'Proper' DAB conversion for valve radios

[agardiner]

So there appears to be a genius, Herbert from HSE, who has developed a DAB+ upgrade for valve radios.

He has designed and makes a custom module which plugs in in place of the mixer valve in a AM radio, converting it to DAB without making any other changes. Simple enough idea, but the complex implementation of it...

The really clever bit is that it scans the DAB bands on startup, while the set warms up, and then spaces the found stations along the dial, so you 'tune' your set as normal!

http://www.hse-radio.de/

Has anyone bought or tried one of these? They are not cheap obviously, (around 132 euro) but are very interesting. Think I might need to try one!

NB - I am in no way affiliated with HSE, just came across them while doing research. I have however emailed Herbert and he will ship to the UK. He builds to order as it obviously depends on the mixer valve.

Ingenious, I bet the dial is a bit crowded as I get 70+ stations on a scan. There wouldn't be any adjacent channel interference though. I have a desire to try one but no real use for one.

[agardiner]

Same here - would love to try one but don't really listen to a lot of DAB anyway. Prefer Radio Caroline on 648! Might succumb though...

don't really listen to a lot of DAB anyway

I do, via my SSTRAN "modulator" (Radio 4 Extra is brilliant through a period set) I just fancied the idea of "real" tuning of DAB stations. In many ways I am glad I didn't think of this (bloomin' obvious in hindsight) it would have cost me many hours and quite a bit of cash to do, good fun though.

I will hold my enthusiasm for a week or so (just in case it recedes) then I will get one for my A22, perhaps, maybe, probably...

[agardiner]

If you get one you must let us know how you get on!

[G6Tanuki]

The idea is intriguing and deeply fascinating; I'd be intrigued to see how well it works in practice.

[For me, an obsolete smartphone with a 32Gb memory-card stuffed with music and hooked to a pantry-transmitter does its thing: I can build my own playlists and so avoid annoying DJ-types interrrupting my listening].

[agardiner]

Heart 70's, Heart 80's, 90's, dance and a whole bunch of annoying DJ free stations await you! And all with super limited play lists.

[G6Tanuki]

Originally Posted by agardiner

Heart 70's, Heart 80's, 90's, dance and a whole bunch of annoying DJ free stations await you! And all with super limited play lists.

Yes, don't stream, download-and-save stuff to build your own playlists on a legacy-phone. Right now I'm 3 hours into a self-compiled "Sovietwave" playlist - and there's another six hours to go.

Why let others choose what you listen to?

[Electronpusher0]

That's fine and stays in your comfort zone, the advantage of listening to someone else's playlist is that you may discover things you like but never heard before.

I am also fascinated by the DAB conversion but the price is a bit steep for me.

Peter

[Radio Wrangler]

Hmmm, now how would one of those work?

A small oscillator circuit to run with the LO tank of the set feeding a frequency counter and that will give a digital word used for station selection.

A normal DAB chipset, but it would need to be a pretty low power consumption one.

Rectify and regulate the heater supply to power it all.

Derive 455/465kHz from the counter clock then AM the sound onto it and feed through a DC block to the anode pin.

I don't suppose there is enough power available from HT via the anode and g2 feeds, so it has to be powered from the heater. 100mA string heaters bouncing up and down with a fair proportion of mains voltage must be awkward, though.

The 455/465kHz could be used to clock an SMPS with low risk of interfering with the IF.

David

[agardiner]

Exactly - a lot of work must have gone into this, including the software.

It may be a bit pricey for most right now, but as AM continues to decline I suspect there will be more and more demand for such products.

[agardiner]

I might be about to order one of these to try. I have a post elsewhere on a troublesome FM tuner based on an ECC85 valve. The performance is very poor and it looks like that may just be the way it is.

I have contacted the German engineer asking about a DAB module to replace the ECC85; if he can make one I will order and report back on its performance and success!

[dave walsh]

It does seem to be a terribly ingenious way to go by converting the valve circuitry directly but of course AM sets never had DAB so even with the cleverly spaced out dial conversion I can't quite see the point-except as a novelty item to confuse future researchers perhaps

Maybe this is because getting the DAB station signal into various bits of equipment eg DVD or CD Recorders, Hi Fi Systems or just different rooms, is always big focus for me. At the onset of DAB little micro converters were on sale for a while but then rapidly disappeared. The options now are quite expensive, eg units designed for in-car use or a few stand-alone DAB Hi Fi Units, even more costly. I tend to source more or less the same cheapo portable DAB radios and wire them in via the earphone output. They have the controls on the front so they can be easily inset into other equipment as well. Battery Power consumption is not an issue as they aren't really so portable anymore.

Dave W

[emeritus]

I suppose it might be useful in Scandinavia or other countries where there are no remaining AM broadcasters.

Here a while ago I postulated receiving the local oscillator from an AM set, "tuning" a DAB radio using the frequency. And then, in fairly big blocks, setting a pantry transmitter. This would give a proper tuning feel without any modifications to the set.

[emeritus]

I see he also does plug-in replacement magic eye tuning indicators that use green leds and apparently behave like the originals.

Using my Samsung phone, the links to the price list do not work in either the Engish or the German sections.

[ajgriff]

Yes the price list is only displayed in German. The DAB conversion for valve radios is Z13 priced at €132 as indicated in the original post.

Alan

[David G4EBT]

Don't want to decry or sound dismissive of the designer's efforts, but it seems like a complex and expensive solution to a simple problem. Not sure what it achieves which couldn't be achieved by a 'pantry transmitter' which will accept inputs from any source without even having to take the back of a radio. As depicted on the website, though the little PCB which plugs into the valve socket look neat, the other electronics shrouded in black tape and the trailing wires looks a bit of a lash-up.

Maybe I'm missing something?

That said, every success to them in trying to meet a perceived need.

Don't want to decry or sound dismissive of the designer's efforts, but it seems like a complex and expensive solution to a simple problem

Yes I agree, but very cool tuning a 1930's set to show off to visitors, or just the joy of having a vintage radio and using it as designed. I still like my idea better.

[dave walsh]

Yes I try not to be at all dismissive David as it is an impressive technical achievement after all. Although [ironically] a bit reminiscent of those early Victorian machines that used a lot of iron work to achieve a relatively simple outcome. The led magic eye device is very intriguing as well!

I don't have any particular issue with the VHF/DAB quality debate. I only got a DAB machine when stations appeared that didn't duplicate FM ones! This was particularly important as Dylan's Theme Time "Radio" Hour was exclusively on 6 Music at first! 4xtra is another must have with it's wealth of great vintage BBC material, often lovingly restored. There's The World Service as well and I only recently discovered [2 years ago] that LBC was on the end of the DAB spectrum, along with one or two of my favourite presenters who have defected from the BBC-what's going on at BH? The commercial station has a different perspective to our National Broadcaster but they both have their positives and deficiencies.

Overall, as I record audio mainly to digital equipment now [ie DVDA or CD] there is an element of convenience re the DAB source. In the kitchen though and elsewhere I tend to have both FM and DAB radios and I might use them to alternate [for example] from one news source to another. Another type of non technical "compare and contrast perhaps?"

Dave W