Drake 50 Watt OPT

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CJ

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this is a nice Drake out of a nice Marshall Super Tremolo

it has a lot more primary turns than the later Drake and Dagnall transformers which mean. s more primary indutance.

i think

i forgot to measure it, so we do not know what the lams will do until we finish the rewind.ing

nothing special about the winding structure, has random wound primary sections, and next to nothing in the way of insulation which does cut down on leakage inductance but makes for a risky coil due to punch through when you hit that high E note on a 24 fret BC Rich Seagull.

Flux is pretty low, 9.4 K Gauss at full power so this thing is loafing along in the comfort zone,

while i was unwinding the secondary i said "this wire is too thin for a 16 ohm tap, and too many turns!", turns out it is a weird PA output, not totally uncommon but uncommon on a git amp if that makes sense,

Drake 50 Watt OPT.jpg
 
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In Marshall terminology, “Super” denotes 100W. So if the Drake OT you describe here came from a Super Tremelo, it should be a 100w transformer.
 
50 watts

can not find much info

here is a guy playing one



the one i am working on turns out to be a reissue, dang it!

can't find much info on it either,

mst.jpg
 
Older Hiwatt amps had a 100v line option on the impedence selector ,
Seems like a dangerous shock hazard by todays standards , especially if theres 4 x KT88's across the primary .
 
yes this amp has 100V on the z switch, i would worry more about some guy going"hey, lets try this 100v out on this 4 x 4 cab and see what happens,".

100v.jpg
 
100 volt 'line' output was common for PA (as in Public Address) speaker connections so you could run hundreds of yards of twin wire around sports fields etc. Why they would retain it on a guitar amp is more of a mystery. Drake Transformer factory was 'just up the road' from where I went to school.
Looking at the transformer winding picture it does indeed say 100 Volt (PA) output.
 
Theatre I used to work in in the west end had a 100v line system for the comms to the dressing room and was indeed powered by a Marshall as we were mainly punks in those days it caused us great amusement that all the old luvvies were being called to the stage via a Marshall. Someone nicked it when we started putting bands on
 
I remember reading about the use of 100v line out tube amps as a kind of invertor drive for synchronous motors , turntables and tape machines by the BBC . I think it was a modified Vortexion 30/50 fed with a sine wave to generate a variable frequency drive signal in the region of 110v RMS . Maybe the 4 KT-88's in my 200W Dave Reeves era Hiwatt could drive the capstan on my C37 with margin to spare .
A modern PA amp with a large transformer of the appropriate ratio across the output would be a more sensible approach but the fan noise might be deal breaker unless you have a machine room .

Partridge Transformers , Devizes,
What ever happened to them , cornerstone of the Hiwatt loud tone,
Ive used a couple of vintage Partridges in amps Ive made ,
they knew their stuff ,
Hopefully the I/P still exists and hasnt been sucked back down the plughole by the A.I.
 
64 ohm outputs were common for restaurants and stuff like that,

that has me wondering, how did they pipe in music into elevators? must be a transmitter,
 
My first official job was at Vortexion. £1.09 an hour. They had moved on to the 'modern' transistors when I was there. Apart from Public Address amplifiers they also make 'talking books for the blind. 2 X 3 inch spools of tape in a plastic 'cassette' so a bit like VHS and by using a 4 track head (and turn the cassette over at half time) running at 15/16 of an inch speed (half the speed of a Phillips cassette?) you could get 13 hours onto the 3 inch spool of tape!
 
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