Stella 105U - latest restoration

[Joe]

Mine's an ex-REME beast of a thing with a low resistance bridge as well.

[attachment=2023]

[Yorkie]

Thanks Joe and Alan for the info on the strange 4 terminal pot. First one I've ever come across, but obviously several makers adopted this set-up. I wonder if it made any perceptible improvement to sound quality? I guess that the only way to know would be to rewire the pot to exclude the tapping to see what change if any there is to the sound. Had the pot not have been repairable, I'd have had to do that anyway, and to fit a standard 0.47M or 0.5M NOS log pot. I think that Stella was an offshoot of Philips, because the 105U chassis is identical to a Philips model of the same era, (1953), which has a different cabinet.

Night night,

David

[tiv48]

see my post no6 only made difference at low volume gave the impresion of bass boost
rob t

[Yorkie]

see my post no6 only made difference at low volume gave the impresion of bass boost
rob t

Thanks Rob. I read it with interest, but overlooked adding you to the list of acknowledgements. When forum members respond to any queries I post, I try to acknowledge their helpfullness as a small courtesy.

Fast becoming a quaint trait in today's world, and at the rate things are going, before too long it will probably be seen as an eccentricty!


David.

[tiv48]

hopefully courtesy will never make anyone an eccentric
rob t

[Yorkie]

I've finally finished the restoration of this 1953 Stella radio, and I must say that I am very pleased with the sound quality. Though it uses the same valve line-up as the ubiquitous Bush DAC90A of the same era, I think it's a much nicer radio, and while beauty is in the eye of the beholder, I think it looks more attractive than the sombre DAC90A, nor is the circuit as skimped as the DAC90A. For example, it has two thermistors to help the HT rise slowly, and it has a much brighter dial light than the dismal offering that Bush incorporated. I'd mentioned earlier that the dial light is 19V 0.1A which I'd imagined would no longer be obtainable, or at least as scarce as the DAC90A 3.15V 0.15A jobbies, but no - there are plenty available at 75p each. (What an odd voltage - why not 15 or 20?)

There were nine paper caps in all to replace - not 'waxies' but pitch encased, so I yanked those out. I did check the capacitances out of curiousity and all were way over what they should be - some barely functioned as capacitors at all. I replaced them with polyester caps, and in several locations, used the 'Col' wire winder to coil new cap connections to minimise disturbance to other components on for example, valveholder tags. What a very useful little gizmo that has proved to be! I used new polyester caps with the exception of the one filter across the mains, where I used an X class cap. I was pleased that all of the resistors were well within tolerance.

I re-strung the dial, which - as always, requires a high frustration threshold and the patience of a saint. It's a task which I always feel should be outsourced to miscreants who are the subject of community punishment orders. I'm convinced that it would be an effective deterrent from further offending. It's no good letting them loose with jet-washers to clean off graffiti - that's not punishment - it's fun, especially for people like me, deprived of water pistols as a child!

I cleaned the tarnnishd knob brights, buffed them up on a buffer, and gave them two coats of aerosol lacquer.

I'd earlier mentioned that the switch was open circuit, and that I'd dismantled it, cleaned and refitted it, and it works fine. Worth bearing in mind on other sets as pots of the right value and shaft length are becoming a bit difficult to find.

The dual smoothing caps reformed nicely after about 4 hours each on my home-brew reformer and there isn't a trace of hum.

The front and back, although of brown bakelite, are sprayed a light cream, which makes the set look far less sombre than it would otherwise look. A respray was needed, so I masked off the front and back, lightly sanded them to provided a key for the new paint job, gave two coats of white primer, and two coats of antique white, which was the nearest match of light cream I could find, and proved to be a good match.

I had the set on the 220 - 250 V tapping, and the voltages were quite a bit down on the spec even with an NOS UY41 rectifer, but as the set worked well with plenty of volume, rather than put it on the 200 - 220V tapping to up the voltage, I preferred to under-run the HT so that the components and valves aren't overstressed.

The built-in frame arial, which had been a bit knocked about, gives a very good account of itself, with serval continental stations on both long and medium wavebands, mostly Dutch and French.

The set has a built-in carrying handle like many sets of that era, often described as 'transportable' or 'occasional' radios, meaning they were for use for all occasions - in the living room, dining room, kitchen, bedroom and so on. Few householders could afford the luxury of more than one radio, so other took the radio from room to room, or sometimes used extension speakers if the set had provision for such a speaker, as larger sets tended to often have. (Many poorer familes couldn't even afford the deposit to buy one radio back in the late 40s early 50s, let alone buy one or more outright. Hence, the widespread renting of sets from the likes of Radio Rentals).

Forum member 'Old John', who is a chum who lives about 18 miles to the east of me, kindly gave me another 105U to use for spares if need be. It isn't complete, and there is damage to internal Bakelite mounting studs, but I'm so impressed with these sets that I have in mind to restore it over time. I'm indebted to John for his kindness.

Hope that's of interest.

David

[tiv48]

a first class restotation and you wire wrap joints look super
rob t

[AlanBeckett]

I'm always amazed when I look under the chassis of these simple sets, and I inclde my Pyes in that comment, how little there is in them. However, even the short ones generally work really well.
Alan