Audiostatic ES 100, mylar replacement

[chinsettawong]

Hi Audiostaticproject,

If I were you, I would leave those speakers alone. If you want to learn, make yourself a new pair might be easier.

About the suppliers of Mylar, you can find them easily on the internet. Ebay.com has it. Eraudio.com also has it.

About the coating materials, there are many types. You can try the DIY recipes or you can buy them from a few suppliers. For DIY versions, Favorite Threads and Posts in "ESL's, Planars, Alternative Technologies" Forum .

Again, if I were you, I would build a new pair and leave those beautiful ones alone.

Good luck.

Wachara C.

[audiostaticproject]

Thanks for your replies!




I won't change membranes since you think its to difficult (i find it easy, i could even tension the membrane using a forcemeter - has anyone use it before - do you know the recommended force that should be applied? )

(...)


Anyway, I bought them second hand from a dirty guy who was trying to sell them for years. The membranes were so dirty that one could hardly hear them playing.


The last few days i managed to clean the membranes to the factory clear state. They play really loud and balanced now, as if they were new.
If you r inerested on doing so to your Audiostatics i can tell you the way to do it. (i took a few pictures as well)


Greetings to all the diyers (who suggest not to diy, instead of giving specific advice)

[Ulf Eliasson]

Originally Posted by MJ Dijkstra

With luck you might find the old mirrordrive electronics of audiostatic es200/300 models. Putting this in the es100 might solve the anemic bass issue and give them a more warm end pleasant sound which will be immediately clear in A/B comparison.

Could you explain what this mirrordrive is!

[bolserst]

Originally Posted by Ulf Eliasson

Could you explain what this mirrordrive is!

The Audiostatic "Mirror Drive" circuit from the ES300 I measured used an AT(autotransformer) with a center tap to boost the voltage by 6dB for frequencies below about 250hz. The step-up transformers were hooked up to the ends of the AT winding.
Basically it works by sending high frequencies directly to the step up transformers thru a coupling capacitor connected to the top of the AT winding, but sends low frequencies to the center tap of the AT which then doubles the voltage at the top of the winding. This creates a shelving network with LF boost of 6dB.

For further details, see the Peters US patent.
Frequency response equalizing ... - Google Patent Search


In general, the circuit seemed to work as expected at drive voltages up to about 15Vrms. With larger voltage inputs, the amount of boost diminished. By 25Vrms(80W @ 8ohm) , the boost was only about 2.5dB. I believe this was because the cores of the step-up transformers were nearing saturation so their primary inductance was dropping and giving a more difficult load for the autotransformer to drive. I'm not sure if this behavior was intentional to limit the maximum voltage applied to the stators, or just a trade-off when sizing the transformer cores.

[Ulf Eliasson]

Thanks, for the explanation. Interesting… it sounds a bit of the same result as I accomplished by increasing the resistors in series with the outer stators from 188k to 312k. A definite recommendation including to use metal-film types (1W have played fine in mine for about a year now).

Unfortunately, I think you are right about the saturation in the step-up transformers. They do not look impressing. Logically a high quality step-up transformer should look equivalent to a high quality valve power amplifier output transformer.

[bolserst]

Originally Posted by Ulf Eliasson

Thanks, for the explanation. Interesting… it sounds a bit of the same result as I accomplished by increasing the resistors in series with the outer stators from 188k to 312k. A definite recommendation including to use metal-film types (1W have played fine in mine for about a year now).

The resulting tonal balance changes are similar, but the efficiency is not.

The mirror drive improves the bass to mid frequency tonal balance by boosting the bass to better match the level of the midrange.

When you increase the value of the resistors feeding the outer stator sections, you reduce the level of the mids while leaving the lows the same; you are in effect cutting the midrange to better match the lower level of the bass.