The "opposite" of the "blowhard" thread ....
You mean "blowjobb"? Working with mouth? Haha yes, here productivity is so high. But may be the power goal (supply voltage) can be lowered a bit...
You are quite hardon them
They inspire , at least (to be more productive).My newest OPS ("arc welder" slew 2.0) can actually be a modest 2 pair
50V rail precision class AB amp. Most builders of similar <100W amps will
use @ a 250mm 3U heatsink . Positions 2 and 4 on the new OPS will ensure
an equal thermal area for all 4 devices.
"Scaleability" with optimum performance is built in.
A small(er) amp is just as good on the slew.
2/4 = 100w , 1/3/5 = 150w ,and all 5 could be 250-400W (depending on device).
The MOST adaptable OPS on the forum !!
OS
That was one of the improvements in V2.0. With the whole 175mm (9") of
device positions , the builder can choose the positions to maximize the thermal
"footprint"for each set of devices.
2 pair in positions 1 and 5 on the V1.x or positions 2/4 on the new V2.0 are
the EXACT same bolt holes. Slew 1.x and V2.0 are the same templates
+ 25mm added length and the extra set of outputs near the driver section.
On a standard 3U (especially) the outer 2 pairs (V1.x) have 2X the radiating area. 5U and up (like yours and evan's) , heat transmits in all 4 directions.
But , even with a 5U ... you could mount on the lower 3U for even more
radiating power (V2.0). Plus 5 pair MT-200 or IRFP is possible. NO need
for 4 different OPS's.
OS
Sounds like I need to start looking for a couple of 250mm 3U heatsinks.
Yes , if you do 2 or even 3 pairs .... A 3U heatsink with the old V1.x OPS
is quite Ideal. Each device in the the one (below) will stay within .5mA
from cold to 60C. Much better than my 5 pair amps.
If a present user "swaps out" to the V2.0 , you could get some used boards.
OS
Attachments
Chinese Aluminum (extrusions).
Another factor in thermal considerations is the sourcing of the extrusion.
I have most definitely noticed the conduction differences in my
Hong kong AL/Mg 3U's versus my Heatsink USA "Virgin" AL extrusions.
Be aware of this , it is rarely mentioned.
Same with most other Chinese raw materials , you must de-rate much further
as the actual raw material is substandard.
(Just about 100% - substandard) I buy EBAY , I must expect it to fail.
I don't buy Ebay NO more - JUNK !! (private seller exceptions).
Dealers/stores on Ebay sell what can't be sold elsewhere - really !!
OS
Another factor in thermal considerations is the sourcing of the extrusion.
I have most definitely noticed the conduction differences in my
Hong kong AL/Mg 3U's versus my Heatsink USA "Virgin" AL extrusions.
Be aware of this , it is rarely mentioned.
Same with most other Chinese raw materials , you must de-rate much further
as the actual raw material is substandard.
(Just about 100% - substandard) I buy EBAY , I must expect it to fail.
I don't buy Ebay NO more - JUNK !! (private seller exceptions).
Dealers/stores on Ebay sell what can't be sold elsewhere - really !!
OS
Purchasing some good used boards sounds like an excellent idea for building my first power amp.
At least I'll know that they should be good-to-go.
Perhaps another member will give me a killer deal on some good used 2-pair V1.x boards.
Thanks OS.
Another factor in thermal considerations is the sourcing of the extrusion.
I have most definitely noticed the conduction differences in my
Hong kong AL/Mg 3U's versus my Heatsink USA "Virgin" AL extrusions.
Be aware of this , it is rarely mentioned.
Same with most other Chinese raw materials , you must de-rate much further
as the actual raw material is substandard.
(Just about 100% - substandard) I buy EBAY , I must expect it to fail.
I don't buy Ebay NO more - JUNK !! (private seller exceptions).
Dealers/stores on Ebay sell what can't be sold elsewhere - really !!
OS
Can you recommend a good source for some good, NONChinese(is that a word?) heatsinks?
Purchasing some good used boards sounds like an excellent idea for building my first power amp.
At least I'll know that they should be good-to-go.
Perhaps another member will give me a killer deal on some good used 2-pair V1.x boards.
Thanks OS.
I was thinking about the 5-pair "slew monster" boards. That's the one in the pix.
2 or 3 pair is absolutely perfect wattage/thermals !!
There are 2P boards , but the pairs are next to each other. While that
would make the 2 pairs the same temp. , the same 2 pairs spread out
5" would be the uniform AND @ 10C cooler.
Thermal derating on a output device is about >20W(per -10C) , added to it's power rating.
A cooler amp is a more powerful amp.
OS
OK, so what I want is a used pair of the "Slew Monster" boards with 2(preferably for me) or 3 pairs of output devices?
So the "Slew Monster" boards don't have a V1.x designation?
Sorry to sound so dumb.
Thanks...
OK, so what I want is a used pair of the "Slew Monster" boards with 2(preferably for me) or 3 pairs of output devices?
So the "Slew Monster" boards don't have a V1.x designation?
Sorry to sound so dumb.
Thanks...
No, I'm "dumb".
I have what you need ! I'll never use (below) those ....
I like HUGE amps ...
1 pair of those monster outputs on those boards will be a healthy
100W amp (60V rails).
OS
Attachments
Another factor in thermal considerations is the sourcing of the extrusion.
I have most definitely noticed the conduction differences in my
Hong kong AL/Mg 3U's versus my Heatsink USA "Virgin" AL extrusions.
Be aware of this , it is rarely mentioned.
Same with most other Chinese raw materials , you must de-rate much further
as the actual raw material is substandard.
(Just about 100% - substandard) I buy EBAY , I must expect it to fail.
I don't buy Ebay NO more - JUNK !! (private seller exceptions).
Dealers/stores on Ebay sell what can't be sold elsewhere - really !!
OS
I wonder if the extrusion shape or the finish is causing the difference in efficiency? Usually recycled aluminum is better than new. All the crap floats off the top when they melt it again. Japanese engine blocks are far superior to American. We've always assumed this is why.
Roadsign aluminum is harder , more brittle material. Harder to drill, too.
Al -98% Mg-1.2% Si-.8%
Typically , this stuff gets into the waste stream back to china.
4000 series ...
As does the 3-5% Cu aluminum alloy.
6000 series...
Beer cans are over 99.5% AL , this seems to be the Heatsink USA base.
Aluminum foil , too. It would break if bent , if it was not.
1000 series .....
So , china alloys are everything - non-spec'ed .... "mystery" materials.
NO way around it , as the scrap yard does not fully differentiate the
alloy grades.
Different thermal conductivity , hardness , and corrosion properties
with all 3 spec'ed grades. China grade is ????
PS - Japanese aluminum could be beer cans + X % Cu + Mg to create
precision spec'ed superior alloy's. Not just unknown scrap thrown into the
pot for hobby heatsinks.
OS
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Most malleable aluminum is 3003(crap) or 5056. The non-malleable, nice to work with stuff is 6061 or 6063 which is what Heatsink USA uses. I don't think you can list a specific alloy for North American engine blocks. That's the dirtiest crap imaginable next to patio furniture aluminum. If you re-smelt 3003 or 5056 the crap bubbles up to the top of the pot and what is left is 6061. 6061 work hardens quickly and becomes impossible to form. Maybe they are dumping garbage into the pot to keep it malleable though. It's hard to tell unless you try welding it.
I've gotten "burnt" on many a Ebay sourcings, had to learn material
science to a degree.
ALL the China raw materials are like this , from plastics to metals.
In fact , they will add industrial waste to products destined for
western markets.
This is the price we pay for doing business with a communist "farce"
of a trading "partner". Our corporations are greedy , cheap traitors
and fleece us in every way .... from substandard toxic materials with
planned obsolescence to the actual outsourcing of the labor.
THEY SUCK .... and what I speak of is the truth.
What is in the local Dollar store now would be treated as toxic
waste 10 years ago. The BBB and EPA are bought and paid for ...
I've been SICK for months from this toxic poop from walmart/dollar stores ,
it's gotten ridiculous. My eyes water in either store from these toxins.
OS
science to a degree.
ALL the China raw materials are like this , from plastics to metals.
In fact , they will add industrial waste to products destined for
western markets.
This is the price we pay for doing business with a communist "farce"
of a trading "partner". Our corporations are greedy , cheap traitors
and fleece us in every way .... from substandard toxic materials with
planned obsolescence to the actual outsourcing of the labor.
THEY SUCK .... and what I speak of is the truth.
What is in the local Dollar store now would be treated as toxic
waste 10 years ago. The BBB and EPA are bought and paid for ...
I've been SICK for months from this toxic poop from walmart/dollar stores ,
it's gotten ridiculous. My eyes water in either store from these toxins.
OS
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This is why I prefer to build everything from raw materials. You never know what you are buying these days. I think it all goes back to people flocking to Walmart. Everyone keeps undercutting the next guy because if their product is 10 cents more expensive nobody will buy it and the go broke. Motorola is a prime example.
One of the projects on the go in my shop now is a restoration on a 1970 Chevelle. The guy doing the job was so happy he could buy all these reproduced parts cheap and just bolt everything in. Now he has all the parts and realized the bolt holes are off 1/4" on most of these parts. He's spent as much time modifying junk to fit as it would have taken to make new parts and the finished product sucks! I'll be glad when the "accountants" give up and we can go back to a quality driven marketplace again.
One of the projects on the go in my shop now is a restoration on a 1970 Chevelle. The guy doing the job was so happy he could buy all these reproduced parts cheap and just bolt everything in. Now he has all the parts and realized the bolt holes are off 1/4" on most of these parts. He's spent as much time modifying junk to fit as it would have taken to make new parts and the finished product sucks! I'll be glad when the "accountants" give up and we can go back to a quality driven marketplace again.