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Digitizing my vinyl using an outboard A2D box

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Anonymous
April 25, 2005 4:23:52 AM

Archived from groups: rec.audio.tech (More info?)

I plan on ripping all my vinyl to mp3's and I figured that (1) since
the computer is a noisy environment and (2) I can't get an analog
signal to make it from my stereo to my computer without a 60 Hz
ground-loop hum, I went and bought an A2D box that has no brand name
and merely calls itself an "AD-2000". It takes RCA stereo audio in,
and puts out digital audio on both toslink and coax.

So, all is now peachy, as my soundcard has toslink in.

Though maybe it's not quite so peachy as I first thought.... the
AD-2000 box has no gain control. The only control it has is a switch
that let's you set its output to either 44.1 kHz or 48.0 kHz.

So, I was figuring for a while that this box must be conservative and
have a relatively low gain so as to not risk saturating the digital
signal. Au contraire -- when I recorded a record onto my hard disk,
the recording meters in the software peak very close to 0 db.

So, I'm guessing now that this box must be making significant use of
compression. The question is how much is this compression going to
ruin the enjoyment of my records? If I'm encoding them to mp3's
anyway (using "lame" and "alt-present-standard"), I'm clearly not
going for a completely golden-ear solution. I would like "reasonably
listenable", however.

What do you guys think?

|>oug
Anonymous
April 25, 2005 2:55:49 PM

Archived from groups: rec.audio.tech (More info?)

Douglas Alan <nessus@mit.edu> writes:
> [...]
> What do you guys think?

Off-the-hip, I think there MUST be a soundcard out there that has
"good enough" performance that you can simply run your audio right
into the inputs.

Alternately, I'm not sure I'd conclude the AD2000 has compression, and
if you feed it from a power amp output you should be able to control
gain from your pre-amp/receiver.
--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124
Anonymous
April 26, 2005 1:18:40 PM

Archived from groups: rec.audio.tech (More info?)

"Douglas Alan" <nessus@mit.edu> wrote in message
news:lcpswjpjqf.fsf@gaffa.mit.edu...
> I plan on ripping all my vinyl to mp3's and I figured that (1) since
> the computer is a noisy environment and (2) I can't get an analog
> signal to make it from my stereo to my computer without a 60 Hz
> ground-loop hum, I went and bought an A2D box that has no brand name
> and merely calls itself an "AD-2000". It takes RCA stereo audio in,
> and puts out digital audio on both toslink and coax.
>
> So, all is now peachy, as my soundcard has toslink in.


Download (for free) Paul Kellett's "Wave Tools" Spectrum Analyser. I've
found it useful in finding where and how serious various audio noise
problems might be. I record my old LPs using ordinary screened coax, but
went to optical fibre when recording from my digital TV decoder as the TV
line timebase was being picked up by the coax. The optical fibre gives me
the lowest noise floor I've seen in domestic recording.

--
M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm
Related resources
Anonymous
April 26, 2005 1:32:50 PM

Archived from groups: rec.audio.tech (More info?)

Randy Yates <randy.yates@sonyericsson.com> writes:

> Douglas Alan <nessus@mit.edu> writes:
> > [...]
> > What do you guys think?
>
> Off-the-hip, I think there MUST be a soundcard out there that has
> "good enough" performance that you can simply run your audio right
> into the inputs.
>

I actually tested converting LP to CD for the first time last winter
and did expect all kinds of noise etc since I used the sound circuitry
on the mother board. To my great surprise the result came out so good
I can hear the difference between the LP and CD only if I do a rather
careful A/B comparison. I have copied several LPs with the same good
outcome since then.

That first test-LP was (still is) a test-LP with various samples
of live, acoustic music choosen and carefully recorded with the
aim to produce an LP for (subjective) assessment of Hifi equipment.
I have been careful with it so it is still in good shape. Hence, if
my HW or SW had behaved badly I think I would have noticed.

HW: Shuttle SK41G (and rather long and cheap cable to the stereo)
SW: Rezound running under Mandrake 9.1 (Linux). I don't remember
what I used for burning the CD but most likely K3b.

Cheers,

--
========================================================================
Martin Schöön <Martin.Schoon@ericsson.com>

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
========================================================================
Anonymous
April 26, 2005 3:33:20 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 25 Apr 2005 00:23:52 -0400, Douglas Alan <nessus@mit.edu>
wrote:

>I plan on ripping all my vinyl to mp3's

MUST you? Well, OK. At least it will make you listen to everything
at least once. I hope you have some pleasant surprises :-)

>and I figured that (1) since
>the computer is a noisy environment and (2) I can't get an analog
>signal to make it from my stereo to my computer without a 60 Hz
>ground-loop hum, I went and bought an A2D box that has no brand name
>and merely calls itself an "AD-2000". It takes RCA stereo audio in,
>and puts out digital audio on both toslink and coax.

A modern computer with a quality sound card isn't a problem
environment for audio recording. Your external converter is a rather
heavy-handed way of curing an earth loop :-) But, if it works -
fine.

You need to present the ADC with the right level signal. Just as you
would have to present the ACD on a soundcard with the right level
signal. It's unlikely that either would have a gain control affecting
the analogue signal BEFORE it hit the DAC. And that's where the
level needs to be right.

If your stereo has no level control on the Line Out, this means you'll
need something between it and the DAC. The small mixers from e.g.
Behringer are affordable and will do the job.

>
>So, all is now peachy, as my soundcard has toslink in.
>
>Though maybe it's not quite so peachy as I first thought.... the
>AD-2000 box has no gain control. The only control it has is a switch
>that let's you set its output to either 44.1 kHz or 48.0 kHz.
>
>So, I was figuring for a while that this box must be conservative and
>have a relatively low gain so as to not risk saturating the digital
>signal. Au contraire -- when I recorded a record onto my hard disk,
>the recording meters in the software peak very close to 0 db.
>
>So, I'm guessing now that this box must be making significant use of
>compression. The question is how much is this compression going to
>ruin the enjoyment of my records? If I'm encoding them to mp3's
>anyway (using "lame" and "alt-present-standard"), I'm clearly not
>going for a completely golden-ear solution. I would like "reasonably
>listenable", however.

The box is unlikely to have compression. You must feed it the right
level. Getting levels right is the key to quality audio recording.
Anonymous
April 27, 2005 8:22:53 PM

Archived from groups: rec.audio.tech (More info?)

Douglas Alan wrote:

> I plan on ripping all my vinyl to mp3's and I figured that (1) since
> the computer is a noisy environment

Hmmmm ...

and (2) I can't get an analog
> signal to make it from my stereo to my computer without a 60 Hz
> ground-loop hum, I went and bought an A2D box that has no brand name
> and merely calls itself an "AD-2000". It takes RCA stereo audio in,
> and puts out digital audio on both toslink and coax.
>
> So, all is now peachy, as my soundcard has toslink in.
>
> Though maybe it's not quite so peachy as I first thought.... the
> AD-2000 box has no gain control. The only control it has is a switch
> that let's you set its output to either 44.1 kHz or 48.0 kHz.
>
> So, I was figuring for a while that this box must be conservative and
> have a relatively low gain so as to not risk saturating the digital
> signal. Au contraire -- when I recorded a record onto my hard disk,
> the recording meters in the software peak very close to 0 db.
>
> So, I'm guessing now that this box must be making significant use of
> compression.

Based on what evidence, have you tried a passive attenuator in front of
it?

> The question is how much is this compression going to
> ruin the enjoyment of my records? If I'm encoding them to mp3's
> anyway (using "lame" and "alt-present-standard"), I'm clearly not
> going for a completely golden-ear solution. I would like "reasonably
> listenable", however.

> What do you guys think?

I use a Midiman Audiophile 2496 pci card for such tasks, there is no
noise problem of any kind of relevance, my card is slightly modded but
in the context of noise the modificiation is irrelevant, quite probably
also in the context of the source material.

> |>oug


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
May 3, 2005 2:07:45 PM

Archived from groups: rec.audio.tech (More info?)

">So, I was figuring for a while that this box must be conservative and
>have a relatively low gain so as to not risk saturating the digital
>signal. Au contraire -- when I recorded a record onto my hard disk,
>the recording meters in the software peak very close to 0 db.

As it takes input from a cartridge, maybe it's designed to cope with the
highest-output cartridges in common use. I'd have guessed that was in the
range of 5-10mv, though some may know better. How close to 0dB are you
getting?

You could if you wanted try recording an LP from the tape monitor outputs of
your amplifier, and compare the range of sound levels with recordings made
with the AD-2000.

You'll need to use your computer's software volume control, which sets the
gain level in the analog mixer section of the sound chip. According to
reports here, not all sound chips have such an on-board analog mixer
section. If you know the chip used, you can probably look up the block
diagram for the chip functions to see if it does have an on-board analog
mixer.

Tim
Anonymous
May 3, 2005 4:00:55 PM

Archived from groups: rec.audio.tech (More info?)

Tim Martin wrote:
> ">So, I was figuring for a while that this box must be conservative
> and
>> have a relatively low gain so as to not risk saturating the digital
>> signal. Au contraire -- when I recorded a record onto my hard disk,
>> the recording meters in the software peak very close to 0 db.
>
> As it takes input from a cartridge, maybe it's designed to cope with
> the highest-output cartridges in common use. I'd have guessed that
> was in the range of 5-10mv, though some may know better. How close
> to 0dB are you getting?
>
> You could if you wanted try recording an LP from the tape monitor
> outputs of your amplifier, and compare the range of sound levels with
> recordings made with the AD-2000.
>
> You'll need to use your computer's software volume control, which
> sets the gain level in the analog mixer section of the sound chip.
> According to reports here, not all sound chips have such an on-board
> analog mixer section. If you know the chip used, you can probably
> look up the block diagram for the chip functions to see if it does
> have an on-board analog mixer.
>
> Tim

Jumping in here...

Has RIAA equalization been accounted for? Just plugging in a phonograph
equipped with a magnetic or most other cartridge types would be completely
inadequate, unless the A/D unit had proper EQ built in.

Mark Z.
Anonymous
June 1, 2005 7:17:59 AM

Archived from groups: rec.audio.tech (More info?)

Take a look at www.behold-highend.de. They can solve your problem!!!

You will see the new PSD192 - a full digital phono stage for MC and MM
at 192kHz/24Bits. The equaliziation will be done by a DSP.

Also the PSD192 has digital and analog outputs. Recording via USB is
also possible.

Greetings
Peter
Anonymous
June 1, 2005 8:39:16 PM

Archived from groups: rec.audio.tech (More info?)

"Tim Martin" <tim2718281@ntlworld.com> writes:

> "So, I was figuring for a while that this box must be conservative and
>> have a relatively low gain so as to not risk saturating the digital
>> signal. Au contraire -- when I recorded a record onto my hard disk,
>> the recording meters in the software peak very close to 0 db.

> As it takes input from a cartridge, maybe it's designed to cope with the
> highest-output cartridges in common use. I'd have guessed that was in the
> range of 5-10mv, though some may know better. How close to 0dB are you
> getting?

It doesn't take input from a cartidge -- it takes line-level inputs.
I have the A2D converter connected to the "monitor" outputs on my
stereo receiver. The receiver has phono jack inputs, so that's there
the phono cartridge EQ is being done.

> You could if you wanted try recording an LP from the tape monitor outputs of
> your amplifier, and compare the range of sound levels with recordings made
> with the AD-2000.

I get a nasty 60 Hz hum if I try to run analog cables from my stereo
to my computer. That's why I switched to using fiber optic cable and
the A2D converter.

|>oug
!