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So, I'm trying to digitise some vinyls. I have a big amplifier, and I might just use the preamp in that, but I might instead get the Radial J33. The Radial J33 is a phono preamp, but it has both RCA outputs and XLR outputs. I believe that the RCA outputs are unbalanced line level, and that the XLR outputs are balanced mic level. Which one of those signals should I use to record from? The cables I use will only be 1.5m long, and I am using a Focusrite 18i8. So either I use two RCA to 1/4 inch cables and use those, or I use two XLR cables. Which is the better option. Using the RCA has the advantage of being line level, but XLR has the advantage of being balanced.

In short, which is better:

   Phono --> Preamp --> BALANCED Mic Level    --> Microphone combi jack input
or Phono --> Preamp --> UNBALANCED Line Level --> Fixed gain line input or line input of combi jack if fixed gain isn't quite the right level
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It would be potentially cleaner (lower distortion) and quieter (better signal-to-noise ratio) to take the line-level output from your phono preamp and feed the signals into the line-level input of the audio interface. Artificially knocking the signal down to mic level and then re-amplifying them is a whole stage that can be easily avoided. Line-level is always preferable to mic-level regardless of what gear you are using.

  • So am I right in concluding that line-level is always preferable to mic-level over short distances EVEN IF THE MIC CABLE IS BALANCED AND THE LINE-LEVEL IS UNBALANCED? – Isaac Adni Aug 3 '16 at 13:18
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    Yes. Because ANY and ALL gain stages introduce additional noise and distortion. And any time you can avoid an additional gain stage you come out ahead of the game. Simple as that. – Richard Crowley Aug 3 '16 at 13:20
  • I'd be a bit more hesitant, but generally yes. If you have a noisy enough environment (RF interference) or bad enough cables, coupled with clean enough pre-amps, it is possible you could end up with more noise from the cable run than from the extra pre-amp run. The J33's block diagram shows that it is dropping the signals after it has pre-amped, but I would try both to experimentally determine which sound you prefer in your situation, particularly since it is outputting consumer line level, which is much weaker than pro line level. – AJ Henderson Aug 5 '16 at 13:37
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Without knowing the specifics of your existing amplifier, I would say you should get the J33 and use the XLR mic-level outputs into the mic inputs on the Focusrite purely to use their pre-amps. Focusrite preamps have a good reputation for being fairly linear.

On the other hand, you may prefer the way the preamps in your big amplifier sound.

In either case, if you get the J33 you'll have a choice between the two.

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    According to the J33's block diagram, the pre-amp in the J33 is still used and then stepped back down to go to mic levels, so you would already have picked up any noise and colorings that the pre-amps would give, you'd just be adding more. – AJ Henderson Aug 5 '16 at 13:34

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