784-139 OT

All about iron and copper.

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flatart
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784-139 OT

Post by flatart » Wed Feb 24, 2010 9:06 am

I would like to build a replica of 784-139 OT.
I've looked all over the net to find all details but I've collected just few info.
I know that these are considered precious secrets and people are doing their business with it ... anyway I try
Here the result of my search, as you can see I miss a lot of info

- winding pattern it seems to be: 0.25 PRIMARY || SECONDARY ||0.5 PRIMARY || SECONDARY ||0.25 PRIMARY
- primary should be 1760 windings, diam 0.31mm
- So I should have: 440 turns PRIMARY || SECONDARY || 880 turns PRIMARY || SECONDARY || 440 turns PRIMARY
- About secondary windings: I dont know if they are connected in series (two windings of 60 turns) or in parallel (like dagnall C1998, so two windings of 120 turns, first 0-16, second 0-4-8-16) and how they are distributed.
- I don't know even secondary diameter, doing some math it should be 1.08mm, but I would like to know exact diameter
- About iron it should be classical "I-E" 96mm x 80mm, 58 laminations x 0.65mm (tot 38mm)
- For iron type I should go for M6

Moreover: I dont know the meanings of "self leads" or " flying leads", can you explain me?

I hope that someone will give me missing infos or at least confirm what I found (even directly to my email)
If not.................
I will buy another great OT from Bryan

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jerrydyer
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Re: 784-139 OT

Post by jerrydyer » Wed Feb 24, 2010 2:36 pm

just buy one in the store. :D
vids.
http://www.youtube.com/user/jerrydyer?feature=mhw4" onclick="window.open(this.href);return false;
http://www.dui-specialist.com" onclick="window.open(this.href);return false;

flatart
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Re: 784-139 OT

Post by flatart » Thu Feb 25, 2010 6:24 am

thanks a lot for your suggestion .... very precious
The main problem is that I live in Europe and if I buy a Marstran, Metro or Mercury OT I spend a lot of money in shipping and tax and moreover USD dollar is growing up....
I dont want to wind coils by myself I'm not crazy. My goal is to collect all the specs and give them to a professional maker I know. This man has been building tranformers for 30 years but unluckily he builds HI-FI stuff.

flatart
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Re: 784-139 OT

Post by flatart » Sat Feb 27, 2010 12:32 pm

I found on a russian site this schema for OT100W 1998
No way to find winding schema for 784-139.
About the schema attched, can someone tell me at least if this is correct?
Attachments
ppp.gif
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Brian Wallace
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Re: 784-139 OT

Post by Brian Wallace » Sat Feb 27, 2010 11:24 pm

I hate to say it but given the time and effort you have spent on the net trying to get an answer, you could have just done a tear down on a real OT yourself and been done with it.
Patience is a virtue.

Wallace amps

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flatart
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Re: 784-139 OT

Post by flatart » Sun Feb 28, 2010 6:49 am

Brian Wallace wrote:I hate to say it but given the time and effort you have spent on the net trying to get an answer, you could have just done a tear down on a real OT yourself and been done with it.
Brian, you didn't get the point: this is not my business, this is my hobby, I've built 4 amps in my life ...
So if I spend 200 USD (150EUR include shipping, tax etc...) to buy your OT replica, for sure I will put it on my plexi clone I'm building and play it loud! The last thing I would do is to tear it down
I'm just trying to get the same thing (or a similar thing) for less than 50EUR.

Anyway I'm givin up..

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jerrydyer
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Re: 784-139 OT

Post by jerrydyer » Thu Mar 04, 2010 11:54 am

P M george maybe he will give ya the specs. I thought our dollar was regressing to its childhood. :D
vids.
http://www.youtube.com/user/jerrydyer?feature=mhw4" onclick="window.open(this.href);return false;
http://www.dui-specialist.com" onclick="window.open(this.href);return false;

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novosibir
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Re: 784-139 OT

Post by novosibir » Sat Mar 13, 2010 11:15 pm

@ flatart

People, who can't say a nice "hello" or something similar in their very first post show oneself as pure cadger and hence can't expect much help of the other, who always help each other :wink:

Think about this for a minute 8)
The fault almost always is sitting in front of the amp :wink:

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