the generators).

[Nick]

I found this article, and somewhere in it (could not see it myself) it says that " Another 24 bit delta sigma ADC I know yields an SNR of 140 dB"

The rest of that line reads "but with an output rate of 7 Hz"

[Cressy Snr]

Cheers Nick,
I wouldn't expect a solution like this to sound as good as a dedicated analogue phono stage.
It just seeems like a decent way to be able to use a DAC like we would have used an old fashioned "control unit"
back in the day. For using vinyl as a secondary source to digital, it could provide pretty decent quality if you weren't after
the ultimate from your records, just the ability to play them at a good level of performance.

[Cressy Snr]

Here's just the thing.
Probably has half an hour's latency

No ....seriously, this would work nicely on the end of an entry level phono stage, (Pro-Ject Phono Box) into my DAC so I could see if vinyl's annoyance value was reduced sufficiently to make me want to get back into it. If vinyl still drove me nuts then I woudn't have lost out by much.
http://www.lindy.co.uk/audio-video-c2/c ... rter-p2730

[Nick]

Not a situation where latency is a issue. Though half a hour would be impressive, it would require at least 302Mb of storage.

[Cressy Snr]

Not a situation where latency is a issue. Though half a hour would be impressive, it would require at least 302Mb of storage.

I talk some right bollocks sometimes don't I

[pre65]

Not a situation where latency is a issue. Though half a hour would be impressive, it would require at least 302Mb of storage.

I talk some right bollocks sometimes don't I

.

[simon]

Might be worth considering one of these Steve?

http://www.twistedpearaudio.com/linestages/retro.aspx

$75 plus a bipolar PS like the Placid for $95 or $55 for the LCDS. Or one of your own. Plus shipping and import.

http://www.twistedpearaudio.com/power/placidbp.aspx

http://www.twistedpearaudio.com/power/lcdps.aspx