2. amps-preamps
  3. 1099866598

Problem with line noise from Phono preamp

I'm hoping someone has had experience with this problem and can help me: I've been trying to connect my turntable to my B&K AVP3090 preamp using use an outboard phono preamp. I've tried 2 different outboard phono pre's with the same results - they play ok, but there's a very noticable AC line noise issue.

The 2 units in question are a Rolls VP129 tube phono pre, and a Music Hall MMF Phono Pack. Both units are powered by similar 12V AC power transformer.

My turntable works fine through my Rotel RC1070 (which I sold recently), and when I connect it to the B&K through an old Adcom GFP-1 preamp.

Can anyone help with this? thanks in advance.
bdgregory

Showing 1 response by bdgregory

bdgregory OP
1,724 posts
 
Hifimaniac had the solution. I knew enough to make sure the tone arm ground was secure, but since there's no obvious place to ground the phone pre chassis to the B&K, it just didn't occur to me to ground it. I also assumed that the phono chassis would be properly grounded through the RCA outputs to the B&K.
I connected a jumper from the ground pole on the phono to the ground sleeve on the B&K preamp input (ie the outer part of the RCA). It sounds great now, and much better than playing it through the Adcom.

thanks !!
More to discover