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-   -   Is this an unrealistic choice to power an ESL? (http://www.diyaudio.com/forums/planars-exotics/193079-unrealistic-choice-power-esl.html)

dochungwell 23rd July 2011 12:46 AM

Is this an unrealistic choice to power an ESL?
 
EMCO seems to have seveal possibilities which may be an ideal compact power supply...they seem to have a new small power supply that is tiny however, I dont know if it is capible of withstanding 2kv for several hours. Is there a min or max ma bias current that is ideal?

I know CharlieM mentioned the G model but, If i could get away with this tiny model........

http://emcohighvoltage.com/pdfs/aseries.pdf

Thanks,
Jerry

geraldfryjr 23rd July 2011 03:37 AM

I had been looking at those for quite some time,But someone had mentioned that they are very costly and it is hard to find a vender,
It would defintely work though,I think think they have a model that is variable as well,which was the one I was looking at like 0v to 5kv or 6kv.
It has been awhile since I have seen any recent data sheets.


jer

Calvin 23rd July 2011 07:36 AM

Hi,

while I had some good experiences with larger EMCO models, I found them quite expensive and not easy to source.
With the A-series I fear that they will be very costly because of their tiny size, not because of their performance. They should generally be usable in this application, but Id worry about their low regulation factor. A 100% to 200% difference between no-load and full-load condition will become problematic, since small differences in leakage of the panels may lead to widely varying membrane bias voltage. Itll also be a bit more difficult to find the right bias point, since the supply tends to run away. Id rather look for a dc-dc-converter with better output regulation.
I use supplies similar to the G30 in a shielded version with a load regulation of <10% (similar as G30) and just 10% of the specced ripple of the G.

jauu
Calvin

alexberg 23rd July 2011 09:12 AM

Taking into account time and money involved into ESL I would look for noting less than PMT HV power supply.
Matsuada, Spellman, Hammamatsu to name a few...

bolserst 25th July 2011 05:11 PM

Quote:

Originally Posted by Calvin (Post 2647525)
while I had some good experiences with larger EMCO models, I found them quite expensive and not easy to source.
With the A-series I fear that they will be very costly because of their tiny size, not because of their performance. They should generally be usable in this application, but Id worry about their low regulation factor. A 100% to 200% difference between no-load and full-load condition will become problematic, since small differences in leakage of the panels may lead to widely varying membrane bias voltage. Itll also be a bit more difficult to find the right bias point, since the supply tends to run away. Id rather look for a dc-dc-converter with better output regulation.
I use supplies similar to the G30 in a shielded version with a load regulation of <10% (similar as G30) and just 10% of the specced ripple of the G.

Hello Calvin,

I agree that the EMCO products are quite costly compared to a typical DIY HV supply made using a 60Hz voltage multiplier.

Can you describe what you mean by the supply tending to "run away"?
Makes it sound like the HV keeps floating up higher and higher if minimal current is being drawn. Is this the case? Do they need a minimum load being drawn to supply a stable voltage like older switch mode computer power supplies?


Concerning Load Regulation:
Obviously it would be nice to have a solid load regulated HV source, but it may not be as advantageous as one might think for ESLs.

Most people run their ESLs in constant charge mode and connect the HV to the diaphragm thru a large series resistance typically of 50Mohm or larger. This being the case, wouldn't the load regulation of the supply be secondary to the voltage drop across the series resistance if some leakage developed in a panel? For example, with only 50uA of leakage, a 50Mohm resistor would drop the HV reaching the panel by 2.5kV.

Basically, the large series resistance keeps you from being able to take full advantage of a load regulated supply.


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