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Topic: Pro-Ject Debut III USB Preamp Advice (Read 11850 times) previous topic - next topic

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Pro-Ject Debut III USB Preamp Advice
Reply #25
Oh, ok, Thanks, dhromed.

I think I understand how to look for clipping now.



So if the sample bumps its head on the roof, as it has done here, it's possibly (but not certainly) clipped.
The Loudness War is over. Now it's a hopeless occupation.

  • AndyH-ha
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Pro-Ject Debut III USB Preamp Advice
Reply #26
If you were looking at music that had been mastered, and remained thereafter, in the digital domain, that is a fairly likely scenario. When you are looking at something you are recording from the analogue domain, actual ADC clipping is far more likely. The shape of the peak, observed at very high zoom, will tell the story.

Clipping in the analogue domain, such as the input of an amplifier, often tends to be softer, the wave shape of the peak less of a guide. I've purchased a couple new test LPs, and collected another 6 to 10 used. Nothing on recordings of any of them has come near to clipping level. Levels have been higher, at a few peaks here and there, on various symphony recordings.

Pro-Ject Debut III USB Preamp Advice
Reply #27
Hey, AndyH (or anybody else reading) ...as long as you're here I was wondering if I could pick your brain on something like this: I found some simple line level attenuators here on Amazon. I don't mind the asking price when comparing it to something like the SM Pro Audio M-Patch 2.

They come in -12, -6, and -3 db varieties. I was thinking the right pair (or combination) of these and this Tascam would be all I need to get all my records digitized as properly as possible. I would, of course, get the Tascam first. That way I could figure out with 100% certainty if the volume adjustments are done in the analogue domain prior to ADC. If not, or if I can't be absolutely certain, I'd just pick up a set of the attenuators as well and get on with it.
The Loudness War is over. Now it's a hopeless occupation.

  • AndyH-ha
  • [*][*][*][*][*]
Pro-Ject Debut III USB Preamp Advice
Reply #28
According to the manufacturer's literature, the Tascam does have an input level adjustment. The same is used for both the microphone and the line level inputs. This probably makes the microphone capabilities somewhat limited but should be what you need for your recording. It can't hurt to make certain that it is indeed analogue, but an on-board adjustment in the digital domain, considering that this is a USB device, would be pretty sophisticated for the price, and would be unlikely to work for a microphone.

A fixed attenuator would work ok, if you knew how much attenuation you needed. That  will have to be determined by trial and error. The preamp output can't be that hot however. It is quite possible that if you just put 3dB attenuators at the output of your TT preamp, any line-level ADC input would work (but, of course, more than 3dB might be necessary).

If you look at the "other items" partway down that Amazon page, you will find similar attenuators by another company that will do the same job for only $4.50. There is also a Koss adjustable volume control that might be adequate.

The Tascam has balanced 1/4" phono jack inputs. Balanced is irrelevant for you purposes, but you will need RCA to 1/4" phono cables (very common, such as the Hosa cables in the "other items" on the Amazon SM-Pro page. (Hosa is not the best choice for long-term reliability, but you don't need the high price end cables either.)). Using the Koss with its 1/8"  I/O will complicate things somewhat.

You will also find other, less expensive passive volume adjustment devices listed on the SM-Pro page.

Pro-Ject Debut III USB Preamp Advice
Reply #29
Great. Thanks for your help, Andy (and also everyone else who commented or PMed...I appreciate it.) 
The Loudness War is over. Now it's a hopeless occupation.