http://64.56.118.35/pe/showdetl.cfm...St3=-75250932&DS_ID=3&Product_ID=123265&DID=7
There are a ton of them listed, but I have no idea which one I should use. Thats one would be for a single PS for both channels, but I'd also liek a recommendation for what would be needed for a dual monoblock config.
There are a ton of them listed, but I have no idea which one I should use. Thats one would be for a single PS for both channels, but I'd also liek a recommendation for what would be needed for a dual monoblock config.
Looks pretty good.
Check out this spreadsheet:
http://www.national.com/appinfo/audio/files/Overture_Design_Guide13.xls
Also, check out the datasheet for a few design equations.
Check out this spreadsheet:
http://www.national.com/appinfo/audio/files/Overture_Design_Guide13.xls
Also, check out the datasheet for a few design equations.
A first guess would be "that'll do", i.e. check the forum or decibel dungeon website, fore example.
A good way to check though is to do the calculations yourself for YOUR output requirements (audio power out). The LM3875 datasheet at www.national.com walks one through the appropriate calcuations.
Hope that helps
A good way to check though is to do the calculations yourself for YOUR output requirements (audio power out). The LM3875 datasheet at www.national.com walks one through the appropriate calcuations.
Hope that helps
http://www.nuvotem.com/en/products/std_pcb2x120v.shtml
These are the ones that I really want, and would prefer. Which ones would you guys use? I've been tryig to the calcs myself, but am curious what the pros on here have used and prefer, since to me, that what matters most.
These are the ones that I really want, and would prefer. Which ones would you guys use? I've been tryig to the calcs myself, but am curious what the pros on here have used and prefer, since to me, that what matters most.
I'm so confused. I know understand what my teacher meant when she said Algibra would save my life one day. Cause I swear at this point, trynig to do the math, makes me want to step in front of traffic. (Never did well with math in school. Everything else, I aced without cracking a book once to study. But math makes me cry 
)
I'd like to see 50 watts rms, and cooling isnt an issue. I want to design the enclosure, once I know what I need. First issue is power.
)I'd like to see 50 watts rms, and cooling isnt an issue. I want to design the enclosure, once I know what I need. First issue is power.
Hey J, for 50W...
Most of the posts that I've read suggest power trannis of 160-250VA(I'd go with higher rating) for monoblocks with secondaries of 25-0-25V, and 330VA+ for single PSU with the same secondaries.
Make your heatsinks big and efficient.
Hopefully, someone with real world experience will chime in.
Most of the posts that I've read suggest power trannis of 160-250VA(I'd go with higher rating) for monoblocks with secondaries of 25-0-25V, and 330VA+ for single PSU with the same secondaries.
Make your heatsinks big and efficient.
Hopefully, someone with real world experience will chime in.
The 25v 330 is the right one of this bunch for you if you intend to run two channels off of the one transformer. 250va would be the minimum I would go with but the cost of getting one a little larger is not signficant.
And Yep all the math you didn't want to study becomes usefull. If only they had taught it that way.
And Yep all the math you didn't want to study becomes usefull. If only they had taught it that way.
Re: Great Excel spreadsheet, Sean....
National did. This is the page of their website it's from:
http://www.national.com/appinfo/audio/
There is a guide to using the spreadsheet and a few interesting application notes on that page.
darkmoebius said:
National did. This is the page of their website it's from:
http://www.national.com/appinfo/audio/
There is a guide to using the spreadsheet and a few interesting application notes on that page.
For 50 W into 8 ohms you want a 25-0-25 VAC 125-225VA (monoblocks), but i wouldn't recommend this much V if you are running lower (or ugly) impedance speakers (most of them).
Note how the power into lower impedances plummets if you have too high a rail.
From the data i figure 18-0-18 VAC or just a bit higher is best (30 W into 8/45 into 4).
dave
Note how the power into lower impedances plummets if you have too high a rail.
From the data i figure 18-0-18 VAC or just a bit higher is best (30 W into 8/45 into 4).
dave
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