Here are the exact notes from Paul (reprint..Thanks Paul!) - RBP - Bottlehead Forum

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Here are the exact notes from Paul (reprint..Thanks Paul!)

209.128.168.96

In Reply to: Attn: Voltsecond, B. Roberts...about doubled output trans... posted by jaybug on June 27, 2001 at 03:18:20:

Thanks - sounds like 8 ohms is the right number. I'll try to
describe the setup in advance, so you can look at it - feedback
welcome!
The second OPT mounts between the original and the power
transformer. (Hopefully it won't pick up hum, the magnetic axes
are perpendicular - but we'll have to try it.) Mounting holes
already exist (the TFA-2004 mounts in the same holes, for the
ParaBee). However, the new transformer will cover up the hole
for the lead wires. One approach is to raise the new transformer
1/8 inch or so with extra washers or something like that.
Another is to drill a new hole between the two OPTs. Maybe you
can think of another alternative.
With paralleled outputs you will use the 0.625-w tap on the
primary instead of the 1.25-w tap, and both transformer
primaries are in parallel. That part should be easy.
To get an 8 ohm secondary, the 4 ohm taps on both transformers
are wired in series. That gets a little tricky, because (I
think) there is no spare terminal lug. Leaving the black wire of
the original transformer connected to terminal 22, unsolder and
insulate the white 8 ohm lead. Strip off insulation from the
yellow 4-ohm lead, and solder it to the black lead of the new
transformer. Insulate that connection with the usual 1-inch bit
of heat shrink, leaving 1/3 of it past the wire. You may want to
tie this down to something so it doesn't flap around. Then the
white 4-ohm lead of the new transformer goes to terminal 24.
OK, does that make sense? If this ever becomes an upgrade kit,
we'll have to resolve these mechanical details, so any comments
on this procedure are welcome.
More later,
-Paul

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Follow Ups Full Thread

Topic - Attn: Voltsecond, B. Roberts...about doubled output trans... - jaybug 03:18:20 06/27/01 (9)

A very good Move. - RBP 14:20:55 06/27/01 (4)

Re: A very good Move. What about "distributed capacitance"? - jaybug 14:59:44 06/27/01 (3)

Once again, Thank You.<nt> - jaybug 22:28:06 06/27/01 (0)

Re: A very good Move. What about "distributed capacitance"? - RBP 22:02:49 06/27/01 (0)

Re: A very good Move. What about "distributed capacitance"? - Paul Joppa 22:01:57 06/27/01 (0)

Thank You both, and Paul too. I'll report findings when I do it. <nt> - jaybug 13:27:54 06/27/01 (0)

Here are the exact notes from Paul (reprint..Thanks Paul!) - RBP 12:42:02 06/27/01 (0)

Re: Attn: Voltsecond, B. Roberts...about doubled output trans... - Panelhead 06:30:46 06/27/01 (0)

almost forgot...Any word on resistance between input windings? <nt> - jaybug 03:24:28 06/27/01 (0)

Follow Ups

Here are the exact notes from Paul (reprint..Thanks Paul!) - RBP 12:42:02 06/27/01 (0)

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