help! mixpre + fostex fr2le setup

[Pedro Cruz]

Hi, hope somebody can clarify this doubt once and for all!

So, I have a fostex fr2-le and recently bought a sound devices mixpre. Not mix-pre D, but the first version. In order to take advantage from the superb preamps, I suppose I need to convert line to mic level, from mixpre +4dbv to fostex -10dbu; meaning I need a 50db atenuator such as Shure a15la, but I also need to go from XLR to 1/4 TRS to bypass fostex preamps.
Is this correct? Is it the best/only setup possible?
I'm not sure if the atenuator is needed, because fostex input is one of those simultaneous XLR/phone input, which means mic/line, so can I assume it can receive either +4dbv in TRS or -10dbu in XLR? In that case I should only need xlr-Trs cable?
I've been reading several threads, but cant find the proper answer.
Thank you!
Pedro

 

[Greg Smith]

You wouldn't need a 50 dB attenuator to go from professional to consumer line level; that's more like a 15 dB difference. 50 dB would be for connecting to a microphone level input, which should be avoided because you don't want to be going through the noisier preamps on the Fostex.

But the MixPre has a "tape out" jack on a stereo 3.5mm connector, which is intended to connect directly to -10 dBv inputs. All you need is an appropriate cable, 3.5mm stereo to two 2-conductor phone plugs in this case.

- Greg

 

[Rick R]

I can't find any pertinent input specs in the ..bizarre.. FR2-LE manual. You need to find out the input levels, either nominal or maximum. In addition the manual shows a 1/4" TS plug, so balanced/unbalanced operation needs to be verified. We know the output for the MixPre. Even if the mic level inputs are used, a 50dB pad is probably excessive. if the Fostex takes -10dB, a twelve or fifteen decibel pad would be the norm.

 

[Alex H.]

Having used one extensively...

The combo inputs on the FR2-LE take balanced XLR mic-level inputs and unbalanced line (-10dB) 1/4" inputs. Running it with a MixPre (original), and later a MixPre-D, I simply used a 1/8" TRS > dual 1/4" TS cable to take the Tape Out from the MixPre to the 1/4" ins on the Fostex. With a short cable (3' or less), there's no noise or degredation of signal. I never had any issues with recordings made that way, and it left the XLR outs on the MixPre open for connecting to a camera if I needed to.

Further, I used a dual RCA > 1/8" TRS to take the Monitor Outs from the Fostex to the return on the MixPre, which allows switchable monitoring on the MixPre. That's crucial in the field, to be able to listen from the recorder but also to listen directly from the mixer when necessary.

There are impedence-matching cables out there that take a balanced XLR line signal and convert them to unbalanced 1/4", which would also work very well.