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VINTAGE RADIO IN HEXHAM

Now isn't this a pretty picture.   Here's Dudley the Westie having a snooze whilst keeping a weather eye on the DAC90A and other associated vintage radios.  Mrs Mullard Magic and I spent a very pleasant half an hour visiting Wardhaugh's at Hexham - you should go and have a look too.

DON'T KILL YOUR WIFE WITH WORK.....

How, I tittered when I saw this little homily, and, quite appropriate today as it's Mrs Mullard Magic's birthday!

COMPONENTRY GIVES RISE TO FEMININE ELECTRICKERY

How I smiled when I saw this pulp magazine cover from 1966.   Bet you never got a blue print for this particular project free with Wireless World and interestingly, from the 'dolly's' midriff trap door she seems to be solid state - unless there are a nice pair of   output beam tetrodes situated a little higher up - could that be a brace of 807s as I am sure I can see some top caps.  Wonderful stuff indeed.

MUTUAL CONDUCTANCE - WHATEVER IS THAT?

I have an e-mail today from Peter in Australia who was asking why my results for a given valve were 1000 times smaller than some he had bought elsewhere - I was concerned as to the uninitiated, my results could suggest that I may be peddling devices which were low emission rubbish!

I smiled wryly as the decadic factor indicated that Peter had bought valves with their Mutual Conductance (gm) expressed in micro-mhos, so, how best to explain this........

OK, let's start with the basics, mutual conductance is the measure of the 'goodness' of a valve  with some people colloquially referring to it as 'the slope' like Jeremy Clarkson (!) and may be expressed using the Van der Bjil equation where μ = device gain and rp = device anode resistance: -

g_m = {\mu \over r_p}

Although I have given you the equation, I have not used any units and this is where it gets interesting for you see, in the USA, gm is expressed in micro-mhos whereas here in the uncivilised world we express it in mA/V.  As a gm of 1000 micro mhos = 1mA/V you can see where the confusion may arise for the unwary and this handy decadic conversion factor should help Peter and any other user interpolate their gm results accordingly.

 
 
JUST BACK FROM THE IMITATION GAME

And what an exceptional film as Benedict Cucumberpatch was...... Alan Turing!  There were a few slight boobs though, the first being the 1951 use of an Eddystone 770R - which wasn't actually on sale until 1953.    Then there was the Anglepoise lamp in Alan's Styal flat - correct colour, correct two stage base BUT with an incorrect non-rolled wired shade rim not first seen until 1958 post austerity and all that.  Sticking with the lighting theme, the Dugdills patent lamp situated to AT's left during the bear joke scene had a fetching but decidedly not period white plastic 1970's bayonet light fitting.   The last thing to be spotted was when Alan & Joan took a train trip to see Mr MI6, they were sitting in an example of outwardly LMS coaching stock but with the corridor compartment unfortunately fitted with 1970's British Rail blue moquette seating.

But other than the above four very minor points  this was a most enjoyable film.

WE'RE BACK BLOGGING!

And here we are, back bloggin' after a break whilst the new website was developed.  For your delectation today, I thought you would like this piece of artwork from a 1940's pulp fiction book where the effects of the evil thermionic valve were effecting the poor hapless user, spooky huh?  Beware the beguiling glow of the firebottles.....: -

THE NEW IMPROVED MULLARD MAGIC

Well, at last we have done it!  The new, improved Mullard Magic website is here, we are still a bit of a work in progress BUT customers should notice a much improved responsive website which provides a more enjoyable web experience.  

We look forward to welcoming customers old and new and serve their needs in the thermionic and vintage collectables market.

With our best regards,  

The Mullard Magic Team. 

WEBSITE REVAMP CONTINUES APACE - LAUNCH IN DEC 2014

 Well, a lot of work has gone into getting the "New Improved Mullard Magic Website" running.  It has been such a lot of work though for my webmaster and now myself   We are now looking for a December 2014 launch so for unregistered customers, keep popping back to see what's happened and for our existing registered customers and friends then an e-mail will wing it's way to you advising you of the launch.   

 

WE'RE RUNNING OUT OF VALVES - TIME FOR A RESTOCK!

Only kidding, but, having looked at website listings, it seems we are due for a restock and this will be happening sometime during October once the NEW IMPROVED MULLARD MAGIC WEBSITE goes live - wahey!

 

 

 

THE MULLARD B9A ENVELOPE MAKING MACHINE

Today's delve into the Mullard Blackburn archive reveals that with the advent of the P series TV valves and their popularity that a means of increasing production and reducing lead time was required.  This was achieved by the introduction of a new B9A envelope making machine that was sourced from Philips Herleen.    The photo below shows this delightfully complex rotary machine below: -



And here is an X ray pictogram of a finished PCF80, the envelope from which was blown on this very machine.