VFT-3R Humming

[Richard E. Root]

I have a VFT-3R hooked up to a Yamaha RX-V2400 with Axiom 22ti main speakers. I am using a NEC MP2 Plasma for the monitor. When the monitor is on and it is receiving a video signal from my VCR, DVD, or Receiver the VFT-3R gives off a low level hum. I have added the cheater plugs to all components - no change. The automatic calibration on the Yamaha has set the crossover frequency at 100 Hz. When I set the variable crossover switch on the back of the VFT-3R to "in", the hum is gone.

Has anyone experienced a similiar problem? Do I lose anything by having the both crossover circuits working? Does this indicate a problem with the VFT-3R in this application?

Thanks for your help.

[Dudley]

As long as the internal crossover is set higher than the external (your receiver) that should work fine.

[Sasha_G]

Having the VTF-3R crossover set to IN will not cause problems, as in most cases people would not notice the small gap (the gap is between where the 90 Hz maximum of the subwoofer and the 100 Hz min of the receiver). Its better not to have the sub play up to 100 Hz anyhow. It would be a little better if your receiver had a lower crossover point, say 80 Hz.

Sounds to me like you have some sort of electrical noise, perhaps some sort of ground loop. Tracking down humming can be very difficult. They issues are complex, and often the hum be carried along cable tv, direct tv coax cables all the way to the system, and then are transmitted on interconnects. One way to tackle this is to unplug various components, starting with cable tv or direct tv. If the humming goes away, you've found the culprit and a ground loop remover can be purchased at Radio Shack and plugged into the offending input cable.

[Richard E. Root]

Currently I have the Yamaha RX-V2400 isolated. It is only connected to a CD player and speakers. I am using a cheater plug on the power cord for both the receiver and VFT-3R. When I play music the VFT-3R works great

I also have the TV monitor isolated. The only thing hooked up to the TV is a DVD player (on a cheater plug and no cable connection.

I have moved the VFT-3R as far away form the monitor as possible (can not remain in this location for the final setup).

When I turn the monitor on there is a slight hum in the VFT-3R with the crossover switch in the "out" position. This level of noise would be acceptable. When I turn the DVD player on so that there is a video signal going to the monitor, the loudness of the hum increases to a non acceptable level. The level of the humming is less with the increased distance of the VFT-3R from the monitor.

I don't believe that this is a ground loop problem, but I don't know for sure. If I had to guess, the problem is caused by a signal coming from the monitor over the air that is picked up by the VFT-3R amplifier. However, I am quite new to this kind of system and this is only a wild guess.

Is anyone else using a VFT-3R with a 50" NEC Plasma Monitor?

[cschang]

Have you tried changing the RCA cable to the sub? Might be getting some interference from the TV.