How much high level exists below 40Hz?

[Tubetec]

It seems likely that two different transformer winders might have slightly different approaches ,maybe one will show better on test than the other due to different core materials or winding techniques .

 

[ruffrecords]

It seems likely that two different transformer winders might have slightly different approaches ,maybe one will show better on test than the other due to different core materials or winding techniques .

Given the small size required in order to fit into the 35mm module, the only way to get the flux density required at the maximum level required at 20Hz is to use Silicon steel. Winding techniques though are another matter. They can affect several parameters which have a direct effect on frequency response, balance and output impedance. I am still exploring those.

Cheers

Ian

 

[abbey road d enfer]

Winding techniques ... can affect several parameters which have a direct effect on frequency response, balance and output impedance.

Certainly, but not very much on LF response. Certain winding techniques used for decreasing stray capacitance actually result in increasing the DC resistance of the winding, which could affect le LF response, and particularly LF distortion, in a negative way.

 

[ruffrecords]

Certainly, but not very much on LF response. Certain winding techniques used for decreasing stray capacitance actually result in increasing the DC resistance of the winding, which could affect le LF response, and particularly LF distortion, in a negative way.

Agreed. I was thinking more of HF response, insertion loss and longitudinal balance. There is probably more to be gained by keeping the core cross section the same and changing the lamination so as to increase the bobbin height to allow more turns or the same number of turns of thicker wire. I am still a noob when it comes to transformer design. I never could get my head around magnetics even at university (and I was a lot younger then) but now I have the time to take it slow and steady. I am a great believer in nothing  is hard to understand once you break it down into a series of smaller understandable chunks.

Cheers

Ian

 

[abbey road d enfer]

Agreed. I was thinking more of HF response, insertion loss and longitudinal balance.

That's exactly what I understood. My comment was more directed to our "ordinary readership".

There is probably more to be gained by keeping the core cross section the same and changing the lamination so as to increase the bobbin height to allow more turns

Not really. The magnetic flux (and resultant induction) is directly related to the ratio of Ampere.turns vs. cross section. More turns would result in less max Amps, for an identical net result.

or the same number of turns of thicker wire.

That is possible; however the resulting increase of the magnetic core's reluctance would probably increase the leakage inductance.

I am a great believer in nothing  is hard to understand once you break it down into a series of smaller understandable chunks.

It all starts with u(t)=L.di/dt

 

[ruffrecords]

Not really. The magnetic flux (and resultant induction) is directly related to the ratio of Ampere.turns vs. cross section. More turns would result in less max Amps, for an identical net result.

But more turns means more volts before saturation is reached.

Cheers

Ian

 

[abbey road d enfer]

But more turns means more volts before saturation is reached.

That is true; this would be also the case when just increasing the number of turns on an unchanged core. The inductance would be higher, so the optimum load source would be higher; in short, the output would not be 600r, it would be 1k or whatever. Measurements on 600r load would not be as good, due to resistive and leakage losses. With an elongated core, you could put more copper, which would reduce the resistive losses, but not increase the poweer transfer capability nor the leakage.
This is not an actual issue for interfacing with modern equipment.
If you specified your equipment to be loaded with 10kohms, you could probably use a smaller core with more turns. The LF voltage would be correct.

 

[CJ]

WE 618-B has a core built for more turns, wish i could get these lams stamped, flat response unloaded and low distortion,  more winding area also means you can use more insulation to tweak response,

notice core dims left side of pic,