Loud turntable buzz since receiver replaced.

I am transferring vinyl (source is a Music Hall MMF 1.0 with Grado Elan cartridge)to CD (Marantz DR4160 cd recorder/player) and have encountered a loud buzz that "seems" to have started when I replaced the notoriously unreliable Marantz 7200 AV receiver with an Onkyo TX-SR700 AV receiver. The primary difference between the Marantz and the Onkyo is that the Onkyo has a built in phono preamp and the Marantz did not. The signal from the turntable is split and fed directly to the Onkyo receiver and also fed to the Marantz CD recorder via a Creek 8.0 phono preamp (previously, the signal was split after the preamp). The loud buzz shows up in both the receiver output and on the recorded CD. I spoke to the folks at Audio Advisor (where I bought the turntable) and they say that they have never heard of a cartridge developing a loud buzz unless the cartridge wires had been damaged, etc. The turntable has never been physically moved since I first intalled it two years ago. Any ideas?
Sounds like it may be a grounding problem. Plus connecting a turntable to two phono preamps simultaneously (which it sounds like you're doing) could cause an impedance mismatch. The cartidge only expects to be connected to a single phono preamp, so as to see a 47kohm input impedance.

Here's how I would connect it:
TT->creek->CD recorder IN
CD recorder out->onkyo receiver CD in.
Then set the onkyo receiver to CD to monitor the recording.

Or, if you want to hear the turntable directly do this:
TT->creek->CD input on receiver
receiver tapeout -> CD recorder
This may give worse recordings since there's an extra component in the path.