Which Digisnake cables

[usinare]

i want to hook up the 192/IO to a keyboard. the keyboard has 1/4 TRS(-10 dbu) outputs. which digisnake do i need.

digi and other experts please help. thanks.

[Barnabas]

Get a pair of nice quality direct boxes that will convert the output of your keyboard to a microphone level signal. (You need two for stereo) Then you need the Digi snake that has XLR connectors for inputs.

[ProdInfo]

To connect the 1/4" TRS balanced output of your keyboard to the 192 I/O, I would recommend using the DB25-TRS DigiSnake cable. The 192 I/O was designed with both +4 dBu and -10 dBV balanced inputs on DB25 connectors. They can't be used simultaneously, but one major advantage of providing both types of input is that the overall specifications of the 192 I/O can be retained at either operating level.

If your keyboard had unbalanced outputs (as many do), it would be best to use a line level shifter that would allow you to convert from an unbalanced to a balanced signal. Depending on the features of the particular line level shifter you used, you could then connect to either the +4 dBu or the -10 dBV inputs.

[D Clementson]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by ProdInfo:

If your keyboard had unbalanced outputs (as many do), it would be best to use a line level shifter that would allow you to convert from an unbalanced to a balanced signal. Depending on the features of the particular line level shifter you used, you could then connect to either the +4 dBu or the -10 dBV inputs.<HR></BLOCKQUOTE>

I have to disagree with our own Product Info guy: Unless you have _really_ long lines to drive where you expect large common-mode interference, I'd recommend that you NOT use an unbalanced-to-balanced converter on the input of your 192. In most cases, all a solid state converter will do is add noise; a transformer unit won't.

In general, I recommend that you connect your synths to the 192's "-10" input jacks, making sure the "hot", "cold", and "ground" pins are connected at the 192 end, but the "cold" and "ground" leads connect together to the TRS "sleeve" terminal at the synth end. This will enable the 192's very good input CMRR to reject as much common-mode ground noise as possible.

If you still find common-mode noise, you can insert a trimpot (the right value could be as low as 10 ohms to as high as 1k) in series with the "cold" terminal, and adjust it to exactly equal the synth's output impedance. Do that by adjusting it until you find the null in the common-mode noise. I'd put the trimpot in a pigtail that stays with the synth. Rob Silfvast of Euphonix presented a paper on this technique at an AES conference some years back. EUPH have a patent on this technique, too, so you may have to seek their permission to use it.

Of course, transformers have nearly perfect CMRR plus incredibly high common-mode impedance, so if you like the way they sound (and you can afford them!), they're definitely the way to get a quiet rig. The Jensen Transformer web site has TONS of info on this subject.

DC

[ProdInfo]

Thanks for the correction and elaboration, Dave. I know that everyone truly appreciates your contributions to the DUC, myself included.

Digidesign Product Information

[michael c]

Originally posted by ProdInfo:
To connect the 1/4" TRS balanced output of your keyboard to the 192 I/O, I would recommend using the DB25-TRS DigiSnake cable. The 192 I/O was designed with both +4 dBu and -10 dBV balanced inputs on DB25 connectors. They can't be used simultaneously, but one major advantage of providing both types of input is that the overall specifications of the 192 I/O can be retained at either operating level.

<font size="2" face="Verdana, Arial">So it isn't possible to run four analog inputs with XLR connections (+4) and say 4 analog inputs for synths with 1/4" -10 connections. Is this correct?

Thank you.

[DigiTechSupt]

[quote]Originally posted by michael c:

So it isn't possible to run four analog inputs with XLR connections (+4) and say 4 analog inputs for synths with 1/4" -10 connections. Is this correct?

<font size="2" face="Verdana, Arial">-According to the above post, yes, this is the assumption....however, it is incorrect. You may select the Reference Input Level, Input Trim Setting and Soft Clip limiter function for each channel (independent of one another).

Brent

[usinare]

get a mixer. run your synths into the mixer and outputs of mixer into 192. you have the option of adjusting the input gain from the mixer to get a hotter signal.

[michael c]

[quote]Originally posted by DigiTechSupt:
<blockquote><font size="1" face="Verdana, Arial">quote:<hr /><font size="2" face="Verdana, Arial">Originally posted by michael c:

So it isn't possible to run four analog inputs with XLR connections (+4) and say 4 analog inputs for synths with 1/4" -10 connections. Is this correct?

<font size="2" face="Verdana, Arial">-According to the above post, yes, this is the assumption....however, it is incorrect. You may select the Reference Input Level, Input Trim Setting and Soft Clip limiter function for each channel (independent of one another).

Brent<hr /></blockquote><font size="2" face="Verdana, Arial">Brent, one last qualification. (Sorry) Can you use BOTH of the analog input sections on the 192 I/O at the same time? Say using 4 inputs on the +4 snake and 4 inputs on the -10 snake. Can you mix those two 8 input connections along with the Digital I/O?

Thank you.

[spong]

yes you can mix and match down to each single analog channel.

Don't know if this helps or not but when I am recording a hi-z output, I just connect it to the high z input on my API preamp and feed the 192 with that. Works great.