Help! Catching A Buzz!

Gulfstrings

With all components powered up I have a buzz coming from both front and the middle speakers. The buzz does not react to volume changes and I don't hear it in the surrounds.

I was thinking that it was a problem in the amp (NAD T955) but Saturday I switched the receiver's (Onkyo 707) center spkr preout cable from the channel 3 input on the NAD to channel 5 input and the buzz followed to that spkr.

I then changed out the cable between the receiver's center out and the amp's channel 3 in ... no effect. Still had the buzz.

Sometimes the buzz is a bit lounder than other times, either way, it's p'n me off that I can't find the source.

Any and all help appreciated.

Thanks,

Dave

Speedskater

Standard trouble shooting procedure is to start as simple as possible and add components one at a time.

a] Disconnect all the interconnects and power cords.
b] Connect the amps power cord and speaker wires.
c] Use a battery powered music source into the amp. Does it hum?
Use a single AC power outlet strip when plugging in more components.
d] Connect your controller's power and the interconnects to the amp. Use a battery powered music source into the controller. Does it hum?
e] Continue adding components one at a time until it starts to hum.

decal

Helping one catch a buzz could turn out to be illegal, or not.smiley_rotflmao.gif

Gulfstrings

'Skater - Appreciate the input but I've no idea how to introduce a battery-powered music source into the amp. I mean the NAD has no other inputs other than the 5 cable inputs from the preamp (in this case the Onkyo receiver's preouts). So don't think that step is possible with my stuff.

I am using a single source power supply, the Panamax.

Re "controller," do you mean the Onkyo? I actually kind of suspect it to be the culprit since it's sending that center speaker signal to the amp - but then why would the two fronts also buzz? (I ask myself)

At this point I'm starting to think that because the "buzz" is a buzz. Seemingly fixed and unaffected by volume adjustments. Not a hum (oh how I wish it were a hum only) and kind of intermitant, the issue must be in the power amplifier.

I have one more troubleshooting step to take - maybe tonite, that is connecting the center speaker directly to the Onkyo's center spkr terminals - not using the amp, and seeing if the buzz is present.

If so, I think I have a source problem. If not, it likely resides in the amp.

Opinions on this idea?

Speedskater

As for a battery powered music source, looking around my house I see a little old CD player, an Ipod and a Clip (anything with an analog output or a headphone output. Get a suitable adapter interconnect cord and you can test two channels at a time.

Yes the Onkyo is what I called a controller. I think of a receiver as having a speaker power amplifier output.

Gulfstrings

NAD's going to the shop. Will post results ...

Gulfstrings

NAD back from the shop. Turns out the #4 amp is shot. That's the 2nd time an amp has blown and the first time a component I've owned has had a failure.

It's being replaced. I can't believe all NAD products have these issues (my NAD is a T955) but my little hunk of 'bullet-proof' archetecture has really disappointed - and cost over $1500 in repairs (NAD paid for the 1st).

I enjoyed the NAD and felt it did what it was asked to do but enough is enough.

chumlie

That sucks. Did you try contacting NAD again about repeat problems ?

Msabot1

Speaks close to a external power source?

Geoff4rfc

Sorry to hear about your amp, not to mention the hefty repair cost, ouch! I've decided to catch a buzz myself!

ken brydson

[QUOTE=Geoff4rfc;1856305}I've decided to catch a buzz myself![/QUOTE]

Beat you there brother...

Gulfstrings

chumlie -

My wife also suggested I contact their US rep and tell him about these issues and agree you both are giving good advice. Will call after holidays.

Gulfstrings

Msabot1 -

Don't think that's a problem.. The amp that went this time was powering a rear surround. The first to go was powering the right front ... at least 6 ft from the Panamax.

I 'grilled' the tech at Pro Audio (warranty shop in Tampa) as to what I could have done to cause these problems and he couldn't see that anything was wrong in the system or its setup.

I used Antec coolers on top of both the NAD and Onkyo. When this happened last year I took temperatures (via infrared) from the tops of both and forwarded that info to the respective companies. Both said I was within recommended operating temps.

Gulfstrings

Some good news! Following my wife's (and chumlie's) good advice, I found my way to an engineer/customer service type guy at NAD (Lenbrook America) and went over the issues I've had with this amp, the T955. Like everyone else, he was surprised that I have had problems and cited the old 'bullet proof' refrain.

After a short chat he put me on hold and returned with a very livable solution: Even though the unit is 5 months out of warranty, they will share the repair costs with me, my part being the shop labor.

I (and the shop) received via email a warranty authorization memo and I'll be taking the T955 over to Tampa in the morning to be repaired.

Have to say that's about as fair as anyone could ask for.

Thank you, NAD.

ErasmusBDragon

Speedskater wrote: »

Standard trouble shooting procedure is to start as simple as possible and add components one at a time.

a] Disconnect all the interconnects and power cords.
b] Connect the amps power cord and speaker wires.
c] Use a battery powered music source into the amp. Does it hum?
Use a single AC power outlet strip when plugging in more components.
d] Connect your controller's power and the interconnects to the amp. Use a battery powered music source into the controller. Does it hum?
e] Continue adding components one at a time until it starts to hum.

nice post, thanks

Souzad

thanks for sharing this post here it is much helpful for the new users on this forum......