ESL hybrid - Page 3 - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th April 2013, 07:38 AM   #21
diyAudio Member
 
Join Date: Nov 2010
excellent work

Quote:
Originally Posted by bolserst View Post
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.
  Reply With Quote
Old 5th April 2013, 07:59 AM   #22
diyAudio Member
 
Join Date: Nov 2010
I found another old measurement.
I did make in the past a transformer for a hybride esl, 1:115, never used it but last year i gave it to a friend.
Unfortunately no impedance measurements are left but i know for sure that it will be not very low (above 8-10Ω at least at 10kHz).


Click the image to open in full size.
  Reply With Quote
Old 5th April 2013, 02:31 PM   #23
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Last night I found a calculator that finally helped me find an answer that I have been searching for, For the last three years!!

What is the Permeability of these cores?

On the page of this calculator it states that the permeability iron is about is about K=200.
Using the my measured data of inductance's of the winding's and knowing the turns, I was able to find out exactly the permeability of the core material that Antek is using and is about K=287.5 .

Here is that calculator,

Inductance of a Toroid

So then I plugged in my data and it all coincides the what I have measured using the AS-1206(modified).
Using the data that Bolserst had posted about the AN-0506 core I was able to interpolate what the actual inductance values should be.

I found much to my surprise that the 50 watt core does indeed have more inductance then that of the 100 watt core.
By as much as 70% to 75% more!!
The AS-1206 26 turn primary measures at about 1.01mh.
The interpolated inductance for the AN-0506 44 turn primary is 1.757mh.
This is great to know especially as it makes for a higher impedance for the ampilifer on the lower frequency side of the curve at 5.52 ohms at 500hz.

When you add a second core to double the transformation ratio the impedance will still be in about the 4 ohm range at 500hz.
As it comes at to 5.52 ohms with one core and 2.76 ohms for two cores and by the time you add another ohm 1 for HF dampening we are now at 3.76 ohms for 500Hz.

However this comes at a cost with 70% to 75% or so of more self capacitance as well.

I measured about 580pf to 700pf depending on the HV winding's series connection configuration.
Using these very same figures shows the increase of capacitance in the the AN-0506 at 1000pf to 1300pf was posted here,

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

Here is my data that I used for this comparison.
I also used the advertised transformation ratio of 1:40 for each core as well.



AN-0506, AS-1206(modified)

Core Permeability K=287.5

Core Area , 25mm(ht)X18mm 4.5^2cm, 36mm(ht)X22mm=7.92^2cm

Toroidal Radius(r) , 2.85cm, 3.075cm

Primary turns , 44T, 26T

Secondary turns , 880T, 520T

Secondary total turns , 1760T, 1040T

Primary inductance , 1.757mh, 1.01mh

Secondary inductance , 703.1mh , 404mh

Secondary inductance total , 2.8124h , 1.607h

Leakage inductance , 2.5mh, 6-8 mh (6.8?)

All of my measured data is within or better than +/- %5 of these calculate as a worst case figure.
In fact the only one that is off is the inductance value of the single secondary winding's at 430mh as measured by themselves.
I am not sure why this is as all of the rest of the measurements are right on with the predicted ones.

The leakage inductance was as measured from the primary winding with the secondary winding's shorted together and verified by both Visual Analyzer and RLC Bridge programs.

My earlier figures using the resonate method gave me some strange results and this may have been due to the electrostatic shield that was in place when I made them.
The primary inductance value coincides the the impedance values in my curve here,

Step-up transformer design

Of approximately 4.12 ohms at 650Hz using this reactance calculator,

L or C Reactance Calculator

P.S. The layout looks great in edit mode, But when I post it, it all gets scrunched up, So I added the comma's to separate the column's. :/

Last edited by geraldfryjr; 5th April 2013 at 02:55 PM.
  Reply With Quote
Old 5th April 2013, 03:19 PM   #24
diyAudio Member
 
Join Date: Nov 2010
It is not so easy to say what the permeability is.
I doubt if your transformer has a permeabilty of 287.5 unless it has a gap.

See page 62 of this pdf: http://www.wiltan.co.uk/client_files...ltan_guide.pdf

Permeabilty is very complex.

Quote:
Originally Posted by geraldfryjr View Post
Last night I found a calculator that finally helped me find an answer that I have been searching for, For the last three years!!

What is the Permeability of these cores?

On the page of this calculator it states that the permeability iron is about is about K=200.
Using the my measured data of inductance's of the winding's and knowing the turns, I was able to find out exactly the permeability of the core material that Antek is using and is about K=287.5 .

Here is that calculator,

Inductance of a Toroid

So then I plugged in my data and it all coincides the what I have measured using the AS-1206(modified).
Using the data that Bolserst had posted about the AN-0506 core I was able to interpolate what the actual inductance values should be.

I found much to my surprise that the 50 watt core does indeed have more inductance then that of the 100 watt core.
By as much as 70% to 75% more!!
The AS-1206 26 turn primary measures at about 1.01mh.
The interpolated inductance for the AN-0506 44 turn primary is 1.757mh.
This is great to know especially as it makes for a higher impedance for the ampilifer on the lower frequency side of the curve at 5.52 ohms at 500hz.

When you add a second core to double the transformation ratio the impedance will still be in about the 4 ohm range at 500hz.
As it comes at to 5.52 ohms with one core and 2.76 ohms for two cores and by the time you add another ohm 1 for HF dampening we are now at 3.76 ohms for 500Hz.

However this comes at a cost with 70% to 75% or so of more self capacitance as well.

I measured about 580pf to 700pf depending on the HV winding's series connection configuration.
Using these very same figures shows the increase of capacitance in the the AN-0506 at 1000pf to 1300pf was posted here,

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

Here is my data that I used for this comparison.
I also used the advertised transformation ratio of 1:40 for each core as well.



AN-0506, AS-1206(modified)

Core Permeability K=287.5

Core Area , 25mm(ht)X18mm 4.5^2cm, 36mm(ht)X22mm=7.92^2cm

Toroidal Radius(r) , 2.85cm, 3.075cm

Primary turns , 44T, 26T

Secondary turns , 880T, 520T

Secondary total turns , 1760T, 1040T

Primary inductance , 1.757mh, 1.01mh

Secondary inductance , 703.1mh , 404mh

Secondary inductance total , 2.8124h , 1.607h

Leakage inductance , 2.5mh, 6-8 mh (6.8?)

All of my measured data is within or better than +/- %5 of these calculate as a worst case figure.
In fact the only one that is off is the inductance value of the single secondary winding's at 430mh as measured by themselves.
I am not sure why this is as all of the rest of the measurements are right on with the predicted ones.

The leakage inductance was as measured from the primary winding with the secondary winding's shorted together and verified by both Visual Analyzer and RLC Bridge programs.

My earlier figures using the resonate method gave me some strange results and this may have been due to the electrostatic shield that was in place when I made them.
The primary inductance value coincides the the impedance values in my curve here,

Step-up transformer design

Of approximately 4.12 ohms at 650Hz using this reactance calculator,

L or C Reactance Calculator

P.S. The layout looks great in edit mode, But when I post it, it all gets scrunched up, So I added the comma's to separate the column's. :/
  Reply With Quote
Old 5th April 2013, 05:11 PM   #25
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Quote:
Originally Posted by esltransformer View Post
I found another old measurement.
I did make in the past a transformer for a hybride esl, 1:115, never used it but last year i gave it to a friend.
Unfortunately no impedance measurements are left but i know for sure that it will be not very low (above 8-10Ω at least at 10kHz).
I had a couple questions concerning your measurements:

1) Do you know what the input impedance was of your measurement setup? The amplitude of the resonance peak for the "no load" and "load=200pF" should not be the same if there is no change in damping resistance between the two cases.

2) When adding the 25K resistors in series with the primary, do the measurements show voltage across the secondary winding? or voltage across the 200pF capacitor.

3) Curious if you recall number of primary turns, and core size. Based on frequency of resonance for "no load" and "load=200pF" leakage inductance would have to be quite lower, perhaps around 5uH, and winding capacitance similarly low around 90pF.



@geraldfryjr
You may recall we had discussed core permiability in the other transformer thread. It is a function of flux density which is directly proportional to input voltage, inversely proportional to core area. For most grain oriented silicon steel transformer cores, a good rule of thumb is an intial permiability of 1500 at low input voltage. The permiability increases with input voltage amplitude(flux density), to a maximum of 5000 to 8000 depending on material, and then abruptly dropping toward zero as the core saturates.

So, as esltransformer mentioned, trying to nail down a single value for primary inductance is difficult. Similarly, it is difficult to compare between transformers when core areas and primary turns will result in different flux densities in their cores.
  Reply With Quote
Old 5th April 2013, 05:37 PM   #26
diyAudio Member
 
Join Date: Nov 2010
For measurements i use a normal "cheap" audio amplifier (NAD 320). I always measure with a 1:10 probe on my Fluke or Tektronix scoop.
I measure between zero and each phase and if a secondairy resistor is connected i still measure on the transformer wire because i want to know what the transformer dos.

I used for this hybride transformer a SU60A c-core with 40 primary turns and 4400 secondary. Original i calculated 38 turns (that makes it a 1:115 transformer) but with 40 turn the final version is of course 1:110. A small differance.

I also found the saturation level back: 20Vrms at 200Hz.

Quote:
Originally Posted by bolserst View Post
I had a couple questions concerning your measurements:

1) Do you know what the input impedance was of your measurement setup? The amplitude of the resonance peak for the "no load" and "load=200pF" should not be the same if there is no change in damping resistance between the two cases.

2) When adding the 25K resistors in series with the primary, do the measurements show voltage across the secondary winding? or voltage across the 200pF capacitor.

3) Curious if you recall number of primary turns, and core size. Based on frequency of resonance for "no load" and "load=200pF" leakage inductance would have to be quite lower, perhaps around 5uH, and winding capacitance similarly low around 90pF.



@geraldfryjr
You may recall we had discussed core permiability in the other transformer thread. It is a function of flux density which is directly proportional to input voltage, inversely proportional to core area. For most grain oriented silicon steel transformer cores, a good rule of thumb is an intial permiability of 1500 at low input voltage. The permiability increases with input voltage amplitude(flux density), to a maximum of 5000 to 8000 depending on material, and then abruptly dropping toward zero as the core saturates.

So, as esltransformer mentioned, trying to nail down a single value for primary inductance is difficult. Similarly, it is difficult to compare between transformers when core areas and primary turns will result in different flux densities in their cores.
  Reply With Quote
Old 5th April 2013, 05:54 PM   #27
diyAudio Member
 
Join Date: Nov 2010
Quote:
Originally Posted by bolserst View Post


@geraldfryjr
You may recall we had discussed core permiability in the other transformer thread. It is a function of flux density which is directly proportional to input voltage, inversely proportional to core area. For most grain oriented silicon steel transformer cores, a good rule of thumb is an intial permiability of 1500 at low input voltage. The permiability increases with input voltage amplitude(flux density), to a maximum of 5000 to 8000 depending on material, and then abruptly dropping toward zero as the core saturates.

So, as esltransformer mentioned, trying to nail down a single value for primary inductance is difficult. Similarly, it is difficult to compare between transformers when core areas and primary turns will result in different flux densities in their cores.
Maybe EI core material has a maximum permeabilty of 8000 but a toroid with very good low loss FeSi can be up to 90000 (if you have HiB material. I use this material for my c-cores)
  Reply With Quote
Old 5th April 2013, 09:25 PM   #28
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Quote:
Originally Posted by esltransformer View Post
For measurements i use a normal "cheap" audio amplifier (NAD 320). I always measure with a 1:10 probe on my Fluke or Tektronix scoop.
I measure between zero and each phase and if a secondairy resistor is connected i still measure on the transformer wire because i want to know what the transformer dos.

I used for this hybride transformer a SU60A c-core with 40 primary turns and 4400 secondary. Original i calculated 38 turns (that makes it a 1:115 transformer) but with 40 turn the final version is of course 1:110. A small differance.

I also found the saturation level back: 20Vrms at 200Hz.
20Vrms(200Hz) sound about right for SU60A c-core with 40 turn primary.

The best fit I could find for your transformer is:
Leakage inductance = 4uH
Winding capacitance = 110pF

The main thing I couldn't match was the Q of the unloaded resonance. Perhaps at the high frequencies there are other losses not included in the model that would damp the resonance. Adding just 0.1 ohm in series with the primary would bring the unloaded resonance peak down in line with the 200pF curve.

Estimated impedance at 10khz would be about 10ohm unloaded, or 4 ohm with 200pF load.
If used to drive a 1000pF load, impedance at 10kHz would be ~ 1 ohm.


Quote:
Originally Posted by esltransformer View Post
...a toroid with very good low loss FeSi can be up to 90000 (if you have HiB material. I use this material for my c-cores)
Agreed. The values I gave were for more common M6(and similar) material.
For ESL step-up use where the primary is driven from a low impedance source, the HiB material is not nearly as advantageous as it is for tube amplifier output transformers.
Attached Images
File Type: gif Tmodel_hybrid.gif (75.5 KB, 73 views)

Last edited by bolserst; 5th April 2013 at 09:27 PM.
  Reply With Quote
Old 5th April 2013, 09:41 PM   #29
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Quote:
Originally Posted by geraldfryjr View Post
...
Transformer : AN-0506, AS-1206(modified)
Leakage inductance: 2.5mh, 6-8 mh (6.8?)
...
P.S. The layout looks great in edit mode, But when I post it, it all gets scrunched up, So I added the comma's to separate the column's. :/
Thanks for the info on the AS-1206

Couple questions on your leakage inductance measurements:
1) Should the units be uH instead of mH?
2) Are the values for a single transformer? or two wired for ESL step-up use.
3) Did you have an AN-0506 handy to compare with the AS-1206? or were you using the 2.5uH value I had posted previously for two AN-0506s.
  Reply With Quote
Old 5th April 2013, 11:06 PM   #30
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
The leakage measurements are uh as in microhenries.

Thank you for catching that!!!
Sorry for the confusion, My Bad !!!!

The values are for a single transformer.

I don't have a AN-0506 to test otherwise I would have used one for a proper comparison so I used the value you posted.

I am looking at a test right now and the values are jumping around at about 8.5uh for a 26 Turn primary.
And 2.9uh for A 13 turn primary winding.
This looks about right.
I hope a better sound card will fix this jumping around issue !!!!
I will recheck this again with a resonate test again a little later.

jer
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Final 0.3 Hybrid ESL TimA Planars & Exotics 36 7th November 2012 12:26 PM
What X-over for a hybrid ESL? markusA Planars & Exotics 39 30th August 2012 11:26 AM
Help with esl hybrid electros Planars & Exotics 8 5th December 2010 10:02 AM
New hybrid ESL Build Freddy G Planars & Exotics 36 30th August 2010 05:25 PM
Geert - Hybrid ESL GeSo Planars & Exotics 21 24th September 2008 07:08 AM


New To Site? Need Help?

All times are GMT. The time now is 04:04 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2