Another Phono Related Hum Question - Lyra Kleos


Here's the system I am working with:

VPI Aries Table with XLR junction box. Aluminum platter, rim drive and outer ring. Two 10.5i arms with Kleos cartridges on each. 1M XLR run of Cardas Golden Reference to a Jeff Rowland Cadence phono stage with a separate power supply. 4M XLR run of Cardas Golden Reference to a Criterion Preamp. 1.5m XLR of Cardas Golden Reference Speaker Cables to the Classe 600 Monoblocks. Dedicated power lines and very stable and clean power.

Hum has kicked in since I switched to the Kleos and the Criterion. Before that, no hum.

The hum is in one channel primarily (but not entirely), and gets louder with a volume increase. Once the volume is turned above 70 db on the Criterion it becomes audible from the listening chair which is about 8 feet from the speakers. It's not audible while music is playing.

All cables are on elevators and separated from power cords. The Criterion just came back from Jeff Rowland with a clean bill of health.

In trying to isolate the hum, I have checked the tonearm connectors for both cartridges. All appear secure. Switched between the two arms and Kleos cartridges. No difference to the quality, placement or volume of the hum. I have actually switched out another Cadence phono stage and power supply. No difference to the quality, placement or volume of the hum. I also have switched out Cardas cables from the turntable to the phono stage and the cable run from the phono stage to the preamp. No difference.

However, when I reverse the Cardas cables running from the turntable junction box to the Cadence, the hum does change channels. It also changes channels when I reverse the Cardas Cables that run from the Cadence phono stage to the Criterion preamp. There is no change in the channel for the hum when I reverse the speaker cables.

The long run between the phono stage and the preamp jumps out as a possible issue, but then why the switch in channels when I reverse the cables from the turntable to the phono stage. Also, I haven't had the issue before the two Kleos and Criterion additions. I was running a Grado Reference Reference moving magnet though.

Any thoughts from the group?
okonrad
I'd try to ID the channel on the cartridge and swap the clips in case if they're misplaced by manufacturer.