Melodium Type E 40 ES Transformer

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CJ

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fresh meat on the chopping  block  from Portugal, full props going out to DIY member Tiago!  ;) ;)

like throwing a steak to a hungry linebacker,

Ribbon mic transformer,  Moving Coil people dig them too.

http://www.coutant.org/melodium/melodium.pdf
http://www.coutant.org/melodium/
http://www.tube-classics.de/TC/MyEquipment/Listening/MCPreamps/MCData.htm





 

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CJ

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low Z input with a ribbon mic,  gonna need super low ohms so we don't eat the microscopic signal,

that means copper foil slit into flat wire, saw this on a Western Electric hack a while back,

you can see the copper ribbon breakout on the left,

possibly from the Ortofon factory, or maybe Sennheiser,

big bucks on ebay
 

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CJ

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secondary wind is open,  got some funky varnish, kind of like early Langevin pine sap smell stuff,

done on a 50 EI, 1/4" stack, 19 lams,

gotta wrap some winds to get inductance, or inject a few mv AC into that low turns secondary,
 

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CJ

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here is the outer layer, those foil tabs were actually the hookup leads for the small secondary wire which looks like #44 AWG.

got some weird fabric mixed in could be silk served wire, ho did they do that?  probably very carefully
 

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Tubetec

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Years ago I scrapped a few big chunky power amps known as 'Vortexion' 30/50's ,they were highly regarded by many players around here for bass and p.a. use.
I reused the chassis for other projects along the way .
What I was left over with was about a dozen 30 ohm to hi-z input transforemers ,they come in a thick cylyndrical  mu metal can about two and a half inches high and an inch and a half in diameter, units of similar quality would cost hundreds a piece nowadays Id imagine.There about twice the size of the usual  input transformers you see  ,I only have a handfull of vlz mics ,so I was thinking at some point of trying to rewind a few into more suitable impedences for modern mics , would this be considered a crime against transformers , seeing as their all working units ,

youll find a picture below of very similar units.

what on earth is that hairy stuff you found in the melodion tx ? :D
 

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PRR

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> could be silk served wire

Could be.

You may have to unravel your girlfriend's pantaloons to fix this wind.
 

Tubetec

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ahahah ,
Pantaloons ,that sounds so old world ,
I'd say its G-strings all the way in Cali these days .
 

CJ

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they might have wound that wire side by side with some thin string to keep the turns apart,

800 bucks holy moly,
 

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Tubetec

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Hmmmm ,
I guess 30 ohm primaries are about right for MC cartridges as well as ribbons and some dynamics with lo-z outputs .
Maye best to hold off hackballing  those Vortexion units I have until I established what their worth, the mu metal sheilds on them are 2mm thick , you just dont get stuff made like that anymore .
 

CJ

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hack job complete,

here is the core tube and the first primary layer

45-54-41=150 T

 

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CJ

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we have a wire shield between the pri and sec,  58 turns,

wire over the start type anchor,
 

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CJ

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really do not know how they did this, finish anchor, wind right over the finish, must have pulled it tight after final turn, way old school technique,

not the flattest platform for winding 5200 turns of thin  secondary wire along with a thread in between turns,

 

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CJ

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secondary start, the lead gets soldered to that copper foil,

some of the string left that gets wound bi fi style with the pi wire,
 

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Tubetec

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Lots of great reading material turned up on another post relating to transformer winding here ,so Im getting stuck into that ,
Im a little intimidated by the math , maybe I should have put more effort in back in my school days ,instead of skipping class ,
drinking beer and chuffing on herbage  ;D
Its not that hard really ,I think its more about becoming familiar with the terminology , a little practice on the formulas and equations and Ill get there alright.
The more I look at the choke loaded parafeed topology the more sense it makes ,cost of components is pricey ,but done right
clean and level frequency response to 100khz is do-able without negative feedback .
The step by step approach with pics really makes a big difference ,Cheers CJ
 

CJ

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checking the lams out, 40 Hz inductance test,

1/4" stack saturated at 20 volts when first energized, but woke up after a while so Henries kept climbing past 20 volts,



 

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CJ

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here is inductance vs frequency, 
 

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Whoops

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Hi CJ,
I'm happy to see you had fun with that transformer.

I'm having fun seeing all the hacking now.

The transformer came with an old shure mic I bought in a random ad. The transfomer was not original on the mic, it was some wired later, it was also not installed in the microphone it was installed in a huge and heavy cylinder shaped shield. I will try to get some pictures when I'm back at the shop

Regards

Tiago
 
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