What do they sound like?
There is a significant improvement in sound quality from the original panels. Low level detail is more discernible, clarity
has improved to another level, imaging is three dimensional and rock steady. The sound-stage is wide with excellent separation between performers.
Off axis listening is now possible without the image collapsing into one speaker.
Pricing has not yet been established but by all means contact us on
firstname.lastname@example.org if this project interests you .
Steve’s Final 0.3 speakers had suffered loss of output from both electrostatic panels. Rather than try to rebuild the original panels he opted to replace
them with a pair of mid / treble panels that have recently been designed as an upgrade for our Acorn full range speaker.
Preliminary tests proved very encouraging so Steve installed the panels with simple MDF plates to allow for the different size of the new panels, the finished and unfinished versions are shown below.
Below, unfinished prototype installation.
Final 0.3 panel substitute
Please note we strongly recommend the use of grille cloth over the panel as shown below, this prevents insects and dust entering the works. While the panels can be used in “see through” mode they will collect dust and insects so will require vacuuming or cleaning from time to time. Failure to clean them for a long period can lead to internal damage.
Above and below, pictures of Steve’s Final 0.3 speakers. The original panel has been removed and replaced with a slightly shorter 920 mm and a little
wider 200mm Acorn
mid / treble panel.
This panel has several advantages over the original Final panel.
The original panel has a single stator that is separated into 3 sections to improve dispersion mechanically. This does work but not especially well because all three sections are still trying to reproduce the full range that is being sent to the panel.
The new Acorn Mid / Treble panel has 3 electrically separate sections. The treble strip is divided into 3 vertical segments, the centre narrow segment is fed with
all high frequencies, if the transformer is capable of delivering say 35kHz into a small load then the strip will reproduce it. Because the strip is narrow dispersion is good. At around 18kHz the signal is fed via four surface mount
devices (SMD) to the adjacent strips so the full width of the treble section reproduces from 18kHz down.
The mid-range panel is driven via 2x (one each side) resistors that filter high frequencies from that section, these are supplied with the panel.
So the end result is a panel that is capable of delivering up to 35kHz, depending on the transformer, a treble strip that is narrow enough to deliver high frequencies with good dispersion and a mid-range section that is not trying to reproduce high frequencies as well, leading to very low IMD (intermodulation distortion).
No modifications to the Final original electronics are required, the new panel uses a very similar voltage to the Final panel but may require a 100 megohm series resistor between the diaphragm and the high voltage supply to reduce voltage and current capability a little.
The crossover capacitors should be upgraded to higher quality types for the best reproduction. If you require advice just contact us on Rob@eraudio.com.au
The same set-up can be used in a number of other commercial ESL’s that have dead panels
We asked Steve how he was getting on after he’s finished the cosmetics and upgraded the Final electronics, here’s his response.
I’m extremely happy with the end result...never thought I’d own a pair of speakers that sounds this good!
They also look good... even the wife says so. I’ve replaced the crossover capacitors with Mundorfs. The capacitors and panels are settling in and wow do they sound good.
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