Neve Transformers

[ruffrecords]

CJ has kindly updated the information at the beginning of this thread so we can now see the differences between the 10468 mic transformer and the 31267 wired backwards. It is clear that the 31267 line input transformer has about 35% more turns on all windings and the dcr of the windings are considerably higher. Overall this means a 31267 wired backwards will have a slightly worse noise performance but the final noise performance is most likely dominated by the first transistor stage so I doubt the effect is noticeable. The higher number of turns may mean the frequency respose at the high end is not as goo but on balance I think it will work OK.

Cheers

Ian

 

[shabtek]

didn't JLM determine that reversed 31267 sounded best when connecting mic to only 1 coil?

the hairball lola sounds very nice and uses a current production 10468 styled xfmr

edit:
http://www.jlmaudio.com/Neve transformer info.htm
looks like he likes only 1 coil of secondary too FWIW

 

[ruffrecords]

didn't JLM determine that reversed 31267 sounded best when connecting mic to only 1 coil?

edit:
http://www.jlmaudio.com/Neve transformer info.htm

I did not see anything on that page that mentioned how the various transformers sounded. It seems it was just a test with a 500Hz square wave. Unfortunately I could find no mention of the source impedance of the test signal which is important.

Cheers

Ian

 

[shabtek]

I did not see anything on that page that mentioned how the various transformers sounded. It seems it was just a test with a 500Hz square wave. Unfortunately I could find no mention of the source impedance of the test signal which is important.

Cheers

Ian

I guess I've always inferred that his criteria for overshoot and distortion resulted in 'better sounding' or more 10468 sounding...but indeed there is no mention of the sound.

towards the top 50Ω and 200Ω are indicated but it is not clear which if either is used for the colored traces.

 

[ruffrecords]

I guess I've always inferred that his criteria for overshoot and distortion resulted in 'better sounding' or more 10468 sounding...but indeed there is no mention of the sound.

towards the top 50Ω and 200Ω are indicated but it is not clear which if either is used for the colored traces.

You are right, they do mention two source impedances, 50 and 200 ohms but it is not clear which one the graph relates to. The thing is, I know from my own tests that with a low source impedance you can get a pronounced peak at 40KHz or so and the response can be a dB up at 20KHz. But when fed from a 150 ohm source, these transformers are flat out to beyond 40KHz. I have seen this effect on Sowter, Jensen and Cinemag mic input transformers.

Cheers

Ian

 

[Uk03878v2]

Sorry for interrupting the thread, looking at the FAO name and address, that brings back some memories
Years ago I had that shell company (Smartaction) and yes it is me but I don't live there anymore - I used it to get the information which got posted here (I was not a sales rep - I pretended to be to get the schematic)