Hi all, I am looking to build a fairly robust P.A. Amp. I apologize if this should be in CHIP AMP. I have a couple of JBL PA speakers (cant remember the model right now)
but i believe they are 250W 8ohm that i would like to power. I have built a couple lm3886 amps before and I have been working in the Audio electronics industry as a tech for 3 years so I would not consider myself a newbie.
my plan i think is to build a couple stereo amps around 300W /8ohm per channel, if i have to i will make mono blocks. I thought i could use some lm3886's but i don't that they can handle the demand's necessary. I have some TDA7294's and TDA7293's kicking around would but from what i've heard i just don't think they are quite there (100W per channel, bridge/parallel 170W or so...). I am not scared of solid state designs either but have limited experience minus the few headphone amps ive done. I can do the layout so component count is not an issue. I have been looking into the LME49830 / LME49810 and am considering this but I have read a couple posts stating that they would be fine for HIFI applications but may not be able to handle the peaks of the MUSIC power. I've read the the DIRTY harry may be a good place to start... are there any other suggestions out there? i liked the idea of the LME's because i would just have to worry about the output stage... but i guess im just being lazy, I just thought that maybe it would be a good place to start. Any words of wisdom, links, schematic would be more then appreciated. Thank you all for your knowledge.
Dave
but i believe they are 250W 8ohm that i would like to power. I have built a couple lm3886 amps before and I have been working in the Audio electronics industry as a tech for 3 years so I would not consider myself a newbie.
my plan i think is to build a couple stereo amps around 300W /8ohm per channel, if i have to i will make mono blocks. I thought i could use some lm3886's but i don't that they can handle the demand's necessary. I have some TDA7294's and TDA7293's kicking around would but from what i've heard i just don't think they are quite there (100W per channel, bridge/parallel 170W or so...). I am not scared of solid state designs either but have limited experience minus the few headphone amps ive done. I can do the layout so component count is not an issue. I have been looking into the LME49830 / LME49810 and am considering this but I have read a couple posts stating that they would be fine for HIFI applications but may not be able to handle the peaks of the MUSIC power. I've read the the DIRTY harry may be a good place to start... are there any other suggestions out there? i liked the idea of the LME's because i would just have to worry about the output stage... but i guess im just being lazy, I just thought that maybe it would be a good place to start. Any words of wisdom, links, schematic would be more then appreciated. Thank you all for your knowledge.
Dave
Hi there,
The sort of power you're talking about isn't too difficult to achieve. I'm working on my first serious amplifier with the intention of it being suitable for PA use.
You're looking at needing somewhere around 65-75V supply rails. 4 pairs of decent bipolar or mosfet output devices should do the trick and give you up to 400W into 4Ohms if you're lucky.
I wouldn't go with the design as-is but Rod Elliots Project 68 gives you an idea of what you're looking at.
http://sound.westhost.com/project68.htm
Also have a look at mine, again it's not a ready-to-go design but it's along the right lines for what you're looking for:
http://www.chaudio.co.uk/AmpDesign/Amp1SchRev2.pdf
The sort of power you're talking about isn't too difficult to achieve. I'm working on my first serious amplifier with the intention of it being suitable for PA use.
You're looking at needing somewhere around 65-75V supply rails. 4 pairs of decent bipolar or mosfet output devices should do the trick and give you up to 400W into 4Ohms if you're lucky.
I wouldn't go with the design as-is but Rod Elliots Project 68 gives you an idea of what you're looking at.
http://sound.westhost.com/project68.htm
Also have a look at mine, again it's not a ready-to-go design but it's along the right lines for what you're looking for:
http://www.chaudio.co.uk/AmpDesign/Amp1SchRev2.pdf
thank you very much for the input, I have some more reading/understanding of solid state amps but i am fairly comfortable of building a already designed one for my first S.S. amp (one that I know has been proven to work) then i would like to start some experimenting on a smaller safer scale. It was actually project 68 that got me thinking about doing this, except it is not suitable for high frequency's...
thanks again
Dave
thanks again
Dave
Just spend a while browsing the threads in this forum. There are lots of amp projects knocking around. You might not find one that is exactly what you want but there is certainly enough information here to do it.
My design is probably closer than P68 to what you're after. Hopefully in the next couple of weeks I'll finalise it. Once I'm happy it'll work reliably you'd be welcome to build one and see what you think.
Chris
My design is probably closer than P68 to what you're after. Hopefully in the next couple of weeks I'll finalise it. Once I'm happy it'll work reliably you'd be welcome to build one and see what you think.
Chris
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