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Megatron Electrostatic Headphone Amplifier


kevin gilmore

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Anything on ebay would be fake too.  Hell most of them have sanding marks and with 2SA1968 laser etched afterwards, not even close to how the original looks. 

 

After helping some users with their Megatron I have some ideas on how to improve the PCB and make it more user friendly.  Swapping to the STN9360 for the CCS would make sense. 

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Thanks, after the whole Dalbani fiasco it's not like anything else should be expected. I just find it funny that they're charging $112 for a fake part, at least the Ebay scammers are more modest.

 

I was thinking of running the front end at 400V (more like 390V, but we'll see how close I can get with the zener references in the PS), which would be pushing the limits for sure with just a single part. Stacking also helps split the power dissipation for the small SOT223 package. Maybe I'll think up a clever way to put in a dropping resistor on the positive rail so I don't have to bother with all of that; suggestions are welcome. All CCSes will be on separate protoboards since I am building from the BATE PCB. I bought adapter boards here, they're super cheap and even come with 90 degree header pins: http://www.ebay.com/itm/271302222232?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Edited by mypasswordis
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There is nothing to be gained from running the front end at 400V, well nothing but bad things that is.  There is already a dropping resistor on the board for just this setup. 

 

Those adapters are cool but there seems to be very little in the way of heatsinking.  Shouldn't be a problem but something to look out for...

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  • 2 weeks later...

Can anyone comment on using Antek transformers for a Megatron/KGST build? I'm trying to reduce my dependency on SumR custom products, and edcor seems to have leadtimes for all the relevant transformers.

 

Antek seems to provide a number of transformers with both HV and filaments on a single toroid- are there any problems with using those filament windings on the output? 

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I'm using the Antek 400VA 430V transform in my KGSSHV build.  It is temporary until SumR finished my transformer.  In this particular application, the transformer is always quiet and cool.  I didn't use the filament windings.

 

This weekend, I will bring up my Megatron build with this transformer (again, waiting for SumR for the proper one).  I'll let you know how it goes.

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  • 4 weeks later...

Well, my PSU powered up without a hitch: +456V,  -452V; +15.15V, -14.86V

Will test the amplifier in next few days. Don't have the 6Ca7's yet and missing one small transformer.

For me, the most difficult part is always the casing.

Never mind the dirty filter :)

The transformer is SumR

post-2299-0-58935400-1400101545_thumb.jp

Edited by eggil
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