Pye Compressor OPT

[CJ]

everybody wants to build this classic compressor, but nobody has the time or the money, plus the output transformer would take a rocket scientist to design,

but hey, why not try the Allen AC1323 solid state coil and see how much smoke we can make?

problem is the 20 leads we have to cut and splice,

so why not just hack 16 grooves into a 625 EI bobbin and get after it?

 

[CJ]

don't ask me why but everybody wants two of everything when it comes to music DIY, 

no wait.......



stereo! that's it, forgot about this recent advancement in audio technology,

hey, The Supremes still sound good thru a mono AM car radio, or maybe it was what we were doing while listening to the music, 

here is coil #1 After we have already spliced and taped a million leads,

this is the second try as we lost track of one lead and had to cut apart one coil already, so be careful and take your time to mark all leads wisely if you try this winder's nightmare,

 

[CJ]

ponder this print while we spool up another coil,

gonna want nickel lams for this one, push pull so no gap,

so we make sure the turn counter is obeyed so we do not get any DC mismatch,

 

[CJ]

section #1, #36 thru a whisker wheel, past a teflon guide mounted to a thin plastic ruler, into a spring with a teflon loop, thru a guide, under some tension foam which also cleans the wire, and onto the bobbin with the DIY middle flange for a two chamber wind,

 

[CJ]

Mag Metals will sell you a box for sampling if you can trick them into thinking that you work for an audio company, (mucho $$$) or buy some from Korea on evilbay,

 

[CJ]

we just spooled up section D-4,

is this more exciting than watching paint dry or what?

 

[CJ]

you can wind the feedback coils by hand, big wire and only 55 turns each,

by the time somebody programs their fancy winding machines and sets the pitch, i'm working out on a Stouffer's chicken pot pie,
with chicken and chicken bi-products, it's all lunch meat to me,

in fact, you could hand wind the whole coil, #36 and only a few hundred turns each section,

 

[shabtek]

Whoa!

where does one get in line for 2

 

[CJ]

reheat this blog,

coils done, hooked up the leads,

 

[CJ]

dang, forgot about the fab work,

nicked some brackets off a Traynor mixer, hard labor needed to make them fit,

coil/core assy has been heated to 225 and then dipped in a can of spar varnish,

polyurethane works ok but this stuff smells better, more retro,

gotta use vintage varnish for that vintage sound, right?

plus that darn poly stuff gets corrupt after long term storage,

wewill see how the varnish keeps,

 

[CJ]

final assy, easier to install brackets after you install the bolts,

 

[CJ]

ready to ship back east to see how they work in the Pye circuit,

flat to 100 KC, as there are only 976 turns on a small core,

has a butterworth response (no rez peaks or dips) so we don't need no Zobel or nutin,

mixed in some M6 I bars to de-stress the nickel core at the bottom end, so we should be good to 18 dbv at 20 Hz which gausses out to about 6.5 kG
inductance? 58 Henries at 20 Hz, should be adequate for this low z source, (2.4K input Z)

this core bracket fab is a solution to not having any U frames on hand, looks kind of industrial, pretty solid, we can squeeze the M6  I bars tight and let the nickel lams breathe as magnetorestriction is an issue with supermalloy,

dip and bake before the brackets are installed as to get plenty of goop in between lams, it oozes out as the brackets are tightened which means the lams get coated good as to not rattle at the bottom end and to prevent rust,

 

[CJ]

here is the circuit which has a feedback winding in the OPT which is why this was subbed out over here as nobody stocks this coil/core  assy.