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Megatron Electrostatic Headphone Amplifier


kevin gilmore

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Inu must be playing with spice biggrin.png

yes it would have to be a 2sa1968, because nothing else is stable at 500 microamps.

or a 2sa1486. The 10m90s won't work. Actually the real number is 450 microamps.

Neither of these are in current production. Could probably get away with ksa1156.

dn2540 also won't work because leakage at likely temperatures is more than 500 microamps.

and with the 12ax7 in the first stage, the gain is a bit high at 65db. so i'm playing

with a 12au7 at the moment. brings the gain down to 52db.

removing the pot probably does not help with the space needed for the current sources.

We will see...

Edited by kevin gilmore
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Which BC560 is the correct one for the Megatron? I don't think there is a BOM or a schematic yet. is there?

http://www.mouser.co...key512-BC560CTA

or this one?

http://www.mouser.co...lkey863-BC560CG

Also, I assume these ones are correct:

http://www.mouser.com/Search/ProductDetail.aspx?R=KA7812ETUvirtualkey51210000virtualkey512-KA7812ETU

and

http://www.mouser.com/Search/ProductDetail.aspx?R=KA7912TUvirtualkey51210000virtualkey512-KA7912TU

Edited by eggil
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That filament was always supposed to be DC powered but 12VDC operation would have been a better idea in hindsight or even running them at 25V.

 

My plan for this one is to run it off a BH power supply with it and the power transformer in a separate chassis.  The amp chassis will also have to have mains running to it as the filament windings for the CCS tubes need to be as close as possible to the tubes.  So that will be 4 transformers for this one and all in the largest Galaxy cases.  Half the size of the ESX for a far more complicated amp... should be fun.... :D

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