Hex and mag pickups all out in separate channels

[fatboy250]

Hello All,

So, I’ll give you a little bit of background surrounding my idea.

First off, I am planning to modify one of my current project 5 string basses so that each magnetic jazz pickup (2 total both passive) and the individual string pickups from my piezo bridge (5 total all passive) will run into a Behringer DI800 Phantom Powered 8-Channel DI-Box for all the impedance issues and then into an ART Firetube8 which is an 8 channel A/D converter to get the separate signals into separate channels for my laptop. Each will have its own dedicated channel for a total of 7 channels used. I then plan to run this by firewire 800 into my MacBook Pro which is running Logic 8.

What I’m concerned with is cable length or wiring length however you want to view it. Each “pickup” will stay passive and essentially run from the bass to the 8 channel DI (approximately 10-15 ft.). What I plan to use is a standard 13 pin plug and wiring similar to that used with synth guitar stuff. I will of course have to modify one end of the plug so that it will mate with the DI inputs. So, I will be sending a passive signal and assigning specific pins to each dedicated channel….not sure how I should ground each yet, maybe you could give me your thoughts.

Will I run into signal degradation or some other problem that you can think at this 10-15 ft distance run before I get it into the 8 channel DI if I go this route? I'm hoping to stay passive and not have to run a preamp.

Also, will the 13 pin wire gauge be sufficient to carry the signal for 15ft?

As a side note, I found the Behringer DI800 Phantom Powered 8-Channel DI-Box. It has a 1 M ohm input impedance and 680 ohm output. This should take care of all the guitar impedance and then bring it down to where it should be for the A/D converter. The Tubefire8 has mic input impedance at 6.4K ohm and line input impedance at 20 K ohm.

So if I understand impedance correctly, as long as the source impedance is less than the input level of the destination then I should be good, RIGHT? For example, "680 ohm < 6.4k ohms". If I’m not understanding this correctly please let me know.

So, if this is the case should I even bother with the line inputs at 20 K ohm? I should be fine with the 6.4K ohm mic inputs, correct?

Also, how does phatom power come into play. Could this be of some use in this application?

Any input on any of this would be greatly appreciated.

Thanks,
Jason