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Old 14th Oct 2018, 11:06 pm   #21
julie_m
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Default Re: What is this 1930s Cabinet Radio?

Sets of that age can have some very interesting designs. The "experimental" age of the 1920s was over. Radios were evolving to look less like slightly-scary laboratory instruments that were the preserve of the eccentric scientist, and more like something that rightly belonged in a "normal person's" home -- but nobody yet had an idea of exactly what a radio receiver "should" look like.
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Old 15th Oct 2018, 12:09 pm   #22
D.Finney
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Default Re: What is this 1930s Cabinet Radio?

I think it has something of an Ultra look about it.
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Old 15th Oct 2018, 1:33 pm   #23
unclemanly
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Default Re: What is this 1930s Cabinet Radio?

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Originally Posted by PJL View Post
Very strange to go to all the effort of building the cabinet, fitting a large speaker, and then only putting in a basic 2 valve radio. Not surprised the company went bankrupt.
Its actually a 3 valve radio (plus rectifier) so not as primitive as it looks!
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Old 15th Oct 2018, 1:50 pm   #24
60136 Alcazar
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Default Re: What is this 1930s Cabinet Radio?

The tuning dial is clearly pre-1935, and the radio section valves are of the earlier balloon shape rather than the shouldered shape which was introduced in 1933 (although they were available long after). I would be suspicious of the MU14 rectifier, as this is a high heater current + high DC output (120 mA) device - the two radio valves would have required no more than 50 to 60 mA, and it is possible that this rectifier valve was a handy replacement for an earlier one with lower output. Critically,though, at 2.5 A heater current, this may be overloading the mains transformer, since early 30s rectifiers operated with 4 volt 1 amp heaters. Pick-up sockets were fitted to some radios from the late 1920s so the set must lie within the period 1929 to 1934; knowledge of the valve line-up would help with the date. The post about Smith's clocks would suggest 1931 to 1933 as the period, whilst the dial appears to be calibrated not in degrees but in metres, suggesting 1932 - 1933 as the probable date.
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Old 15th Oct 2018, 7:57 pm   #25
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Default Re: What is this 1930s Cabinet Radio?

I've taken the back off again and snapped a couple of pictures. Sorry about the picture quality, it was dark. The valve with the red wire attached is a Mazda AC/SG. The green wire goes to a Mazda AC/PEN. The valve with the grey coating isn't marked at all. The dial is calibrated in metres.

Now you've got me worried about the MU14. If its the wrong type, what should the rectifier be?
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Old 16th Oct 2018, 3:01 pm   #26
60136 Alcazar
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Default Re: What is this 1930s Cabinet Radio?

These are all B5 based valves, which further supports the pre-1933 date since the B7 base was introduced from 1933 for new developments. The unmarked valve is most probably a triode (it looks like a Marconi MH4). Given the presence of the AC/SG and AC/PEN (both Mazda B5 based with side contact), this may originally have been an AC/HL, but set makers in the 30s did not always use a single valve manufacturer in their line-ups.Total HT current would therefore be around 42 mA. All the heaters are rated at 4 volts, 1 amp. The original rectifier could be expected to have a similar heater rating, and be capable of delivering 60 mA, so, on the assumption that indirect heating was a requirement (to limit the charging rate for the smoothing capacitors), a Mazda UU2 (equivalent to Brimar R1 and Ever-Ready S11A) should fit the bill. The only proviso is the measured AC voltage being applied to the anodes, which for these valves should be 250V AC or less. If more than this and less than 350V AC, then a more modern rectifier would be needed.

High current rectifiers were introduced in 1933, so it may just be that an MU12, IW3 (later IW4/350), or A11B was indeed fitted to the PSU as it may have had other applications besides this radio. Although frequently regarded as equivalent to the MU12, and sometimes marked as MU12/14, the MU14 will deliver higher voltage at higher current than the MU12. Pre-war higher efficiency specimens were extracted from the production batch and marked MU14, whilst the less efficient ones were marked MU12. Much later production saw them marked MU12/14.
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Old 16th Oct 2018, 9:09 pm   #27
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Default Re: What is this 1930s Cabinet Radio?

The picture in post 25 of the clock face is interesting as very few clocks I've encountered used that unorthodox typeface and arrangement of numerals.

Barrie Smith's book has a picture of an identical face & bezel, on a single model called the "Bath", which Barrie states was only listed in the 1933 catalogues.

HTH,
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Old 17th Oct 2018, 9:24 am   #28
unclemanly
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Default Re: What is this 1930s Cabinet Radio?

Quote:
Originally Posted by 60136 Alcazar View Post
These are all B5 based valves, which further supports the pre-1933 date since the B7 base was introduced from 1933 for new developments. The unmarked valve is most probably a triode (it looks like a Marconi MH4). Given the presence of the AC/SG and AC/PEN (both Mazda B5 based with side contact), this may originally have been an AC/HL, but set makers in the 30s did not always use a single valve manufacturer in their line-ups.Total HT current would therefore be around 42 mA. All the heaters are rated at 4 volts, 1 amp. The original rectifier could be expected to have a similar heater rating, and be capable of delivering 60 mA, so, on the assumption that indirect heating was a requirement (to limit the charging rate for the smoothing capacitors), a Mazda UU2 (equivalent to Brimar R1 and Ever-Ready S11A) should fit the bill. The only proviso is the measured AC voltage being applied to the anodes, which for these valves should be 250V AC or less. If more than this and less than 350V AC, then a more modern rectifier would be needed.

High current rectifiers were introduced in 1933, so it may just be that an MU12, IW3 (later IW4/350), or A11B was indeed fitted to the PSU as it may have had other applications besides this radio. Although frequently regarded as equivalent to the MU12, and sometimes marked as MU12/14, the MU14 will deliver higher voltage at higher current than the MU12. Pre-war higher efficiency specimens were extracted from the production batch and marked MU14, whilst the less efficient ones were marked MU12. Much later production saw them marked MU12/14.
Thanks for that info. The power supply and the radio chassis look to be much of a piece with each other so I doubt the power supply was some general purpose unit. In that case I'd better keep an eye out for a UU2 rectifier.
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Old 17th Oct 2018, 9:26 am   #29
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Default Re: What is this 1930s Cabinet Radio?

Quote:
Originally Posted by Nickthedentist View Post
The picture in post 25 of the clock face is interesting as very few clocks I've encountered used that unorthodox typeface and arrangement of numerals.

Barrie Smith's book has a picture of an identical face & bezel, on a single model called the "Bath", which Barrie states was only listed in the 1933 catalogues.
Thank Nick. Its starting to look like 1933 for a production date.
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Old 17th Oct 2018, 10:06 am   #30
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Default Re: What is this 1930s Cabinet Radio?

A most interesting find and I would not be able to wait and get it running.
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Old 17th Oct 2018, 10:14 am   #31
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Default Re: What is this 1930s Cabinet Radio?

Yes, genuinely rare.

You look like you have the right kind of decor to accomodate it somewhere
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Old 17th Oct 2018, 10:49 am   #32
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Default Re: What is this 1930s Cabinet Radio?

It's actually growing on me, with the door shut you wouldn't know it's a radio too.
The interesting speaker position in the cabinet would give it a very good bass reprocess but not much treble.
I would imagine with the radio on an unexpecting person would be puzzled to know where the soft / deep sound would be coming from.
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Old 17th Oct 2018, 8:38 pm   #33
unclemanly
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Originally Posted by Nickthedentist View Post
Yes, genuinely rare.

You look like you have the right kind of decor to accomodate it somewhere
Well actually I've had it for twenty years and I'm finding we dont really have a huge amount of space for it these days and it might have to go. Sounds daft after finding out more about it in the last few days, but I've never quite got round to investigating it before now.
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