Type 45 tube Permalloy Output Transformers

[Simply Audio]

Over the years I have tried many types of output transformers, Double C core EI core , Hashimoto, Amorphous NPA ,Electra Print, Tamura, Audiofeast/ Noguchi Finemet , but had read so much about Permalloy / Nickel being very nice I went in search of some .
I tried the small Sony / Tamradio Nickel 5K transformers , they were very nice but lacked frequency extension at each end.

Tamura 7000 @ 38% Nickel - Permalloy series are no longer made and silly prices on ebay .

Nickel Permalloy has become my new go to for cores .

 

[Zeta4]

Hi

Ive built lots of small signal transformers including sut's and TVC's in 50 and 80% nickel with both thick and thin laminations plus amorphous and nano crystalline
versions. Ive come to my own personal conclusion as to which material I prefer. Ive not built any interstage or OPT's but someday I would like to give it a go so I
would be very interested in your experiences.

 

[57786]

You are winding them yourself?.

 

[Zeta4]

Yes I wind them myself, The simple ones on a manual winding m/c I have, the other more complicated ones on a friends automatic m/c.

 

[schmike]

Over the years I have tried many types of output transformers, Double C core EI core , Hashimoto, Amorphous NPA ,Electra Print, Tamura, Audiofeast/ Noguchi Finemet , but had read so much about Permalloy / Nickel being very nice I went in search of some .
I tried the small Sony / Tamradio Nickel 5K transformers , they were very nice but lacked frequency extension at each end.

Tamura 7000 @ 38% Nickel - Permalloy series are no longer made and silly prices on ebay .

One guy in the USA winds Nickel / Permalloy and one in Malaysia but at over $1000 USD a pair ,very expensive .

So decided to import EI96 %50 Nickel / Permalloy laminations from South Korea .
EI96 x 40mm thick was needed , probably 80mm for 2A3 and 100mm for a 300B .
They came without holes so need to arrange CNC cutting 4.2mm holes on the E and I laminations .

Next having a master winder designing the layering , winding , Inductance , keeping leakage capacitance levels low to the performance I wanted .

As a SE45 only requires 5K/ 8 ohms 2 watts 34-36mA then setting the Max output to 5 watts @ 50mA was sufficient .
10Hz -1db 60KHz -2db 1KHz at full power has been achieved .
Monitor the impedance versus frequency, the phase difference too that has to be kept as minimum as possible <30 deg
I will have more tech info soon .

These will be built into a single ended 45 driven by a C3g in triode so am looking forward to measuring the performance on the Tektronix Audio Analyzer.
Will post my findings as to how the sound compared to Hashimoto Orient Steel ( Grain Orientated typically M4 ) Double C cores of GOSS M3 , Amorphous and Finemet, also EI M19 steel .

I may then look to try %80 Nickel / Permalloy .

Hi sir,

Can you let me know where can I buy the laminate?
May I have the contact?
Thanks