Why is it so?

[rick57]

Electrostatics are known particularly for great midrange – transparency, speed and detail. This is usually attributed to the membrane’s ultra low moving mass.

Yes dynamic drivers work *very differently, though basically both use magnets to move diaphragms.

A low moving mass is such a remarkable advantage to an ESL, yet I’m told by a few long experienced locals that it is *always bad for a dynamic driver, as it always introduces lack of damping > resonances > colouration.

Why (is that really) so?

Cheers

[sreten]

Hi,

the low moving mass of an electrostatic is highly coupled to the air
load, consequently the air damps the behaviour of the diaphragm.

For a moving coil driver the coupling is low, the air might as well
not be there, so the accuracy of the driver depends on its own
control of the diaphragm, and it seems to me obvious the more
mass you have to play with the stiffer the cone you can make.

Low mm is not always bad for a dynamic driver, its a compromise.
If you want high efficiency and don't mind big boxes then for
example you would choose a driver with low mm for its size.

/sreten.

[planet10]

Originally posted by rick57
basically both use magnets to move diaphragms.

no magnets in an ESL

The ESL midrange advantage is more likely from the entire surface being driven,

Its disadvantage is that the amps you need to drive them often don't have the best midrange....

dave

[rick57]

dave

> Its disadvantage is that the amps you need to drive them often don't have the best midrange....

Very good points
. . as you’re *not an ESLer, any independent (devil’s advocate?) suggested amps, or comments on topologies that can output 40+ watts, good current drive to handle those highly reactive loads . .

KT 66/ 88 PP (4 per channel)
Pass SE amps?

[planet10]

Originally posted by rick57
. . as you’re *not an ESLer, any independent (devil’s advocate?) suggested amps

Not an ESLer? I've owned at least a couple sets of Quad 57s, lived with Acoustat X and SY has my old Acoustat 2s so i've fantisized a lot about what a good ESL amp would look like...

Tubes, probably push-pull, with the outputs driving a low turns step-up transformer to more directly drive the ESLs. If you did it with 211s or 845s, you could get away with something like a 3 or 4 to 1 step-up. Iron for this isn't going to be cheap, and working with 1-1.2 kV B+ is real scary & REAL dangerous, but it should work REALLY well.

Using something with more modest B+ would be cheaper and safer, but you'd need a higher turns ratio (still ALOT less than either that in a typical tube amp or an ESL -- and you'd only need 1) SY has a thread here somewhere with that theme.

dave

[rick57]

I didn’t know of your ESL experience

I just got a cheap Chinese 845 SE, and was likely to “hot rod” it with better caps, NOS tubes, and I have Tamura 845 OPT (F-2013) from when I was going to scratch build an 845 SE . .

The ESLs I am looking at have a spare pair of panels, so go Tamura > 3 or 4 to 1 step-up > panels?

Any suggestions for sources for the 3 or 4 to 1 step-ups?

Cheers

[planet10]

Originally posted by rick57
The ESLs I am looking at have a spare pair of panels, so go Tamura > 3 or 4 to 1 step-up > panels?

Any suggestions for sources for the 3 or 4 to 1 step-ups?

basically... something like the (voltage the ESLs run at/the Voltage the output tubes run at) will be your required step-up.

Someone will likely need to wind those special for you.

dave

[phase_accurate]

I know that there are DC-coupled tube amps around that drive ESLs directly. But are there any x-former-coupled and tube-driven ESL solutions around that take NFB from the output of the step-up transfomer ?

Regards

Charles

[rick57]

dave

> basically... something like (voltage the ESLs run at/ the output tubes Voltage)

So I could potentially sell the Tamuras, funding custom step-up iron ($$, but < Tamura $$$), and skip a stage . . which should sound . . more . . transparent?

To improve transparency over the supposedly very transparent Tamuras, would the step-up trannies need to have any particular electrical attributes . . before purchase, how could there quality be judged?

Who might do HV custom step-ups - Jensen ?

cheers

[planet10]

Originally posted by rick57
To improve transparency over the supposedly very transparent Tamuras, would the step-up trannies need to have any particular electrical attributes . . before purchase, how could there quality be judged?

Who might do HV custom step-ups - Jensen ?

I didn't get too far beyond theroizing on the subject... i know Menno van der Veen said he'd build it (Plitron) when we discussed it with him, but i'd check locally (isn't there a very well respected trafo winder in Oz -- Black something?)

Also check out SY's thread.

dave