Hi guys I have an unknown radio its a family friends and they would like me to get it cleaned up and going for them but I'm not sure what is it any ideas piks below and its missing a valve

http://i246.photobucket.com/albums/gg83/blingbling_2008/P1050128.jpg

http://i246.photobucket.com/albums/gg83/blingbling_2008/P1050129.jpg.

http://i246.photobucket.com/albums/gg83/blingbling_2008/P1050130.jpg.

http://i246.photobucket.com/albums/gg83/blingbling_2008/P1050131.jpg.

A challenge would be part of the answer.

Early twenties with those valves & if the transformer is original AWA

It may pay to carefully remove them & see if they have numbers like R1 as a clue.

Marc

Going by the construction of the large transformer and the bends and brackets on the chassis, is this possibly a home made set?

Closest I found by cabinet design..very close to early Stromberg Carlson, chassis unknown... I would say a bitsa!!

Would agree with the Bitsa. The valves appear to be of early construction, hence request for number.

The AWA transformer seems to be a misfit and the chassis does not look "commercial".

Marc

Definitely a re-fit Marc, It seems the original chassis has been discarded at some stage for unknown reasons...burnout maybe? and have recreated their own make although not that good, commercial it isnt....notice the screen grid (excutcheon) is out of allignment from the front view and their appears to be no provision for a speaker...which leads me to believe a external was used?
I see on photo 3 underneath the chassis, maybe this is the remains of what was a speaker?
until we hear from blingbling for further information, then it just remains guess work

Bryan

I would suggest that there is insufficient room for a speaker in that cabinet.

That is a 1920's type speaker surround and would have sat on top. Whist it is difficult to tell from the debris; I would predict that that is a pre- "Rice Kellogg" (1928) speaker and was of the moving reed (rocking armature) type.

Rice Kellogg was the first moving coil and I have actually handled one and heard it running (after I fixed the set).

I would note that some manufacturers were "rough" so I do not reject commercial. I am feeling that there is someing American about it.

Marc

Moving armature speakers were mounted horizontally in some early radios eg an early Philips radio that I cannot immediately give a modlel name or number. Perhaps this was the same.

The cabinets blocks appear to have been re-glued carelessly.

I see no evidence of the speaker being mounted within the cabinet and would think it odd to put a neat Escutcheon underneath for the cat & mice to look at.

Homemade regenerative set using first generation of AC valves. Ca. 1929/1930. Even the power transformer is homemade.
Looking at it, the design appears to be the usual 3 valve job with a grid leak detector feeding the output valve via the AWA interstage transformer.
That there are only two windings on the aerial coil is interesting. With a circuit like this there should be three, unless the aerial is fed into the grid winding via a low value condenser, thus dispensing with the aerial winding.
One would assume by looking at the number of turns that the lower winding is for feedback, whilst the upper is obviously the grid winding.

The valves look to be the usual American types, from what I can see of them. Typical types would be 24,27 or 56 for the detector and 45 or 47 for the output. The output valve would most likely use back bias. Rectifier would be an 80. It's old enough to use paper condensers for the filtering (usually 4 or 8uF), rather than wet electrolytics. However, that's all general assumptions without actually being able to see the details of above and under the chassis.
The valve shield shown was never intended to be used like that.
I presume the rectifier goes behind the power transformer or perhaps it goes in the empty valve socket behind the interstage transformer.
The mess at the bottom looks like the remnants of a late 20's magnetic cone speaker. As this has a high impedance voice coil it doesn't need a speaker transformer.

Keep in mind that it was possible to buy blank commercially made cabinets up until the 1950's, so one should not automatically assume there was once another chassis inside it.

I don't find two windings unusual. I have repaired a couple of sets of late where they only had on winding for tuning & the other for regeneration.

I have not seen 27 as an S17 it is a heater tube, the only ones of those I have handled were in a (1929) Lyric 70 series and they were ST. The valves in this appear to be circa 1925 as they are S17 Bulbs. probably UX-201-A.

I have asked for numbers so as to confirm what they really are & predict what is missing. They could actually be Phillps A series? We can only guess.

The Electrolytic is unpredictable I have a 1936 Bandmaster (9 valve superhet) on the bench and it was built with Non polarised papers on the HT rail.

The speaker could be RCA and I think the correct term is "balanced armature" & these were sold well into the thirties.

Marc

I would have thought the chunky transformer on the side of the chassis was a mains power transformer. If so then valves like UX201 and Philips A series are totally unsuitable as these are directly heated battery valves.
The pin style visible on the shielded valve is of the American UX type. Given the valve closest to the tuning coil has no top cap, type 27or 56 is quite likely.

I wouldn't take too much notice of envelope shapes; it's the type number and base that counts. 24's and the like were made into the G era, and the 80 came out with a GT envelope in the 50's.

AC valves did not appear until the late 20's. Early attempts at getting valves to work with AC on their heaters involved thick filaments drawing high current. The idea being the thermal inertia would carry on emitting electrons as the heater voltage rises and falls over the 20mS mains cycle.
This technique was used in a number of output valves such as the 45. For detector and low level audio use this method still wasn't good enough and so the indirectly heated cathode was developed. 27 was the first of the American series, used as a detector, and later as the local oscillator for first generation mains powered superhets.

The Lyric (TRF) used two 27's and the 26's, 80 and 50 filament tubes were all run on AC... No hum.

We do need more info on this thing. Perhaps more photo's of the speaker remains only and a top & bottom shot of the pan.