For Sale Pair(s) of vintage NFLü-325

[Rodeodave]

One of these days imma do a frequency and distortion sweep on my Boonton 1121A with these...

They do sound lovely btw

 

[jean-paul]

Did the original boxes come with any additional goodies such as spec sheets or graphs or anything?

No unfortunately. I was hoping for a clearly drawn schematic. What I have is too basic. There were some schematics on a Korean or Japanese website but they are deleted or untraceable.

Sometimes they show up, often spelled wrongly. They are called NFLü-325 not NFLU-325:

https://xfoaudio.com/products/2-cha...ansformer-isolation-saturation-coloration-box

 

[jean-paul]

If one promises one should deliver. Not the electrical datasheet of the Niederfrequenz – Fernleitungsübertrager (NFLÜ) but it may be helpful.

 

[jean-paul]

Juts another possibly useful drawing.

 

[LongRanger]

https://newaudioportal.com/topic/926-аудио-трансформаторы-для-малых-сигналов/page/2/
I think this is the source that the picture.
20,7 and 22,4 H at 100 Hz for the primary is probably more accurate. Its still very impressive for a 13 Ohm winding.

 

[jean-paul]

They are impressive transformers in many aspects provided one takes the time to implement them optimally but I don't have any anymore as I like relatively small devices. I use Haufe transformers instead.