I am trying or want to try to build a 4:2ohm Impedance transformer.
I am going with an EI type but then found out there are many different types of silicon laminations.
I've come across H18, Z9, Z11...
What type of silicon steel laminations would be best for impedance transformers?
I am going with an EI type but then found out there are many different types of silicon laminations.
I've come across H18, Z9, Z11...
What type of silicon steel laminations would be best for impedance transformers?
I can't answer your question, but I suspect someone who can answer your question will need to know more about the application, for example, power handling and frequency response.
Sure. What I know is it is for an audio application running up to 200watt at 100Hz-12KHz.
The one I have that failed is using a cardboard former that is 52mmX30mm and the 124 EI laminations are 85.8mm wide and 71.6mm high with a thickness of 0.35mm
The one I have that failed is using a cardboard former that is 52mmX30mm and the 124 EI laminations are 85.8mm wide and 71.6mm high with a thickness of 0.35mm
What is the application, can you reconfigure the load for 4 ohms instead?
But what is your application? Exactly what is the load, are there multiple speakers in parallel?
There are many disadvantages to using a 2 ohm load.
There are many disadvantages to using a 2 ohm load.
You are talking about a high power audio transformer. This is big iron if it really has to handle 200W at 100Hz. And if it saturates you'll take out the driving amp... The key parameters of a core is the cross-sectional area of the magnetic circuit, the length of the magnetic circuit, and the core material (which is likely to be electrical steel (silicon steel)). From these you can figure out specific inductance of the core and its saturation flux.
Did the old unit work? I guess if it failed there was an issue?
Did the old unit work? I guess if it failed there was an issue?
I made an auto transformer out of the core of a microwave oven transformer with some no. 10 insulated stranded wire and filled the core with wire and tapped it half the way, about 20 turns then tap and another 20 turns, works a charm for high power.
Note that a 50% tap is a 4:1 impedance ratio, not 2:1. 2:1 impedance tap is at 71%. A transformer doesn't actually have an impedance so an 8 Ohm/4 Ohm transformer would work well, with a bit of loss. The rated impedance is related to the frequency range etc.
https://www.ebay.com/itm/2260259941...oc:2&msclkid=8d13e11adcc518bb1e4686ff4f0cb5f7
But using transformers for audio is a big compromise and to be avoided if possible. I would double the output transistors on the amp, and/or reduce the power supply voltage to 70% if possible. You could also build a buffer amp etc. Replacing the power amp is probably cheaper than making a transformer and definitely provides better results.
https://www.ebay.com/itm/2260259941...oc:2&msclkid=8d13e11adcc518bb1e4686ff4f0cb5f7
But using transformers for audio is a big compromise and to be avoided if possible. I would double the output transistors on the amp, and/or reduce the power supply voltage to 70% if possible. You could also build a buffer amp etc. Replacing the power amp is probably cheaper than making a transformer and definitely provides better results.
Somehow I knew someone was going to jump on that....but you know what in the real world it actually works fairly good, sure one could change the ratio to be more in line with theory but it adds complexity. I have done this to get more power into an 8 ohm speaker with an amp capable of driving 4 ohms...was simple and it worked good. There are losses in that cheap core and the wire...it was sounded good too with no loss of bass being a core for 60 hz as it is. Of course the highs were not as sparkly but it was for guitar so didn't matter much. Thanks for the theory though it needed to be said.
Its easy for an auto-transformer, 20 turns in total, tap at the 14th for 2:1 impedance. Or 10 and 7, 70 and 50, .....
Your gonna need more than 20 turns as you really don't want more than 1 volt per turn or you will saturate the core, so for 400 watts RMS max into 4 ohms that's 40 volts, so 40 turns total.
I should have indicated these are figures I drew out of thin air as examplars... Indeed you need to do the calculations based on the core material and dimensions..
Why exactly? The usual and way simpler/cheaper way is to adapt either the source or the load. Less losses too.
Please explain the why in this story. The numbers are unrealistic and the transformer will have many negative aspects probably while it is not even necessary. If things are not common usually that is because it does not make much sense to develop them. Things don't need to be difficult but with 200W requirement it will not work out handy. It will likely be a Quasimodo solution.
Vital information is lacking for an adequate answer. Assumption: if the power amplifier is not able to drive 2 Ohm then simplest is to adapt the power amplifier to that impedance. The other solution would be to make the load 4 .. 8 Ohm like the standard is.
If it is about bridging amplifiers like you asked in another thread well forget it. Amplifier number 1 will feedback to amplifier number 2 via the transformer. That is their business: transforming both ways. Very long ago I tested a distribution transformer by putting a test voltage at the secondary windings not grasping that the HV side would indeed give HV! Well I learnt fast 🙂
Last edited:
Are you able to dismantle your defective transformer and do you have winding skills and equipment? If your answer is Yes to both, I'd suggest to unwind the defective and and copy the winding turns numbers, wire cross sections and winding arrangement.
Best regadrs!