Ekco Radio.

[Murphyv310]

Thanks Brian & Jeremy.
Both valid points. The Ekco transformer is unlike others, designed round the set it would appear, I'll try the RC coupling first and see how the set performs, perhaps a rewind might be on the cards though

[Brianc]

Hi Trevor
The construction of the transformer suggests that the primary and secondary are wound in separate sections on the bobbin (or even separate bobbins). That would, of course, make rewinding much easier however, these old audio transformers normally have loads of turns of very fine wire - hence the highish failure rate. Let's hope that the R/C coupling works well enough.

[Murphyv310]

Hi Brian.
I'm going to give it a go later when David Boynes is here, got to have a play with some proper electronics when he's here
Looking forward to this weekend.

[Murphyv310]

Hi.
I’ve now completed the work on the set.
I will post some pictures on the forum tomorrow as I've only managed to take one this evening.
I discretely added RC coupling to the output stage and also added suitable series resistance to the rectifier after I discovered the "new" selenium rectifer was duff.
The performance and audio output is more than adequate so the RC coupling will stay.
More pics tomorrow.

   
   

[radioman]

Hi Trevor,
I'm glad that the RC coupling worked out ok, much easier than rewinding the transformer !
It certainly is a very nice looking set.

Andy

[Aerodyne]

I931 or 1932, an interesting TRF. I restored one a few years back - https://www.youtube.com/watch?v=p6vufuWHBd8
and as I recall, the interstage transformer was OC too. Obviously a common problem, very fine wire. I used either R/C coupling or I might have used the intact winding on the transformer in choke-capacity mode.
Set shouldn't be confused with the externally identical RS2, which uses a cone dynamic loudspeaker (not OPT) and somewhat different circuitry. The M23 came about because of the loss of design plans due to a severe fire at the Ekco works, which put the production of a replacement for the RS2 on hold, so the same cabinet moulds were used but with the updated chassis.
I once possessed an RS2. Because they are now scarce, they do find a better market than the more common M23 amongst collectors. Having a very sensitive cone LS, the RS2 versions work very well indeed, other than a loss of overall sound quality. Reaction helps, of course.
Very nice restoration, Trevor.
Tony