Tascam 38 +4dbu ???

[janusz konar]

Is it possible to caibrate my tascam 38 to perform at +4dbu?

I now have soundcraft 500 board that is switchable between -10/+4 and could just set it at -10, but can I then use other outboard devices like compressors that work at +4?
I will apriciate any information...

 

[jpmorris]

I doubt it. It's intended to run at -10 only, so if you did manage it you'd have basically no headroom. What you need is a balancing converter, like the Fostex 5030, or failing that a set of ART Cleanbox Pros (you'd need 4 as they're stereo).

EDIT: What might be more effective is to run most of the system at -10, and use a Cleanbox Pro or two to connect to the +4 devices.

 

[mdainsd]

I avoid level shifting. going from +4 to -10 you reduce the dynamic range, when you go the other way you raise the noise floor.

 

[janusz konar]

Thanks for clearing this up.

One more corresponding question: I have some outboard pres and eq's that I might want to use while tracking, but Im afraid they (preamps) may give to hot output for my tascam reel to reel. Can I use gear you mentioned between preamp and tape to attenuate the signal?

 

[jpmorris]

Maybe it's time to take a step back. What are you actually plugging into the deck? AFAIK most mixing desks can accept either +4 or -10 input simply by altering the gain on the channel, so you shouldn't need to alter the output level of the deck.

I think the big question is, what are you intending to plug in to the deck, and how? How many simultaneous inputs do you need on the recorder?

I don't normally use more than 2 inputs myself, so I can use a small sub-mixer. With a 4-way Y lead, I can route the left channel to tracks 1,3,5 and 7, and the right output to 2,4,6,8. That way, I can plug the instruments into the sub-mixer, and use the -10 outputs from the mixer regardless of what the instrument or preamp is doing. I can route tracks simply by arming the channel I want to record. However, this doesn't work very well if you need to record more than 2 channels at once.

 

[janusz konar]

I want to record up to 5-6 tracks at once, sometimes all 8.
I want to use some other preamps for tracking (like very hot output sony sra-2 tube reel to reel amp, or even hotter german telefunken/siemens danner type preamp module) Sometimes I will also want to use soundcraft 500 direct out from a channel, but mixing desk will be used for mixing mostly. So my chain would be: mic>stand alone preamp>Tascam38. And then: Tascam38>Soundcraft desk>ART Cleanbox>compressor etc>ART Cleanbox> Soundcraft (via insert) As you suggested I coud run desk and tascam both -10. Just for outboard processing I sould use ART Cleanbox Pro that you suggested. So thats fine.

My question was, Can I additionaly use ART Cleanbox to attenuate signal of hot preamp signal before it hits tape, or is it better to add a pad to preamps.

Sorry if im not being clear.

 

[jpmorris]

The cleanbox can go both ways, -10 to +4, and +4 to -10. It can do both at once, so you can have a +4 mixer outputting to a -10 FX unit and back, with both channels. But you could use it to do two completely separate conversions.

What I did notice with mine was that the two output controls seem to interact with each other - I was hoping to use to trim the signals to the exact same voltage for calibration, but adjusting one affects the other too. This made lining up very awkward until I figured out what was happening (and not much easier afterwards).

 

[Beck]

(This is almost identical to a post I posted sometime ago, but I can’t find it back at the moment using the search)

It’s very easy to make a balanced XLR-to-Unbalanced RCA adaptor. This will help you if you want to connect +4 outputs into the Tascam 38, or if you set your board to -10, to connect a pre with +4 balanced outs to the board. But it doesn't help you the other way, -10 to +4, obviously. All you need are:

- XLR connector (Male or female, depending on what you’re connecting)
- Male RCA connector or ¼” phone jack, depending on what’s on the other side
- ¼ watt 4.7k ohm and ¼ watt 1.5k ohm metal film resistors
- Desired length 2-conductor, shielded Coax cable

All the parts are available at Radio Shack, or Mouser, DigiKey, etc. This takes balanced +4 dBm (Pin 2 hot) to unbalanced –10 dBv RCA or 1/4" plug. You can put the resistors inside the XLR connector. Since some devices are pin-3 hot you can do it that way too. Just make sure you know what the equipment on the balanced side is wired as. Excuse my sloppy drawing.