from elliott sound products:
The average performance of a typical heat sink is linearly proportional to the width of a heat sink in the direction perpendicular to the airflow, and approximately proportional to the square root of the fin length in the direction parallel to the flow. For example, an increase in the width of a heat sink by a factor of two would increase the heat dissipation capability by a factor of two, whereas doubling the depth or height will only increase the heat dissipation capability by a factor of 1.4. Therefore, if the choice is available, it is beneficial to increase the width of a heat sink rather than the length of the heat sink fins. Also, the effect of radiation heat transfer is very important in natural convection, as it can be responsible of up to 25% of the total heat dissipation. Unless the heatsink is facing a hotter surface nearby, it is imperative to have the heat sink surfaces painted or anodised to enhance radiation.
The reason for the difference is simply that as the height is increased, the air at the top of the heatsink is hotter than that entering at the bottom. If the fin depth is increased, there is more mutual radiation between fins, and as the spacing is reduced, mutual radiation increases again. Airflow is also restricted because of the smaller physical area for air to pass, since more of the available space is occupied by the heatsink itself.
The average performance of a typical heat sink is linearly proportional to the width of a heat sink in the direction perpendicular to the airflow, and approximately proportional to the square root of the fin length in the direction parallel to the flow. For example, an increase in the width of a heat sink by a factor of two would increase the heat dissipation capability by a factor of two, whereas doubling the depth or height will only increase the heat dissipation capability by a factor of 1.4. Therefore, if the choice is available, it is beneficial to increase the width of a heat sink rather than the length of the heat sink fins. Also, the effect of radiation heat transfer is very important in natural convection, as it can be responsible of up to 25% of the total heat dissipation. Unless the heatsink is facing a hotter surface nearby, it is imperative to have the heat sink surfaces painted or anodised to enhance radiation.
The reason for the difference is simply that as the height is increased, the air at the top of the heatsink is hotter than that entering at the bottom. If the fin depth is increased, there is more mutual radiation between fins, and as the spacing is reduced, mutual radiation increases again. Airflow is also restricted because of the smaller physical area for air to pass, since more of the available space is occupied by the heatsink itself.
Firstly to each their own , my beef is that it's being presented as being cheaper to do, it is not . I have owned class-a amplifiers (200w/ch) it was one chassis ,i have owned mono blocs that weren't class-a. Papa has single chassis class-a amplifiers, currently and in the past, had a few of those too... ( aleph)
Anyway if it was cheaper to do mono's you would see them more, it's not, Also they take up more space and a proverbial pain in the ****. I sold my last set of mono bloc's because of such, i don't have the space for multi-amping with mono's.
To split the boards and do mono's is the most expensive way to do it, just let those involved know that, as it does not matter which way this ends up for me, i can do the 8 boards in a dual mono single case , it has to fit in a 19w x 14hx16d space in my stereo rack ...
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San ,
I increased your numbers in my response, your original post had parts for one mono amp. The heatsinks in stereo is not necessarily 4 times the size and most if not all expressed using fans..
the numbers in the list was for one. the total numbers at the end was for 2 monoblcks. forget about the damn fan. we was talking about IF NOT TO USE FANS!!!!
Even if i had monster heat sinks i would still use a temperature controlled fan for the case and i still say you cannot fit 4 boards , caps, rectifiers and transformer in a 3 inch tall case, so your numbers are off...
with a depth of 20"(500mm) you can fit 2 bords side by side. but you dont need to. IT IS 2 BOARDS pr ch. and you have 2 sides with sinks! is your stereo amp that has to fit 2 boards pr side.
so YOUR numbers are WAY off. not mine. and your stereo amp need 2 PSU boards. my monoblocks only need one.
Killer! That should bring down costs on the PCB a bit. What's the spacing of the fets? Sorry to ask again, but is the universal mounting spec still out of the question?
About the monoblock vs stereo chassis? Monoblocks will be lighter and easier to move, and one would be less likely to have a hernia, so the long run, it's probably cheaper. Even if you looked at the NRE, it's most likely a wash as the stereo chassis will probably need cooling and that added cost will offset some if not most of the cost for the additional aluminum needed for monoblocks. Most will have WAF constraints to deal with first.
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why the hell do you think aleph2 are monoblocks and not stereo amp? to get it more expensive? NO!!!!!
If we cut the traces in the middle of the board, then one half could be used for the p channel and the other the n channel right? If yes, then could we add jumpers in the middle of the board? Those who want the 4 pairs use two boards and jumper in the middle, but those who need need less power could use just one input board and one output board per channel with the n and p transistors.
Does this make any sense?
Does this make any sense?
1 p channel pcb, 1 n channel pcb, 1 flatamp /input stage pcb, 1 psu board and from this you get 2 boards/ch ....
ur right , they were 3 inchs tall .....
........
1 p channel pcb, 1 n channel pcb, 1 flatamp /input stage pcb, 1 psu board and from this you get 2 boards/ch ....
i don't know about you. but i'm not mounting frontend board and PSU boards on the heatsinks. only the 2 (TWO) outputs boards. in your stereo amp you have twice as many bord! that was the point here. and same bottomplate to mount PSU's transformers and front-end's!
OK... first reasonable response for mono's
So i get my honcho's and we 1,2,3, lift into the rack and never touch again ...of course after all is good and done
Stereo amp will weight 30KGand had only been 6" tall as stereo amp? no wait. you dont need bigger chassis for stereo amp. i forgot. jiiiises.1 p channel pcb, 1 n channel pcb, 1 flatamp /input stage pcb, 1 psu board and from this you get 2 boards/ch ....
ur right , they were 3 inchs tall .....
Yes , but we went from a simply setup that gets more complicated by the minute ...
This doesn't really complicate anything, it's just cutting the rails in the middle and placing holes. If one wants an all n or all p channel boards, jumper the holes. For a board with n and p together, leave them open. This would allow people building stereo amps with less power output to use one less board.
we are talking about 2 ch. VS 1 ch. in one chassis. the 2 ch. will need 4 times taller heatsinks to handle the power then one monoblock need to handle the powr from 1ch. so total of twice the heatsink in a stereo amp. (taken the same type of sinks and depth)
Why not stack two monoblocks, separating the heatsinks, and place them next to an air duct. I'm not sure if you tied a string to it that you could call that a stereo amp, but if you wanted an apples-to-apples build, that's probably where you would need to start.
It's pretty clear that a reasonable sized stereo chassis will have to have forced air, an added expense and complication. You will probably also want to improve the internal bracing and also add front and rear handles so you can easily deal with the weight when compared to monoblocks and that's another added expense and complication. You might even have to throttle back the turbo, which to some might be a drawback while others are fine with that. It's probably a debate between 2 4U/5U chassis vs 1 5U chassis with compromises.
I think you both might be talking past each other here.
It's pretty clear that a reasonable sized stereo chassis will have to have forced air, an added expense and complication. You will probably also want to improve the internal bracing and also add front and rear handles so you can easily deal with the weight when compared to monoblocks and that's another added expense and complication. You might even have to throttle back the turbo, which to some might be a drawback while others are fine with that. It's probably a debate between 2 4U/5U chassis vs 1 5U chassis with compromises.
I think you both might be talking past each other here.
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Well with split boards it benefit many more people. And the split boards can be used to make stereo amps. Much harder the other way around.
Are you worried about the few extra $$ the boards will cost because it's split? I'd be more inclined to worry about how many could successfully build a stereo amp of that size. Probably, Not many.
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thank you
and yes. stacking to monoblocks will take less room then a stereoamp. but you need good space between them. the best will be to place them side by side in the middle of the rack. think thats easyer too. depending on your setup of course.
Are you worried about the cost ..? did i say i was worried about the cost ? San said it would be cheaper , I'm pointing out it is not...
Interesting to see how many of you actually build Mono's .....
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