Willesden EM 20014 Transformer Standon Herts England

never seen one of these before, from England, probably used in some sort of mixing setup from over there, maybe a Neve or something like that,  what's a routing module, anybody ever heard about one of those?

so it is a new kid on the block for the old fart down the street, 

so let's get to a hackin and a hewin,

we got a template, now all that's left is to fill in the blanks,

40 Hz saturation test, this alloy looks like square loop, quick on the rise, then hits the wall like a stock car with a stuck throttle,

inductance quits at 1.4 V-rms, would be better to keep your level at maybe 500 mv if your were serious,

has to be a mic input,

this graph could be thought of as a B-H loop with out the hysteresis on the way back down,

resonance at 60 KC

overshoot, no network

delam on isle 5

30 EI which means a tongue of 0.3937 , nearest match is 38 EI (English)

0.308" x 0.3937" = 0.1213 in^2 x (2.54^2) = 0.1213 x 6.4516 = 0.7826 cm^2 core area.

we need the coef of inductance for this metric lam,

not listed in the mag met pages, we can calculate perm after we get the turns, to see what alloy we have,

formula for inductance from which we extrapolate >

darn, we need the magnetic path length, wtf?

ok then, we extrapolate that too.

average path is the path the flux takes around the outside plus the shorter path inside divided by 2.

why do we not use the path around the complete core?
do i look like a rocket scientist to you? how the f should i know,  ;D


anyway, we are not dealing with exact science, we are dealing with transformers. 


15mm + 15mm +25mm + 25mm = 80 mm and

5mm + 5 mm + 15 mm + 15mm = 40 mm

80 + 40 = 120

120/2 = 60 mm MPL  for 30 EI metric laminations

ok we have everything to build the coef ind

L=0.4 pi N^2 A u/MPL x 10^8

note that we should build for a sq stack, so A has to be adjusted from above,  10mm^2 = 1cm x 1cm=1cm^2

simplify

L= 1.2566 N^2  x 1 x u /  6.0 cm x 10^8  so

L= 0.2094 x ^-8  N^2 u  where N=turns and u = effective permeabillity,

we can  cross check with a lam that is close,  38 EI (Imperial),

  Coef Ind 38 EI = 0.1560^-8    looks like we are ok,

there is probably a metric catalog out there with all this but the Social Security age prediction chart asks "do you use your brain frequently?" 

last thing to do is unwind the coil but let's have some fun with the spreadsheet,

we already have some inductance and saturation figures, can we guess the turns?

here is the new sheet generated for a 30 EI metric lam with the stack area and coef ind added,

looks like 350 turns is a balance between semi-real saturation and induction data,  based on the inductance curve for the primary,

looks like some serious alloy if we guess 150,000 for the u-eff.

time to unwind the coil and see,

Similare to Belclere I guess as I've seen both types in Neve modules.

Tekay said:

Similare to Belclere I guess as I've seen both types in Neve modules.

Click to expand...

Must have been later Neve's as, according to Companies House, they did not begin trading until the mid 90s which would make it AMS/Neve only. Unfortunately the company no longer exists (it was dissolved).

Cheers

Ian

20015 mentioned in an add>

"Here is the Belclere/Willesden TF10015/EM10015 transformer as used in Neve 8108 consoles, also neve 5104(baby V) and others. You are buying ONE transformer; I have shown more in the pictures to show the sizes and that the 2 part numbers are the same item. I have measured these and they are stellar transfos; feeding tones into the primary, I measure each secondary having its rolloff -3dB at about 3 hz, and -3dB at 39Khz.  I've shown the schematic from a Neve mic preamp, and you can see there is a single primary and 2 secondaries."

very similar to Marinair, same type of bobbin with pins, shields done the same, 42 turns per layer hand wound which is the same, ratio about the same, only done on an EI core,

coil structure is sec-pri-sec,

outside secondary>

one of two shields coming off, copper foil wrapped in poly tape and then 2 1/2 more wraps of tape,

center section is the primary, looks like #32 AWG,  552 turns,  42 T/L,  another shield under that wind as well.

shield hookup, that sleaving is real squishy, it flattens out real nice after a few turns so as not to upset the coil shape,  would love to find a source for that stuff,

and the bobbin,

does not say ICM on it like the Marinair forms, but it is brittle like  molded Bakelite/Phenolic material.

so on our turns estimate, we were going to be off on either our saturation level or our core perm,

turns out the saturation level was off, a perm of 140,000 seemed optimistic for sure, and we could have traveled further out on our B-H curve and still had plenty of Henries,

so the perm comes down to 54,000 and the saturation goes up to 3.4 volts at 40 Hz.

conclusion: better to do a turns estimate by core perm than saturation level.


here is the print>

This where they were based, see last paragraph....
http://cinematreasures.org/theaters/43922

CJ said:

20015 mentioned in an add>

"Here is the Belclere/Willesden TF10015/EM10015 transformer as used in Neve 8108 consoles, also neve 5104(baby V) and others. You are buying ONE transformer; I have shown more in the pictures to show the sizes and that the 2 part numbers are the same item. I have measured these and they are stellar transfos; feeding tones into the primary, I measure each secondary having its rolloff -3dB at about 3 hz, and -3dB at 39Khz.  I've shown the schematic from a Neve mic preamp, and you can see there is a single primary and 2 secondaries."

Click to expand...

People say all sorts of things in adverts. The 8108 came out in the mid 80s which appears to be before Willesden existed ( 1995). Maybe they were a second source in the late 90s until Willesden folded on 2002. Do you have a link to the ad?

Cheers

Ian