Alpha Nirvana 39w 8ohm Class A Amp

[zman01]

Making the one click shopping cart is easy after others have done the hard work. And I've had plenty of practice.

What would be the polite thing to say now? Something like "don't mention it"

 

[xrk971]

“de nada.”

But truth is, it’s a lot of work. Somehow JPS64 has Fusion360 generate the BOM with Mouser part numbers in one click. But the part number had to be entered st some point. So I think most of it is JPS64’s tireless work of data entry and layout!

Thank you, JP!

 

[AKSA]

Absolutely, JP, thank you so much for BOTH the pcb layout AND the BOM!
And to Zia for the cart, nothing starts until the BOM is finished, those three tasks, schematic, layout and BOM are all equally crucial to a working product......

Hugh

 

[daanve]

How about life expectancy of the output fets?
I learned that about 25W continuous dissipation / ~ 50 degrees celsius heatsink temperature is what guarantees the output devices to last, but this design is about double that dissipation.
How about doubling the output pair?

 

[xrk971]

How about life expectancy of the output fets?
I learned that about 25W continuous dissipation / ~ 50 degrees celsius heatsink temperature is what guarantees the output devices to last, but this design is about double that dissipation.
How about doubling the output pair?

Nahh, never use multiples when a single with higher power dissipation rating is available. If running an IRFP240/9240 at 45w keeps you up at night...

Just use the Fairchild FQA40N25 TO-3P's rated at 280W ($3.43ea):

FQA40N25 ON Semiconductor / Fairchild | Mouser

and FQA36P15 for $2.79 ea:

FQA36P15 ON Semiconductor / Fairchild | Mouser

No matching needed, costs less, and only one pair to connect.

And if you are still concerned, just use IXYS 890w units - they are pricey though at $15 ea, but indestructable. I have actually fogotten to turn on the fan on my CPU cooler once and left it on overnight pumping out 100w (ea). Yikes - but still works like a champ.

IXFH94N30P3 $10ea IXFH94N30P3 IXYS | Mouser

IXTK90P20P $15 ea IXTK90P20P IXYS | Mouser

 

[AKSA]

If you keep case below 50C on an IRFP at 45W you could expect them to last about ten years used two hours a day. I should know; I have quite a few at this temp and all work fine after 25 years. Each increase by 11C starting at 25C will half the MTBF, so 4-5 times less life at these ratings IF YOU CAN KEEP TEMPS BELOW 55C.

Otherwise, for wonderful life, use a CPU cooling tower with fan. Cheap and effective!

HD

 

[Vunce]

Otherwise, for wonderful life, use a CPU cooling tower with fan. Cheap and effective!
HD

Something like these

 

[zman01]

Something like these

Cool! (Literally!)

 

[gary s]

Again to all concerned - you guys are incredible, keep up the good work around here. This will be one very serious and interesting amp.

X - are you working towards a GB and how will it be presented?

Cheers,

Gary..

 

[xrk971]

Hi Gary,
Yes, this is the development thread. Once the verification build is proven we will have a GB thread and take pre-orders as usual.
Cheers,
X

 

[gary s]

Thanks X, I am going to have to work harder and longer hours to get all these amps done next year - my wife will be pleased

 

[meanie]

My ABBB amp is currently on hold....as i have not decided on which heat dissipating methods to adopt.

But this one is so tempting!

 

[thompsontechs]

Hi Gary,
Yes, this is the development thread. Once the verification build is proven we will have a GB thread and take pre-orders as usual.
Cheers,
X

Well get on that build X!

 

[xrk971]

Yes, PCBs to arrive by end of week and Mouser BOM arrives Thursday. Finding the time is the challenge though. Often best to build in 2 hr blocks rather than one all night session.

 

[thompsontechs]

Yes, PCBs to arrive by end of week and Mouser BOM arrives Thursday. Finding the time is the challenge though. Often best to build in 2 hr blocks rather than one all night session.

I for one and looking forward to the results and to try a build if all looks good.

 

[xrk971]

I also have an order in for an Antek AN-6224 600VA 24v trafo to make circa 27v to 29v under load for both channels.

Mouser BOM in transit.

PCBs completed manufacturing and test soon to be shipped.

Locked and loaded, we are ready to roll!

 

[thompsontechs]

I also have an order in for an Antek AN-6224 600VA 24v trafo to make circa 27v to 29v under load for both channels.

Mouser BOM in transit.

PCBs completed manufacturing and test soon to be shipped.

Locked and loaded, we are ready to roll!

Apropos of the day.



Thanks to all who serve.

 

[daanve]

If you keep case below 50C on an IRFP at 45W you could expect them to last about ten years used two hours a day. I should know; I have quite a few at this temp and all work fine after 25 years. Each increase by 11C starting at 25C will half the MTBF, so 4-5 times less life at these ratings IF YOU CAN KEEP TEMPS BELOW 55C.

Otherwise, for wonderful life, use a CPU cooling tower with fan. Cheap and effective!

HD

Mmmm.....I have my stereo switched on 10-12 hours per day.
So that would reduce life expectancy to some two years?? Not a funny prospect
What happens when power fets fail in this design? Do they take along my precious loudspeakers?
Do you guys consider some sort of DC protection?
I do understand the excitement but at the same time have my doubts about the design being good in the several necessary departments...

 

[poseidonsvoice]

XRK,

Looking forward to the build and measurements once you get the prototype going.

daanve,

For DC protection, you can always look into this. It is the RTR SSR, designed by Jan Hofland.

Best,
Anand.

 

[daanve]

daanve,

For DC protection, you can always look into this. It is the RTR SSR, designed by Jan Hofland.

Best,
Anand.

Is that € 37.72 for one channel?