luvdunhill said:
The chassis kit is black anodize only or unfinished. You can add the anodize option and send me a note to leave your front plate out of the anodize batch and refinish it yourself.
One method of refinishing is the tedious task of fine sanding aluminum in one direction only and in parallel lines to achieve a brushed finish look. Then protect it with clear laquer, looks good when done really well.
You can get everything black anodized and have a completely black amplifier.
You can get the heatsinks clear and the chassis kit black, my personal Favorite.
There will be accomodation to allow for a flush mount of the thicker top plate.
Regards
Anthony
luvdunhill said:
Officially 40 to keep the price of $32 CAD. When we hit 20 the price will be $38 CAD, I plan on arm twisting R-Theta into a better price on the 6" profile to get the average price of the 6" to $32 CAD if we do not hit 40.
From the feedback I have had I would have thought that offering a 6" profile would have attracted more members.
This brings up another point I was chatting about with a member yesterday. Some of the PCB designs being offered lately do not lend themselves to splitting the output devices to evenly space for heatsink distribution. Some boards have so many devices in a small footprint that you can only mount the board on one large heatsink.
With Boards like the F5 with only 2 devices it is not too bad if they are far enough appart to get them across two heatsinks. In fact this is what I will be doing with the boards I got from Cvilier.
I have a set of PD boards coming for the F4 and they are going to be a challenge to mount on split heatsinks unless I turn the board sideways and align the devices vertically instead of horizontally. This is not the optimum as you want all the devices to be in the same plane that is perpindicular to thermal conduction.
I may look at a copper spreader plate for these instances, but there are at least three drawbacks; Cost, Complexity, C/W rating of another junction to the formula.
Regards
Anthony
ok, so the 5"/6" will not be an option until 20 is met?
My situation is similar to the above. I have 2 TO-220 devices that are the primary heat producing devices that are about 45mm center-to-center. Then there are some of those "glass transistors". My PCB is 7" wide. I think I could make the smaller profile work for me, but when I sit down and compare the the 9013 to the 9025 profile (which is similar to the barrredboss profile), it's a harder decision. I agree that the 9013 should be the better profile, but instead of whittling down the PCB, or milling a groove into the front panel, and have it barely fit, the wider profile has some appeal. I'm assuming that the wider, but less fin barrredboss profile is somewhat equivalent to the 9025 and thus somewhat equivalent to the 9013 (correct me if my logic is faulty).
The reason that the small chassis kit is problematic, is now I have a larger heat sink to work with (~14" wide), but I have to spread the heat as you mention, due to the bad placement of the TO-220 devices (my board, my fault), I'm just not sure how effective this will be. Furthermore, I'm most likely stuck to 2 chassis anyways, as I have a lot of PSU and a large toroid to fit, and after lots of effort of various less than ideal mounting configurations, things just aren't fitting.
Anyways, I really like the suggested profile, I'm just trying to get it to work for me!
My situation is similar to the above. I have 2 TO-220 devices that are the primary heat producing devices that are about 45mm center-to-center. Then there are some of those "glass transistors". My PCB is 7" wide. I think I could make the smaller profile work for me, but when I sit down and compare the the 9013 to the 9025 profile (which is similar to the barrredboss profile), it's a harder decision. I agree that the 9013 should be the better profile, but instead of whittling down the PCB, or milling a groove into the front panel, and have it barely fit, the wider profile has some appeal. I'm assuming that the wider, but less fin barrredboss profile is somewhat equivalent to the 9025 and thus somewhat equivalent to the 9013 (correct me if my logic is faulty).
The reason that the small chassis kit is problematic, is now I have a larger heat sink to work with (~14" wide), but I have to spread the heat as you mention, due to the bad placement of the TO-220 devices (my board, my fault), I'm just not sure how effective this will be. Furthermore, I'm most likely stuck to 2 chassis anyways, as I have a lot of PSU and a large toroid to fit, and after lots of effort of various less than ideal mounting configurations, things just aren't fitting.
Anyways, I really like the suggested profile, I'm just trying to get it to work for me!
Coulomb said:
you know, I thought this too. I did some simulation using R-Tools in the F4 thread using the monster R-Theta heat sinks from your last group buy. I ended up getting better numbers with the devices mounted vertically and have gone forward with that layout. I can try and find the simulations if you're interested.
luvdunhill said:
I will have to relook at that, as it does not make kitchen table sense to me. 🙂
Anthony
luvdunhill said:
Well we could run a simulation to see how well your devices would work on the 10" profile if you rotated the board 90 degrees.
Anthony
F3 Chassis
I mentioned before about F3 and frankly I'm not very good with heat issues but I found this post from jameshillj which should help someone smarter than I am recommend what combination in this buy would work with an F3:
http://www.diyaudio.com/forums/showthread.php?postid=1789258#post1789258
Hi all,
There seems to be some confusion about how much heat this F3 amp actually generates.
For each channel, the rail is close to 46 volts, add few more for diodes, resistors, transformer, etc to a neat round figure of 50V (dc).
Okay so far?
The current thru each channel is, or should be, approx 1.6 amps, so consumption is approx 80 Watts/ channel and with no power going out to the speakers, this is all dissapated by the heatsink (plus case).
Now, heatsinks - If you look at the Conrad sinks, for example, the 350mm long X 150mm high 15" X 6") flat back have a thermal rate of 0.28 *C/W (0.28 degree centigrade temp rise for each watt injected into it)
However, it's never this simple -_ this 0.28 is measured at 80*C and as it's going to work about 50*C, the heatsink is LESS efficient and so the 0.28 is derated by a factor of about 1.15 (15%) so this becomes 0.32*C/W at 50*C._
If your having a nice day and the ambient temp is 25*C, then you're looking for a temp rise of about 25*C._
Pumping 80 watts into a sink of 0.32C/W will actually give you a calculated temp rise of about 27*C - close enough!
An example - Nelson's F3 heatsinks are about 350 X 125mm (15" x 5") with the 5 horizontal fins and the thermometer rises from room temp of 23*C to 46*C in the middle groove to give a temp rise of 23*C with no output into speakers - the amp does have a big 10mm slab of Ali across the front and also has it's top off that does increase dissapation a bit, but you get the idea.
The F3 clone runs the bigger Conrad sinks and it's temp rise is about 17*C = an R of 0.22*C/W. The developing shunt supply will increase consumtion up to about 2.5A/ ch (at about the same 50V total), then dissapation goes up to about 120W (per channel) which will increase the temp rise to about 25*C - this is a bit of a "guess-timate" and it'll be interesting to see what actually happens in practice..
Incidently, for some reason, this amp does show a quite clear difference with the internal wiring! - so I suggest you fit good quality wire right from those ultrafast diodes that I know everyone is now using(!) to the output terminals.jameshilljjameshillj
I mentioned before about F3 and frankly I'm not very good with heat issues but I found this post from jameshillj which should help someone smarter than I am recommend what combination in this buy would work with an F3:
http://www.diyaudio.com/forums/showthread.php?postid=1789258#post1789258
Hi all,
There seems to be some confusion about how much heat this F3 amp actually generates.
For each channel, the rail is close to 46 volts, add few more for diodes, resistors, transformer, etc to a neat round figure of 50V (dc).
Okay so far?
The current thru each channel is, or should be, approx 1.6 amps, so consumption is approx 80 Watts/ channel and with no power going out to the speakers, this is all dissapated by the heatsink (plus case).
Now, heatsinks - If you look at the Conrad sinks, for example, the 350mm long X 150mm high 15" X 6") flat back have a thermal rate of 0.28 *C/W (0.28 degree centigrade temp rise for each watt injected into it)
However, it's never this simple -_ this 0.28 is measured at 80*C and as it's going to work about 50*C, the heatsink is LESS efficient and so the 0.28 is derated by a factor of about 1.15 (15%) so this becomes 0.32*C/W at 50*C._
If your having a nice day and the ambient temp is 25*C, then you're looking for a temp rise of about 25*C._
Pumping 80 watts into a sink of 0.32C/W will actually give you a calculated temp rise of about 27*C - close enough!
An example - Nelson's F3 heatsinks are about 350 X 125mm (15" x 5") with the 5 horizontal fins and the thermometer rises from room temp of 23*C to 46*C in the middle groove to give a temp rise of 23*C with no output into speakers - the amp does have a big 10mm slab of Ali across the front and also has it's top off that does increase dissapation a bit, but you get the idea.
The F3 clone runs the bigger Conrad sinks and it's temp rise is about 17*C = an R of 0.22*C/W. The developing shunt supply will increase consumtion up to about 2.5A/ ch (at about the same 50V total), then dissapation goes up to about 120W (per channel) which will increase the temp rise to about 25*C - this is a bit of a "guess-timate" and it'll be interesting to see what actually happens in practice..
Incidently, for some reason, this amp does show a quite clear difference with the internal wiring! - so I suggest you fit good quality wire right from those ultrafast diodes that I know everyone is now using(!) to the output terminals.jameshilljjameshillj
Re: F3 Chassis
A sink rating using DeltaT=80Cdegrees will not de-rate by that 1.15 factor when DeltaT=25Cdegrees.
The derating from 80C to 25C is more likely to be between 1.3 and 1.5.
it's worse than that.tbrooke said:
A sink rating using DeltaT=80Cdegrees will not de-rate by that 1.15 factor when DeltaT=25Cdegrees.
The derating from 80C to 25C is more likely to be between 1.3 and 1.5.
samoloko said:
You don't seem to be listening. That rating is for an 80 degree temperature RISE! If you want a hot plate to heat a tea kettle, you've got one. If you want a more manageble 25-30 degree rise above room temperature, you cannot figure 0.21 C/W
About 2/3 of the way down on this page is Conrad's derating chart. The center of Andrew's range was only off by .02 - I read the derating factor for 25C over ambient at 1.38.
So figure a coefficient of .29 for an MF35-151.5 in our application, which results in max dissipation of roughly 85 watts to keep sane heat sink temperatures.
So figure a coefficient of .29 for an MF35-151.5 in our application, which results in max dissipation of roughly 85 watts to keep sane heat sink temperatures.
I have used the MF35-151.5 for a Zv9 and it stays at a nice temp. I can keep my hands on the fins indefinitly. Personally I think that would be a great sink for this chassis kit. A nice one piece.
Well moving right along.....
Here is how I plan on implementing Peter Daniel's F4 boards using four of the 6" 9013 profiles I will be using from this GB.
I plan on mounting the board across the center of two heatsinks that form one side of the chassis. The overlap is 30mm on each side of the seam between the two heatsink sections. The 3 devices per section will be rotated 90 Deg. and I will connect them to the boards with about 40mm of wire. In this configuration I can easily run a stereo F4 in this chassis configuration, 4 x 6" 9013.
Here is a little bit of kitchen table science, a 3" piece of one 9013 is rated at .8C/W at room temperature. Effectively two of these 3" sections side by side would have a total capacity of .4C/W at room temperature.
Think about that .4C/W for 3" x 13.90" at room temperature. Now double the hieght to 6" and only taking half the increase into effect that would be .3C/W for 6" x 13.90" at room temperature.
Room temperature being approx 24 Deg C.
Here is my thermal plot for my proposed F4 configuration.
Regards
Anthony
Here is how I plan on implementing Peter Daniel's F4 boards using four of the 6" 9013 profiles I will be using from this GB.
I plan on mounting the board across the center of two heatsinks that form one side of the chassis. The overlap is 30mm on each side of the seam between the two heatsink sections. The 3 devices per section will be rotated 90 Deg. and I will connect them to the boards with about 40mm of wire. In this configuration I can easily run a stereo F4 in this chassis configuration, 4 x 6" 9013.
Here is a little bit of kitchen table science, a 3" piece of one 9013 is rated at .8C/W at room temperature. Effectively two of these 3" sections side by side would have a total capacity of .4C/W at room temperature.
Think about that .4C/W for 3" x 13.90" at room temperature. Now double the hieght to 6" and only taking half the increase into effect that would be .3C/W for 6" x 13.90" at room temperature.
Room temperature being approx 24 Deg C.
Here is my thermal plot for my proposed F4 configuration.
Regards
Anthony
Is there be difference - better cooling If you do simulation placing the components horisontal - as I see now they are placed vertically along heatsink fins
samoloko said:
Horizontally would most definately be a little more effective in heat dissipation away from the devices. The advantage of keeping really short leads is a compelling argument for the vertical arrangement to accomodate Peter Daniel's F4 boards. The overal Tsink-Avg is hardly effected with either arrangement the temperature around the devices casing is effected slightly.
Regards
Anthony
- Status
- Not open for further replies.