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Plugging preamp into FW1814

I've been happily using my FW1814 for a while. I recently purchased a UA Solo/610 preamp to use with it. This pre's output is an XLR. The FW1814 has unbalanced 1/4" inputs on the back and and two combi jacks labelled "Mic/inst" on the front. What's the best way to hook this thing up? Can I run a balanced signal into the unbalanced inputs?

Comments

AudioGaff Sat, 12/02/2006 - 21:35
The best way is to check the manual for the 610 where it should state how best to connect it's balanced output to an unbalanced input of any external device.

Most likely you can just use a XLR to TRS balanced cable to the 1814 unblanced input. You may lose 6-10db of gain and a little worse S/N ratio, but it should still work. Check your 1814 manual. Does it state you can use balanced cables with it's unblanced inputs?

Like it is in most cases, it all comes down to reading the manuals to fully understand the gear that you own or are using.

CoyoteTrax Tue, 12/05/2006 - 20:13
I have an 1814 and like it alot. Use the XLR in's on the front with the mic/instr button in the "out" position. Make sure the phantom power is not engaged and use the gain control for that channel appropriately. You'll get a fantastic signal that way. IME the XLR input is the "best" way to interface with a quality, balanced, tube mic pre.

Kev Tue, 12/05/2006 - 22:38
AudioGaff wrote: Like it is in most cases, it all comes down to reading the manuals to fully understand the gear that you own or are using.

http://www.uaudio.com/_works/pdf/manuals/SOLO-manual.pdf

often the expensive gear can benefit from a simple interface unit
it can be as simple as a plastic box with some resistors and a switch or two
something to terminate the source and get some current flowing through the output
something to PAD back the output level which can be higher than a modern interface

HOWEVER
the solo 610
Maximum Output Level into 600 ohms +14 dBu, 1% THD+N Ratio
Maximum Output Level into 100k ohms +18 dBu, 1.0% THD+N Ratio

it could be that all you need is the right wiring of your cable

AudioGaff suggested the a XLR to TRS balanced cable
I think you should also try a ground lifted version
XL pin 2 and 3 to tip and sleeve ... drop the ground

you should have some XL and TRS with flying leads at the other end so you can trial and error some of the options ... then make the right leads

lunar Sat, 12/09/2006 - 12:16
Thanks for all the suggestions. I tried a balanced TRS cable and it did not work (no sound at all)... this was a new cable.

Kev wrote: I think you should also try a ground lifted version
XL pin 2 and 3 to tip and sleeve ... drop the ground
I will try building a cable without the ground wire. Would it also be a good idea to try just connecting the two -ve wires like this:
http://www.mediacollege.com/audio/connection/xlr-jack-mono.html ?

CoyoteTrax wrote: IME the XLR input is the "best" way to interface with a quality, balanced, tube mic pre.
Coyote, if I plug it into the XLR inputs isn't this running the signal through a second preamp (one of the built in M-Audio ones) and therefore degrading the signal?

Kev Sat, 12/09/2006 - 13:28
yep

I generally make the #1 option and then you decide to use or not use the ground (pin 1)
and I tend to use TRS connectors even if I only need Tip and Sleeve ... it keeps the options open
(yes there can be some power on - off issues but a simple link from R and S can solve that)

#1


#2




yes it could be argued that the M-Audio pre-amps will degrade the sound
it could also be that the line in and the mic-pre use the same circuit
without seeing a schematic I can't know for sure

sometimes these things can't be worked around

using the better quality mic-pre for the high gain jobs may still be a better option even though you do also go through the M-Audio pre-amps at lower gain

CoyoteTrax Sat, 12/09/2006 - 14:57
Lunar, you're right, you are using the 1814's pre's but IMO the 1814's pre's are so uncolored and wide open that I've always been able to hear the full character of any pre I'm actually powering the mic/instrument with on the front end. I feel there's no issue as far as degrading your signal because in the end you're ultimately using the same A/D converters. It's a matter of taste and/or preference I suppose. You have a couple of different routing options. It just comes down to listening to the results of each and deciding for yourself which option works and sounds best for you. Kev's advice has been fantastic.

There may even be times when you'll want to use the 1814's pre's just for a different "sound". Especially with AC guitar's and ambient/room mic's that you're not compressing. They're very clean, very crisp.

dementedchord Sun, 12/10/2006 - 01:29
i would not dream(well maybe nightmare) of driving a micpre from another mic pre... take kevs advice... you'll fry far fewer pre's in your tascam... why on earth would one WANT to pad down the output of your UA???(increasing the noise floor)... only to the have to further pad the input of the tascam (so as not to overdrive it still)... when there's a perfectly usable line level input sitting there having been designed just for such uses?????

CoyoteTrax Sun, 12/10/2006 - 08:00
dementedchord wrote: i would not dream(well maybe nightmare) of driving a micpre from another mic pre... take kevs advice... you'll fry far fewer pre's in your tascam... why on earth would one WANT to pad down the output of your UA???(increasing the noise floor)... only to the have to further pad the input of the tascam (so as not to overdrive it still)... when there's a perfectly usable line level input sitting there having been designed just for such uses?????

Demented, he's using an 1814 which is m-audio, not Tascam. And the 1814's 1/4" inputs are not balanced, they're unbalanced. The ONLY balance inputs on an 1814 are the 2 xlr in's at the front of the unit.

And the xlr inputs on the front of the unit are really more like mixer inputs than they are mic pre's. They're very nuetral and just happen to have a phantom power feature. So when you're looking to use the balance xlr outputs on a decent mic pre like a 610 the natural thing to do is use the balanced xlr inputs on the 1814.

Also, if he's driving the 610 really hard with drums or a guitar cabinet or wants a super-focused effect for background vocals, effects percussion, etc., it's a great "effect" and/or tool. It also gives you another tool to use with really noisey mic pre's that while being noisey might have incredible tone (the EHX 12AY7 comes to mind).

dementedchord Sun, 12/10/2006 - 13:42
my bad on the model... but am still unsure that driving the xlr input is still the best thing to do in terms of gain staging which was really my original point... would be able to give more diffinative answer if i had access to a schemo... and though i usually prefer balanced ins and outs... please realize that one of if not the first thing done when entering a unit is to UNBALANCE the signal....

hueseph Tue, 12/12/2006 - 01:25
lunar wrote: Thanks for all the suggestions. I tried a balanced TRS cable and it did not work (no sound at all)... this was a new cable.


This was to one of the balanced line ins right? Not the combination input? Sorry. Just covering the obvious.

[edit]-my mistake the combo inputs are in fact balanced TRS. But, you did switch them to line right? Again just covering the obvious.

lunar Tue, 12/26/2006 - 08:28
my mistake the combo inputs are in fact balanced TRS. But, you did switch them to line right? Again just covering the obvious.

I was plugging the balanced TRS cable into the unbalanced line-ins on the back, not the combination inputs on the front. But, to answer your question, I did hit the switch to tell it to listen to the line-in I was using.
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