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The DIY Electrostatic amp thread


spritzer

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  • 4 weeks later...

Thanks spritzer I have the larger heatsinks with the trannies pasted to them, temps hovering around 60 Degree C heatsinks are anodized so thats the insolation....

Adjusting balance and offset varies a few volt either way, might look at the led volts.

When adjusting the balance and offset, gather it's done with nothing connected, into or output, not even the input volume pot?

Also, I have 2 balanced stepped attenuators, one 50K the other 10K, does it matter with input resistance?

When using SE input, is the - input(unused) grounded or left floating?

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I like to keep it straight and simple...... just like me

I havn't wired up the rca's yet.

I'll probably make perf-board with relays to switch between the two.

It can sit between the two inputs on the back panel....

I'm using it balanced from a B3

Also

Just updated to a larger pic in that post (I was surprised I could modify it)

The better pic should show where I drilled holes in the pcb under the heatsinks..

I used flouro yellow nail varnish on the pcb holes for insulation..

And before anyone asks if the color of the nail varnish matters to the sound?

I have no comment:)

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  • 3 weeks later...
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  • 5 months later...

I am trying to use the BATE boards I got from Birgir to make a BEA/baby Megatron, but have a couple of dumb questions first. Is it alright to use a separate transformer "stacked" onto the HV transformer to generate C- 430V? Also, any foreseeable problems with 10M90S cascode CCS on output tubes? What DC should I "float" the output tube heaters at. and what's the best place from which to derive this voltage? Finally, planning on using simple LM317 based circuit to power the input tube heaters, should I run this in current mode or voltage mode and do I bother with a soft start? TIA.

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Great, thanks! I think that's all the info I need to start sourcing parts and begin this project. Will certainly have more questions along the way. Preliminary searching brought up something like this for the amp chassis/heatsinking the CCSes. http://www.ebay.com/itm/111110701287?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

A parts question, what circular connectors/sockets do you recommend? I think I'm going to need around 10 contacts. 400v, -400v, -430v, -15v, gnd, 580v bias, 230v bias, 6.3v heater x2, 12.6v heater, I think that's it?

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The -430V is generated on the psu board by stacking a TL783 supply "underneath" the -400V supply. 

 

No need to cascode the 10M90's, single units per tube are just fine. 

 

Heaters can just be left floating or take a voltage divider from the B- line.  Stax tied the heater directly to the B- line in the T2 so that would work here too. 

 

That chassis is similar to what I'm using for the small KGSSHV and they are nice to work with.  The umbilical connector can be something like this:

 

http://www.ebay.com/itm/1-Military-Gold-10-Pin-Twist-Male-Female-Connector-M10P-/300562711241?pt=LH_DefaultDomain_0&hash=item45faef02c9

 

Been using them for years and there is also a female version.  You can also just generate the normal bias from the B+ inside the amp chassis via a voltage divider. 

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Yes I know the supplies are stacked, just wanted to make sure two transformers can be stacked. :) Dumb question, but better safe than sorry.

 

I should go over the enormous T2 thread at some point, I'm sure I'd learn a lot. Leaving things actually floating seems a bit scary to me (obviously I did not grow up in the tubes era) so I will tie to B-. That way I can make sure the heater-cathode voltage is in spec.

 

Thanks, those connectors look really hardcore and are inexpensive to boot.

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