'Proper' DAB conversion for valve radios

[Clayb1964]

Hello thanks for letting me join I sure I was a member many years ago. A websearch brought up this old thread about DAB conversions of valve radios which is unfortuneatly closed.

I lost intrest in old several old radios I still have several years ago because of the move to digital and the impracticality of old sets although I still love the asthetics of them. I stumbled across this HSE conversions at least five years ago and did enquire with a veiw to making a purchase but lost interest. I played with the idea of a DAB conversion a decade or more back wanting to use the original controls with possibly the valve amplification curcuit hence my interest in this which is really the ultimate solution for anyone wanting to make practical use of an old MW LW radio since a rebroadcaster is nothing more than a speaker.

I intended to try and use one on a 1954 Ferranti 545 LW MW which developed a fault I never fixed so any information on this radio and if anyone else purchased and put on of these units to work would be very helpful.

[Silicon]

The impracticalities of the Ferranti 545 are that there is no mains transformer, the output valve is a UL41 and the other valves are not commonplace.

There seems to be only three control knobs :- On/Off & Volume, Waveband and Tuning.

A set with a mains transformer and a tone control would make your job easier, it would give you more options for modification.

If I was going to do a conversion I would like to give future owners the option of returning the radio to its original condition.

A tone control knob could be temporarily converted to an input selector switch.

[Clayb1964]

Thanks for that I guess you know a bit about these sets. From what I recall all the valves appear good and the HSE dab conversion pugs into one of the valve bases. I sure there is a transformer of some sort on it could you please be more specific as to how the 545 differs to the norm my knowledge is limited.

[Hybrid tellies]

I think the best way to go is to use an AM pantry transmitter or AM modulator. This means that you are still using all stages of the radio and you can have a wide choice of audio feeds including CD, MP3, FM, DAB.
This is also the safest way to do it as no electrical connections to the valved circuitry is required.

[PaulR]

Originally Posted by Hybrid tellies

I think the best way to go is to use an AM pantry transmitter or AM modulator. This means that you are still using all stages of the radio and you can have a wide choice of audio feeds including CD, MP3, FM, DAB.
This is also the safest way to do it as no electrical connections to the valved circuitry is required.

And you can run as many different AM radios from it as you want.

[agardiner]

If you have more than one vintage set, then I agree that a pantry transmitter is the way to go. Far more cost effective.

I have converted a few radios for customers using the HSE modules; both the FM one and the DAB one. The really nice thing is that you retain almost the entire set in its original form, and you continue to operate (tune) the set the same way as before. They work really well and just replace the mixer/oscillator valve. Each unit is therefore prepared for your specific radio and it matters not whether the set is a live chassis or transformer based. However, the set does have to work fully before you fit the unit. As it converts the FM/DAB to an AM IF signal, if the set has other faults then this unit will not work.

[Sideband]

Originally Posted by Clayb1964

I sure there is a transformer of some sort on it could you please be more specific as to how the 545 differs to the norm my knowledge is limited.

Yes that will be the output transformer that drives the speaker, not a mains isolating transformer.

Your set has one side of the mains connected directly to the chassis and is not really practical for the sort of conversion you want to do.

A pantry transmitter is a much better (and safer) way to do things since you don't have to do anything to the radio at all.

[Gabe001]

Sideband is right of course, especially from a safety perspective.

If the OP can be persuaded to consider Bluetooth instead, there's a lot of info in the "which Bluetooth module" sticky (modern technology) on how to do this in a live chassis set, without destroying the radio