SX-28 Power Transformer

[WA8RVD]

Hello All,
I have a bad power transformer in my SX-28.  The manual says it should have a 580 volt center tapped @ 185 ma secondary. I have found Hammond transformers - one with a 550 v @ 230 ma secondary and one with a 600 v @ 230 ma secondary.  Which would be the better choice?

Mike
WA8RVD

[KM1H]

The lower one as long as it fits. You dont need a high B+ in that radio anyway as there is already excessive gain and I doubt you will be running the audio at full bore.

Plus the higher line voltage today will likely make up for the difference.

Carl

[The Slab Bacon]

Make sure that the 6.3V filament winding has enough BAs to carry all of the tubes. That radio has a pretty serious filament load.

[WA8RVD]

Thanks, Carl
That's what I was thinking but I already made one big mistake yesterday and have lost confidence in my own judgement.  Glad to hear from you - I greatly value your contributions to the forum.
Thanks,
Mike

[WA8RVD]

It is a Hammond;
270HX 115v pri,  550V C.T. @ 230 ma. 5V C.T. @ 3A 6.3V C.T. @ 6A
the SX-28 manual part description is: 580v C.T. @ 185 ma.  5v @ 3A.  6.3 @ 5.5A
So I should be OK and it should fit.

Thanks all

[KB2WIG]

" That radio has a pretty serious filament load."

Ya can always ss the power supply and save 3 amps on the 5z3.  And series up the 5v winding to drop the primary voltage a bit.


klc

[ke7trp]

That sounds like a great transformer for the 28.  While you are at it, Pick up the hammond Audio transformer. It makes one hell of a difference in sound quality.  Its so hi fi you think where listening to an FM station on a Good stereo system.

C

[n1ps]

There are some people who rewind xformers.  This is another option.  I think Gary still offers this:  xfrmrs@roadrunner.com

Peter

[WA8RVD]

If this were the original xfmr I would have it rewound but it was also a replacement.  The new one is less money than a rewind.

[WA8RVD]

UPDATE:
The transformer works well and fit well!
This SX-28 lives again!