[Easy!] Proper way to connect converters to headphone amp

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Aj

Well-known member
Joined
Aug 18, 2005
Messages
63
Location
Greater Ann Arbor, MI, USA
Ok, I hope this is a super-easy question (even though I'm a bit perplexed):

What is the "best" way to connect my balanced converter outs to my unbalanced headphone amp inputs?

I currently use a Rane HC-6 headphone amp, a six-channel unit which nicely enables six different headphone mixes (which is great - I like to give every player their own custom mix).  All the headphone mixes are coming from my Tango 24 converters.  

The problem?  The inputs on the Rane HC-6 are single unbalanced TRS stereo jacks.  The outputs on the Tango are balanced 1/4" mono jacks (so I need to use a PAIR of outputs for each L-R pair).

To make the connection, I've been using standard insert Y-cables - one 1/4" TRS male (headphone amp input) to a pair of 1/4" TS male connectors (converter outputs).  But is this the best way?  It seems like it, but I feel like I'm missing something - is it ok to go from balanced to unbalanced this way?  Is there some sort of custom cable I could build that is better suited for this task?  (And am I missing something, from either a fidelity or noise-protection standpoint, using the insert Y-cables?)

Aj
 
I could be bold and say that if you can't hear any distortion you're probably fine.

The chancey part is that you're grounding the cold side of your converter outputs which might be overloading the op-amp driving that side, if there is no build-out resistor protecting it.

I'm not familiar with the Tango but it would be a pretty poor converter (IMO) that did not have this protection built in. Did it come with a manual? If so, does it say whether the outputs can be run unbalanced?
 
Thanks MagnetoSound.  Here's all the manual says about the outputs on the Tango:

"The Tango24 converter box has 8 analog inputs and 8 analog outputs.  Each can accept balanced 1/4" TRS (tip/ring/sleeve) plugs which have three metal bands for the three wires (hot/cold/ground) in a balanced audio connection, and are physically identical to 1/4" stereo plugs.  Tango24 can also be used with 1/4" mono plugs which have only two metal bands, but this is an unbalanced connection which can pick up more noise than a balanced connection."

(There's also a straightforward bit about changing internal jumpers for +4 or -10 operation.)

As far as distortion goes, all seems well although I have noticed that very low bass instruments (particular upright bass, for example) tend to "fart out" in the headphones (a mild distortion?  it almost sounds like the headphone transducers are buzzing or rattling during very low bass passages - oddly, never during playback but only during monitoring of live tracking.  FYI, I use Sony 7506 phones and have several sets.  They all seem to do this - and upright bass players have complained occasionally).

Mostly, I'm wondering what the "best" way to connect a set-up like this would be.  I'm interested in having a custom multi-channel cable made so that I can get rid of the insert cords, and want to know exactly what to spec out before it's built (standard single TRS stereo unbalanced to dual unbalanced TS mono?).
 
Well, the manual tells you it's OK. They may simply be impedance balanced outputs with no signal drive on the cold side, but either way it seems you have no problem.

As there is clearly no way to physically connect two balanced outputs to each of your headphone amps, the only other way I can think of would be to use a pair of 1:1 transformers and common the cold side of each secondary to ground. Unless you want to fork out money for good iron, with no guaranteed improvement to show for it, you are already doing it the best way because there is no other way.

The Rane is only designed to accept unbalanced inputs. By using TS jacks on the Tango, you are unbalancing the signal to make it appropriate for the Rane to accept, at no detriment to the signal (other than, as the manual points out, the possibility of more noise being picked up by the cable, which is true of any unbalanced line and not generally a problem at line level except for very long runs).

 
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