Whoops, make that the right channel, I replugged the spkr wires bkwds



On Tue, 03 Feb 2009 15:45:27 -0500, wrote:

Thanks Tim
I switched to MM and cut the sound down by half or more.
I have confirmed that the sound is only on the left channel, and I
would descibe it not so much as hum as the sound of wind blowing on a
vocal microphone. Anyway........
The other settings you recommended have no real effect, but I have
them where you suggested.

Where from here?

Thanks again.
Gene









On Mon, 02 Feb 2009 12:01:20 GMT, Tim Schwartz
wrote:

wrote:
Hi
I'm not a tech in any way, but before I take this for repair, I want
to make sure it's not a simple connection/hookup issue.

I got this and a Technics turntable on Ebay, and I'm very happy with
them so far. The receiver is hooked up, radio works great, audio from
DVD/TV works great.

When I select Listen/Phono, I get a loud rumble through the speakers,
whether the TT is on or not, and whether it is plugged into the back
of the REC or not.

The noise goes up and down when the volume is turned.

The TT does work and play records, but the rumbling is underneath.

Also, the ( I assume) ground lead from the back of the TT, where does
that get connected?

Good morning,

On the back of your NAD 7150 to the left of the phono input jacks are 3
items that require your attention. On top is a switch marked "MC MM"
to set the phono preamp for Moving Coil or Moving Magnet type
cartridges. Moving Magnet are more common, so that is where I'd try
setting the switch first. Just below that is the ground screw where you
can attach your turntable's ground wire. The lowest item of the 3 is
the phono capacitance switch, which I would leave in the center position
for now.

I suggest moving both of the switches back and forth a few times to
clean up their contacts, as that could be your entire problem. Try the
MM position first. The MC position will give more gain, but overload
more easily. As for the phono capacitance, I'm not sure what setting to
suggest, as it depends on your cartridge, so try the middle first, and
see how it sounds. You won't hurt anything by trying the other
positions for a sound you like.

The phono stage in this receiver does not use a common op amp, it uses
discrete (separate) transistors, and uses an FET input differential
pair. I'd agree with the other posters that if both channels have the
same problem, then the power supply could be the cause too.

Lastly, there are 3 other switches on the rear of your receiver and I'd
suggest you set the as follows (for normal stereo use):

Bridging: Off

Soft Clipping: On

Speaker Impedance: Normal


Regards,
Tim Schwartz
Bristol Electronics