Meat Plow wrote in message
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On Wed, 22 Sep 2010 17:39:27 +0100, N_Cook wrote:
Meat Plow wrote in message
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On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:
Known history with this , from its purchase in Germany onwards,
including its original set of valves (not in there and used now, but
will test out of curiosity). What are the main potential
safety/reliability issues with an amp of this age? All the cotton
covered wiring looks good but is there some test/procedure more
convincing as to insualting value? Bakelite brittleness in the valve
bases? metallurgical failure of springiness of valve contacts?
Someone modified to 3 core mains cable and made an earth point, for
240V land, at some point in its history. Numerous caps replaced in
1991 and 1997 and some carbon R replaced with MO at some point. I've
not checked the main caps yet.
No known safety issues other than mains wiring. These were pretty
reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
into a 100 watt model by replacing the iron and adding two octals to
the already blanked out chassis. I ripped all that stuff out and put
new output iron in it. It's not worth much but it does sound sweet.
--
Live Fast, Die Young and Leave a Pretty Corpse
Closer look and the cotton covering to the wiring between the output
heaters is "perished", crumbling to dust, and needs replacing. Strange
having a load of Mullard, Brimar and Z&I Aero valves to test
Since the heater wiring is twisted it would be a good idea to replace if
it is that poor of a state. I don't recall ever seeing the LV wiring in
any Fender of that era in that state and the state of all the wiring is
what I usually inspect first on any P2P wired vintage amp.
--
Live Fast, Die Young and Leave a Pretty Corpse
The conductor size, under the insulation, is only 0.7mm presumably not
enough for the current plus localised heating. Will replace with silicon
sleeved wire with "Refrasil" glass sleeving over that , dulled down with
dark green permanent ink felt tip pen, gives a very convincing contemporary
look, and surprisingly does not wipe off the glass