WOW. what is happening with this setup?

[brevity1]

Just to play, I plugged my Dual into my receiver. It doesn't have a strobe, so my tuning method is crude: I put on a record and the same CD and played them in sync, and switched between them to set the speed.

This was the first time in a while I plugged in this turntable into my system... the last time I had speaker grille over the speakers, so if this was happening, I didn't see it.

I noticed when I was switched to the turntable, the midrange cone started going nuts. NUTS. It looked like it was going to pop out of the cabinet. I'd switch back to the CD (which sounded much louder) and it returned to normal.

What the heck is happening????

[kelsci]

Do you have the ground wire of the turntable hooked up to the ground terminal of the receiver? Check your right and left wires going into the receiver form the turntable to see if they are tight. Is this happening on both speakers or just one. If it is just one, one of your wires on your turntable may have a bad connection. That can ususally be the phono plug(s) themselves.

[basite]

midrange?

do you have woofers too? or is it a 2 way bookshelf unit with just a tweeter and a mid/woofer?

what you see is rumble. Common with turntables. rumbling is caused by vibrations picked up by the cartridge, and then amplified and sent through your speakers. They are, as a matter of fact, very low frequency tones.

one can avoid (or minimize) rumbling by: isolating the turntable,
and making sure the cartridge makes a good match with the tonearm.
and of course, correctly setting up the tt...

so, worst case scenario would look like this:
completely mismatched cart on tonearm (like low compliance on low mass tonearm, or really high compliance on high mass tonearm), with the turntable placed on the speakers...

how to solve:
get a different cartridge (well, or another tt, that does match), and isolate that tt, best option is to wallmount it on a shelf.

if you can't isolate your tt well enough to please you, there are some phonostages that include subsonic filters (or rumble filters), these will solve your problem too, but it kills the sound in a way...

oh, and be sure to plug in your tt to the PHONO input on your receiver...


Keep them spinning,
Bert.

[kelsci]

Basite's comments are also another possibility.