Replica Marinair LO1166 transformer.
« on: November 09, 2011, 03:30:43 PM »
I usually build audio transformers, but until now always for tube output. For tube line output I use “EI” European core, normally with 20 mm x 20 mm section (4 square centimetres section). I also use the 16 mm x 16 mm, always wit Grain Oriented transformer steel M-6.

Now I am interested in build LO 1166 replica for NEVE Microphone preamplifier

I can remember their specifications:

200 : 600 Ohms
1 : 1,7 turns ratio (+4dB)
Core = 20 x 20 mm approximately
I don’t know if the core is Grain Oriented M-6 or Ni Iron, that’s right, I have only M-6….!
Gapped, (when I make gapped cores I put a very thin sheet of paper).

When I make tube output transformers, the primary winding has some thousand turns, (because it shows some KOhms impedance). But in this case the primary shows only 200 Ohms (and secondary 600).

Someone can provide me any suggestions regarding the better number of turns to start experimenting?.




Re: Replica Marinair LO1166 transformer.
« Reply #1 on: November 09, 2011, 04:42:52 PM »
sure, with 20mm x 20mm core, try something like 600 turns primary to 1020 turns secondary.  wind with 5 sections similar to how you would do a tube output.  if you use regular paper in the gap, get the thinnest you can.



Re: Replica Marinair LO1166 transformer.
« Reply #2 on: November 10, 2011, 02:33:40 AM »
Thomas "TK" Kristiansson
"The Sound Is In The Iron"
www.vintagedesign.se  www.tkaudio.se


Re: Replica Marinair LO1166 transformer.
« Reply #3 on: November 10, 2011, 06:17:12 AM »
Oh, my God

Very good thread. I had not found when I searched. Excuse me.

Now I need to read completely…..

In any case, the links to vacuumbrain are broken.

Would it be possible to rejuvenate for all of us. Or, at least, the photos.




Re: Replica Marinair LO1166 transformer.
« Reply #4 on: November 12, 2011, 06:27:24 AM »
Very interesting

I have a question:

In that post I read that he disarmed one unity of LO2567. The LO2567 is exactly the LO1166 without gap. Anyway the post includes the number of turns for LO1166 (which is very similar, of course, but not identical, mystery...) and number of turns for the Reissue Carnhill and for the Sowter 8751.

Anyone know of any way to knowing the number of turns for a transformer without disassembly it?

Very thanks



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