<4f64ep$mp--(at)--anyon.sr.hp.
Lines: 50
(part of reply from Dr Distortion)
DD> A PCB-based amp that also uses rugged connectors and full-sized
chassis-mounted pots would probably be pretty reliable.
Certainly....Marshall used to make one - I haven't seen much in print
about this version, but I used to work on them when I lived in London -
Mostly replacing worn-out input jacks and pots. They used regular
hard-wired pots and jacks, mounted on the chassis, and all the
connection wires from the PCB were anchored by each re-passing through a
second (larger) hole, next to the soldered connection. I believe they
lster shifted to a less expensive construction.
If anyone is interested, this method of stress-relief of flexible wires
soldered to a PCB costs nothing more than a bit more board space and a
second row of holes just large enough to clear the wire's insulation.
On the evidence I have seen, it survived much vibration in use and
transport, and I never had any problems from the PCB's or the leadout
wires. I certainly could *not* say the same about modern
ribbon-wiring, or about board-mounted pots and jacks - which seem to be
the most common causes of amp failure.
And perhaps I could add another one ...board-mounted main fuses at
the rear of the chassis!
I have had problems with the PCB-mounted rear fuseholders on "reissue"
Fender '93 Supers and Concerts. The fuse holder is held only by thin
solder tags at the rear and middle, and a small plastic stud at the
"outer" end of the barrel. If the plastic stud cracks, the next thing to
go is the mid-barrel solder tag, resulting in an intermittent or
completely dead amp.
If you relieve the front edge of the fuseholder PCB between the
mounting screw-posts (Dremel motor and coarse grinding point);
and file the chassis hole slightly larger and upwards (towards the open
face of the chassis), making the usual double-flatted-circle shape;
....it is just possible to install a regular 1 1/4 inch chassis-mounting
fuseholder and hard-wire it to the PCB. (Littelfuse recent safety-type,
w/small bayonet cap)
BTW....does anyone have a schematic for Fender 160PS tube PA amp
I am also looking for cheap, blown, old Fender Bassman, Acro, or
similar PP O/P transformers, around 20-50 watt, which still have their
original winding construction undisturbed. I am particularly interested
to see examples of early paper-interleaved transformers, and also the
Triad? early Bassman transformer referred to in Kendrick's book as
having a more complex interleaving of windings than later models.
Regards to all,
Stephen.
stephen.delf--(at)--elcom.gen.nz
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