04-16-2014, 03:01 PM
Well, I thought I should start a new thread on this Philco 90 I picked up the other evening with no speaker assembly.
If I can't find a compatible field coil speaker with output transformer I may
just put in a 3K resistor for the coil and then come up with some
universal output transformer.
In simulating the PS circuit in my
Tina Pro simulator it looks like if I just bump up the output cap
value a bit I'll get good low ripple. I'd go with 10 uF max input cap
so as not to stress the 80 Rect. tube too much.
It also appears that I can do even better on ripple if I split the
3K resistor into two 1.5K ones with an extra C in between. May
try that also. Has anyone done this before?
Does anyone have an idea where the best place to get such
a generic audio output transformer might be?
This is the early 90 with 2 x type 45 push pull output tubes.
Philco speaker web page lists it as a K-2 variety speaker assembly
with xfrmr Zpri = 6700 Ohms, Rpri=500 Ohms.
Will post pictures soon I hope!
Herb S.
Ithaca NY
If I can't find a compatible field coil speaker with output transformer I may
just put in a 3K resistor for the coil and then come up with some
universal output transformer.
In simulating the PS circuit in my
Tina Pro simulator it looks like if I just bump up the output cap
value a bit I'll get good low ripple. I'd go with 10 uF max input cap
so as not to stress the 80 Rect. tube too much.
It also appears that I can do even better on ripple if I split the
3K resistor into two 1.5K ones with an extra C in between. May
try that also. Has anyone done this before?
Does anyone have an idea where the best place to get such
a generic audio output transformer might be?
This is the early 90 with 2 x type 45 push pull output tubes.
Philco speaker web page lists it as a K-2 variety speaker assembly
with xfrmr Zpri = 6700 Ohms, Rpri=500 Ohms.
Will post pictures soon I hope!
Herb S.
Ithaca NY
