M-Audio Delta balanced I/O... isn't!

[ofajen]

You may recall recent discussion in one of these general discussion forums about how M-Audio Delta series interfaces claim to have "balanced" ins and outs, or at least, if you read the manual, that the inputs and outputs are "compatible" with balanced audio. However, the inputs aren't actually balanced.

After being tipped off here on homerec, and verifying that on my own equipment, I have been badgering M-Audio technical staff to cough up the truth. Here's what I know so far:

My Omni I/O was designed by a third party engineer. While inputs 1 and 2 are balanced mike/line inputs, inputs 3 and 4 aren't balanced .... really. The input has a TRS jack, but the R connector is floating. This unbalances the input properly for some gear, but not all. It's perfectly appropriate for connecting up typical active balanced gear, since leaving the minus side floating is the perferred option for unbalancing.

However, when connecting a transformer balanced output, you should go ahead and unbalance the signal at the output by tying the minus leg to ground, rather than using a balanced cable connection to the input, since the minus leg will be left floating, and the signal will not be properly unbalanced. This is easily done if you use a balanced TRS patchbay by simply plugging in from the transformered output to the M-Audio input with an unbalanced TS patch cord. That ensures the transformered output will be properly unbalanced. It would have been nice if they had mentioned this in the manual.

I suspect these unbalanced inputs are similar to inputs on Delta 44s, Delta 66s and Delta 1010s, and I will ask for confirmation on that.

I suspect the outputs have TRS jacks with the R contact tied to ground. The final step will be to verify that this is true.

Cheers,

Otto

 

[dementedchord]

that's a drag dude... as a long time tech i was constantly amazed at shit like this... often on lower-end stuff you'll see this in the form of a resister to ground on the ring... and then the manufacture quibbles about the definition of balanced vs terminated... sick fux..

 

[boingoman]

I suspect the outputs have TRS jacks with the R contact tied to ground. The final step will be to verify that this is true.

Cheers,

Otto

Otto,

Nice job tracking that down.

 

[ofajen]

You may recall recent discussion in one of these general discussion forums about how M-Audio Delta series interfaces claim to have "balanced" ins and outs, or at least, if you read the manual, that the inputs and outputs are "compatible" with balanced audio. However, the inputs aren't actually balanced.

After being tipped off here on homerec, and verifying that on my own equipment, I have been badgering M-Audio technical staff to cough up the truth. Here's what I know so far:

My Omni I/O was designed by a third party engineer. While inputs 1 and 2 are balanced mike/line inputs, inputs 3 and 4 aren't balanced .... really. The input has a TRS jack, but the R connector is floating. This unbalances the input properly for some gear, but not all. It's perfectly appropriate for connecting up typical active balanced gear, since leaving the minus side floating is the perferred option for unbalancing.

I suspect these unbalanced inputs are similar to inputs on Delta 44s, Delta 66s and Delta 1010s, and I will ask for confirmation on that.

I suspect the outputs have TRS jacks with the R contact tied to ground. The final step will be to verify that this is true.

Following up...

The M-Audio engineering guy's response to my questions is that the Omni I/O does have TRS balanced outputs. The Delta 1010, he says, has TRS balanced inputs and TRS balanced outputs, but the output signal is asymmetrical, meaning that more of the signal is on the plus leg and less on the minus leg.

So... there you have it. Assuming what I was told is true.

Cheers,

Otto