Hi all. I've just been going through some of my mum's old collections and come across what I believe to be quite a valuable radio. It's an Airwave model 5057A chassis 537A.
It was among a few other oldies but I just wanted to get peoples opinion on this radio and perhaps what they value it at in good condition.
Any help is greatly appreciated.

That sounds like an Airzone Symphony Leader from 1939, such as this one:

https://d3ecqbn6etsqar.cloudfront.net/PsuB5FDTu7MGsowyr2BPKCEh61Q=/104293.jpg

That's exactly what it looks like. The only thing perhaps is the manufacturer year. Ive found some info on this model and I thought it said it was a 1938 model but I'm not entirely sure.

I thought it said it was a 1938 model but I'm not entirely sure.

Circa 1939 is close enough. That era is the heyday of radio set production and they were being churned out by numerous manufacturers at a phenomenal rate.

Any idea on what it might be worth?

When it comes to the question of "worth" of any object I am consistent: It is worth what a buyer will pay you for it on the day you must sell it.

I have been at HRSA auctions where a set like that has been bid up to a few hundred dollars, and at other times there has been little interest and it's been passed in.

That's quite true regarding the sale of any item really. The market dictates the price. If the radio is indeed a Symphony Leader then yes, it's a fairly sought after radio and can, at times, command big dollars on Ebay or even at a live auction where enough people are in attendance to provide some stiff competition.

Regardless of what make or model it is though, the radios that get the most attention are the ones with nice polished cabinets that are free of large scratches, cracks and breaks. Ideally, the radio innards should at the very least be complete, allowing a restorer an inexpensive path to getting the set going again. If the radio has been internally restored - all the better.

A further note regarding condition ... it can't be be said often enough that under no circumstances should such a set be powered up. Doing so -- even to see "if the valves light up" -- can result in collateral damage that will make restoration more difficult, if not impossible.

If you put it up for sale, simply describe it as 'untested', if that is the situation..

Hmm... well we powered it up and had it working as we wanted to test it worked properly. Whoops!

A lot of radios found after being stored for so many years can still work with faulty components. Unfortunately it is not a widely known issue outside the vintage radio fraternity. It's quite understandable that people are curious though it will do damage in the long run. The most critical component is probably the power transformer. Valve radios rarely came equipped with fuses to protect the transformer from an overload caused by ageing components so the risk of the transformer being cooked is better than average.

Related to case that has been posted: It may run after long storage but long enough for a filter cap to get very hot & explode, or cook the transformer.

I know this has been said before but it bears repeating:

If you are going to plug it in without a thorough check, use a dim bulb tester. That is, a 60 watt or 100 watt incandescent lamp ( hard to find these days) wired in series with the mains Active.

A short on B+ for example or a shorted turn in the mains transformer will light the lamp and do no damage.

If the electros need forming, the dim bulb tester will do it safely - let it run for about 12 hours. The lamp will get dimmer as the current drain of the radio drops and since the lamp is effectively a PTC thermistor it will drop its resistance and let more volts through as the electros reform.

This is the method I use for bringing up gear that looks in reasonable condition. For example a Kriesler 11-77 that had been out of service for at least 30 years came up running on the dim bulb after a few minutes forming of the electros - complete with original paper caps and all.

For large items like TVs, you can start with a 100 watt lamp and increase to 200 watts (if you can find one - two lamps in parallel?).

Standard test equipment for switch mode power supplies in the early days of colour television.
Sure beat blindness or sound shock from exploding 4 amp mains fuses.
JJ

You must have worked on KC series Blaupunkts!
A fellow tech used to refer to the process of switching on the first time after repair as "flash-up"!

Yes, I still use the dim bulb method when bringing up a prototype of a new design for the first time.

It's funny how service experience influences product design. Pretty much all my designs can withstand shorted rails or even some accidental IC pin shorts with no damage. It's usually easy to build current limiting into power supplies, I don't know why more designers don't do it.

When someone asks me what a radio is worth I think a little different to others. I put it this way even if it is worth a thousand dollars that in this day and age is a weeks wages more or less and tell me how long does it take to spend a weeks wages? For me if it is a radio that I am not likely to see very often then I will keep it.
A example of what I am talking about are the Vintage army field phones I have in the vintage telephone section of this forum. They are as they left the factory and the only use they have had was when they were tested. Ie they are New Old Stock and I doubt that I will ever see such items again. they have been valued at $500 each so there is the $1000 weekly wage I am talking about. Your Radio is fairly scarce now and if its in good condition then I urge you to keep it because its worth it.
Also please do not be tempted to switch it on again untill a qualified tech has gone right over it for you. Yes they can short out and smoke but they can also KILL YOU. Hopefully you can post some pictures on this site for us.

Regards Carl