Take a look my friend. Nickel core. I use the 1:5 as 5:1 in a few SS microphones. I use the 1:2 in a few M1 style mic pres. I actually use a stereo mic pre with those 1:2 amping my passive summing box. The 1:8 is in a FET and octal tube mic pre. No mu metal can just a foil shield, but sensible placement can work satisfactorily.I only see one Edcor 1:8 for mic pre duty on their site and, since it's M6 steel and not in a mu shield can, I'll make a guess as to how it might be "pointed" in any mic pre I built... I'd point that 1:8 sucker straight in the bin.
No disrespect to Analag or Edcor.
My bad, I clicked the wrong Google link which took me to a steel core 1:8.Take a look my friend. Nickel core. I use the 1:5 as 5:1 in a few SS microphones.
I´ve been playing around winding my own IPT on nanocrystalline toroidal cores.
Nice I dont have any good measuring tools. So I cannot determine were it self resonance... THD... , but the details are great and it has an egde on the noise perforamnce side. I´ve seen some hifi guys winding SUT on similar cores. You reach a resonable primary inductance with few turns on this cores, and that really hepls with all the trafo parameters... The sectioned secondary is layed in a progressive maner... and you just circle the toroid ones...Nice - around here, we're also experimenting with winding our own toroid amorph's for microphone inputs (for a upcoming G25 recording amp, probably). Still fighting assymmetries in secondary capacitance distribution, but fun and a great way to learn..
If you have 260 turns on the primary you got 4H at 10K, that should be even higher at lower freq. Secondary is then 2000 turns. Maybe easier to go for 1:5. 260T:1300T? The goal would be to do a easy to DIY toroid IPT... To do layers of pri and sec is to hard if you wind by hand.... The "semi" progressive as I described is probabably the best/simplest to do it without machinery...What primary impedance at what frequency and what input level are you aiming for? From quick calculation the way I would set it up I would estimate your primary turns are too low by maybe a factor 2, but that depends on your chosen constraints.
Also if you only wind secondary straight on the primary I think you might run into problems with high-end, particularly at a high ratio like 1:8. Look at the sectioning of the V72 input transformer in order to avoid capacitance between the windings or other dissections from CJ of more conventional input transformers.
Yes and no. This is very true for traditional nickel-based high-AL cores like mu-metal and radiometall - but for (most) nanochryst materials there is not this raise at lower frequencies, so we need to incorporate ALL the needed primary inductance for lower frequencies..If you have 260 turns on the primary you got 4H at 10K, that should be even higher at lower freq.
I will look that up I have MAC at home hope it worksREW = room Eq wizard . A fantastic and free software capable of audio measurements ,bandwidth and distortion etc. It works with your existing audio hardware seamlessly . You can generate a test signal , feed it through what ever you want to test and get a graph of frequency responce .
As mentioned by Abbey and Winston input transformers rely on capacitive balance between sections to get good HF responce , thats hard to achieve with hand winding . There was one Polish company winding sectionalised toroids but he was keeping tight lipped on his methodology , he seemed to be spacing out the sections equally around the circumference of the ring core.
Im actually going to get a better LC meter so I can measure at diffrent freq. What are your thoughts on minimum primary impedance. A bare minimum seems to be 2H but many IPT has much higher inductance. And you are trading primary inductance against all the other parameters. I have 2 options. A singel layer with 0,2 mm wire=4H 260T or 0,15 mm = 7H 360T?Yes and no. This is very true for traditional nickel-based high-AL cores like mu-metal and radiometall - but for (most) nanochryst materials there is not this raise at lower frequencies, so we need to incorporate ALL the needed primary inductance for lower frequencies..