Class AB transformer Hum - Replacement Options?

[OldDIY]

Check the # 1 primary wiring diagram.
Tighten the nuts on the threaded rods.

 

[Vrystaat]

Some slight other benefits though .............. 🙄😛

and that would NOT be smokes or booze !😀

 

[mjona]

Looking at my transformer very closely, I actually suspect someone has had a go at this before. There was a varnish over the transformer that I've not seen on all the transformer windings we usually deal with. I could be wrong, of course. But anyway, it doesn't change the result, I haven't had any success.

I have a C-Core transformer going for free to a good home. This one runs dead silent with an ear an inch or so from the core with no load. It is quieter than any toroid I have used.

I bought this for a 1980s high power stereo amplifier of 200W into 8R that never got built - it does not figure in my future plans. The magazine projects specified EI transformers and this item was an upgraded specification.

The item weighs 7.4kg and re available space has dimensions of 19.5cm (L)14.5cm (W) 10.5cm (H).

The secondary ac voltages are 49.3 each which will give lower dc rail voltages and less power than your present EI.
There is another set of secondaries for line level use.

If appearances are important then the item could do with some sprucing up with the masking and black electrical tape (cosmetics in both cases).

PM me if you are interested.

 

[Mainframe]

^^That's an awesome offer thankyou mjona - however my electronics knowledge is comparable to that of an Ogre - I can figure out what components are what and swap out broke things, but I've no Idea what effect installing a transformer of lower secondary voltage might do, would the amp still run fine just with lower power? In that case, I could be keen (if it fits, will check) and could someone tell me what kind of power I would still have?

I'm already $70 worth of varnish in the hole, and its looking like 270 landed to get that toroid I posted earlier and $370 landed to get the Hypex SMPS. (for US readers, easy to just cut those numbers by 2/3). The remaining varnish will get used though so not all bad.

I've other amps to use meantime, but this ones my favorite. I'm not sure where I'd tap out to get it running quiet.