Vintage radio - identification help needed

[3delta2lb]

I have just acquired this rather large (guessing about 16" x 16" x 8") 5-valve vintage TRF RX. The construction is in two parts (i) a row of five B4 valve holders + RC compoents, visible at the rear and separated by a plywood panel from (ii) the main components (inc. interstage and output transformers). There is a large rod-driven paper-cone loudspeaker.Internal construction is clearly "home-brew" and wiiring of anm extremely poor standard...at first glance, components are mixed U.K. but the valves are Austrian...
Top-panel controls are a SHORT (?)/LONG wave switch + two small mica dielectric variable capacitors. The only coils are two physically separated frame-aerial type the size of the inside of the box. I haven't had time to attempt any kind of circuit analysis so cannot even say if it is a regenerative circuit (tapped "frame-aerial " coils?).
I am rather hoping someone on the forum will perhaps recognise this type of 5-valve set as a published home-brew (perhaps partially in kit-form), and even more hopefully, might have the circuit diagram for it or a similar 5-valver. Right at this moment, I cannot devote the time to trace out the circuit. I will attempt to add a couple of picture...Thanks for any suggestions or help...André, GM3VLB

[HamishBoxer]

I thought straight away homebrew but that speaker grill looks as though it could be a bit more interesting.

David GM8JET

[Steve_P]

I reckon it's from the.Brown stable. The only one I have is the Brown AC Receiver, but it's only a 3 valve, 4 if you count the rectifier.

A Brown, I reckon.

Cheers,

Steve P.

[dallaslaff]

Hi, The letters C and B are formed by the grill design, which could be B for Brown, as Steve suggests. Or is it a very early CB?
Les

[chipp1968]

If its home made its very nicely done , with a bought in cabinet or as you say kit . There were still alot of small businesses building sets for sale in the late 20s early 30s though

[HamishBoxer]

Just a point but this looks a battery set not mains?? With room underneath for same.

David

[mickjjo]

That does look home made, I would say it dates from the late 1920s and probably uses a 5 triode circuit with 2 HF stages, detector and 2 AF stages. This was popular before screen grid valves came along but triodes were not very good as RF amplifiers. Attached is a typical circuit from Newnes Wireless Encyclopaedia of a 5 triode portable with frame aerial, In those days "Medium Wave" was often called "Short Wave" which explains the Short/Long switch markings.

Regards, Mick.

[3delta2lb]

Hi Guys...sorry I couldn't get on earlier...
This site never ceases to amaze me...an encyclopaedia of knowledge...

David GM8JET: It's a "battery" set - came with the batteries..The LT accumulator is a VARLEY V-60 with a label that says "Charge not later than 12 July 1945"!
(It currently gives 0.47V!!!)
The HT battery (& combined Grid-bias) s a VIDOR L5045...reading 1.08V between GB -9 and HT +120V !!

Steve: - very observant!! I thought it was just a nice bit of fretwork ,which was a popular hobby when I was a young lad in the 40s

Les: I really like that suggestion - an early CB set !!!

Chipp1968: As you say, a nice box, but the wiring inside is really awful...In fact, I've rarely seen such bad wiring...However, we need to hand it to the brave person who probably took this on as a first-time project all these years ago, having either gathered bits and pieces (as we all still do today) or purchased them as a kit...I go more for the former,as the two transformers are different makes...I'll need to look more closely at the various components...

Mickjjo: That circuit is really is a superb contribution...I really know little about real "vintage" - not 1950s vintage! It's only in the last 18 months that I've "entered the minefield", following acquisition (in Canada) and subsequent restoration of two 2-valve (sorry 2-toob) 1920s RCA Radiola IIIs. I've since also renovated one or two crystal sets (nostalgia - I came into the hobby in 1949, aged 11, after building my first one). I've had no time to really examine this current set other than count the valves, note the R/C coupling, the two interstage transformers, two variable C's and the frame aerial, but I would almost bet that this is exactly the circuit I'm going to decode Mick...There are indeed also a couple iof crudely wound narrow multi-layer coils which I did suspect might be anode chokes...I don't have that Newnes book or indeed any vintage radio book, but I'm sure glad you do!

The actual radio will definitely need a complete rebuild. 4 of the valves are intact (not tested yet) but my friend dropped the 5th while packing it and it didn't bounce!!
In the meantime, thank you all ever so much - I'll try another couple of pictures...André GM3VLB

[dr peppers]

Cant really tell from the photo, but theres a little coil to the right of the transformer, must be only a few uh, and it looks like enamelled copper wire, a modification maybe.

[chipp1968]

I would be tempted to keep as original as possible ,as only replacing perished wire etc . Untidy solid wiring if serviceable is as it was built ,as is the wonky placing of components. Not very aesthetically pleasing ,which probably shows that the builder didn't make the cabinet

[3delta2lb]

Originally Posted by dr peppers

Cant really tell from the photo, but theres a little coil to the right of the transformer, must be only a few uh, and it looks like enamelled copper wire, a modification maybe.

That little coil has puzzled me also...In view of the rest of the wiring, it's unlikely to have been a mod' to stop parasitic oscillation! I assume the two coils "on their backs" are anode chokes,although they don't seem to have enough inductance. I wonder myself whether this radio ever actually worked...

[Aerodyne]

Late twenties in origin but to me, the wiring of the valve panel is somewhat at odds with the remainder of the wiring - neat, professional (for the time) with well-soldered and placed cap and straight connecting wires. I suspect that either the valve panel was lifted from another set or along with the dynamic LS was originally part of the set that occupied this cabinet, the remainder being added haphazardly by persons unknown, as the components do seem to be a mix of vintage (all old, true, but perhaps some older than others). Another look at the components seems to indicate that some original solid wiring exists alongside 'newer'.
It would be nice to know the provenance.
-Tony

[3delta2lb]

Originally Posted by chipp1968

I would be tempted to keep as original as possible ,as only replacing perished wire etc . Untidy solid wiring if serviceable is as it was built ,as is the wonky placing of components. Not very aesthetically pleasing ,which probably shows that the builder didn't make the cabinet

Good morning...Unlike myself, you're obviously a real purist! I think it's a shame for these old masterpieces to end up in the electrical, mechanical or aesthetic condition in which they do...Don't know it it's true, but I'm told many keen collectors (some with large collectios) don't care if the radio (or other equipment) works or not, as long as the French polish is OK and it "looks" good on the shelf..I have a friend like that...I couldn't have a radio which wasn't looking and working virtually as well as the day it was born, even if it means using (disguising if necessary or possible) modern components...I hope not too many readers are throwing their hands up in horror!...
Best wishes...André

[3delta2lb]

Originally Posted by Aerodyne

Late twenties in origin but to me, the wiring of the valve panel is somewhat at odds with the remainder of the wiring - neat, professional (for the time) with well-soldered and placed cap and straight connecting wires. I suspect that either the valve panel was lifted from another set or along with the dynamic LS was originally part of the set that occupied this cabinet, the remainder being added haphazardly by persons unknown, as the components do seem to be a mix of vintage (all old, true, but perhaps some older than others). Another look at the components seems to indicate that some original solid wiring exists alongside 'newer'.
It would be nice to know the provenance.
-Tony

Hi Tony...I full agree with you (although hadn't actually thought about that aspect until you mentioned it)... the valve base line-up is very professional...the rest is more a "rat's nest"...Maybe the valve-base unit came as a pre-assembled kit?
I would love to "get right into it" but I just dare not at the moment due to other pressures...
Re' provenance, I have let my "donor" know that I'm seeking suggestions on this site...As I recall, I think he said a "car boot sale" or maybe a radio rally. He is an academic/ professional electronics engineer as well as a radio ham, and bought it purely out of curiosity and as part of his interst in the history of radio...He said he never had any intention of doing anything with/to it, and almost certainly had no time...
Maybe someone will yet come on and a say "Hey, that was my radio"!!
Best wishes...André

[wireful3]

To expand on Tony's comment it is possible that the original set stopped working and was scrapped. At some time later it was salvaged by an enthusiastic beginner, who stripped out the bulk of the set that he did not understand and grafted onto the valve panel something more tractable. Most likely using salvaged components with a circuit from some Hobby magazine.

I must admit it is the sort of thing I might have done in my early teens. Looking at the components this might have been done in the 30s when interest in radios in our sense was nil. However it would have been very attractive to make a set that worked at low cost.

[Radio_Dave]

Hi,

I looking at a 1932 copy of Popular Wireless. The back pages have several cabinet manufacturers who are selling, just, really nicely made cabinets for the magazines published circuit and other homebrew circuits.

Unfortunately nothing matches your cabinet but I imagine you have something along these lines

David

[chipp1968]

If mine I certainly would like it to be working as it should be too .Would be interesting to decide what its history is .If any major modifications have been done there should be evidence of screwholes etc

[Aerodyne]

André, you can be sure that some readers will not entirely agree with you about your restoration ethic (although I think 'throwing hands up in horror' is unlikely, given the sensible nature of the members of this forum!)

I have never made a secret of the fact that I far prefer a neat, fully restored and working set. I understand why original finish is cherished, but if it is too far gone to be retrieved, I am far from averse to refinishing. As for the insides, yes, where visible I like to disguise any replacements by fitting inside original cases etc.

With this set, a good deal is definitely not original to the late 20s. I doubt it would have been a kit set and I feel sure that John (wireful) is on the right track with his amateur experimenter hypothesis.
So, what to do? I know what I'd do. Plenty of original circuitry around, so a rebuild would be the thing. Whatever, a rebuild would be carried out with the intention of making as authentic a set as possible, even if not 'original' in the sense that it is precisely rebuilt to the maker's spec. Vintage parts (caps for refilling, chokes etc) come up from time to time on eBay or at rallies/swapmeets etc and it is possible that a post asking for parts on this forum will get a positive response.
Good luck with the set and keep us posted.
-Tony

[3delta2lb]

Hi Tony...Sorry I didn't get back to you yesterday...I think the thread has come to a natural end (at least until I drag the set out and set to...I'm actually off shortly on 2/3-week visit to my brother in the States).

I spent considerable time last night searching, without success, for other "schematics" of 5-valve battery regen vintage TRFs - the trouble is that when you hit Dave Schmarder's site, you just can't tear yourself away! I am therefore extremely grateful to Mick (mickjjo) for locating the one "schematic" which must certainly be very close to the actual version.

I would like to think that someone who acquires this or any of my other radios, perhaps long after I have gone, will be delighted to do so and won't try to "restore" it's current condition, as shown in the above photographs.

BTW, I would say the speaker cone is beyond resuscitation...I'm happy to make one...Is any sort of paper/card suitable or should a particular type be sought?

Thanks and best wishes, André

[HamishBoxer]

Originally Posted by 3delta2lb

I would like to think that someone who acquires this or any of my other radios, perhaps long after I have gone, will be delighted to do so and won't try to "restore" it's current condition, as shown in the above photographs.

Without going too far off topic and as a comparison, a chassis and engine, no body, of a rare Bentley was found in a cellar near where I lived. This was rebuilt to original spec and certainly was very worthy of that. So if you can search for further info on this set maybe that's what will happen in this case. If not restore what's there as is.

David GM8JET