Handling Unbalanced Signals with the Model 12

[whynot]

Hi all,

(This is my first post on the forum—glad to be here!)

I’m currently researching the Model 12 before buying and trying to wrap my head around the TRS balanced inputs and outputs. On my current mixer and soundcard, I can use TRS or TS cables interchangeably without issues (per the manuals).

After checking with the very helpful team at Tascam support, they confirmed that it's important to convert a TS unbalanced signal to TRS balanced before using the channel. They mentioned:

"Using a TS jack could result in damage to the input op-amps, as one leg of the balanced input will be shorted."

Their recommendation is to use a DI box, such as the ART DualZDirect.

I have a couple of unbalanced line-out instruments:

• Novation BassStation Mk1
• Behringer TD-3

And a couple of effects:

• Delay pedal (between Aux and channel in)
• Korg Kaoss Pad (between Sub and channel in)

I’m curious—what solutions have others come up with for handling unbalanced signals with the Model 12?


Any insight would be greatly appreciated! Thanks in advance.


(BTW, I might be a little slow to reply sometimes.)

​

 

[Mark Richards]

Welcome to the forum, @whynot.
I'm not an owner of a Model 12, but here's the relevant pages of the Model 12 OM showing a typical connection setup. If you don't yet have it, the OM pdf is on the TASCAM website under the "Support" section.

 

[Max Relic]

Using a TS jack could result in damage to the input op-amps, as one leg of the balanced input will be shorted.

Hi @whynot , I would rate that sentence more misleading than helpful.

For a line level signal input, shorting one input leg of a differential op-amp (Operational Amplifier) to ground should be considered not harmful, in that it consists in no signal reaching one side of the amp stage (while the other side still works).
Shorting the output of any amplifying device can be harmful or even dangerous depending on voltage and current rating involved.
For a phantom-powered microphone input stage there could be the risk of burning a fuse or some component (likely in the power supply board) because of voltage/current circulation.

From a signal quality perspective, balanced connection should be adopted whenever equipment is connected to the mixer with long cables and/or signal level is weak (i.e.mic level); a full-balanced line (from instrument output to mixer input) grants lesser noise and better Signal to Noise Ratio than unbalanced line.
That said, in my Model 12 I use indifferently balanced and unbalanced connections depending on the gear. No input op-amp were harmed in the last 40 years.

I suggest reading some Mackie mixer owner's manual to learn some useful notions about connections, they are well written and funny to read.