CHAMP ELECTRONICS -" THE VALVE AMP HOSPITAL"

NOTTINGHAM, ENGLAND

 

THE RESTORATION OF A 1960's LINEAR CONCHORD 30 Watt AUDIO AMPLIFIER

 

 

A. BEFORE RESTORATION:

 

 

 

A gentleman, who runs a second hand music shop in Mansfield, Nottinghamshire, turned up at my workshop door one day with this rather sad looking 1960's Linear Conchord 30 watt, " bird cage" style amplifier. He explained that this was the first amplifier he had owned (not the actual one) to play his bass guitar through, as a youngster back in the sixties. It had come into his shop as a non-working part- exchange many years ago and had since been stored in his very damp lock-up at the back of the shop; hence the mass of rust. He had a place in his heart for this old amp, and simply wanted it restoring back to rights and as close to originality as possible. I agreed to take on the task and so he left it with me.

 

 

On first examination the output transformer was discovered to be open circuit on one half of the primary so, the first job was to re-wind this. On doing so the amp did in fact come to life, though dreadfully as many of the components had long died (on the photo below you can in-fact see the re-wound output transformer lying on the workbench, not bolted to the chassis but actually wired in for this testing purpose).

Blobbing a few components in here and there saw things improving, so now knowing all was going to be well the whole thing came apart for the re-build.

 

 

 

The photos really tell the rest of the story. However, I will tell you that the finished article only retains the following original items/parts:


1. The chassis, base plate, cover and handles.
2. The pilot "on lamp" and lens assembly.
3. The power transformer.
4. The potentiometers.
5. Both the EF86's and the ECC83 pre-amp valves - all Mullard. 

(One of the original Mullard EL34's was duff, whilst the other was well tired; as too was the GZ34 rectifier. I have replaced all these with JJ tubes, which I find quite good).


Apart from the above, all the other components were either faulty/tired or totally kaput.

 

B. AFTER RESTORATION:

 

 

 

 

 

 

 

 

I used to have a couple of these myself also as a kid back in the sixties, and also for bass guitar use. I seem to remember them being about 15 guineas? (I stand to be corrected there!) They were always quite noisy. However, with this re-build/renovation using today's improved components, you can't even tell this baby is switched on? Better now than when it was new!!

Cheers for your interest, John. 

 


 

LINEAR CONCHORD 30 SCHEMATIC DIAGRAMS

(Produced by John Chambers. Re-re-drawn by Giulio Maiocco. Many thanks, Giulio!)

 



 

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