UTC A-24

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CJ

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ei1j6o.jpg
 

CJ

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quick to kill, don't you want the vitals first?  sheesh! they could use a few good young men like you ,

ok then, chew on this while i chew on a utc transformer,  :D >
2cnw6qq.jpg
 

gemini86

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CJ, keep em comin... All these deconstruction threads are a goldmine for anybody trying to diy a transformer!
 

kato

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kazper said:
UTC "the magic is in the uneven stack of lam's"

Now someone can market an authentic repro and charge double for their painstakingly exact recreation of the original uneven lam stack. "For creamier tone" sez the marketing material.
 

CJ

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here we go,

this winder was so good, she used the same turns per layer on both coils, exactly.

never seen coils matched so good. full props to winder #15!
1j5a29.jpg
 

CJ

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more carnage>

28jijrt.jpg


no, not midget protection, thats is interlayer insl., fool!
2prtyl4.jpg


winder 15 did a great job on this A 24,
16jh5sj.jpg


this is the last layer of the first winding, it has 120 turns, 60 and 60, both coils had the same thing,

1j47px.jpg


ei8o6u.jpg


that long loop of wire is a sec to sec splice, it gets tucked inside the window with some pressboard,

ju72g4.jpg


pri/sec insl, and a sec layer underneath,

312h6hs.jpg


bigger margin on the bottom of coil for lead breakout,

15d5m2p.jpg


sec spacing on light layers

dyrwnq.jpg



now where's that HA-100X?

;D :mad: :eek: ??? ::) :p :-[ :-X :-\ :'( :-* :D ;) :) ;D
 

BudP

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The layer wound dielectric material is Glasiene paper, rice paper with beeswax infused. Likely about 0.001 to 0.0015 inches thick. Used so that it would not be impregnated with the varnish, just coated. This will make a big difference in eventual sound quality, as all tone is E Field losses or storage.

By the way is the D you reference a dissipation number for the capacitance?

Bud
 

MatthisD

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You wouldn't remember the wire gauge by any chance? A rough calculation based on the DCR points me towards 41AWG for the primary.

Thanks for the thread once again.
 

CJ

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we can do this, two coils involved but they are both identical,

so we can use DCR from one of the coils,

33 lams x .014" lam thickness = 0.462" stack,
a 31 UI lam has legs that are 5/16" wide,
so the core tube is .3125" x 0.462" and about 0.1" thick,
MLT calculator gives 2.25" x 2900 turns = 6525"
6525/12=544 feet of wire,

DCR is 734 ohms per coil (pri)

1000ft/544ft = 1.838 so if this wire were 1000 ft long it would ohm out to
1.838 x 734 = 1349 ohms per 1000 ft,

our wire chart says that #41 has a DCR of 1323 ohms so you have made a very good guess as to the pri wire size!  :D

 

MatthisD

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My first guess was 40AWG, it being a round number but when I worked out the average length per turn the total DCR would been about 1Kohms so too little for the primary winding. Good stuff then, 41AWG for the A-24.
 

CJ

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you can get some of that thin paper here>

http://www.dickblick.com/products/glassine-interleaving-paper/
 

bancho

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Oct 18, 2012
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I couldn't find it anywhere so I think this thread in the most appropriate...
What are the differences in different UTC versions of this transformer? There are black, dark grey and light grey versions. The black is supposed to be the oldest version... what about the other two? Any obvious sonic differences?
 

CJ

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there might be some differences in the core material, as the years went by, perm went up, so inductance might be different between the different vintages,

there is probably the biggest difference between the old black transformers and the later versions, not so  much difference between light gray/dark gray and green,

more inductance would mean the bass freq curve will extend lower,

 

lukas

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Sep 29, 2010
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Poland
Thx for blueprint this good transformer, ...for precision ...i can't see secondary wire size...?
 

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