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Old 19th January 2007, 06:24 PM   #1
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Default 3 channel lm3875 help/advice

Hi,

I finally finished my lm3875 kits a few months ago(Peter Daniel's kits) and now i'm setting up some active 3-way speak's and would like to minimize the amount of boxes (limited rack space). What would I need to do to run 3 channels off of one transformer?

Also, and slightly off topic, i'm tired of feeling like such a newb all the time when it comes to amp's are there any good online resources to learn about amplifier design/basics so I can stop bugging the experts with these stupid questions? I've been steadily reading over the articles on Rod Elliot's site, and those have helped but i'm looking for something a little more substantial. I went to Chapters today, but all they had were books on tube amps.

Thanks in advance,
Tristan
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Old 19th January 2007, 06:53 PM   #2
CarlosT is offline CarlosT  United States
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Amazon carries books on op amps but reading some of the reviews there, it's hard to tell which are trash and which are not.

Jung has a book that's like $65 which I almost got. He seems to be the only author that didn't get dissed...boy these audiosnobophiles are brutal on each other.

Don't waste your time going to Borders or Barnes & Noble for amp books.
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Old 19th January 2007, 06:56 PM   #3
CarlosT is offline CarlosT  United States
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Technically, you could parallel tap 3 sets of V- PG- PG+ V+ outputs outta one rectifier board and this would work for 3 equally loaded channels...just don't expect miracles

The AudioSector recitifier board is already set up to have 2 sets of outputs for the obvious 2 amps/2 channels.
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Old 20th January 2007, 06:11 PM   #4
gootee is offline gootee  United States
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Default Re: 3 channel lm3875 help/advice

Quote:
Originally posted by Tristanc1
Hi,

Also, and slightly off topic, i'm tired of feeling like such a newb all the time when it comes to amp's are there any good online resources to learn about amplifier design/basics so I can stop bugging the experts with these stupid questions? I've been steadily reading over the articles on Rod Elliot's site, and those have helped but i'm looking for something a little more substantial. I went to Chapters today, but all they had were books on tube amps.

Thanks in advance,
Tristan
Some great material is available on chip manufacturers' websites. Try http://www.national.com , http://www.analog.com , http://www.linear.com , http://www.ti.com , http://www.apexmicrotech.com , and others. Check their Application Notes and other technical literature sections. There are some generalized appnotes about amplifiers and related topics, on those sites, although you might have to dig a little to find them among the many more-specific appnotes.

There is also a "book", online, that's pretty good, called "Opamps for Everyone". Sorry, I don't have a URL at hand. But you should be able to easily find it by googling.

I think that documents like Analog Devices' classic Appnote AN-202, for example, should be required reading for everyone working with ICs.

Tom Gootee

http://www.fullnet.com/~tomg/index.html

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Old 20th January 2007, 10:29 PM   #5
gootee is offline gootee  United States
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Default "Op Amp Applications Handbook", Jung et al: DOWNLOADABLE FREE

You can find the entire "Op Amp Applications Handbook" (Jung, et al), on line, at http://www.analog.com/library/analog..._handbook.html . (Gee, and I went and paid $60 for it, at Barnes and Noble, less than a year ago.) It's pretty good. They have it available in sections AND as a 17MB zip file of the entire book.

- Tom Gootee

http://www.fullnet.com/~tomg/index.html

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Old 21st January 2007, 01:17 AM   #6
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Thanks a tonne for the info so far guys! That downloadable op-amp book looks great, i'll chew over that for a bit and see if I have some more questions

Tristan
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Old 21st January 2007, 02:35 AM   #7
CarlosT is offline CarlosT  United States
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Default Re: "Op Amp Applications Handbook", Jung et al: DOWNLOADABLE FREE

Quote:
Originally posted by gootee
You can find the entire "Op Amp Applications Handbook" (Jung, et al), on line, at http://www.analog.com/library/analog..._handbook.html . (Gee, and I went and paid $60 for it, at Barnes and Noble, less than a year ago.)...
Yeah...you'll spend $60 worth of toner printing it all

Great link though...thanks!
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Old 22nd January 2007, 01:50 PM   #8
CarlosT is offline CarlosT  United States
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This is by far the single best source of information I got for op amps...really breaks it down to a simple level and with none of the "soft" science (fluff) and ego trips that many free sites have.

This chapter deals in op amps but the whole set of "All About Circuits" is just awesome.

http://www.ibiblio.org/kuphaldt/elec...s/Semi/pdf.jpg

If you wanna understand all the talk about inverting versus non-inverting and DC offset and all that, this is the chapter.

All of chapters are here...you need to dig down to each chapter to find the pdf link.

http://www.ibiblio.org/kuphaldt/electricCircuits/
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Old 22nd January 2007, 05:04 PM   #9
AndrewT is offline AndrewT  Scotland
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Hi,
read Leach and D.Self
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