Antek Toroidal power transformer for Step-up, Measurements (part 1/2)

[bolserst]

...you had stated that the Core Area of the Antek AN-0506 was about .7 square inches.
I was wondering if you could post the O.D. x I.D. x HT dimensions of the bare core in mm.

OD = 75 mm
ID = 39 mm
HT = 25mm

 

[geraldfryjr]

Thanks, bolserst!!!

Much appreciated !!!!



jer

 

[jeronimo83]

Hello guys, hope you don't mind me interfering in this discussion. First post here.

I'm building a ESL for the first time and looking into transformer options, following this discussion closely. The ESL will be a wire stator. Membrane with 7500v high voltage bias supply.

I came across these toroids in my country by the company called Amplimo which produced (and possibly still produces) step up transformers for ESL:

380V transformator - Ringkerntrafo.nl

There is a PDF with specs that can be downloaded. Do you think I can use the 3 volt secondary winding to produce a step up of 1:127 with this toroid? If so, is there an alternative to connect the high voltage bias supply to instead of the missing center tap of this toroid? Or do I have to use 2 toroids per ESL for that? Furthermore, is it possible to make any assumption of the lowest frequency that will be possibly to produce with this transformer with a 2x80 watt amplifier?

I apologize for any stupid questions, I'm just a beginner and have almost no knowledge about electronics... yet

 

[bolserst]

Do you think I can use the 3 volt secondary winding to produce a step up of 1:127 with this toroid? If so, is there an alternative to connect the high voltage bias supply to instead of the missing center tap of this toroid? Or do I have to use 2 toroids per ESL for that? Furthermore, is it possible to make any assumption of the lowest frequency that will be possibly to produce with this transformer with a 2x80 watt amplifier?

If you drove the 3 volt secondary with an 80Watt amplifier, the lowest frequency you could expect the transformer to handle without running into core saturation problems is about 450Hz.
More details here:
http://www.diyaudio.com/forums/planars-exotics/186011-diy-bass-transformer-esls.html#post2520512

If you want to use a transformer that does not have a center tap on its secondary, you can create a virtual CT using two 10Mohm resistors. Acoustat used this technique in their MK-141 interface.

 

[esltransformer]

I made myself a esl transformer for a electrical segmented esl on a large c-core. Stepup 1:125

An externally hosted image should be here but it was not working when we last tested it.

 

[bolserst]

I made myself a esl transformer for a electrical segmented esl on a large c-core. Stepup 1:125

That is a very nice response for a step-up ratio of 1:125.
Can you share how many primary turns were used and what the core size is?

 

[esltransformer]

That is a very nice response for a step-up ratio of 1:125.
Can you share how many primary turns were used and what the core size is?

Sure i can.
I use a c-core type: SU90B (600W/50Hz) with 54 windings primary and 6750 windings secondary.

I think impedance of a transformer is even more important then frequency response.
Here some more details from the transformer i made: impedance and saturation

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[bolserst]

Sure i can.
I use a c-core type: SU90B (600W/50Hz) with 54 windings primary and 6750 windings secondary...Here some more details from the transformer i made: impedance and saturation.

I believe the SU90B core area is about 13.4cm^2.

If so, saturation starting at about 15Vrms is very impressive core capability with only 54 primary turns.
This would indicate flux density of about 18,000 Gauss = 1.8 Tesla if there was no resistance in the primary circuit.

Do you know what type of metal alloy the core is made from?
Did you have any external resistor in series with the primary?
What is the resistance of the primary winding?


Thanks for sharing the results of your transformer design.

 

[esltransformer]

I believe the SU90B core area is about 13.4cm^2.

If so, saturation starting at about 15Vrms is very impressive core capability with only 54 primary turns.
This would indicate flux density of about 18,000 Gauss = 1.8 Tesla if there was no resistance in the primary circuit.

Do you know what type of metal alloy the core is made from?
Did you have any external resistor in series with the primary?
What is the resistance of the primary winding?


Thanks for sharing the results of your transformer design.

Indeed, 13.4cm^2 and at 20Vrms the core will be at 2T (then the core is almost saturated)

The core material i use is M0 (or HiB). The primary resistance is about 0.15 Ohm and normally i use a 1 Ohm serie resistance to protect my amplifier.