eXStata Build thread : Electrostatic amp designed by Alex Cavalli - Page 3

Quote:

Originally Posted by bidoux 

I didn't use the mica insulator but those for the amp although I will have to use mica mor the mosfet.

 

The transformer is 25VA which means the amp will consume 25W at max.I was hopping not to spend to much on the casing but I think I'll eventually have to buy the Galaxy case and send it to schaeffer.Is schaeffer this website ? I don't see the pricing anywhere. Do you have an idea of how much they are going to charge me for a few holes on the front and back panel ands some ventilation holes ?

25VA might be too low. I had a custom transformer built to the exact specs on the Exstata BOM and it was 30VA.

For those who didn't get in on the beta run of PCB's Alex is going to run a group buy for them, see thread here:

http://www.head-fi.org/forum/thread/497255/exstata-boards

Quote:

Originally Posted by bidoux 

In the BOM, the transformer specified for the SS build is "Transformer 240VAC > 65mA" and the reference to Mouser is "553-VPS230-110"

or "237-1269-ND" for Digikey.

I think they are both the same tranformer, and it is 25VA. Did I get an obsolete version of the BOM ?

These transformers are a bit different as Alex explained somewhere. They don't regulate properly while on a load and is the only reason why they can reach the 250VAC out.

Either way, they do work. I'm using them in mine. The perforated panels you linked to look fine for the solid state.

Quote:

Originally Posted by bidoux 

In the BOM, the transformer specified for the SS build is "Transformer 240VAC > 65mA" and the reference to Mouser is "553-VPS230-110"

or "237-1269-ND" for Digikey.

I think they are both the same tranformer, and it is 25VA. Did I get an obsolete version of the BOM ?

Yes, but you need two of them which actually gives 50VA in total.

Quote:

Originally Posted by bidoux 

I didn't notice that. So another mouser order for me !..

It would seem so. Check the wiring page for the Triads: http://www.cavalliaudio.com/exstata/main.php?page=instructions/triad

I don't suppose it's too difficult to build in a set of loop out in an eXStata?

It's as difficult as in any other amplifier since the loop out is not involved in the circuit anywhere.

You just connect it in parallel to the input.

Quote:

Originally Posted by transient orca 

I don't suppose it's too difficult to build in a set of loop out in an eXStata?

It would have to be passive as there isn't a way to get the signal off the boards so the split just occurs after the volume attenuator before you bring it into the boards.   A 4PDT switch will take care of the routing. 

You could add TVA iron for a gain stage on the pre outs, but the wiring gets more complicated and you would be better off just adding the necessary gain stage to your other amp. 

Also, I wanted to offer up two PS transformers. 

One is for the Hybrid with 480V CT @ 70mA, and (2) 6.3V @ 1.3A secondaries and the other is for the SS with 480V CT @ 75mA.  

Both are being sold at my cost from E-P which was $95 plus shipping to you.  PM me if you're interested and I can give you the dimensions.