The dipole sub-project is now on hold, as I rebuilt one basspanel this weekend - it plays bass with good output from 25-30Hz! 
I'm now only using the 3mm PVC spacers and thin doublesided tape as glue (d/s was 4mm before). The inside of the stators got a couple of coatings with automotive clear coat when I had them apart.
The 6µm Mylar has been changed to 12µm for better stability and the panel is now divided into only two sections.
To restrict the speakers from overdrive and the basspanels arcing, I would like to install a protection circuit. I'm thinking of a simple "crowbar" with a SCR but I have read about differet protectioncircuits here someware.
I can't find that thread again - can some one point me in the right direction?
/Roger
I'm now only using the 3mm PVC spacers and thin doublesided tape as glue (d/s was 4mm before). The inside of the stators got a couple of coatings with automotive clear coat when I had them apart.
The 6µm Mylar has been changed to 12µm for better stability and the panel is now divided into only two sections.
To restrict the speakers from overdrive and the basspanels arcing, I would like to install a protection circuit. I'm thinking of a simple "crowbar" with a SCR but I have read about differet protectioncircuits here someware.
I can't find that thread again - can some one point me in the right direction?
/Roger
Is this what you were looking for?
http://www.diyaudio.com/forums/planars-exotics/190698-martin-logan-sl3-crossover.html#post2613316
jer
http://www.diyaudio.com/forums/planars-exotics/190698-martin-logan-sl3-crossover.html#post2613316
jer
Please let us know how the 12um mylar works for you on your bass panels.
I was planning a 11.5" (290mm) wide panel to check the stability of my 6um mylar as well.
I remember I had problems on my 8" (200mm) wide panels also until I had got enough tension on them.
I will be rebuilding them soon to give them another try as the last time I had them running was in 2003 for a short time and I never tested them throughly.
jer
I was planning a 11.5" (290mm) wide panel to check the stability of my 6um mylar as well.
I remember I had problems on my 8" (200mm) wide panels also until I had got enough tension on them.
I will be rebuilding them soon to give them another try as the last time I had them running was in 2003 for a short time and I never tested them throughly.
jer
I have only rebuilt one panel as it takes quite some time to split them apart and clean everything.
The one I have working right now plays deeper and has better output, but thats expecter going from 4mm d/s to 3mm.
The panel is divided by one horisontal strip resulting in a 660mm and 820mm high and 210mm wide sections.
With this sectioning I can get the membrane to stick to the stators if I crank the EHT to high, this did not happen with the old ones dividen into five cells.
The sectioning or placement off supports is something that seldom is mentioned but plays a big part in how the panels sound and how high you can play before they arc.
Roger
The one I have working right now plays deeper and has better output, but thats expecter going from 4mm d/s to 3mm.
The panel is divided by one horisontal strip resulting in a 660mm and 820mm high and 210mm wide sections.
With this sectioning I can get the membrane to stick to the stators if I crank the EHT to high, this did not happen with the old ones dividen into five cells.
The sectioning or placement off supports is something that seldom is mentioned but plays a big part in how the panels sound and how high you can play before they arc.
Roger
Yes and no!
I decided to do a total rebuild of the panels!
When I took my second speaker apart to rebuild the basspanel I noticed a small, small hole in the tweeter diaphragm. Splitting the panel I saw that there was a small section where the paint had chipped off the inside of the stator causing arcs that evidently had burned a hole in the diaphragm.
I have now repaired the section that was chipped and also given the stators three coats of automotive clear coat. When I had everything apart I made some new PVC spacers for the treble/tweeter panals as well.
This weekend I repaired one speaker and it is now up and running again. I have not made any measurements yet, but will do so soon.
The panels are now:
Treble/tweeter, 2mm PVC-spacers, 6µm Mylar, tesion 4kg/5cm
Bass, 3mm PVC-spacers, 6µm Mylar, tesion 4kg/5cm
I have alot more tension on the film, so I expect the lower fs to bi a bit higher in this version. I have also divided the basspanel in three sections for better mechanical stability.
Will post some pictures later.
Roger
The main reason for going back to 6µm is to be able to try and run the panels as "fullrange without XO-filter", both panels same tension, same film, but different sectioning!
I have been glancing at Aucostats solution with separate transformers for bass/mid-high but then driving all the panels with the same audiosignal.
I will have to do some frequency sweeps to determine if this will be possible with the different spacing/sectioning I now use.
If I blow air on the different sections I get a nice dih, dah, doh-tone so hopefully It'll work!
Nope- but I shure hope so!
When I did a stetch test on the Mylar I use, I needed abt. 4kg off tension to get a 1% stretch.(the film not heat treated)
I wanted to try as high tensioning as possible to get a stable panel that can take some abuse before the film hits the stators!
Time will tell if the tape will hold or not, but when building the panels I could not se any tendencys of creep wich I could the last time using another brand of tape! (now use a much thinner tape - sticks like .....to the Mylar and spacers)
Roger
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Hi Roger,
I think it's OK to use thinner diaphragm. I'm using 2 micron and run mine full range and I love them. Good transformers sure make lots of difference.
I didn't realize that you need to go up to 4 Kg to get 1% stretch. I use 1.5% and I think it's a bit too much. My thin double sided tape can't hold this force that long. I'm going to redo mine pretty soon, and I might try 1 or 1.25%.
Are you not going to inject some silicone dots in between? I think it helps stabilize the diaphragm quite a bit and the bass doesn't suffer that much.
Wachara C.
I think it's OK to use thinner diaphragm. I'm using 2 micron and run mine full range and I love them. Good transformers sure make lots of difference.
I didn't realize that you need to go up to 4 Kg to get 1% stretch. I use 1.5% and I think it's a bit too much. My thin double sided tape can't hold this force that long. I'm going to redo mine pretty soon, and I might try 1 or 1.25%.
Are you not going to inject some silicone dots in between? I think it helps stabilize the diaphragm quite a bit and the bass doesn't suffer that much.
Wachara C.
I used 2µm in my mid/tweeter panels before, but whent for 6µm this time as it should be a bit more "arc resistant".
My basspanel is divided in three sections using 10mm PVC strips. I hope this will be enough as dividing it further (using silicone dots or strips) has totaly killed the bass when trying this before.
Will post pitures soon, but we are currently in "the dark age", winter time and all, so I'ts hard to take good photos of the speaker.
Roger
My basspanel is divided in three sections using 10mm PVC strips. I hope this will be enough as dividing it further (using silicone dots or strips) has totaly killed the bass when trying this before.
Will post pitures soon, but we are currently in "the dark age", winter time and all, so I'ts hard to take good photos of the speaker.
Roger
Quad 63`s use three micron film. I think the trick is to build stator panels which don`t leak and have enough dielectric strength to meet normal rquirements. That said there is nothing wrong with six micron film.
Small pin holes are not a performance issue as most all of these hole self cotorize anyway. I have had acoustat panels (very old ones) with holes as large as a half inch and you could not hear where they were as they were simply dead spots as far as output went. They are still working normally without any issues. Moray James.
Small pin holes are not a performance issue as most all of these hole self cotorize anyway. I have had acoustat panels (very old ones) with holes as large as a half inch and you could not hear where they were as they were simply dead spots as far as output went. They are still working normally without any issues. Moray James.
Just to clear things out, I used 6µm film in both panels as i would like to run them "fullrange" ( Going thinner would not let me get the tension I was aiming for in my tweeterpanel) - thats the main reason!
Using 2 or 3µm Mylar makes the highs a bit better, but as one usualy has to use a series resistor to make the load to the amplifier acceptable, most of the benefits are lost. (in my observations)
I think 6µm is a good compromise, but I know that it is just that - A compromise!
Roger
Using 2 or 3µm Mylar makes the highs a bit better, but as one usualy has to use a series resistor to make the load to the amplifier acceptable, most of the benefits are lost. (in my observations)
I think 6µm is a good compromise, but I know that it is just that - A compromise!
Roger
The plan is to use the same transformers, but run them "Acoustat-style" with the secondarys in paralell!
I have had Acoustats for 30years...an have done a lot of work with the panels an the bias...an Tranfourmers....if you use the Acoustats tranformer setup you well lose output ....the best sound i have got with the T1 an T2 Acoustat Tranfourmers is to run them as one for the high T2...to it own panel..an the bass T2 to it own panels...with nothing on the secondarys... An this is where the Non-pushpull transfourmer set up come in.....Keep up the ESL work an thanks for all your info...keep it comeing...hoho
I have had Acoustats for 30years...an have done a lot of work with the panels an the bias...an Tranfourmers....if you use the Acoustats tranformer setup you well lose output ....the best sound i have got with the T1 an T2 Acoustat Tranfourmers is to run them as one for the high T2...to it own panel..an the bass T2 to it own panels...with nothing on the secondarys... An this is where the Non-pushpull transfourmer set up come in.....Keep up the ESL work an thanks for all your info...keep it comeing...hoho
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