How to build the F5

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#761
You can gogle up the Kerafoll 86/83 I am using nice 1 page data sheet.
Or wait till I learn how to cut and paste from the PDF

any way 8 W/mK

and litle graph shows how much the termal resistance drop with the increase in pressure
K/W =0.2 at 29 PSI or 0.1 at 87 PSI

Which is way I don't use a single screw on the mosfets.
 
#764
My 1st F5 PSU own handcrafted build

Hi Folks,

please see attached pictures of my PSU config. What do you think?
looks it reasonable, will it work? I'm a liitle bit afraid of turn it on the
first time.

Any hints and thought are welcome!

Cheers,
Mallard
 
#767
As long as you have your rectifier and cap polarities correct, you should be OK. Do use the variac or series-light-bulb for testing.....

I'd be a little careful, about your resistor configuration. You appear to have have copper lugs and have resistors between them. Copper (as you know by now) can be pretty flexible, if one of those lugs (or any of the leads from the resistors) flex and contact your main copper plate (at ground potential), there will be some interesting fireworks....(and that would release Acrid, the ancient Greek god of pungent smoke!). Best to go with shorter lugs (or terminals) that could not touch the copper plate. I'd also run some spaghetti over the resistor leads.... (as in thin plastic tubing--not as in penne pasta or cannolli....)
 
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#773
looks good
but I would be worried about the resistor connection being that close to ground
looks a bit dangerous

and I would shorten resistor legs
use more copper plate instead
drill small holes for the resistor legs
better connection than just solder
 
#774
Another night at my day job so

Pseudo haiku

Oh acrid smoke
and the conquered tower
what is next Papa?

Still working on the second channel
And listening in mono

4 hour runs and Dc offset is riducusly low (2mV) and temperature at the spreaders at 48 C
I am really tempted to connect the 24 V taps (using 20 V taps at present)

I gave the clamps screws one more quarter turn today and I am wondering how well I could further improve on the matching of the mosfets pairs with this method as VGS is temperature dependent.

Ideas for loads of little tweaks keep popping up while I work o the second channel at least the front panel is holy now (took 2 days).
1 more day on polishing the other 2 heath spreaders

The amplifier seems to be sounding much better today maybe just hart playing ticks on the brain still sweet extended hi and the lower range drums like seems to have lost a bit of the pum pum and be more on the tum tum (much faster attack) side.

What I would really like is to have a place in the UK where to listen and compare the sound of those amplifiers whit other members.

Food for toughs if you are as half as wakoo as your truly.
Really expensive ideas out of my range.
What if I had same really flat surfaces (Strange things seems to happens but no alphabet after my name to explain) apparently there are same in Greenwich science museum or such and they have to be very careful not to put them together otherwise they will stick to each other.

This may be possible for the coupling of the heath spreader and the heat sinks I am using same 10.5 k/w graphite based goop

And what about thin diamond wafers instead of mica or kerafol on the mosfets.

Quote from Wikipedia>Electrical conductivityOther specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most diamonds, which are excellent electrical insulators.[21] The conductivity and blue color originate from boron impurity. Boron substitutes for carbon atoms in the diamond lattice, donating a hole into the valence band.[21]

Quote from Wikipedia>

Drawing method In 2004, the Manchester group obtained graphene by mechanical exfoliation of graphite. They used cohesive tape to repeatedly split graphite crystals into increasingly thinner pieces. The tape with attached optically transparent flakes was dissolved in acetone, and, after a few further steps, the flakes including monolayers were sedimented on a silicon wafer. Individual atomic planes were then hunted in an optical microscope. A year later, the researchers simplified the technique and started using dry deposition, avoiding the stage when graphene floated in a liquid. Relatively large crystallites (first, only a few micrometres in size but, eventually, larger than 1 mm and visible by a naked eye) were obtained by the technique. It is often referred to as a scotch tape or drawing method.


Pity graphene is electricaly conductive so not good there (graphene mono molecular layer grapite waffer going rate was 100,000 square cm maybe cheaper now)

But maybe if you read troug they mention a way to split mica to very thin film

So maybe Wako reading got same value.
 
#778
CanAm Man said:
As long as you have your rectifier and cap polarities correct, you should be OK. Do use the variac or series-light-bulb for testing.....

I'd be a little careful, about your resistor configuration. You appear to have have copper lugs and have resistors between them. Copper (as you know by now) can be pretty flexible, if one of those lugs (or any of the leads from the resistors) flex and contact your main copper plate (at ground potential), there will be some interesting fireworks....(and that would release Acrid, the ancient Greek god of pungent smoke!). Best to go with shorter lugs (or terminals) that could not touch the copper plate. I'd also run some spaghetti over the resistor leads.... (as in thin plastic tubing--not as in penne pasta or cannolli....)
Click to expand...

I will use poor mans protection solution -> Lightbulb in series of the 230V line!

Ok good hint about the resistor lugs. I'll see how to make it more safety.

Thanks,
Mallard
 
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