Neve LO1166 gapped transformers

[Spencerleehorton]

Had some EI75 lams sitting around so I thought I’d build some LO1166 gapped output transformers.
Specs wise they come out as per original winding sheet with a little more inductance which is nice.
Pri A - 9.2R (80mh) Pri B - 8R (80mh)
Sec A - 21R (220mh) Sec B - 21.2R (220mh)

Will test them in a Neve 1290 and a 2254.

Have built 5 pairs so far.

 

[CJ]

Holy shit!

 

[Spencerleehorton]

Not varnished yet and still need to trim the bolts as they are a tad long.
Used an I and slotted the turret board, took your advise as well CJ with clamping the I to the E then securing all the bolts, made my own bobbins which turned out well.
Very happy with them so far and they fit inside a 1U as they are only 38mm wide.

 

[peterc]

Very nice.

 

[Whoops]

Very nice, congrats

What did you use for the gap? and how thick?

 

[Spencerleehorton]

I used a bit of masking tape which measured the same as what was on the winding sheet. I did find a mistake on the winding sheet which I rectified.

 

[Whoops]

I did find a mistake on the winding sheet which I rectified.

Thanks

Was the winding sheet from CJ?

Could you please share what was the mistake?

 

[Spencerleehorton]

It’s in the tech docs section under Neve
Sec B should be 0.010” (0.25mm) gauge rather than 0.033”(0.314mm).
Winding what it says on there ends up being only 14ohm on the sec B and needs to be 21 ohms same as sec A.

Masking tape measures about 0.7mm

 

[Moby]

Looks nice! Do you know the manufacturer of the laminations? Are you happy with the inductance value? Can you measure it?