CHAMP ELECTRONICS -" THE VINTAGE VALVE
AMP HOSPITAL"
NOTTINGHAM, ENGLAND
SERVICING A 1968 SELMER P.A.100/REVERB AMPLIFIER
As received.
As above.
As above.
As above.
Top view right-hand side showing the output transformer
and reverb drive transformer.
Top-middle
view showing the choke. Selmer were the only company that I can remember who actually had a large enough choke to pull all the 4 x EL34 anodes/plates through it on all their 100 watt
models. This makes for a much better smoothing at the cost of more weight.
Top-left view of the power transformer
and all the smoothing caps.
I hate to see tape
wrapped around wires…..Errrrr!
A previously fitted bias-pot. Always a good thing to do as virtually none of the Selmer’s had one!
Whilst almost all Philips/Mullard mustard caps are usually fine,
most of the Wima’s are too, but….for some strange reason, when you get a pair of the Wima caps @ 600 volts driving the output
tubes, these often are very leaky! This pair had to go.
New Silicone-Rubber power cord & switch.
Every Selmer 100 watt amp that uses 4 x EL34’s…..regardless of model has a very silly design issue….I will never know why Selmer did this the way they did as it can clearly cause a problem! With NOS (new old stock) or original old tubes the amp(s) are absolutely fine however, put a new set of any modern day tubes in one and the amp will go into a massive squeal! I’m not prepared to give away technicians secrets here but; what I will say is the clue is in this photo!
Design mod corrected; four nice EL34B’s & red speaker socket nuts…….all done!