How does splitting a signal in a patchbay affect the signal?

[heavi5ide]

Hey y'all. Here's my scenario: I've been using a Digimax FS 8-channel preamp/converter as my converters for awhile, feeding into the ADAT input of an M-audio box (the Projectmix i/o interface/control surface). When recording most overdubs, specifically vocals, I normally run the output of my preamp (say, an SCA N72) into a line input of the Digimax, and then take the direct output from that Digimax channel, feed it into a compressor, and run the output of the compressor into another Digimax line input. So in my DAW I have the raw, uncompressed signal, and then also the compressed signal. Sometimes I record both for blending later, and sometimes I just record the raw track and use the compressed track for monitoring -- I feel that monitoring a compressed vocal helps the vocalist hear all of the details in their voice (tails of words, breaths, etc), and gives it an inspiring "larger than life" sound in the phones while tracking.

Anyway, I recently upgraded a bunch of equipment, and now have an RME ADI-8 DS as my 8-channel lightpipe converter. This unit doesn't have any direct outputs for its input channels, so I can't take a copy of the mic signal to run it to the compressor from here like I do with the Digimax. I've also added a couple of Neutrik TRS patchbays (yes, the cheap Chinese-built ones), and have the mic preamp outputs half-normalled into the converter inputs. Now I can take a copy of the preamp output at the patchbay by plugging a patch cable into the preamp output jack on the patchbay; because it's half-normalled the signal still goes to the converter as well. So that's good, but I noticed the input level to the converter dropped when I split the signal at the patchbay, and so I'm wondering how else this is affecting my input signal. I'm guessing since the patchbay is completely passive, splitting the signal at the patchbay is really just like using a Y-cable to split the signal, so am I screwing up my converter input by taking this split signal into a compressor? Like, does the impedance change because I have the output of the preamp plugged into two inputs? Just wondering if there's some better way to do this. I never noticed an input level drop when I plugged into the direct outputs of the Digimax FS - does that mean that those direct outputs are actively amplified and not just "passed-through" copies of the input signals?

Sorry if my question is confusing. I think I know more about electrical jargon than I actually do. =) Basically, I'm wondering why the level drops when I split the signal (I have an idea on that I guess), and whether any of the really experienced engineers can point out any other issues this splitting might cause (like introducing unwanted noise or artifacts into the raw uncompressed input into the converter). Thanks for any help!

Nick