NAD 304 Transformer?

[Glarf]

I have an NAD 304 amp - sounds fantastic and works well, but it's developed an increasingly audible buzz from the transformer, which is annoying in the small, quiet room it's in (it's supposed to supply 'mood music' for paying dinner guests)...

The amp's a bit old, and this problem has developed over time and the buzz from the transformer seems to be slowly getting louder.

When I sent it in for a service, the NAD parts supplier in Australia informed me that the problem is indeed with the transformer ("Ya Ning GTR4. 700. 875"), but that it's no longer in production, and that they can't get me a direct replacement either from Australia or elsewhere within NAD's service network.

Wondering if anyone can help suggest where I might get a replacement transformer for the NAD 304 - either the same transformer or something that'll serve as a good replacement (and is more or less equivalent in size).

I don't know much about electronics or amp circuitry, but replacing the transformer won't be too difficult. Any help anyone can offer is much appreciated!

[sreten]

Hi,

post a photo of the transformer, there are a few
tricks to try, but it depends in the way it is made.

/sreten.

[jaycee]

Measure the voltage of it's outputs. If youre lucky it's a single centre tapped secondary and you can buy a similar transformer anywhere.

[Leolabs]

Actually the secondaries are HxV-LxV-0V-LxV-HxV,they give around 50 something and 30 something after rectification.

[derguteton]

you can find Servicemanual 304 at www.sharefx.com

[AndrewT]

Hi,
is the 304 the model that had selectable voltage to suit either 8ohm or 4ohm load?

If so, it should still be easy to obtain a close replacement to suit the high or low load requirement.

To create an identical two tap version would need some rewinding of the secondaries.

[AKN]

Noise is problably on of the shielding plates surrounding transformer that's vibrating. Try to put one washer between chassie and one of mountings of transformer to twist plates a tiny bit, it may help.

Or buy some plastic spray for use in electronics to fill hollow spaces between plates.

[Glarf]

Lots of responses, looks like I came to the right place. Thanks guys

4fun
Noise is problably on of the shielding plates surrounding transformer that's vibrating.

That's what I began thinking immediately after I posted - really don't know much about electronics so (as lazy as it sounds) I'd prefer to think it's a "mechanical" problem (as so many problems are). Will definitely try this first...

derguteton
you can find Servicemanual 304 at www.sharefx.com

Thanks, downloaded it already!

sreten
post a photo of the transformer, there are a few tricks to try, but it depends in the way it is made.

Will do this - I'll try dampening it first (as per 4fun's suggestion), if that doesn't work I'll pull it out, take a photo and post it here.

Leolabs
Actually the secondaries are HxV-LxV-0V-LxV-HxV,they give around 50 something and 30 something after rectification.

jaycee
Measure the voltage of it's outputs. If youre lucky it's a single centre tapped secondary and you can buy a similar transformer anywhere.

Will read around, see if I can figure out where I should be probing. Apologies, as I said I'm just learning (I realise there's probably a little prior knowledge expected on this forum). Appreciate your help and patience guys!