USB Interface to Use with ext. Preamps

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quiet stv
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USB Interface to Use with ext. Preamps

Post by quiet stv » Mon Mar 21, 2016 7:28 pm

Hi,

I've been asked to work in several folks' private studios, all with computer-based
systems, various different interfaces.

I've also been asked to bring along some mics & preamps. The clients' interfaces seem to all have preamps and it also seems that the way to get in from my preamps is usualy thru the interfaces' preamps. I'd prefer not to go thru another preamp stage if at all possible.

So I'm wondering if I can find a USB interface to carry along.
Is there a USB interface suited to taking a signal from a mic preamp to the A/D converters without going thru its own preamp? Bonus points for portabilitiy. ;-)

Thanks very much!

stv

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Post by vvv » Tue Mar 22, 2016 4:20 am

On the inexpensive side, I use an old M-Audio Delta 44, tho' I use it on XP Pro, exactly like that.

I also have a cuppla M-Track Plus's, and they do have a mic/line switch; I have so far only used 'em for playback, tho', on Win10.
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Post by kslight » Tue Mar 22, 2016 6:12 am

You didn't specify how many inputs you need, but I'm a fan of the Motu AVB line...I have the 1248 but there's also the 16a if you don't want any preamps at all. There's the ultralite avb on a budget at the cost of inputs..

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Post by quiet stv » Tue Mar 22, 2016 6:23 am

kslight - A number of the studios in which I'll be working use MOTU interfaces.
So the 16a can accept a +4 line level signal from a preamp, great, thanks.
I'l have a look at that one.

Much of the basic tracking has been done on these projects, so I won't need
more than a couple of inputs at once. Sorry I left that out. I'm joining to
finish projects and add a few elements and vocals.

Thanks, vvv, for the word on the Delta 44. Inexpensive is good. ;-)

stv

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Nick Sevilla
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Post by Nick Sevilla » Tue Mar 22, 2016 7:08 am

I'd also recommend something from Motu.

As to what you are bringing, let me ask:

Microphones.
Your own computer and DAW
Your own audio interface, which has yet to be purchased.
Various cabling for these items.

Is that correct?
Howling at the neighbors. Hoping they have more mic cables.

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Post by quiet stv » Tue Mar 22, 2016 7:23 am

Hi Nick,

My original plan, as requested, was to carry along preamps and mics with audio and power cabling for those.

I'll be working with my clients' computers and DAW systems with their interfaces already in place. There is among them quite a variety of USB A/D interfaces (and software).

The use of external preamps is unusual for these studios so I'd like to learn about
interfaces that best accomodate inputs from external preamps without going
thru another preamp (gain) stage.

It might smooth things for me to carry my own interface to use with my mic
preamps, but I'm not familiar with USB interface options for this purpose.

I hope that clarifies my situation.

Thanks very much,
stv

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Post by kslight » Tue Mar 22, 2016 8:10 am

quiet stv wrote:kslight - A number of the studios in which I'll be working use MOTU interfaces.
So the 16a can accept a +4 line level signal from a preamp, great, thanks.
I'l have a look at that one.

Much of the basic tracking has been done on these projects, so I won't need
more than a couple of inputs at once. Sorry I left that out. I'm joining to
finish projects and add a few elements and vocals.

Thanks, vvv, for the word on the Delta 44. Inexpensive is good. ;-)

stv
The Motu has very flexible software control of each input individually, accepting an external pre should be no issue.

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Post by quiet stv » Tue Mar 22, 2016 12:37 pm

"The Motu has very flexible software control of each input individually, accepting an external pre should be no issue."

I'm sure that's true, but it wasn't my concern.

I see that some of the larger MOTU boxes have -10/+4 line inputs, but a number of the smaller ones only accept line in via a preamp circuit.

I'd like to find out if folks here know of a good short-path USB interface w/o a
gain stage on the input, so that I can use preamp outputs into it directly.

A couple have been suggested, I wonder if there are others.

Thanks much,
stv

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Post by Nick Sevilla » Wed Mar 23, 2016 1:36 pm

Most mic preamplifiers which are external, output +4 line level.

This would go into any converter's line inputs, set to accept +4 line level signal.

You would NOT go through a mic input on the converter. Too much gain to begin with there, you'd most likely distort the signal.

Most USB converters have a pair or more line inputs. Some have trims, some do not.

Cheers
Howling at the neighbors. Hoping they have more mic cables.

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Post by quiet stv » Wed Mar 23, 2016 1:42 pm

Well said, Nick.

I've been to one fellow's place, equipped with a MOTU 8Pre, and our
experience with that was of a gain stage that affected the line input
from my preamps. The signal didn't distort and we could manage
the gain staging, but the added sound of the 8Pre was definitely different
from my experience of my mic & preamp otherwise.

This reinforced my idea that perhaps someone could suggest an interface
that I could carry to such places.

Thanks,

stv

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Post by vvv » Thu Mar 24, 2016 4:07 am

When I was researching this stuff last year, I read that many of the cheaper interfaces apparently actually do run the line inputs through the interface's own mic pre's, just using a kinda pad on the inputs.

Supposedly, the gain knob does not actually function as a "trim", but rather as an actual gain control, because even when switched to "line" (vs. mic) the input signal is going through the mic preamp circuit.

From what I read, the thing to look for is an interface where, when you switch the input to "line", the gain control has no effect, and/or where there is a separate "trim" knob.

For example, the M-Audio M Track Plus info says, "The 1/4" input can be set to receive line level signal, or switched to allow an electric guitar, bass or any other instrument level source to be plugged directly into the M-Track Plus, while the gain knob ensures the proper input level." cite

My interp of that is that the line-level signal is still going through the mic pre of the interface. At this point, I only use mine instead of my laptops' sound cards playback, so they work for me (paid US$90 or so when they first came out.)

As I recall, the Focusrite 6i6 might have a "straight through" line input because it "boasts two preamp-equipped front panel mic/ line/instrument inputs, and two rear-mounted balanced TRS line level inputs. There are four rear-mounted balanced TRS outputs, and the six in/out spec is completed by rear-mounted stereo S/PDIF in/out." cite
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Post by mrc » Thu Jul 07, 2016 10:44 pm

I've got an old Alesis AI3 i'm planning on sending to them. i've also got a pro40 i've sent to the, and it's amazing after the mod. Also an Audient Asp 880. It allows inserts and bypasses on channels you choose. You'll most likely need 2 DB25 to trs, and enough patcbay patch bay to handle your I/O's.

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Post by vvv » Fri Jul 08, 2016 4:31 am

mrc wrote:I've got an old Alesis AI3 i'm planning on sending to them. i've also got a pro40 i've sent to the, and it's amazing after the mod. Also an Audient Asp 880. It allows inserts and bypasses on channels you choose. You'll most likely need 2 DB25 to trs, and enough patcbay patch bay to handle your I/O's.

Hmmm, wrong thread for this post? 8)

Spurious guess: you are speaking of BLA, or similar?
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Post by mrc » Tue Jul 12, 2016 7:31 am

Yes, sorry been busy. The Focusrite boxes that have line ins as input count are just line ins, and the Bla mods improve them as well. Sorry I wasn't clear.

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