Armstrong 222 Valve Amp Speaker Connections

[Dylanthecat]

Hi, I have just obtained an Armstrong 222 valve amp but unfortunately have no manual. I have ordered some two round pin speaker connection plugs (not 2 pin DIN) from the net.

My main queries is which in the positive and negative. Is the larger hole the positive? I assume that this is a constant regardless of the ohms and you turn the plug 180 degrees depending on the speakers.

In addition it came with a pair of home-mades with some Goodmans Axiom 10 drivers. I note that the drivers are connected directly to the 2 Pin Din female sockets. There is nothing in line just a insulated wire link. Is this correct/ safe? Should there not be some protection/ filter?

Many thanks in advance, Martin

22794

[snowman_al]

Hi Martin,
Its really quite a sweet amplifier.
Basic answer to the question is: it does not matter as long as you use the same pin for the + on both plugs and that connection goes to the same terminal at each speaker. That way the speakers are 'in phase' (ie. both cones move in and out together with the same signal).
As it happens, the larger hole/pin on the Armstrong is 'chassis ground' so you could say it's negative. But there is no convention for that connector type.

I guess the Axioms are full range drivers and so there shouldn't be a filter.
Not sure what you mean by safe? You are very unlikely to harm the speaker or amp with that combination.
Just remember not to run a valve amplifier without the speakers connected, you just could damage the output transformers.

Alan

[Dylanthecat]

Thank you Alan for the very clear response. The 222 cleaned up like a new pin. It has gold pin Mullards throughout. I will connect it up today. I have placed the amp chassis on a black marble plinth. Now just need to fold a s/steel perforated cage. It should look very nice when complete. Martin

[Dylanthecat]

Hi Alan, 'safe' was in reference to the drivers being damaged. Martin

[Dylanthecat]

Hi all connected up now and sounding very nice. Beyond my expectations. Clear as a whistle after a good deox. All for the princely sum of £0.00. Martin