Carver CT28v preamp hum issue

michaeljhsda2

When I connect my CD player directly to the Carver TFM 35 amp there is no hum whatsoever, even at full gain (the CD player is powered on but it is not playing) When I put the Carver CT 28v preamp into the chain, hum is heard from the speakers from ¾ to full gain on the amp. My conclusion is that there is definitely a ground loop issue with the preamp. I repeated the same process with a Carver CT 27v preamp and it also hums as well. Would the above device eliminate the hum or should I replace the preamp with another brand that has balanced outputs? Does this device work?

http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=3952333&SRCCODE=CNETFEED&cm_mmc_o=2mHCjC2WHaCjCVqHCjCdwwp

http://www.radioshack.com/pwr/product-reviews/Car/Accessories/Car-A-V-accessories/RadioShack/p/2062214-Ground-Loop-Isolator.html

fbm211

I had a problem like that and ran a grounding wire from the Cd transport chassis to the preamp ground lug and hum gone...

michaeljhsda2

I connected other CD players to the preamp and it still hums. BTW there is nothing else connected to the preamp except the CD player (no cable tv, subwoofer connection,etc). In fact, without any CD player hooked up...it hums.

Systems

A gound loop would cause hum regardless of gain setting.Because of the gain in the pre any noise preceeding it will be amplified especially with the pot fully open.Besides unless your amps input sensitivity is on the low side you probably will not need to set the volume pot beyond 1/2 it's rotation.

michaeljhsda2

GV#27 wrote: »

A gound loop would cause hum regardless of gain setting.The design of that pre likely places the gain stage following the volume pot so any noise preceeding it will be amplified.Besides unless your amps input sensitivity is on the low side you probably will not need to set the volume pot beyond 1/2 it's rotation.

That explains it. Thanks