Simple high audio amp

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jwzumwalt
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Simple high audio amp

Post by jwzumwalt » Wed Feb 01, 2006 11:49 pm

1) I am interested in a very simple high power audio amp circuit for a church PA system. Modest quality is fine. Can someone suggest a high power IC/transister & circuit for this application? I would prefer a single chip but a push/pull would be fine.

I looked for single chip solutions from Dallas and other sites. They seem to be geared toward low power cell phones etc.

2) I once saw a circuit in "Electronics Now" for a dual "XLR" or "1/4" audio pre-amp input circuit. Does anyone have a schematic that could be sent my direction?

Thanks, JZ

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Chris Smith
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Re: Simple high audio amp

Post by Chris Smith » Thu Feb 02, 2006 8:28 am

The TDA series single chip used to have power amps of varying power levels.

Start at the lower power level chips like the TDA2002 [2000 series] and look for their bigger brother.

LM1875 [25w]
TDA2009 [10w]

http://home.mira.net/~gnb/audio/lm4780.html
60 watt dual

http://www.electrokits.com/electronics/ ... rs/198.htm
25 watt kit $15

http://www.hobbyprojects.com/A/power_amplifiers.html
100 watt kits

<small>[ February 02, 2006, 09:19 AM: Message edited by: Chris Smith ]</small>

Robert Reed
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Re: Simple high audio amp

Post by Robert Reed » Thu Feb 02, 2006 8:57 am

Look at National semiconductors site. They have oodles of single chip power amplifiers in any power level you would want. Go to the analog--audio section and call up their data sheets. Lots of good design info here. The real expense involved here is the supply to drive these, but design could not be simpler.

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philba
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Re: Simple high audio amp

Post by philba » Thu Feb 02, 2006 10:29 am

please make sure your system is fully isolated and the AC circuit that drives it is GFCI protected.

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haklesup
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Re: Simple high audio amp

Post by haklesup » Thu Feb 02, 2006 12:38 pm

Maxim is rolling out a line of new D class amplifiers with part numbers like MAX9708. It is a 20W stereo/40W mono amp that looks pretty easy to use and has great specs and requires minimal heat sinking. Only problem is the 64 lead QFN package but a socket can take care of that. MAX9709 and MAX9741 are also worth looking at if you like that one. They are new parts so they should be sampling them now.

Nice thing about a D class amp is you can run them from a noisier supply. The PSSR on these is very high. Using a Switcher as a source without further filtering should be possible. These are designed for automotive where the 12V is very very noisy.

Use a cordless mic for any baptisims. I can't help thinking of that poor pastor who got electrocuted from an unisolated mic when he stepped into the pool.

Mike
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Re: Simple high audio amp

Post by Mike » Thu Feb 02, 2006 4:45 pm

Those amplifiers hacklesup mentioned are very nice, Class D is great. But since he wants simple, high power, the only way to go is with either Texas Instruments OPA541 or 549 chips or National Semiconductors LM3975 or LM3886 chips.

My personal reccomendation is either of the National Semiconductors chips. They can take much more abuse and since they are Class A/B rather than Class B, you get less distortion. They also can run of much higher supply voltages.

I have on my website the schematic and PCB for a stereo LM3875 amp, as well as a single channel LM3886 amp. For what you're doing, I'd suggest the LM3886. It has more power and can handle 4-ohm speakers, not just 8-ohm as the LM3875

Here is the schematic and PCB for the LM3875 amp:

http://electronet.dyndns.org/electronet ... lm3875.htm

And Here is the schematic and PCB for the LM3886 amp:

http://electronet.dyndns.org/electronet ... lm3886.htm

jwzumwalt
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Re: Simple high audio amp

Post by jwzumwalt » Sun Feb 05, 2006 2:54 am

I just wanted to thank everyone for the help. I browsed some of the links you folks provided and found what I needed.

Jan Zumwalt

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