[bidoux]

It is a continuation of this thread : "eXStata DIY Electrostatic Amp for Intermediate DIYers"  which has been locked for some commercial reasons.
Here you can find some informations about the design, it is Alex Cavalli's website.
 
I'm not sure if there is already a build thread. If there is, this one can be deleted.
 
Happy diying !

 

[bidoux]

I'm going to start seeking for advices.,
 
I populated my PS board yesterday but now I have to questions :
 
Can I use another LED (orange or green) for L1 L2 ? The green have around 2.1V of voltage drop which seems enough. I also have red LEDs but they are 1.7V (used for Dynalo current sources).
 
Second question is about the heatsinks. I have searched on AMB's website (here on "instructions") and other forums but I didn't understand how to secure the heatsink to the PS board. Is there any trick to do this properly ? (or any picture would be really helpful)
 
Thanks for any answer !

 

[runeight]

You should use the 2.1V leds, especially if you are using resistors instead of LEDs.
 
The heatsinks don't attach to the boards. This was on purpose to minimize any voltage arcing problems for new builders. This type of problem is very unlikely, but I did it anyway so it wouldn't ever happen.
 
The heatsinks will be held down by their devices and if you don't shake the amp really really hard they will work this way forever.

 

[BoilermakerFan]

Quote:

I'm going to start seeking for advices.,
 
I populated my PS board yesterday but now I have to questions :
 
Can I use another LED (orange or green) for L1 L2 ? The green have around 2.1V of voltage drop which seems enough. I also have red LEDs but they are 1.7V (used for Dynalo current sources).
 
Second question is about the heatsinks. I have searched on AMB's website (here on "instructions") and other forums but I didn't understand how to secure the heatsink to the PS board. Is there any trick to do this properly ? (or any picture would be really helpful)
 
Thanks for any answer !

 
The best way to mount the heat sinks is to knock the pins out, then tap the heat sink with a 4-40 or 3mm tap and screw them on with a 15mm or longer machine screw.
 

 

 

[bidoux]

Thank you runeight and Boilermakerfan for your answers, it really helps !
Quote:

You should use the 2.1V leds, especially if you are using resistors instead of LEDs.

So do you mean it is not a problem to use green leds as long as they are 2.1V ? BTW I will be using the constant current diodes. But I don't really understand what you are saying by "using resistors instead of leds".

 
Quote:

The heatsinks will be held down by their devices and if you don't shake the amp really really hard they will work this way forever.

So this is simple, it is going to save time looking for the right screws in differents shops.
 
Boilermakerfan, I will try to understand a bit better your method, I'm quite tired right now.

 

[Lou Erickson]

One of these months I'll get to my build.  I have boards, and I believe I have all the parts.  I've been trying to make sure I had everything so once I started there's a chance I could finish. 
 
I haven't forgotten, and I still plan on doing the build.
 
There's this pesky "working two jobs and gone back to school" thing that's been taking all my time.

 

[bidoux]

I'm thinking of putting my amp in a Hifi2000 case, the Galaxy 80mm should do it fine. Now, has anyone anb idea about the size I should take ? Thanks for any advice

 

[Sathimas]

330x280x80 mm should be big enough, smaller could give you trouble if you can not keep the wires apart.

 

[bidoux]

Thanks, I will get something around this size.

 

[n_maher]

Quote:

330x280x80 mm should be big enough, smaller could give you trouble if you can not keep the wires apart.

This size should work but will definitely take planning to accomplish well especially if you want any extras inside the case.  Here's an internal shot of the exstata that I built in a 12" x 12" par-metals enclosure.
 

 
The Galaxy cases also aren't particularly well ventilated (no vents in the side panels) so I'd guess that the amp will run quite hot in one of those enclosures which could be a problem. 

 

[Sathimas]

http://www.bilder-hochladen.net/files/4bhv-39-jpg.html



 
This is what the inside of my case looks like.
 
It's right that those cases are not ventilated very well.
You could by a perforated cover for it or simply have some decorative holes cut in the top
 
http://www.bilder-hochladen.net/files/4bhv-2o-jpg.html

 

[bidoux]

Thanks to reply and, those are two sweet looking and clean builds. n_Maher, I think you knows cool things to get universal voltage

 
Sathimas, are you using a GX388 (Galaxy GX388 80x330x280) ? It looks like you will have some room inside. I will not be building an hybrid but a solid state amp, but I think the boards are of a similar dimension. This case would do a good job, if I don't mess mine.
 
About this ventilation problem, I will try to get the case perfored (It might look nicer but it'll surely look cooler...) or maybe get something like this and this.
 
A little bonus question, I have mounted the KSC5042f on heatsink with insulator, but is it really necessary to use insulator ? The component looks entirely mad of plastic.
 
The amp will come soon but I have troubles to locally source the P channel mosfet, I ordered two kind of N channel.

 

[Emooze]

What sort of insulator are you using?
 
Something like a thermasil pad not only provides insulation but also better thermal contact. If the package is indeed isolated, you'd still want some sort of thermal grease between the part and heat sink

 

[Sathimas]

I am indeed using a 330x280x80mm case with the 10mm frontplate and also aluminium top cover.
The brushed and anodized aluminium looks much nicer than the normal covers.
 
The perforated cover will the enough to allow the heat to dissipate I think.
The solid state amp draws less power than the hybrid which already needs
15 watts for tube-heating. (Solid state amp comsumes about 30watts in total I think)
 
Will you send the panels to schaeffer for drilling?
If you are using the 10mm frontpanel you'll have no other choice anyway,
even the 3mm thick aluminium is quite difficult to handle.
 
If I were you I'd design a nice ventilation-hole-pattern and have a 3mm aluminium-cover custom-made.
Costs more than the "Couvercle de boîtier perforé 19" 400mm" but wills surely look much nicer.

 

[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 ?