Can I use integrated as standalone pre and/or amp?

My main system is suffering from a weak left channel, especially noticeable at low volumes. I've ruled out source as the culprit, as the problem exists with both turntable and CD player. I've also checked and double checked to make sure all connections are secure, and even swapped interconnects. With source and interconnects ruled out, that leaves either the amp or preamp.

I don't have another amp or preamp to slot in for the purpose of ruling one or the other out, but I do have a Marantz PM6004 integrated in my secondary system. Can I run my preamplifier into a source input on the integrated, thereby using it as an amplifier? Or, could I possibly use the integrated as a standalone preamp by connecting my amp to the recorder out jacks? (Sorry if these are silly questions.)

If using the integrated won't work, does anyone have a guess as to what might be causing my weak left channel?

My amp is an Odyssey Khartago Extreme, and my pre is a Decware CSP2+.

Thanks for your help.
Rischa, your Marantz PM6004 does not appear to have any pre out/amp in jacks like most integrated amplifiers have, so this probably won't work.

You CANNOT use the recorder out jacks directly into your amplifier, as this will provide full power output, with no volume control to regulate the levels. You may damage your speakers and amplifier (and hearing). You could conceivably run your preamp out into a source input, however, you would still be going through the preamp AND amplifier section of your integrated amp. Therefore, without the proper pre out/amp in jacks, there is no way to isolate the preamp section from the amplifier section of your integrated amp for testing.
Connect the Left output of Decware preamp to Right input on Odyssey amp, and Right of preamp to Left of amp. If your weak channel moves to the right, preamp is the problem. If weak channel stays on the left, amp is the problem.

Also, the Decware preamp has independent output level controls. Have you checked their adjustment?
Also don't rule out the cable running from pre to amp as the culprit. You should be able to narrow it down with simple cable swapping as the above poster mentions.
Thanks for the guidance. I had a feeling this would be the case, but was hoping I was wrong. I appreciate you saving me from blowing my system out!
Brilliant! I'll try it. As for the output level controls, this was one of the first things I checked, along with the input level controls.

Did this. Spent a good hour swapping, rotating, and securing all interconnects yesterday. My wife thought I'd gone off the deep-end.
04-08-13: Rischa
My wife thought I'd gone off the deep-end.

LOL! My wife figured that out years ago. :)
If the problem is in the preamp and if the difference in level between the two channels gets worse the lower you go I'd suspect that your volume pot is not tracking very evenly at low levels.
OK, did as Tls49 suggested; switched the L & R channels from pre to amp. The weak channel moved to the right! Guess I'll be packing up the Decware and sipping it off for repair. What a PITA.
Thanks for everyone's help on this.

Rischa, It could be something as simple as one of the tubes. The front signal tube (directly behind the volume control) is common to both channels, but the next two could be swapped (unit turned off and some time to cool) since the left one is left channel and right one is right channel. Again, if the problem moves, it's that left channel tube. The rectifier tube is also common to both channels.

You will need to call Decware to return unit for service, so why not talk with them.
Forgot to mention in the first post that I also rotated the tubes, but it didn't help. I'll have to call Decware. Decware offers a lifetime warranty, which is great, but I was hoping not to have to ship it in for repairs as they charge 100 bucks to pack it up and ship it back once they've fixed it. All well, that's life I guess.