DVD/Cable Howl

[Regis]

Hope any of you can help with my howling (besides shielding myself from moonlight). But seriously. I've got a mixed system of pro and regular home gear with a DVD player and TV. I've got a audio switching box, that allows me to switch from the CD player to the DVD player on the older NAD Pre-Amp. Even with the switch selected to the CD Player, I get an awful feedback type howl from the speakers. So I'm forced to unplug the DVD output from the switching box when listening to the audio.

The DVD, once switched and hooked up plays fine through the speakers, but you have to pull the cable from the TV, so it won't howl! Once you disconnect the cable from the TV, everything is fine. It's running straight into the TV from the outside, so it's not going through the VHS player.

The system consists of a NAD Pre-amp, Carvin 400w amp, Sony DVD, Teac CD and it's hooked up to a mid-90's 32 inch Sharp. The speakers are JBL 4320's. If you make all the accomodations, everything sounds superb. But leave either the DVD or the Cable in unison and it's awful. Any ideas? (Great site BTW!)

[SY]

Is the switchbox connected in the preamp's tape loop? Maybe a quick diagram of the hookup with all input and output cables indicated might help with diagnosis. You can attach it to your post.

Palmdale, huh? I used to do a weekly jazz/record review column for the Antelope Valley Press back when I lived there.