troystg said:"assuming termal resistance scales linearly"
I was informed that doubling the height of a heat sink does not double the capacity. As the air rises it heats and is not the same as two separate heat sinks side by side.
Yours may indeed work; I am just repeating what I was told by a manufacturer about height.
The manufacturer disappointed me with news about my height, and my girlfriend disappointed me with news about my length. Rough times I tell ya..
Height and length should bre pretty much equivalent. Everything else is wrong!
I have sent an email to Conrad to see if they can do a massive 45 cm high (that is massive!) sink. I asked for 30 width, which I'm sure will satisfy even the most demanding people here.
Hi,Patrik Floding said:
the Rth s-a is approximately inversely proportional to square root of the height.
twice the height will give about 40% lower Rth s-a PROVIDED the Radius to thickness ratio does not exceed ~10 from the devices to the extreme corners.
Four times the height will roughly half the Rth s-a. i.e. 0.29 becomes 0.145 when about 600mm high.
Remember to de-rate from the deltaT=80Cdeg to about 25Cdeg.
when de-rated for both radius and for delta T one may find that Rth s-a has gone back up by 50% or worse for large area sinks and very much worse for thin sinks.
Hi,
look for Wakefield's design guide. It's on their site.
It tells you how to de-rate for temperature, how to place components to maximise efficiency, how to convert for different heights, confirms that increasing the width increases Rth s-a linearly. It confirms that the whole backplate should be at the test temperature to achieve the published Rth s-a values.
It does not say how to estimate the loss of efficiency for a thin backplate to radius ratio. But distributed devices alleviate this problem.
I think Fischer has a less comprehensive design guide and Conrad has a cut down design guide.
Go read.
look for Wakefield's design guide. It's on their site.
It tells you how to de-rate for temperature, how to place components to maximise efficiency, how to convert for different heights, confirms that increasing the width increases Rth s-a linearly. It confirms that the whole backplate should be at the test temperature to achieve the published Rth s-a values.
It does not say how to estimate the loss of efficiency for a thin backplate to radius ratio. But distributed devices alleviate this problem.
I think Fischer has a less comprehensive design guide and Conrad has a cut down design guide.
Go read.
Hi Mark,
When you get back home please don't forget to also send me my ten boards and diodes.
As soon as we have the boards Pierre Watts can start building and possibly be one of the first to finish a no holds barred KSA clone and possibly guide others re problems experienced.
There are three very anxious builders waiting for the boards in Cape Town....
Regards
Jozua
Cape Town
South Africa
When you get back home please don't forget to also send me my ten boards and diodes.
As soon as we have the boards Pierre Watts can start building and possibly be one of the first to finish a no holds barred KSA clone and possibly guide others re problems experienced.
There are three very anxious builders waiting for the boards in Cape Town....
Regards
Jozua
Cape Town
South Africa
Krell KAV-250
Gents:
Are we ready for a higher output Krell? If there's interest to work on the KAV-250. I can post schematics and layouts but won't do so for the heck of it.
Here are my conditions :
Al does the Boards.
Mark does the GB.
Troy makes me my kit
Let me know if there is interest in actually doing this.
I own a KAV-250 and love it, As nice as the KSA-100. Mkii sounded, I sold it after I heard the KAV-250. This is one Krell I'd really like to build.
At about 325 watts per channel into 8 ohms (rated 250) and 1000 watts bridged, good enough for almost any application, this is the amp to make !
K-amps
Gents:
Are we ready for a higher output Krell? If there's interest to work on the KAV-250. I can post schematics and layouts but won't do so for the heck of it.
Here are my conditions :
Al does the Boards.
Mark does the GB.
Troy makes me my kit
Let me know if there is interest in actually doing this.
I own a KAV-250 and love it, As nice as the KSA-100. Mkii sounded, I sold it after I heard the KAV-250. This is one Krell I'd really like to build.
At about 325 watts per channel into 8 ohms (rated 250) and 1000 watts bridged, good enough for almost any application, this is the amp to make !
K-amps
KAV 250
K-amps
Maybe you should first audition the new KSA 100 clone before you jump into a KAV 250 as there are many subtle improvements which might just make it sound better than the original.....
That is why we should start building these amps as soon as possible to hear how it sounds.
Personally this is going to be my last DIY amp so it going to be a "No-holds-barred" version. I have to draw the line with all my DIY projects.
Jozua
K-amps
Maybe you should first audition the new KSA 100 clone before you jump into a KAV 250 as there are many subtle improvements which might just make it sound better than the original.....
That is why we should start building these amps as soon as possible to hear how it sounds.
Personally this is going to be my last DIY amp so it going to be a "No-holds-barred" version. I have to draw the line with all my DIY projects.
Jozua
Re: Krell KAV-250
Hi K-amps. Yes Im in and I would like to join this Krell clone project as I did to the KSA 100 clone project. If this would be a real project, Im in for at least 6 boards.
I liked what I read about the KAV 250a and what I really liked was its balanced input design, something I lack for the KSA 100. Is it possible to implement that solution to the KSA 100 amp? If yes, it could be a part (# 1) of the whole KAV 250a project?
Could you say anything about the technical solutions used in this model? Are the balanced input configuration build on a separate PCB or is it a part of the front end at the main board?
Regards
K-amps said:
Hi K-amps. Yes Im in and I would like to join this Krell clone project as I did to the KSA 100 clone project. If this would be a real project, Im in for at least 6 boards.
I liked what I read about the KAV 250a and what I really liked was its balanced input design, something I lack for the KSA 100. Is it possible to implement that solution to the KSA 100 amp? If yes, it could be a part (# 1) of the whole KAV 250a project?
Could you say anything about the technical solutions used in this model? Are the balanced input configuration build on a separate PCB or is it a part of the front end at the main board?
Regards
Congratulations + prosperity, Mark. 