CHAMP ELECTRONICS -" THE VINTAGE VALVE
SERVICING A c1967 SELMER ZODIAC 100 AMPLIFIER HEAD
(CONVERSION FROM A ZODIAC 100 COMBO AMPLIFIER)
This one is very interesting. It came from a nice guy named
Mark from the London area and belongs to the bass player (I believe this was Dick Taylor at the time) of the British sixties band “The Pretty Things”. They had a few hits back then and probably their best known song was “Don’t Bring Me Down”. They could be compared to the “Rolling Stones” for their style of music. The band is still going strong…even today with most of them now in their sixties……..nice one guy’s!
Moving on to the amp itself, this was originally a 100 watt 2 x 12” combo
which is quite a rare combo indeed. Many years ago it had been cut-down to be used as just a head with whatever speaker cab was
According to Dick & Mark it just didn’t sound very good anymore and in-fact hadn’t done so for a long time. It had apparently been hocked around from one so-called service engineer to another….in
and around the London area but none of them could sort it out. On receiving it back from yet another
(and the last engineer in the area) all it was now doing was screaming……and was totally useless! This is when the guys contacted me through the website. I told them to get it to me and I
would sort it for them once-and-for-all.
This they did and it soon became blatantly obvious that all these engineers had butchered, bodged, unnecessarily mod’d, and changed so many things that it was no wonder it was now just a load of useless crap!
I couldn’t believe how bad this thing was!
I removed all the mod’s and crap wiring.
Drilled & fitted a jack socket for the Tremolo….better than just having the wire hanging out.
Drilled & fitted a second jack socket for the speakers (with being a combo originally, this only had one extension socket as the internal combo speakers would have been hard-wired). I also fitted a speaker impedance selector
as the output transformer did have the three choices (4, 8 & 16 ohms) but originally she was fixed to just 8 ohms.
Replaced many duff and bad components.
……and yet again (I don’t know how many times I have had to do this?) change the bad design problem that wont let these Selmer 100 watt amps with 4 x EL34’s run correctly with new, modern tubes.
…..and even yet again….the addition of a 20 turn bias-pot.
New HT diodes.
Full new set of nice knobs. All the ones on it were odd, broken or just pretty scruffy.
Looking and working like it really should now!
All finished. I have recommended to the lads that, as the case has been made so small
and tight, they should remove the back panel and replace this with some grill instead. This will allow a better air-flow around the 4 output tubes which do get pretty hot. I have since heard from the guy’s and they love it again now…I’m not surprised!