Having listened to both Nickel %50 ie Perma 50 and Nickel %78 MU Metal there is a difference in sound regardless if they are C core EI cores with the purity of metal is the most important .
For instance I have Double C cores Perma 50 with pure Silver Primary and Secondaries just like Kondo Ongaku Perma 50 then the %78 Nickel EI 96 cores with OCC copper sound better IMHO , I know AN UK will differ on this ie IE v C core Nickel and used to charge a fortune for their C core and silvers , Large EI96 Nickel %78 & OCC copper wire suited me and more natural sounding , so a great deal of Hype around the Ongaku , low vibration capacitors etc , you would need to actually hear these products before believing any of the reviews that generally come with lots of adds as part of the deal .
For instance I have Double C cores Perma 50 with pure Silver Primary and Secondaries just like Kondo Ongaku Perma 50 then the %78 Nickel EI 96 cores with OCC copper sound better IMHO , I know AN UK will differ on this ie IE v C core Nickel and used to charge a fortune for their C core and silvers , Large EI96 Nickel %78 & OCC copper wire suited me and more natural sounding , so a great deal of Hype around the Ongaku , low vibration capacitors etc , you would need to actually hear these products before believing any of the reviews that generally come with lots of adds as part of the deal .
Last edited:
He was getting really spicy in another thread and got moderated. Don’t know if he was banned or if he left in a huff. Neither would surprise me.
Thanks,
I need to do some reading to brush up on my understanding so apologies for dumbness and lazyness on my part. What little I know about transformers has faded from memory.
I imagine for 78% vs 50% Nickel, a much bigger core would be needed for 78% to reach the same LF roll off. But as a starting point how much bigger % size core are we talking. Have you posted photos; I haven't read all the posts here nor that "show me your iron/winding thread"; (it's on my to do list). If so could you please point me to them.
I used to think that as a general rule bigger cores lead to poor HF response but then realised/ was informed that is not true and in truth that good HF can be attained with big cores; budget permitting being the constraint.
I gather 50% is available in c-core but the higher % Nickel types are (generally) only in EI. Is that right.
Silver must be mighty expensive, if I recall the silver vs copper conductivity is only a small % difference. I would have assumed tight winding making full use of the window, correctly sized teflon/paper, and square wire would have bigger impact than silver. Does skin effect come into play, wonder if silver plated magnet wire is available / worth considering. Only ever seen magnet wire in full copper round and occassionally square; never silver but clearly it is/was being manufactured somewhere. I did wonder if the varnish/enamal matters much, type & thinkness, is it a choice between polyester and polyurethane.
And then there is PI winding, have there been any recent examples/ testing/ designs done to see if this is a better compromise.
I need to do some reading to brush up on my understanding so apologies for dumbness and lazyness on my part. What little I know about transformers has faded from memory.
I imagine for 78% vs 50% Nickel, a much bigger core would be needed for 78% to reach the same LF roll off. But as a starting point how much bigger % size core are we talking. Have you posted photos; I haven't read all the posts here nor that "show me your iron/winding thread"; (it's on my to do list). If so could you please point me to them.
I used to think that as a general rule bigger cores lead to poor HF response but then realised/ was informed that is not true and in truth that good HF can be attained with big cores; budget permitting being the constraint.
I gather 50% is available in c-core but the higher % Nickel types are (generally) only in EI. Is that right.
Silver must be mighty expensive, if I recall the silver vs copper conductivity is only a small % difference. I would have assumed tight winding making full use of the window, correctly sized teflon/paper, and square wire would have bigger impact than silver. Does skin effect come into play, wonder if silver plated magnet wire is available / worth considering. Only ever seen magnet wire in full copper round and occassionally square; never silver but clearly it is/was being manufactured somewhere. I did wonder if the varnish/enamal matters much, type & thinkness, is it a choice between polyester and polyurethane.
And then there is PI winding, have there been any recent examples/ testing/ designs done to see if this is a better compromise.
Last edited:
.....so I found enamelled 99.99% silver 1750USD/Kg, Silver plated for $100 and flat copper $30, round copper $15. Thats quite a difference.
Silver 7% more conductive than Copper, both have a T/C of around 0.39%, which got me wondering about the magnetic properties of the core materials at different temperatures. Visions of using a Peltier,heatsink and insulated metal-can come to mind as does condensation and HT. Does anyone have links to temperature relationship for core materials; I would assume the research exists.
Thanks
Silver 7% more conductive than Copper, both have a T/C of around 0.39%, which got me wondering about the magnetic properties of the core materials at different temperatures. Visions of using a Peltier,heatsink and insulated metal-can come to mind as does condensation and HT. Does anyone have links to temperature relationship for core materials; I would assume the research exists.
Thanks
..... so I stumbled across this. Only quick scanned it, but seems to suggest (if I am reading it right?), that temperature a bit above ambient is optimum for the core. So I need to cook the core but not the winding.
See fig 11 on paper 24 or 26
https://vacuumschmelze.com/03_Documents/Brochures/PHT 001 en.pdf
See fig 11 on paper 24 or 26
https://vacuumschmelze.com/03_Documents/Brochures/PHT 001 en.pdf
Attachments
From a technical point of view, not worth it. Even tube amp chokes with an iron core, for most of the part need no more than two vertical splits. Otherwise, core to coil capacitance takes over, killing the idea.
As far as interleaving goes, you get the same capacitance vs leakage inductance laws. In PI interleaving, the leakage inductance decrease this time depends on the coil thickness, not length. So cores with a big window are prefered for PI interleaving.
My best idea with PI winding so far was stacking PCBs with trace windings to demonstrate different interleaving strategies with leakage inductance and capacitance distributions. You could stack, connect and demonstrate in a hurry. The idea was not yet put into practice due to time scarcity.
Transformers with bigger cores are always easier to achieve a higher bandwidth, as core surface area increases by a square factor, compared to the Mean Turn Length of the core. With a bigger core, you need a lesser amount of primary turns to achieve the same leakage inductance value, then you can get less interleavings. And the little P/S interfaces you get, the more you can cheat to decrease capacitance by redirecting primary layers, getting better Ls * Cps ratios. Ideally, one can get zero primary to secondary layer capacitance with a single P/S interface.
The main limitations for bigger transformers are:
-Footprint
-Materials cost
-Finding available huge enclosures on the market. How often do you see potted 100W SE transformers in boxes?
-Probably the lack of strong lower back musculature in many audio enthusiasts, except for floorstand speaker builders.
Last edited:
I have used Parafeed Nickel Autoformers as discussed earlier and they work well and can be much smaller , but having said all of this through my journey I was happy with Double C HiB core and would not loose any sleep if I could no longer get any Nickel .
Remember you will need a stack of EI96 Mu metal about 5 kgs for a 2A3 as it saturates so quickly , Auto formers are the easiest way around this problem , but then your Anode Choke Load has to be excellent and very well wound for Audio use. I also found the coupling capacitor needs to be of good quality 3.9-4.7uF , metalized polyprops are fine as the signal level / current post the Anode Choke is quite high , you wont need to spend zillions to find something a 4.7uF / 600v Mundorf Mcap Supreme or a 3.9uF would suit, I actually found the bass response of a 3.9uF measured well in the final result and less sluggish sound more speed .
I hope my findings are useful and prevent others spending a lot of money trying all these core types in the hope of audio nirvana , Nickel mixed with M6 works well puts more meat on the bones .
Remember you will need a stack of EI96 Mu metal about 5 kgs for a 2A3 as it saturates so quickly , Auto formers are the easiest way around this problem , but then your Anode Choke Load has to be excellent and very well wound for Audio use. I also found the coupling capacitor needs to be of good quality 3.9-4.7uF , metalized polyprops are fine as the signal level / current post the Anode Choke is quite high , you wont need to spend zillions to find something a 4.7uF / 600v Mundorf Mcap Supreme or a 3.9uF would suit, I actually found the bass response of a 3.9uF measured well in the final result and less sluggish sound more speed .
I hope my findings are useful and prevent others spending a lot of money trying all these core types in the hope of audio nirvana , Nickel mixed with M6 works well puts more meat on the bones .
Last edited: