Fender Bandmaster Output XFMR

this one had been on the Devil's hit list for quite some time now.

was waiting for a Bandmaster to come in with a bad one. 

Schumacher  built, flat from 20 to 100K Hz, with no interleaving, just primary secondary.

no speaker taps, 

the coil is laced up Lap 1 on some 0.018" 100 EI, non grain orient.

all pruned up and ready to go,

leads are stapled to some pressboard,  probably 10 PB as we called it at the winding shop, .  (.010")

Rome Cable #22 600 Volt  105 Degrees,

no legals codes stamped on the wire back then,

secondary lead plate,

black = start

notice that the big wire is not folded over its self as in the smaller primary hookups,

another 10 PB shoulder pad to keep the staples from gouging the wire underneath,

#17 AWG  speaker wind, pretty hefty,  they did a good job winding it without any deformation of the # 32 primary wire underneath,

72 turns , 3 layers,

what does 45 mean? probably the winder's number.  QC. 

a transformer comes back and they got your number.  :-X

cloth anchors have given up the ghost after 50 years of solvent and heat,

they snap like a dry twig in a stiff desert wind,

looks like winder #40 did the primary and passed the stick o coils to the guy with the biceps for the #17,

or the girl, Myrtle could bench press 240 on the free weights, 

very nice winding job, that is about as close to a perfect wind (no air) as you are gonna get>

gotta hit that core hard to get 45 watts, some like the over driven xfmr, some wish for punch,

works good for small clubs,

print>

inductance vs frequency

this transformer was barking like a dog at max level, causing spurious response that was blowing fuses and taking out tubes,

the first 1000 turns were completely dry of varnish, so they did not vacuum impregnate or leave it in the tank long enough.

we will rewind and dip it good this time, and maybe try a full 1" stack of EI 100 in 29M6 steel and see if we can not get a little more punch at the low end,

it will be interesting to see what happens to the 100 K Hz freq response and sq wave tests.

the extra varnish should bring the response down to around 60 K.  so this is a good troubleshooting tool, if the response is too good, there might be a wax or varnish problem.

MaCintosh asked Doc Hoyer to build them some outputs for some power amps with no varnish,
he told them they were crazy, that the wires would break, 
they wanted them anyway for the extra flat response so he shipped them and the wires broke. 

here are some sq wave pics , secondary open,