Fender OPT 1958 Tweed DeLuxe 50246

let's get after this relic, long lost ungapped  cousin to the gapped Triad 108  OPT,

58 tweed deluxe,

start of 8 ohm  speaker secondary is yellow sleeved #21,  finish gets soldered to the frame as ground requiring tight contact with chassis for optimum performance over time,

something different with every transformer, this time even before we open up the carcass,

notice weird color code, blk-org-org

one org is CT of P-P, which one? of course, the weird one in the middle with the different diameter wire to signify CT,

and more weirdness, lam stacking goes

1-2-2-2-2-2-2-2-3-2-2-2-3-2-2-2-1

if you want to stack like original,  use to think this was an error, Gus may be right about this being done for a reason, as this is the 2nd or 3rd time we have seen this,

solder job on sec wire

square wave response as seen on secondary,  take with a grain of salt as this transformer may or may not have health problems, like rotted primary ready to snap and a secondary insl scratch exposing bare wire of spk wind to core,

we have a collapsed core tube, note lack of wood wedge which keeps core tube tight and adds a touch of convection cooling of hard worked first layer of primary,

coil is wound pri-sec like Triad 108

ok so the core lacer guy knows he is blowin it, why?

look at the lines on the coil caused by the oversized coil getting scratched by the lams,

he knows that there is a chance of the sharp lam cutting through the KP wrapper and shorting out the coil because those lams are going in with a struggle, but who will see it? nobody. QC will not take apart a varnished xfmr to check for damage, and the damage is hidden underneath the core.

you can see that the lams have scraped the enamel off the wire and that the core is shorted to the secondary coil, 

last layer spacing and margins, Triad 108 has 4 layers , this guy has 5 layers, same wire, same turns, that is why the coil build of the 50246 is wider than the build of the 108.

we can rewind with 5 layers to be true to the original if we use a Nomex wrapper which is tougher than the kraft paper. and maybe wind a little tighter.

or we can be safe and wind 4 layers which probably will not alter response in the guitar  region.

secondary lead breakout

sorry, that was my inner voice speaking, 

sec leads>

primary leads

speaker wind  has no taps, noting margins, and varnish job,

taking notes on the tape job,

looks like 12 + 12 layers for the primary halves, 175 turns per layer plus a partial layer for about 2100 turns each = 4200 total primary turns of #37 AWG.

the Triad 108 has about 4000 turns primary.

showing the buckled core tube

first layer showing margins and tape used to create a slight arc in the coil to prevent buckling which unfortunately did not compensate for blocking the coil to the core with a wooden wedge.

and last the paper former built for a sq stk of EI 87.

permeabillity (inductance) at 20 Hz, primary,

initial perm is lower thus the slow start, which corresponds also to B-H curve near axis,