[AMRadio] Thordarson transformer question

Todd Bigelow - PS tbigelow at pop.state.vt.us
Wed Dec 31 12:09:32 EST 2003


Brett Gazdzinski wrote:

>Thordarson used some type of push pins, they came with the iron.
>
>I had a BIG mod transformer, the T-11m78 that had screw terminals,
>I used it in the 30K-1, and it went with it when I sold it.
>I have the same transformer with the push pins, its
>much smaller, has rounded sides, push pins on the side.
>Must have been a change, the older ones having the terminals?
>  
>
Okay, this makes sense. Mine is the one with the rounded corners, 
wrinkle paint on the end bells. Nice nickel-plated 'acorn' cap nuts on 
the ends. The openings look too small for a banana plug but they 
definitely don't looked threaded either. What do these push pins look 
like and does anyone have a picture or know of a site that shows them? I 
don't recall seeing anything anywhere here that would work, but they 
could be in a parts drawer or box full of 'stuff' and without knowing 
what to look for, I could pass them over easily (I have a lot of 'stuff').

>The T-11M78 worked very well in the 30K-1, at 2500 volts.
>Sounded quite good to me.
>

This one is about the size, maybe a bit larger than the plate 
transformer in my 30K-5, the side tag says 300-500 watts.

>I have not looked at it, but its likely possible to change out
>the push pins, by replacing the entire insulators, or adding
>a screw through each push pin with nuts, lock washers, etc.
>

Looks like you'd have to pull the entire side panel off and replace the 
insulators as one unit on this one, but I could be wrong. One could 
probably stuff large diameter, stiff wire into the holes too, but I'd 
like to do it as close to 'right' as possible.

>I have some of the push pins, but you need quite a few in
>some configurations, my pair of 4D32 transmitter will be low
>impedance, and need to parallel up both the primary and secondary,
>lots of push pins!
>

Sounds like these pins must have a hollow head, allowing you to stuff 
one inside another to double things up?  This one has 6 insulators down 
each side, and the holes are maybe 2-3 times the diameter of a pencil 
lead. Physically it appears to be the same size as the mod transformer 
for the 300G, with more connections. But I'm assuming that since the mod 
transformer for the 300G was a specific unit (instead of multi-match), 
it required fewer connection points and used studs instead of push pins. 
The opening for those push pins looks wimpy as all hell compared to the 
studs.

~ Todd  KA1KAQ




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