Graves Vulcan Battery Set

[Mark R]

I was lucky enough to get one of these sets dating from around 1938, it is a set I won at the last Wooton Bassett auction but did not know about it until it was thrust at me yesterday at the Golborne meet.

It is very similar to the Aerial set I have already done, the details are here

http://golbornevintageradio.org/forum/sh...php?tid=41&highlight=graves+aerial

Does anyone have the circuit for the Vulcan?

cheers Mark

[Yorkie]

I was lucky enough to get one of these sets dating from around 1938, it is a set I won at the last Wooton Bassett auction but did not know about it until it was thrust at me yesterday at the Golborne meet.

It is very similar to the Aerial set I have already done, the details are here

http://golbornevintageradio.org/forum/sh...php?tid=41&highlight=graves+aerial

Does anyone have the circuit for the Vulcan?

cheers Mark

Only got the 'Vulcan 2', which featured in December 1928 Wirless World. It uses two battery valves - PM1HF & PM2, requires two HTs, a Grid Bias and LT (the voltages of which aren't stated). The article says that the original Vulcan was reviewed in the July 1927 Wireless World, so it sounds like it's not at all the same set as yours, which you believe was made a decade later, even though it has the same name 'Vulcan'.

It's a very simple TRF design, in which the reaction is varied by swining the 'wave-wound' coil through 180 degrees in relation to the coil for each waveband.

I'm not sure that any of this is much use to you Mark as it probably has no relation to your own newly acquired set.

[Mark R]

David, I have that cct, but what is swining?
Been in the silver shadow too long lol

cheers Mark

[Steve_P]

You mean this, don't you Mark.

http://www.radiomuseum.org/r/graves_vulc...perhe.html

The output valve is a PM22A, which has a 2 volt heater, so the LT is 2 Volts. The HT is around 135 Volts, 130 will do. HT only has to be in the ballpark, as Batteries wore out and the HT would drop. Don't go above 135v, but they will probably work to about 100v.

No cquirkit I'm afraid, but you can work without one!

Cheers,

Steve P.

[Yorkie]

David, I have that cct, but what is swining?
Been in the silver shadow too long lol

cheers Mark

Please don't put me in a home!

'Swinging' of course - a term which has taken on a whole new meaning since the Graves era!

Steve's come up with a pic - all that's needed now is to come up with the circuit.

[Mark R]

You mean this, don't you Mark.

http://www.radiomuseum.org/r/graves_vulc...perhe.html

The output valve is a PM22A, which has a 2 volt heater, so the LT is 2 Volts. The HT is around 135 Volts, 130 will do. HT only has to be in the ballpark, as Batteries wore out and the HT would drop. Don't go above 135v, but they will probably work to about 100v.

No cquirkit I'm afraid, but you can work without one!

Cheers,

Steve P.

That is the rascal, I am guessing it will be like the Aerial and that trainer advert "Just do it"

cheers Mark

[Mark R]

David, I have that cct, but what is swining?
Been in the silver shadow too long lol

cheers Mark

Please don't put me in a home!

That will cost you my good man, you need to lay off the Rolls!

cheers Mark

[Yorkie]

That will cost you my good man, you need to lay off the Rolls!

cheers Mark

Well at least I don't need to lay off 'rolling my own' tee hee

Looks like you might have to 'roll your own' circuit for the Graves Mark.

Nice sets - I know they were a Sheffield firm, but I'm not sure of the scale of the operation, how many sets they produced, or how long the firm existed.

[Joe]

I saw that and thought it looked familiar but couldn't place it. I'd have been tempted myself.

- Joe

[Yorkie]

I saw that and thought it looked familiar but couldn't place it. I'd have been tempted myself.

- Joe

He who hesitates is lost!

Besides which, you came away with enough clobber as it was Joe!!

(Have you had a look at Mark's before and after pics of his Graves in the gallery? Quite a transformation!)