Beyer Bv 37530

[CJ]

just a quickie on this cute xfmr,

sec was open, so we dissect,

Pri: 1.2 Henries @ 5 Hz  5 Henries @ 20 Hz, 3.1 @ 100 and 0.64 @ 1 Khz,

DCR Pri: 48 ohms,

these things are Not DIY friendly, and a real PITA to take apart,

the mu cans are pressed together tight, so you have to cut off the back of the larger can and hope for the best,
the lams are 1 piece with two  sections of bobbin glued around the middle leg, ....did i say middle leg?  ;D

anyway Beavis, they then put a wheel up next to the bobbin and spin on the wire, this makes for an ultra low leakage, high inductance (for their size) xfmr, which is what you want in a small mic input,

so the coil is a real pain to remove, you have to cut and file mu metal, which is always fun, 

 

[CJ]

no joy in getting the turns, but this is next to impossible to DIY, so it is just for sh*ts and giggles, the weird construction is kind of unique,

winding structure is Pri-Sec, only about 5 or 6 lams, high Ni,
here is another pic and i'm out....

 

[MatthisD]

I removed one from the can (so it would fit in a SDC mic), gently squishing it in a hobby vice to slightly oval it and it just popped apart. What do you call this one piece lam, double sun-roof?

 

[CJ]

double sun roof, hah!  ;D ;D ;D

just like my dad's head!

thanks for the squishing technique,

most of the beyers are done on the same lam, same pri-sec structure (what elese with a spin on system, taps would be a pain) same cans, just the turns get changed to protect the innocent,

 

[MatthisD]

I see you opened one like that with a vice-grips in an older thread...you've so many transformer threads I haven't found them all yet!

I can't imagine how the wire goes on without snapping, Look at this one, 1:1 with 750H each winding 7.7K and 5.6K DCR. I thought there might have been a bigger core inside the case but you can see the same size can inside there.