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Levels to use when recording vinyl, do I need amp before line-in, etc., [split from “Archiving vinyl once only 96/24?”/thread 100121/TOS #5]
zerowalker
post Mar 30 2013, 03:45
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Little off topic maybe, but if you use Line In on a compture to record.
Is the volume of that Line In the same as using an Amp?
Or is the volume corrected after it has been digitalized?

Just wondering as i also want to maximise ADC coverage.
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AndyH-ha
post Mar 30 2013, 09:13
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A professional line level input is just an input. It may be switchable between the two line level standards, +4dBu and -10dBV (professional and consumer), but it is not variable. In a mixer interface there could be a line level preamp (generally providing +10dB or +12dB gain and some larger attenuation), but that is an extra, not actually part of a real line level input. Gaming and entertainment cards are a whole different thing and must be investigated individually.

The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

Mostly, for taking the signal from a phono preamp, the consumer level line-in is appropriate. The +4dBu input expects a much higher level signal and would thus be recording way down from 0dBfs of the ADC, but there are exceptions.

The outputs of both phono cartridges and phono preamps vary considerably from one construction to another. Sometimes the combination you happen to have produces a very good signal for your ADC line in, sometimes you need to adjust up or down.

If the signal level is too high, it will clip in the ADC and that cannot be corrected post recording; it must be done in the analogue domain.

Signals that peak as much as 20dBfs down are probably quite ok, and can be normalized after recording. If that doesn't satisfy you, or if you need to attenuate the signal before the ADC, you need a line level preamp between the phono preamp and the line level ADC input. A small analogue mixer is usually the least expensive fix.

If you just need attenuation, a passive volume control, or even a fixed resistor attenuator, isn't hard to implement.
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Paul Sanders
post Mar 30 2013, 10:37
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QUOTE (AndyH-ha @ Mar 30 2013, 09:13) *
The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

You keep saying that but it's not true. What makes you believe that?


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I am an independent software developer (VinylStudio) based in UK
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aztec_mystic
post Mar 30 2013, 14:44
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QUOTE (Paul Sanders @ Mar 30 2013, 10:37) *
QUOTE (AndyH-ha @ Mar 30 2013, 09:13) *
The input controls on most ADC are digital, after the signal has been sampled, and are best set at maximum. They cannot prevent clipping, and they cannot improve on the ADC output.

You keep saying that but it's not true.

Which part do you consider false? The statement that the input controls on most ADCs are digital?

All the ADCs I use--that includes onboard audio as well as some semi-pro gear--lack an analog input gain. It actually became an issue during vinyl recording a few times. Specifically, in certain scenarios, the ADC would clip. Turning down the volume of the recording device in Windows didn't help. It led to nothing but an attenuation of the already-clipped signal.
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Paul Sanders
post Mar 30 2013, 19:08
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OK, I have written a little utility to report whether or not each of the input devices on any particular system does or does not have a hardware input level control. It runs on Windows Vista or later (the information is not available on XP) and you can get it here:

http://www.alpinesoft.co.uk/private/report...vel_control.exe

Here is what is reported on the two systems I have here. Both are running Windows 7 and have Intel High Definition Audio Device (HDA) on-board audio, which is very common on machines purchased in the last few years:

System 1:

Microphone (High Definition Audio Device) DOES have a hardware level control
Line In (High Definition Audio Device) DOES have a hardware level control
Microphone (iMic USB audio system) DOES have a hardware level control
Line (ADL GT40 USB DAC) DOES have a hardware level control
Line In (ADL ESPRIT USB DAC) DOES have a hardware level control
Microphone (USB Audio CODEC) does NOT have a hardware level control (this is a NAD PP-3 phono preamp)

System 2:

Microphone (High Definition Audio Device) DOES have a hardware level control
Line In (High Definition Audio Device) DOES have a hardware level control
Digital Audio (S/PDIF) (High Definition Audio Device) does NOT have a hardware level control

The ADL GT40 and Esprit are relatively high-end devices (especially the Esprit). The only devices without a hardware level control are the NAD PP-3 as previously mentioned (reported by Windows as USB Audio CODEC) and the S/PDIF input (which I guess makes sense).

I'd be interested to know what other HA members' systems report. It might also be possible to determine this information on OS X, if anyone is interested.


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I am an independent software developer (VinylStudio) based in UK
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zerowalker
post Mar 31 2013, 07:37
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Thanks for the software, it showed that all of mine had hardware control currently.
Really bad indeed that you won´t know it unless a software tells you.

Appreciate it for telling me, probably many more then me that didn´t know about this.
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Posts in this topic
- zerowalker   Levels to use when recording vinyl, do I need amp before line-in, etc.   Mar 30 2013, 03:45
- - AndyH-ha   A professional line level input is just an input. ...   Mar 30 2013, 09:13
|- - Paul Sanders   QUOTE (AndyH-ha @ Mar 30 2013, 09:13...   Mar 30 2013, 10:37
|- - zerowalker   QUOTE (Paul Sanders @ Mar 30 2013, 10:37)...   Mar 30 2013, 11:01
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 10:01) I...   Mar 30 2013, 11:11
||- - zerowalker   QUOTE (Paul Sanders @ Mar 30 2013, 11:11)...   Mar 30 2013, 12:17
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 11:17) S...   Mar 30 2013, 13:24
||- - zerowalker   QUOTE What then causes a lot of confusion is that ...   Mar 30 2013, 13:28
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 12:28) W...   Mar 30 2013, 13:50
||- - zerowalker   But, doesn´t that then mean that if i increase the...   Mar 30 2013, 14:15
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 13:15) B...   Mar 30 2013, 14:33
||- - zerowalker   Ah, so XP only showed the slider when it was ...   Mar 30 2013, 14:36
||- - julf   QUOTE (zerowalker @ Mar 30 2013, 14:36) W...   Mar 30 2013, 14:47
||- - Paul Sanders   QUOTE (zerowalker @ Mar 30 2013, 13:36) A...   Mar 30 2013, 16:58
|- - aztec_mystic   QUOTE (Paul Sanders @ Mar 30 2013, 10:37)...   Mar 30 2013, 14:44
||- - Paul Sanders   QUOTE (aztec_mystic @ Mar 30 2013, 13:44)...   Mar 30 2013, 16:30
||- - Paul Sanders   OK, I have written a little utility to report whet...   Mar 30 2013, 19:08
||- - Paul Sanders   (Edit:) Added a 'set digital gain to 1' bu...   Mar 30 2013, 20:34
||- - zerowalker   Thanks for the software, it showed that all of min...   Mar 31 2013, 07:37
|- - 2Bdecided   QUOTE (Paul Sanders @ Mar 30 2013, 09:37)...   Mar 30 2013, 20:20
|- - Paul Sanders   QUOTE (2Bdecided @ Mar 30 2013, 19:20) Be...   Mar 30 2013, 20:29
- - zerowalker   Not sure i understood all that. But atleast i und...   Mar 30 2013, 09:44
- - aztec_mystic   Thanks for this tool! This is from my laptop (...   Mar 30 2013, 19:52
- - AndyH-ha   If the OP question was primarily about a phono pre...   Mar 30 2013, 21:05
|- - Paul Sanders   QUOTE (AndyH-ha @ Mar 30 2013, 20:05...   Mar 30 2013, 21:29
- - AndyH-ha   You disagree because you think the schematics lie?...   Mar 31 2013, 07:52
- - Paul Sanders   QUOTE (AndyH-ha @ Mar 31 2013, 06:52...   Mar 31 2013, 11:27
- - aztec_mystic   System 2: Traktor Kontrol S4 Ch C (Kontrol S4 WDM...   Mar 31 2013, 11:45
- - Paul Sanders   Interesting. Thank you for posting.   Mar 31 2013, 12:26


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