unbalanced guitar signals into balanced interface inputs?

[bassalisk]

Hey,

I have an Apogee Ensemble. There are 4 pre-amps on channels 1-4 and I'm trying to send a guitar signal into each. Channels 1 and 2 have hi-z unbalanced ins on the front panel... perfect.

3 and 4 have hi-z ins but they are TRS connectors according the manual... is there any danger or disadvantage in plugging a TS guitar cable right into the TRS inputs?


Thank you..

[Snarl 12/8]

My understanding (and experience) is that balanced ins (and outs) kindof "fail gracefully" if you plug in a TS (unbalanced) cable. You lose 6 db's of level, but not much else on short cable runs.

Try it, if it sounds good, it is good.

[bassalisk]

Thanks Carl

[farview]

Most of the interfaces are balanced in such a way that you don't lose 6db. The only danger is an impedance mismatch, but if the guitar sounds good, it is good.

[The Scum]

Actually, you don't lose 6 dB in this situation - if the source is unbalanced, you never had them to begin with.

It might help to know what Apogee mean by "Hi-Z"...in general you'd want something like a MegaOhm for an instrument input. Apogee lose a couple credibility points in my book, because I can't seem to find anything resembling engineering specs for the Ensemble on their website. For a company that thrives on it's high performance reputation, you'd think they'd be more forthcoming about things like frequency response, THD and input impedance.

Anyways, with passive guitars, you might find that they're kinda thin sounding if the input impedance is too low.

With active pickups, there probably won't be much difference.

[audioboffin]

Typical Fender input schematics show a pair of 34 k resistors with a 1 meg resistor to deck, reducing the 1 meg input impedance of the following stage in order to control vulnerability to noise. From memory a strat single coil pickup is around 6.8k. If you want an ideal impedance match to that pickup then an input impedance in the realm of 68k to 100k should give a nice balance between bandwidth, dynamics and immunity from high impedance related noise when using decent short shielded cable. Another line of thought is that 1 meg is needed to match the pair of 500k volume pots in say a Les Paul.

Many so called "instrument inputs" are 10k input impedance and as such might load down vulnerable high impedance guitar pickups. Those 10k inputs are a better match for devices with active outputs such as synths and guitars with active onboard preamps etc. If in doubt use a decent DI box patched into a mic input and compare the sonic differences.

[Andy Peters]

3 and 4 have hi-z ins but they are TRS connectors according the manual... is there any danger or disadvantage in plugging a TS guitar cable right into the TRS inputs?

Use a direct box.

-a

[drumsound]

3 and 4 have hi-z ins but they are TRS connectors according the manual... is there any danger or disadvantage in plugging a TS guitar cable right into the TRS inputs?

Use a direct box.

-a

This.

[Bill @ Irie Lab]

A favorite pedal can make a good "go-between", trust your ears in all things great and small.