Setting gain in multi-stage (phono preamp -> 10/4 box -> Presonus interface) setup?

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Setting gain in multi-stage (phono preamp -> 10/4 box -> Presonus interface) setup?

Hello, all. I'm looking to record LPs onto a MacBook Pro using a Presonus USB AudioBox. I'll be using a Radio Shack standalone phono preamp, with an Aphex 124-A 10/4 box to match the preamp's RCA outputs to the AudioBox's balanced inputs. There are two places to set gain in this configuration:

(1) The 10/4 box has a +/- 6dB level control per balanced output. The clip warning LED lights up 5dB before clipping.
(2) The USB interface has the usual input level control and clip LED per channel.

Should I leave the controls on the 10/4 box at zero and make adjustments using only the audio interface's gain controls? Or should I try to set the 10/4 box output as high as possible before clipping?

Thanks,
Jim
 
Let me try and remember about phonographs.

There is something about their output that is different. Not to mention that you have to ground them as well.

It's heck getting old you know.
 
Let me try and remember about phonographs.

There is something about their output that is different. Not to mention that you have to ground them as well.

It's heck getting old you know.

I have a phono preamp. That's not the part I'm asking about. There are two gain controls in the path: one on the level/impedance adapter and one on the recording interface. My question concerns the interaction of the two. I suppose I'll just experiment until I get the results I want and hope I don't fry aything. That's what I usually end up doing anyway.
 
So 209 recording gurus are suddenly speechless on the subject of gain structure. Go figure.

You talking about the view count? You'd be lucky if 5 of those were regular members or even real people, Diggy.

I don't see any line inputs on the presonus. There are instrument inputs which are the wrong level and, of course, unbalanced.
Maybe you have a different model to the one I'm looking at?


Anyway, if your interface had true line inputs there wouldn't be a gain control on the way in.
What's more there'd probably be an option for -10/+4 built in. I know my motu has that on the line ins.

The 10/4 matches consumer to professional gear so it doesn't need 'calibrated' or anything.
I guess the gain control on it is just to compensate for a weak source.
 
You talking about the view count? You'd be lucky if 5 of those were regular members or even real people, Diggy.

I don't see any line inputs on the presonus.

Ordinarily you'd want true line inputs on your interface, so there wouldn't be a second gain control.

The 10/4 matches consumer to professional gear so it doesn't need 'calibrated' or anything.
I guess the gain control on it is just to compensate for a weak source.

There aren't any line inputs on the Presonus. That's why I'm using the 10/4. Are you saying I should leave the 10/4 gain at zero?
 
There aren't any line inputs on the Presonus. That's why I'm using the 10/4. Are you saying I should leave the 10/4 gain at zero?

Nope.
Unless I've misread/misunderstood, the 10/4 is a converter between consumer line level and professional line level.

Instrument level is neither of these.
I'm saying I think you need proper line inputs.

Many interfaces with line level inputs will have that 10/4 built in on every channel.
 
I'm running the 10/4 into the mic preamps, not the instrument jacks. This 10/4 box converts unbalanced consumer RCA to balanced XLR. What I want to do is avoid overdriving the preamps. If anything, I would think I need to set the 10/4 output to -6dB.
 
This 10/4 box converts unbalanced consumer RCA to balanced XLR.
The connection type is unimportant; It's the signal level that matters.

The 10/4 is a line level to line level device.

Your XLR inputs are expecting microphone level.
No matter what way you set it your signal will be far too hot.



A consumer standalone radio has line level outputs and your studio reference amp has line level inputs but one is +4 and one is -10.
The 10/4 goes between devices like that, as far as I can tell.

What outputs does this radio shack preamp have?
 
The phono preamp only has consumer line level outputs. I don't want to run it directly into the Presonus because there would be no RIAA equalization in that setup.
 
I don't want to run it directly into the Presonus because there would be no RIAA equalization in that setup.

Yehp, fair enough.

IDK, maybe someone else can advise but without line inputs on the interface I think you're stuck.
You can do it, but I don't think it'll be ideal with the gear you have.
 
I was mistaken in my previous post. There would be RIAA in the path, but the signal into the Presonus would be consumer line level.

This is the sort of thing that happens when I get to tooling around with digital. It takes me far afield from what I'm trying to accomplish. I'm going back to the original plan and using a tape deck. Thanks for your help, Steenie. :)
 
I have a phono preamp. That's not the part I'm asking about. There are two gain controls in the path: one on the level/impedance adapter and one on the recording interface. My question concerns the interaction of the two. I suppose I'll just experiment until I get the results I want and hope I don't fry aything. That's what I usually end up doing anyway.


Sorry Jim. I misunderstood your equipment set up. :o
 
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