Rebuilding Janszen panels

johneboy

Member
2009-12-09 3:46 am
Hi, I have 8 janszen panels that I would like to rebuild. The first one came apart pretty easily and is ready for a new membrane. Since it will not be used below 1800 or so I'm thinking a thinner, 3 micron? The panels are only 5x5 so would heating be enough to tighten the membrane? Would window tape work for attaching the membrane? Spacers?
Hopefully someone can give me some guidance.

Thanks
John
 

tyu

Member
2009-07-18 8:16 pm
Need some more..,.all mine still work........I use Acoustat high frc tran to drive an go with them..... sounds vary good.....3k up...... good luck
 

Attachments

  • janz 004.JPG
    janz 004.JPG
    760.4 KB · Views: 262
The last panel I made, I used a wooden square with holes in it, taped string to the membrane, and threaded the string through the holes in the wooden square and attached small weights.

For the next panel, I will get some washers, and tape these to the membrane, then poke holes with soldering iron, and use fishing swivels to clip the string to the membranes attached washers.

I don't think the tension is terribly critical, as the first time I did it I just taped the membrane to a square and pushed the stator down so the wrinkles where gone.

This said, I have yet to got for matched stereo panels, thats later in my investigations.
 
the trick with the Janzen's (iirc) is that they used graphite for the coating. this works well for a long time, but when it doesn't, the cells cease to function.

The ones I had did NOT want to come apart cleanly. :(

When I could still hear above 20kHz, I found these panels annoying up there, but that may have been a function of the amplification, not the cells. I don't really see any reason that they could not be done with thinner membrane, but there may or may not be a real advantage. Perhaps the thing to do is to repair one, but clamp it together for testing, and measure to see what the change is. Doesn't need to be pretty.

They have a rather noticeable limit for both SPL and HV bias. Above a certain bias voltage they start to "sizzle". Maybe less in a dry climate? Also they have a definite LF limit.

It's not obvious from the outside, but they are actually a series of edge-to-edge vertical cells, not little square cells all together. The HF dispersion leaves a bit to be desired.

They were my first ESLs!

Had a tweeter array whose mfr name I can not presently recall, I think 4 of them horizontally, looking a bit like the front of a small horn. Great fun back in the day!

_-_-

The Infinity Servo Statiks used in house made mid panels and half cells (at first they cut them in half) of the Janzens, later they used the blue RTR tweeters, which are the identical technology.
 
Had a tweeter array whose mfr name I can not presently recall, I think 4 of them horizontally, looking a bit like the front of a small horn. Great fun back in the day!

Dennisen?

Dennisen and Janzen (?) worked together on a number of ESL projects and hard to tell which brain did what. But those small ESLs from the early 60's inspired many of us.

I'm sure Rice-Kellogg moving coil cone driver crowd are puzzled when I refer to their mechanism as making sound by shaking heavy cardboard.

Ben
 
Last edited:

AstroMick

Member
2016-01-30 3:46 am
Hi guys,
I just bought a pair of JansZen , 10" woofer (RS)/2 tweeter panel in a crappy box. I want to use this tweeter panels in a experimental OB with a Peerless 12"
Can't find spec of this ES tweeters... should I use a mid (I have Vifa 5"/16ohm) or can I x-over to woofer @ 800Hz?

ps. would this units handle higher voltage... for increased efficiency?

Cheers,
Mick
 
Hi guys,
I just bought a pair of JansZen , 10" woofer (RS)/2 tweeter panel in a crappy box. I want to use this tweeter panels in a experimental OB with a Peerless 12"
Can't find spec of this ES tweeters... should I use a mid (I have Vifa 5"/16ohm) or can I x-over to woofer @ 800Hz?

ps. would this units handle higher voltage... for increased efficiency?

Cheers,
Mick

Not likely to make it to 800Hz.
probably 1500Hz with 2 panels is stretching things...

There is a practical limit to the HV, probably below 3kv, iirc. Above that they tend to produce a corona buzz...

bentoronto, not Dennisen. Something like Harbach, I think. They merely bought the cells and mounted them, sold as a product...

_-_-bear
 
If I recall, stator is made by weaving ordinary hook-up wire through grooves in plastic pieces (and the way the Dennisens are made - they are just circular panels about 4-inches across).

I've always thought much the heartache and effort of ESL builders on this forum would be reduced if they just started with some kind of egg-crate plastic molding (like the "lens" of a hung-ceiling fluorescent lamp). Then painted on conductive paint to form the stator.

Or, like Janzen, wrapped wire around.

Ben