BTH type VR3 Form BA

[unrealdave]

BTH type VR3 Form BA

This is interesting.  It’s a BTH type VR3 Form BA with its original horn speaker.  I also got a pair of BTH headphones that seem to work

I have never seen valve holders like it – big chunky things that have the anode resistance, capacitor and grid leak all in the base.  Is this the first example of an integrated circuit?

There are no valves with it so I am going to use a HR210 for the detector, then a PM2dx followed by a Marconi output valve.  I can’t see a number but it works on other battery sets fairly well so I will use it here.

There is some good info here  http://www.bvws.org.uk/publications/bull...n_09_4.pdf see page 13

All in all its a great looking radio and displays well - I just need a bigger house

[Yorkie]

Interesting stuff - the link to the BVWS Bulletin shows just how far the society has come over the years in terms of presentation, from what looks like a typewritten, stapled together effort, (albeit packed with information),  to today's full colour glossy magazine, which outclasses any other national society magazine or news-stand offerings that I can bring to mind. Each edition seems to surpass the previous one! All credit to the BVWS team, not least the editor, Carl Glover.

[Alan Douglas]

Is this the first example of an integrated circuit?

I can't offhand think of a previous version, though it was about that time that Loewe was putting all those components inside the valve envelope.

[peter scott]

Very nice simple receiver. Is yours the same set that belonged to R J Holmes?

Peter

[unrealdave]

Very nice simple receiver. Is yours the same set that belonged to R J Holmes?

Peter

No - I don't think so.  I have opened it up and the anode and grid leak resistors are all out by a fair bit in my one - he had sorted the ones on his set.  I have redone them now in my set in the same way he did

Also on the circuit diagram for the Holmes set it shows a .0004 capacitor coupling the second and third valve - on my set its .004 - But I think R Holmes put an extra 0 in there by mistake.  .004 is fine for AF coupling I think.  I am also going to try a .5m for the second valves anode resistance on mine to see what that's like.

All in all this is a really fine example of this model - I am going to fire it up this weekend as I have been told I'm busy till then

[ppppenguin]

0.004uF (4nF) sounds OK for AF coupling. A tenth of that, 400pF, seems very low for audio coupling.

[unrealdave]

I fired this up at the weekend and played with various values of ht and also the resistances.

This runs quite well, not overly loud but a fair few stations and great reception on from a AMT3000.  I Used 90 volts HT and -9 on gb 1, -1.5 on gb2

The resistors were all out and if you look at the base there is someone’s writing but ignore that – I put .25mOhm on the first anode and .5mOhm on the second, and 2mOhm on both grid leaks – that worked best.  The valve holders are really neat and make the set easy to trace – a good thing for me

This is really a good looking set with the horn (how do you get the throat cover to stay in?) so its up on a shelf were I suppose it will stay till the kids take it down

I got hold of another valve holder that does more than just hold the valve, and a 1920's printed circuit board - I will take a pick later

[Crackle]

Hi Dave
I thought I would just mention that Mega is normally abbreviated to M (capital m) to distinguish it from milli, which is abbreviated to a lower case m. I was confused a little for a while until I saw the photos of the resistors.

Nice radio.

Mike

[unrealdave]

Hi Dave
I thought I would just mention that Mega is normally abbreviated to M (capital m) to distinguish it from milli, which is abbreviated to a lower case m. I was confused a little for a while until I saw the photos of the resistors.

Nice radio.

Mike

OK M it is

Here is a pick of the Ediswan valve holder and the Lewcos circuit board.

The valve holder plugs into the next one along taking the LT with it on the pin's - neat.

[AlanBeckett]

Ooooh, I want one
That must have cost a Bomb in its day.
Was it meant for the Amateur Market or a Commercial Product?

Alan