In a pinch...

http://forums.musicplayer.com/ubbthread ... ced_cable_

I wouldn’t plug a guitar into a mic input. At best the signal will be distorted due to the impedance mismatch, at worst it will destroy the preamp.

SwitchBack wroteI wouldn’t plug a guitar into a mic input. At best the signal will be distorted due to the impedance mismatch, at worst it will destroy the preamp.

But 1-2 front IN are Mic/line/instr. so we always do that.
When I plug an instrument with a TRS/TS I also have to enable the inst. switch so as to go to the preamp and not to the ADC (as far as I understand from the manual)
When quantum feels a jack inside it goes to +4 -10.
When it feels an xlr it goes to preamp (0-100)
I think the risk occurs when you send a stronger signal than weaker.
If I plug the drum (line) to the interface using a xlr i would push the line signal to the preamps instead of adc.
Months ago I missed TRS-TRS cables to connect the drum and I did exactly the above mentioned connection.
The signal was very loud but no damages thanks God (at least for the few days I used that sort of connection)

A combo socket combines an xlr input and a jack input in the same space. But they are still two separate inputs, each with their own properties.

- Mic inputs have low impedance (1 kOhms or so) and high sensitivity (think milliVolts). These are balanced inputs (3 terminals), typically use the xlr part of combo sockets, especially if they have phantom power capability too.
- Instrument inputs have high impedance (1 MOhm or so) and medium sensitivity (think Volts). Instrument inputs are not balanced (2 terminals), have no phantom power, and typically use the jack part on combo’s.
- Line inputs have medium impedance (10 kOhms or so) and the lowest sensitivity of the three (think Volts or up). Line inputs can be balanced, have no phantom power, and typically use the jack part on combo’s.

For a quality connection both the sensitivity and the impedance have to be compatible with the source or it can lead to weak signals, distortion or even damage.

Some interfaces have a switch to toggle the jack part of the combo between line and instrument input function, but the Quantum 2 interfaces don’t have that afaik.

SwitchBack wrote
Some interfaces have a switch to toggle the jack part of the combo between line and instrument input function, but the Quantum 2 interfaces don’t have that afaik.

You mean the inst/line switch??

Yes, that switch on the Quantum (not the Quantum 2). It switches only the jack part of the combo.