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Old 3rd April 2013, 06:44 PM   #11
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Location: Jackson,michigan
I posted this information in post 7.
The First 2 pictures are with the 120V winding's in series as I had noted the dip at about 10Khz.
This dip is not there when the 120V winding's are open or in Parallel.

This dip still exist's even with the shields removed.

Here are two more pictures of a comparison of the 120V windings in series and parallel.

The yellow line is the impedance for a Series connection with green line for the phase.
The red line is the impedance for a Parallel connection with the blue line for the phase.

The only thing that is changed in the comparison of the two curves is the position of the peak of the impedance curve, and, the halving of the impedance at higher frequency's due to the doubling of the winding ratio and/or doubling secondary capacitance from the series connection.

If another core was added to increase the ratio by 2, having the primary's in parallel would cut all these impedance's, again, in half as well.

I have checked all of the configurations using another set of cores as I only have one of the AS-1206's from Antek.

I will be taking a closer look at this at a later time after I finish my latest thread of how to find the parameters of a transformer thread.

I have found that the double stacking method that I have used in the past shows a good compromise for getting a fairly high transformation ratio without having to low of an impedance for the amplifier to drive using power toroidial transformers.

I have done some Spice models from the data of my measurment's and the curves are right in alignment to what I have measured.

I don't have any of this data organized to present at the moment, as I am re-doing this in a step by step method in the new thread that I have started on ESLDIY.

Once I get them all together I will gladly post them here as well.

Sorry that it has taken so long as I have many projects going on at once again.
This always happens when I am trying to concentrate on one thing !!!!! He,he,he

jer

P.S. The glitches are caused by my Flakey ALC892 motherboard sound chip.
It is from the output side of the chip as I can see it dropping out while I am monitoring the signal on my oscilloscope.
Attached Images
File Type: jpg 1206ppss 1.jpg (214.0 KB, 128 views)
File Type: jpg 1206ppss 2.jpg (222.0 KB, 125 views)

Last edited by geraldfryjr; 3rd April 2013 at 06:52 PM.
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Old 3rd April 2013, 06:53 PM   #12
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Quote:
Originally Posted by esltransformer View Post
I forgot to tell that not every transformer has identical frequency response for the both phases.
I measured a Sowter1:60 transformer (without load)

I am curious to see what the Anteks do for the 2 secondary windings (115+115V).
Many times large measured differences like you are showing are due to unexpected side effects of the measurements setup...in particular AC ground reference. Once I started using a differential probe, large measured differences(dips or peaks) between windings went away, leaving only minor differences that could be explained by differences in leakage inductance, winding capactance, or winding to winding capacitance.

I posted measured response for two Antek AN-0506 driving 1200pF load here:
Toroids for ESL's

I can post response and impedance for other load combinations later if you are interested.

Oh, speaking of impedance, it is best to stick with the lower wattage(50W) Antek transformers as they will have higher turn count on the 6V winding which will be used as the primary for ESL step-up use. Primary inductance increased with number of turns squared. The larger 100W Antek has about half the primary turns, so 1/4 the impedance at frequencies in the 200Hz - 400Hz crossover range.

Power handling at core saturation for the AN-0506 can be found here:
Antek Toroidal power transformer for Step-up, Measurements (part 1/2)

General method of estimating power handling of small power toroids used for ESL step-up here:
DIY bass transformer for ESLs ?
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Old 3rd April 2013, 07:07 PM   #13
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Join Date: Feb 2008
Location: Jackson,michigan
I would be interested in seeing that data Bolserst.
I have been thinking about this a lot lately.
The physical measurement the the 100 Watt core don't seem to line up with what Antek says it is supposed to be.
It is a bit smaller than what I was expecting.

The antek core is 80mm in dia. and the core area is about 22.5mm X 35mm if not a little smaller.
This comes to 7.875 cm^2 of core area.

It is only slightly smaller than the 210 watt cores that I have been using at a 90mm dia. and about the same core area !!

jer

P.S. I just re-read your dimension figures of about 4cm^2 of core area and I had interpreted them wrong sorry about the confusion.

Last edited by geraldfryjr; 3rd April 2013 at 07:33 PM.
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Old 3rd April 2013, 07:18 PM   #14
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Many times i see transformers who are not semetrical wound, the Sowther transformer for instance, and that is what you see also in the measurments.

Quote:
Originally Posted by bolserst View Post
Many times large measured differences like you are showing are due to unexpected side effects of the measurements setup...in particular AC ground reference. Once I started using a differential probe, large measured differences(dips or peaks) between windings went away, leaving only minor differences that could be explained by differences in leakage inductance, winding capactance, or winding to winding capacitance.

I posted measured response for two Antek AN-0506 driving 1200pF load here:
Toroids for ESL's

I can post response and impedance for other load combinations later if you are interested.

Oh, speaking of impedance, it is best to stick with the lower wattage(50W) Antek transformers as they will have higher turn count on the 6V winding which will be used as the primary for ESL step-up use. Primary inductance increased with number of turns squared. The larger 100W Antek has about half the primary turns, so 1/4 the impedance at frequencies in the 200Hz - 400Hz crossover range.

Power handling at core saturation for the AN-0506 can be found here:
Antek Toroidal power transformer for Step-up, Measurements (part 1/2)

General method of estimating power handling of small power toroids used for ESL step-up here:
DIY bass transformer for ESLs ?
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Old 3rd April 2013, 07:45 PM   #15
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Thanks for explaning but still i find it hard to read. To many lines in your graphes and some axes are lineair will it would be easier if it was logorithmic. But it is very good that people as you measure.



Quote:
Originally Posted by geraldfryjr View Post
I posted this information in post 7.
The First 2 pictures are with the 120V winding's in series as I had noted the dip at about 10Khz.
This dip is not there when the 120V winding's are open or in Parallel.

This dip still exist's even with the shields removed.

Here are two more pictures of a comparison of the 120V windings in series and parallel.

The yellow line is the impedance for a Series connection with green line for the phase.
The red line is the impedance for a Parallel connection with the blue line for the phase.

The only thing that is changed in the comparison of the two curves is the position of the peak of the impedance curve, and, the halving of the impedance at higher frequency's due to the doubling of the winding ratio and/or doubling secondary capacitance from the series connection.

If another core was added to increase the ratio by 2, having the primary's in parallel would cut all these impedance's, again, in half as well.

I have checked all of the configurations using another set of cores as I only have one of the AS-1206's from Antek.

I will be taking a closer look at this at a later time after I finish my latest thread of how to find the parameters of a transformer thread.

I have found that the double stacking method that I have used in the past shows a good compromise for getting a fairly high transformation ratio without having to low of an impedance for the amplifier to drive using power toroidial transformers.

I have done some Spice models from the data of my measurment's and the curves are right in alignment to what I have measured.

I don't have any of this data organized to present at the moment, as I am re-doing this in a step by step method in the new thread that I have started on ESLDIY.

Once I get them all together I will gladly post them here as well.

Sorry that it has taken so long as I have many projects going on at once again.
This always happens when I am trying to concentrate on one thing !!!!! He,he,he

jer

P.S. The glitches are caused by my Flakey ALC892 motherboard sound chip.
It is from the output side of the chip as I can see it dropping out while I am monitoring the signal on my oscilloscope.
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Old 3rd April 2013, 07:50 PM   #16
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Join Date: Nov 2010
Quote:
Originally Posted by bolserst View Post
Many times large measured differences like you are showing are due to unexpected side effects of the measurements setup...in particular AC ground reference. Once I started using a differential probe, large measured differences(dips or peaks) between windings went away, leaving only minor differences that could be explained by differences in leakage inductance, winding capactance, or winding to winding capacitance.

I posted measured response for two Antek AN-0506 driving 1200pF load here:
Toroids for ESL's

I can post response and impedance for other load combinations later if you are interested.

Oh, speaking of impedance, it is best to stick with the lower wattage(50W) Antek transformers as they will have higher turn count on the 6V winding which will be used as the primary for ESL step-up use. Primary inductance increased with number of turns squared. The larger 100W Antek has about half the primary turns, so 1/4 the impedance at frequencies in the 200Hz - 400Hz crossover range.

Power handling at core saturation for the AN-0506 can be found here:
Antek Toroidal power transformer for Step-up, Measurements (part 1/2)

General method of estimating power handling of small power toroids used for ESL step-up here:
DIY bass transformer for ESLs ?
I expect very low impedance at high frequency because 1200pF is very much load for 1:75

Last edited by esltransformer; 3rd April 2013 at 07:53 PM.
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Old 3rd April 2013, 10:55 PM   #17
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Quote:
Originally Posted by esltransformer View Post
I expect very low impedance at high frequency because 1200pF is very much load for 1:75
Indeed. Impedance is < 1 ohm at HF.
This is due partly to the large capacitive loading, and partly due to the fact that with low leakage inductance the XL/R ratio dictates only minimal resistance can be put in series with the primary before overdamping the resonance.

For the dual Antek setup, the damping resistance value needs to be kept < 1 ohm to avoid overdamping the HF resonance. However, often larger resistance value are used to roll of the HF response to compensate for the rising response of wide, flat, unsegmented panels.This is quite different from the situation for segmented panels where you can use transformers designed with much higher leakage inductance which allow larger damping resistance values before overdamping the resonance.

I'll see if I can dig up some impedance plots tomorrow as well.

Last edited by bolserst; 3rd April 2013 at 10:58 PM.
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Old 3rd April 2013, 11:49 PM   #18
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Location: Jackson,michigan
The software I was using at the time was SimpleS,

New speaker impedance tool, SimpeS

I was using the first version and I have not used the latest issues yet.

The frequency scale is set to log and the Impedance is in a linear scale.

The impedance plots that I posted here,

Step-up transformer design

Are of one test as described with the graphs re-scaled within the program using the same test data to show a better resolution of the impedance in those areas.

Since then I have been getting better results using the newest version of REW.

HELP required

jer

Last edited by geraldfryjr; 4th April 2013 at 12:01 AM.
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Old 4th April 2013, 05:58 AM   #19
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I calculated 2.35Ohm at 10khz if the transformer has no influens except the 1:75 ratio.
I would not like to have such low impedance. Not many amplifiers are suitable to drive such loads.

Quote:
Originally Posted by bolserst View Post
Indeed. Impedance is < 1 ohm at HF.
This is due partly to the large capacitive loading, and partly due to the fact that with low leakage inductance the XL/R ratio dictates only minimal resistance can be put in series with the primary before overdamping the resonance.

For the dual Antek setup, the damping resistance value needs to be kept < 1 ohm to avoid overdamping the HF resonance. However, often larger resistance value are used to roll of the HF response to compensate for the rising response of wide, flat, unsegmented panels.This is quite different from the situation for segmented panels where you can use transformers designed with much higher leakage inductance which allow larger damping resistance values before overdamping the resonance.

I'll see if I can dig up some impedance plots tomorrow as well.
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Old 4th April 2013, 10:14 PM   #20
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Quote:
Originally Posted by esltransformer View Post
I calculated 2.35Ohm at 10khz if the transformer has no influens except the 1:75 ratio.
I would not like to have such low impedance. Not many amplifiers are suitable to drive such loads.
Yes, 2.35ohm if leakage inductance and winding capacitance is ignored. Actual impedance will be significantly less. Most solid state amplifiers rated for 4 ohm loads seem to have no problems if the impedance drops to 1.5 - 2.0 ohm in the top octave since there doesn't tend to be high amplitude audio content there.

Using the parastics posted for the Antek-0506 it is easy enough to calculate response and impedance with good accuracy using this spreadsheet:
ESL electronics 101 for the electronics challenged


In the attached plots, C= ESL capacitance, R= resistance in series with primary
Pic #1: Shows impedance and response trends for increasing capacitive load with R = 0 ohm

Pic #2: Shows trends for varying R, with C = 1200pF
This is the typical capacitance for a "jazzman-style" flat, unsegmented ESL, for which the Anteks are used.
Note that R = 1 ohm provides a -3dB slope in the top octave which is exactly what is needed flatten the +3dB slope of the on-axis response of an ESL line source. Reduction in R might be desired if listening is done slightly off-axis.

Pic #3 and #4: Shows trends for varying C with R = 1 ohm and 2 ohm.

Pic #5: Shows impedance and response trends for increasing capacitive load with R adjusted for maximumally flat stator response.
Attached Images
File Type: gif Antek_01.gif (51.2 KB, 108 views)
File Type: gif Antek_02.gif (50.5 KB, 103 views)
File Type: gif Antek_03.gif (49.3 KB, 100 views)
File Type: gif Antek_04.gif (49.4 KB, 14 views)
File Type: gif Antek_05.gif (49.6 KB, 16 views)
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