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Vortexion EG20


From Vortexion
Probably one of the very earliest British electric guitar amplifiers.  This one turned up on eBay in September 2010.

 
From Vortexion
 
From Vortexion
 
From Vortexion
 
From Vortexion
From Vortexion
From Vortexion
 


Valves


Speaker

  • 12 inch Goodmans Audiom 60.  15 ohm, 15 watt. 

Here's an advert for the "new" Vortexion EG/10 from Wireless World November 1947.  This looks to have a smaller loudspeaker, probably 10 inch like the Dance Band amplifier advertised at the same time.  My guess is that the EG/10 used a pair of CL33 in push-pull rather than the four CL33 in parallel push-pull of the EG/20 - but it's only an educated guess.  Again I'd guess that the EG/20 was produced about the same time and few were made. No adverts for either amplifier appeared in Wireless World after November 1947.
 
From gadgets

Later there were other, far more popular, British guitar amplifiers, e.g. Vox.  See also http://www.vintagehofner.co.uk/gallery/gallery3/selm.html



Restoration

In the condition it was found in it made no sense to power up.  Some folks will just apply power and see what happens,  I often see items advertised on Ebay with a note that "all the valves light up".  I'd be far more interested if the seller hadn't risked blowing it up taken a test meter and checked continuity of the transformer windings. I wonder what happens to the stuff that folks find and goes BANG! when they check to see it it "lights up"? 

As with any amplifier or radio of this age what I expected to find was that most, perhaps all, of the capacitors had failed.  Some large electrolytic capacitors have extraordinarily long lives, so I favour testing them and giving them a chance to "reform".  With this amp I found that the two larger capacitors were good, but the dual electrolytic smoothing HT for the two EF40 had failed, perhaps due to heat from the metal rectifier. 

Here are some photos taken after the defective capacitors and the heater dropper resistor had been replaced.

From Vortexion
The wire to the dropper doesn't look great -but this is a temporary measure for testing.
 
From Vortexion
  The replacement electrolytic is a NOS Plessey from the late 1960s.  Take care when using old capacitor stock - some are no good at all.  Old capacitors are not something I'd ever pay for, but if you have them they can be worth trying out.
From Vortexion
 
From Vortexion
 

 
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