Anyone built a valve radio from scratch?

I found a lovely timber cabinet the other day and know I have no hope of finding the missing chassis.

I have designed an AM receiver based on the following line up:
6AN7 frequency convertor
6N8 IF amplifier, detector and agc
6MB8 Audio pre and power amp
The power supply is solid state

I need help sourcing parts:
RF coils and dual gang tuning capacitor
IF transformers
Power and audio output transformer, although I may buy these new.

I'd like to hear from anyone who may have some of these parts in you junkbox.

Thoughts and comments or alternative suggestions on the line up are most welcome.
Marc

Had one in recently for minor repair; where the guy had taken out what was left of the battery set & built a mains set to a HMV circuit.

HMV circuits tend to be good. Try to aviod using 6N8. Several in the Radio Club I am in have commented on those and I am also not a fan of their behaviour & general unreliability.

Marc

Thanks Marc,

What would you recommend in its place? I am happy for the diodes to be solid state, This stage has AGC so I guess it would need to be variable mu.

Tell me a little about the Radio Club? I used to be in one when I was a teenager many years ago, They are great value.

Any chance you can help me out with the Coils, Tuning Gang or the IFTs?

Can you point me in the direction of the HMV schematics?

The other Marc

If you can get hold of the later AORSM's there are several in there, Try to pick one that uses 6AN7 as that is a good converter followed by something like a 6BA6.

A lot of these use 6AV6's which tend to have a habit of being microphonic, however they tend to be a little more reliable. A "Viton" ring around them often shuts them up & they often need an external shield.

My advice would be to keep an eye out for something like a "Little Nipper, as I have seen several with wrecked cabinets. I think a mate of mine has a couple like that. I would have to check. Plastics do not command huge sums & bent ones should make a lot less.

No-one much want's Stereograms much either, those can be ratted.

Ihave a salvaged, module only, out of a Radiola 570GA (Mono).
Refitted ready to drop back into one of them or something else. Cabinet was a write off. I have circuit, requires speakers. Originally had Woofer & tweeter.

Chassis is a hanging type.


Marc

Hi Marc,

Thanks for the tips.

Can you please enquire of your friend about the "Little Nipper", is it available, and how much would he be prepared to accept?

About the Radiola 570GA, are you saying that this is avaialble? if so how much?

Kind regards,
Marc

570GA module is available owes me parts, as it has been overhauled. Say around $40.

This unit is ready to drop back into a cabinet or could be built into a bedside arangement etc. just as a radio. As said no speakers, but has dial and knobs.

I will check what the mate has in my shed. It would be better to get an unrestored wreck, with circuit & go from there as you are not destroying pefectly good components used in a restored unit.

Besides joined wires can look quite tatty & unprofesional.

Marc

Have you got pictures of the 570? Its really only of use if it can be made to fit the cabinet.

I agree unrestored would probably be better, the object is to build a set from scratch and I would be ratting the chassis for IFTs, coils, tuning gangs, audio and power transformers. The rest would be constructed from componenets purchased new.

Marc2

In case you havent seen the cabinet in question, its here.

http://vintage-radio.com.au/default.asp?f=1&th=170

Marc

That cabinet looks a bit like a Kingsley, from the dial face. Emmco used thet control lay out as well (different dial ... drum)

It would be preferable to put a 1930's style chassis in it. These are not exactly unprocurable. The dial is another story. I have a chassis of a 1930's AWA that has been seriously knocked around but may fix and a 1940's chassis that has had its dial assy smashed. that chassis should run.

570GA is unsuitable for that cabinet.

I looked at the Nippers of which there are three two 64-52's and one 64-52's. only one of these has a dial glass and the cabinet you have takes a round dial. Both of the 64-52's run badly and need overhaul all have damaged cabinets. Fortunately both 64-52's are red and we can make an almost, or just presentable case out of the two.

Despite me having one in service, the 62-52 is one that we would part with, but there are serious differences. 62-52 takes minature valves, of which it has none. ... totally out of era. The chassis would fit however, four shafts & the tuning gang is on the end.

Needs a lot of thinking about, before acting on a retro fit. Lots of hassle making a new chassis.

Marc

Thanks Marc,

I will check out these models, I am under no illusion that a ready made chassis would fit or even retrofit with mods to the cabinet or the chassis.

I have absolutely no qualms about building a chassis from scratch, thats all part of the fun and where the ultimate reward will lay. I dont mind using miniature valves even though these are not fitting to the era of the cabinet.

Marc

The 62-52 circuit is pretty much the same as 62-51 only the accounts department (most likely) caused the screen resistors, parallel 22K 1Watt to be changed to 10K 1 Watt. (I squared R = overload.) and there is a tendency for some of them to cook.

Valves are common types 6BE6, 6BA6, 6AV6, 6M5, 6X4. This has a seperate on off switch, which could be easily eliminated or substituted for a switch pot. to accomodate three holes.

You could do something like the Philips 132L, with the gang. It has one similar to the early transistor sets, mounted above chassis.

Drive pulleys are easily made. Made some for an STC last year.

Photo's sent to Brad

Marc

Photos have been passed on.

Brad ... thanks.... Marc