Murphy A316G record player

[Amie]

Hi Albert, and thanks!

Hello Mike, super, many thanks, much appreciated. I have read a few articles on their products in the Murphy magazine, and it's probably the only insight I'll find into the  reasons for the designs being as they were.

I will look forward to the email!

Thanks,
Amie.

[Amie]

Loft ladder was ascended and valve inspected
Valve brand is a Mazda, though it has a four way pinch and etched production number on the base, (28, Phillips signifying PCL83, + factory code for Mullard), so bought in by Mazda?

Looking through other subsequent models of Murphy record players, and the A1 and A2 Amplifiers, it does seem that at least Murphy were happy to continue using the amplifier design with its odd choice of a TV frame output valve, without change.

[Murphyv310]

The PCL83 was used for a time in the Pye Black Box record player.
It's actually a very poor choice, a horrible little valve.
They failed more often than other triode pentodes in TV applications.

[Amie]

Just a quick update, the preventative things were done to the little amplifier in this record player, suspect capacitors were replaced, as was the selenium rectifier. Electrolytic capacitors were fine so were left.

I'm being supplied with a new idler for the record deck but otherwise its only in need of a clean and some lubrication. A really impressive piece of engineering considering it was low end, price wise, (though probably equivalent to four weeks wages when new).

The horrible little ECL83 worked fine and is in good order! Makes me wonder what a "good" valve could do.

Not powerful or HiFi but pleasant enough sound for all that. Its odd electronics assembly method does make it very easy to repair.

One of Great Gran's 78's albums was played to her to her great delight, a 1926 Columbia recording of Holst conducting the LSO in his Planet Suite, (a set of seven discs!), that she bought for a few shillings from a junk shop in Nottingham in around 1960.

[ppppenguin]

Is that recording of The Planets auto-coupled? For those not familiar, it's where the sides are ordered so that if you put the stack of discs on an autochanger they will play in the correct order. Then you turn over the stack for the remaining sides.

[Murphyv310]

Hi.
Was the auto coupled discs available in 1926?
I don't think there were many auto changers then if any!

[Amie]

Clarification, 1926 recording, (first "electric" recording of the work) later pressing, were available I believe as side one, side eight on first disc, side two, side nine, on second, but not these ones, each movement on its own disc.

Shellac disc on an autochanger not such a great idea?....

BTW I called the valve an E, whereas as we know its a P....

[ppppenguin]

78s work fine on most autochangers. They are amply tough enough to withstand the drop. One problem is that they can slip on each other as the next disc runs up to speed.

We'll forgive you about the E/P confusion. I think we all knew what was meant.

[Kalee20]

Why not use an ECL83 so as only one tapping would be required for heaters and the pilot bulb, or a 12v bulb with the PCL83?

Synchrodyne on UKVRR (hugely knowledgeable about valve choices and what led to them) has provided a couple of answers to explain this.

First, the PCL83 has a more suitable triode for the record player amplifier, with a μ of 17. The ECL83 has a triode with a μ of 85, which would give excess gain. (The ECL83 and PCL83 do have similar pentodes).

Second, and this does tie in with your own point Trevor about the Mazda-Murphy agreement, that Mazda by 1958 were offering the PCL83 in their list of valves... But not the ECL83 (Synchrodyne has a 1958 Mazda data book).

Amie's post on 13th Sept confirms her record player has a Mazda branded valve, which is completely consistent with the second point.

[Amie]

Hello Amie,

I have the Original Murphy News article and the Murphy manual here.

I have the e-mail that you sent me and will also reply to that shortly.

I can supply both to you.

I also have an A316G in my Murphy collection here.

Mike...

I'm very grateful to Mike as he has supplied scans of the Murphy news article, I now have enough for one of my winter projects 

Thanks!
Amie.