Armstrong 521 Amplifier

seanww69 · 11th July 2007, 10:31 AM

HI
Hope someone can help, I have just acquired an Armstrong 521 Amplifier but i am stuck to find out what spear plugs i need for it.
Can anyone help.
Thanks
Sean

AndrewT · 11th July 2007, 12:04 PM

Hi,
what is a spear plug?
What are you trying to connect?
The 521 is getting quite old, it may help to post a pic of the rear panel.

As far as I know the 521 is not a chipamp.
ask the mods to move this to solid state.

seanww69 · 11th July 2007, 02:06 PM

Hi Andrew Thanks for your reply I have enclosed pic of back of amp, I am trying to connect speakers to the unit.
Many Thanks for your help
Regards
Sean

AndrewT · 11th July 2007, 02:24 PM

Hi,
don't recognise those sockets.
I guess they are about 2mm diameter, two pole plugs.

It might be easier to replace the sockets with others that fit the spaces available.

Gordy · 11th July 2007, 02:37 PM

I have seen sockets such as those on old commercial valve amplifiers.

If you have no luck here I would suggest starting a thread on the valve amp section of the forum and include your socket picture in the first post. Don't mention the amp name in the thread title as it is not important, instead call the thread something like "Please help identify which plug I need for this socket". The valve amp crowd are nicely enthusiastic, and someone will surely know the answer...

Good luck.

seanww69 · 11th July 2007, 02:50 PM

Hi Guys

Thanks for your help, i'll repost and see where i go from there.

Again Thanks
Sean

sreten · 11th July 2007, 02:51 PM

Hi,

The sockets are very old, the pins have different diameters for phasing.

You need a special plug or two types of old split plugs similar to
banana plugs but smaller diameter. I have not seen either of
these for a long time, used to be fairly common.

Split plugs looked like short cotter pins

With a threaded ring with cutouts for the loop on the shaft.
You threaded your cable through and then screwed the
plastic covers onto the ring.

Simplest idea is probably to fit a pair of these, on the left (Maplin) :

edit : or find someone with a good old spare parts bin.

/sreten.

poynton · 11th July 2007, 04:39 PM

Hi

As posted on your other thread....

EBAY !!

http://cgi.ebay.co.uk/2-PIN-SPEAKER-...QQcmdZViewItem

Regards
Andy

sreten · 11th July 2007, 05:44 PM

http://cgi.ebay.co.uk/eBayISAPI.dll?...m=120140396790

make sure you do not use these .........

/sreten.

Gordy · 11th July 2007, 10:13 PM

...and for general info on the amp try here...

http://www.st-and.demon.co.uk/Audio/armstrong.html

(Link checked and live at time of posting)

11th July 2007, 10:31 AM	#1
seanww69 diyAudio Member Join Date: Jun 2007	Armstrong 521 Amplifier HI Hope someone can help, I have just acquired an Armstrong 521 Amplifier but i am stuck to find out what spear plugs i need for it. Can anyone help. Thanks Sean

11th July 2007, 12:04 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, what is a spear plug? What are you trying to connect? The 521 is getting quite old, it may help to post a pic of the rear panel. As far as I know the 521 is not a chipamp. ask the mods to move this to solid state. __________________ regards Andrew T.

11th July 2007, 02:24 PM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, don't recognise those sockets. I guess they are about 2mm diameter, two pole plugs. It might be easier to replace the sockets with others that fit the spaces available. __________________ regards Andrew T.

11th July 2007, 02:50 PM	#6
seanww69 diyAudio Member Join Date: Jun 2007	Re: Armstrong 521 Speaker Connections Hi Guys Thanks for your help, i'll repost and see where i go from there. Again Thanks Sean

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11th July 2007, 02:37 PM	#5
Gordy diyAudio Member Join Date: Nov 2006	I have seen sockets such as those on old commercial valve amplifiers. If you have no luck here I would suggest starting a thread on the valve amp section of the forum and include your socket picture in the first post. Don't mention the amp name in the thread title as it is not important, instead call the thread something like "Please help identify which plug I need for this socket". The valve amp crowd are nicely enthusiastic, and someone will surely know the answer... Good luck.

11th July 2007, 02:51 PM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, The sockets are very old, the pins have different diameters for phasing. You need a special plug or two types of old split plugs similar to banana plugs but smaller diameter. I have not seen either of these for a long time, used to be fairly common. Split plugs looked like short cotter pins With a threaded ring with cutouts for the loop on the shaft. You threaded your cable through and then screwed the plastic covers onto the ring. Simplest idea is probably to fit a pair of these, on the left (Maplin) : edit : or find someone with a good old spare parts bin. /sreten.

11th July 2007, 05:44 PM	#9
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	http://cgi.ebay.co.uk/eBayISAPI.dll?...m=120140396790 make sure you do not use these ......... /sreten.

11th July 2007, 10:13 PM	#10
Gordy diyAudio Member Join Date: Nov 2006	...and for general info on the amp try here... http://www.st-and.demon.co.uk/Audio/armstrong.html (Link checked and live at time of posting)

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