Philco a-535b mark iii

[FrankSinatra]

I have acquired this today only intended to use the case to house an Alexa for cosmetic reasons but it looks in great condition inside and out.

The plug has never been changed but all looks in tact.

Any advice do’s and donts?

[Tim]

Keep it as a radio and don’t spoil it?

[FrankSinatra]

I will only put a smart speaker inside the case no modifications it looks in such good condition.

Can’t have been used for years based on the plug.

[Edward Huggins]

How will the Smart Speaker's sound come out if it's inside the case?

[FrankSinatra]

Pure volume Edward the back is a cardboard type.

Very tempting to wire a new plug on and switch it on but not sure this is the right thing to do?

[music-centre]

I certainly wouldnt just plug it in but if you do a search there's plenty of info on the Forum on the best way to power up a set for the first time.

That mains lead looks frayed so change that and the grid coupling Capacitor to the output valve ( a 6V6?) will need changing before powering up and safety checks with a meter on the mains side/Transformer.

That Toggle switch on the back of the Chassis looks to have been added at some time, possibly to switch the speaker off?

Not too difficult though and certainly better than making it into a smart speaker in my opinion.
Steve

[FrankSinatra]

Thanks for the comments according to the manual the switch is for a tone change it seems.

It has a gram PU port on the back which I’d like to use but will need some researching time.

[FrankSinatra]

I have been looking at amplifier modules to utilise the existing speaker but add Bluetooth, took the back off tonight to have a poke around.

Not sure where to start with this speaker as looks different to examples I’ve seen, it’s a Rola 6-Z.

Also one of the valves was loose in its seat and came off at a touch, it’s a Brimar 6v6.

Could replace the valve assuming I can and then attempt a power up with guidance notes or carry on with new amplifier to the speaker, thoughts?

[FrankSinatra]

Some other photos

[Simon Gittins]

You now know why valves should be removed by holding the base and not the glass!

[FrankSinatra]

Inside the chassis

[FrankSinatra]

Originally Posted by Simon Gittins

You now know why valves should be removed by holding the base and not the glass!

It basically fell off when touched looks like the connections are in bits.

[Simon Gittins]

Yes, looking again I haven't seen one as bad as that so no harm done.

Here is the link to initial power up advice:
https://www.vintage-radio.com/repair...ion/index.html

[FrankSinatra]

Think it maybe stretching my capability I love the case and the idea of the original speaker of nothing else, any help with how to wire that up to a new amplifier module would be gratefully appreciated.

[music-centre]

If you are going to just use the speaker make sure it’s a permanent magnet type as some variants of these sets used “mains energised” speakers where it’s an electromagnet instead and you would need the power supply of the radio working to be able to use it.See how many wires are going into the speaker itself (not the output transformer that’s mounted on it)

[FrankSinatra]

I think it’s two wires I’ve packed away for the evening will confirm for certain tomorrow, assume just remove the transformer and see what’s connected?

[Cathovisor]

Originally Posted by music-centre

If you are going to just use the speaker make sure it’s a permanent magnet type as some variants of these sets used “mains energised” speakers where it’s an electromagnet instead and you would need the power supply of the radio working to be able to use it.See how many wires are going into the speaker itself (not the output transformer that’s mounted on it)

Go look at post 9.

[Simon Gittins]

Yes, check carefully but it looks to me like an energised speaker that you won't be able to use with a modern amplifier. A few more photos of the wiring to the speaker would help to confirm this.

[FrankSinatra]

Found this on the model of the radio, suggests

Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil)

[cathoderay57]

That speaker has a field coil so it won't work by simply connecting a modern amplifier to the speech coil. Sorry to be a killjoy. You would have to replace the speaker with a permanent magnet type. Seems a shame to do that from my perspective, but it's your set to do what you want with. They aren't particularly rare or valuable but if the cabinet is crack-free I'd say it would be worth restoring properly and using either a Minimod pantry transmitter placed near the aerial wire, or a Bluetooth module plugged into the gram input. Either solution would facilitate streaming sounds into the set. Just crossed with your last post. There were at least 3 variants of that set. Yours is a Mk III that definitely has a field coil - and I can see it in your photo. https://www.radiomuseum.org/r/philco_a535b_mklll.html Jerry.