Hi Russellc, like Buzz said: don't give up!
If you have the 5U store chassis it will work with option 1.
Placing your MOSFET's at 1/3 at the two sides of the sinks is no problem. Look at my picture, the amp board/heatsink on the right is F5Tv2. I had no problems with heat distribution. Sinks are 300 x200 mm.
Walter
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I dont think the extra height will help that much from what I've read here. Seems that width is what you are after...Those sinks are quite good and 4 of them will give considerably more sink than my 5u chassis. I should have done that as well.
Russellc
If I were using sinks that large I woudnt be so concerned. The M&M sinks on my F-5 are 12" by 6.5" just slightly shorter than yours. The heat sink USA for my 2nd F-5 are 8" tall 10.08 wide with 2.5 inch fins. My M&M sinks have 2 inch fins. Both of them have a thicker base as well when compared to 5U sinks, whose fins are just over an inch....Total size sounds good, approx. 16 x 8.5......but they are 2 sinks not one, base isnt all that thick, about 1/4 of an inch or so and with the shorter fins I just dont think its sufficient.
I'm shelving it until I see more.
Russellc
Hi Walter,
Now that you have had your V3 up and running for some time, how much bias are you running?
The heat sink issue is also holding me back some. I was considering making my own heatsinks 400 x 200mm and using Tea's boards. But his boards are only 250mm in length and that includes the front end section so all the Mosfets are clustered in about a 200mm length, so I am not sure whether I will get good distribution over the 400mm length heatsink. Maybe a board of around 350mm length with all the Mosfets on one side and the diodes on the other, that way the length of Mosfets could be placed close to the center line of a 200 mm height heatsink and the diodes mounted towards the bottom of the sink?
Nash
Now that you have had your V3 up and running for some time, how much bias are you running?
The heat sink issue is also holding me back some. I was considering making my own heatsinks 400 x 200mm and using Tea's boards. But his boards are only 250mm in length and that includes the front end section so all the Mosfets are clustered in about a 200mm length, so I am not sure whether I will get good distribution over the 400mm length heatsink. Maybe a board of around 350mm length with all the Mosfets on one side and the diodes on the other, that way the length of Mosfets could be placed close to the center line of a 200 mm height heatsink and the diodes mounted towards the bottom of the sink?
Nash
How wide are thinking of making your chassis, I was thinking 18" overall, which would make the main cavity approx. 15 in wide by 20.16 deep. I would hope this would be plenty of room for all the components. Maybe its to big.
If the outside isnt too big for you, the inside can never be to big generally speaking...I like lots of room to work in!
Russellc
Funny you should ask... I am still pondering that. The heatsinks are 5 3/4 in. wide alone. 18 in. overall only leaves 12 1/4 in. and the transformer is a bit over 6 in. But like Russell says big is good. I am leaning towards a square overall, that would leave me with the cavity size of 16 in. x 20.6 in. That is my current thinking.
that is about 3" wider cavity then mine. that is plenty of room.
this one is 11*20*6"
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I've seen bigger.
An externally hosted image should be here but it was not working when we last tested it.
Say, I just noticed that the one on the Left is V3? If this worked, (I assume it did) then surely my V2 will survive....hmmmmmmmm
Russellc
Say, I just noticed that the one on the Left is V3? If this worked, (I assume it did) then surely my V2 will survive....hmmmmmmmm
Russellc
I don't know... Big is relative I think. I am 6'2" 300lbs that's kinda big so a 2'x 2' 50lb amp would not be too big.
I used to be taller than you Billy, but I lost over an inch thinking I could lift about anything. When I get my 6 level lumbar fusion I should regain at least that much.
Randy Newman - Short People - YouTube My dear daughter is a short person, so know this is totally tongue in cheek. Besides, it's Billy's fault for making me think of it.
Randy Newman - Short People - YouTube My dear daughter is a short person, so know this is totally tongue in cheek. Besides, it's Billy's fault for making me think of it.
Yes, that's what I am listening to right now
Upgraded a v2 to a v3.
Heat distribution is even better with more MOSFETs at a lower bias per MOSFET. Heat dissipation is the same of course.
In the center of the heatsink around 55 degrees C, at the edges around 48-49 degrees Celsius.
@ nashbap: bias is now 2 Ampere per rail @32 Volt, so around 4 Ampere class A bias.
2,5 Ampere which I aimed for is too much, maybe in the winter when my T ambient is around 18 a 19 C.
I think you could use the 400 x 200 mm heatsinks with Teabags board but it depends on how thick is the base of your heatsink. Mines are 12 mm, but I've seen heatsinks with even a 15 mm base.
Do you have more specs?
Walter
and that's just one channel
think of 7.1 ( even if you certainly wouldn't need that .1)
I will have 3 on my fronts which will take a bit of space.