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Best audio amplifier circuits

B

blahblah99

Platinum Member
I am planning to build a high quality, low-distortion/noise power amplifier (around 1000W range) for home audio use. What are the BEST one's that you have come across? I have that orange book entitled "Audio power amplifier design" which is pretty good and contains some nice, compleete designs... Are there any other designs that are better that are available publicly?

I searched google and a lot came up, but most of them are generic designs.
 
The best designs in anything are almost always in-house and private. Maybe even patented and stuff. I'm sure a company like Bose, for example, has lots of awesome circuit schematics and layouts to make the very best amplifiers possible today. Will you ever get Bose to let you see them? ... .yea right, good luck. Public-domain designs aren't always bad per se, but when you need the VERY best around.... public access can only get so far. The very best circuit designers are always working for a company, which is why you can't get to their genius ideas.
 
Basically, for an amp that big, you will almost undoubtedly need to go with a Class AB push-pull design or a Class-D switching amp.

Class AB designs are EASY in their most basic form to design/work with. Class D is by far the most challenging, becuase you PWM controllers, big inductors/caps, etc. Although... there is probably some sort of very integrated controller from Cirrus Logic or TI/Burr Brown that will work.

Why the heck do you need 1000W?? In fact, at those volumes (unless you're using grossly inefficient speakers), you're ears will be so overdriven that your cochlea or whatever that thing is in your ear is will be distorting, and blood will flow from your ears. At home, if I have my receiver on 4 (out of 10), that is about the max I can listen without discomfort... and that is putting out 20-40W RMS at the most!!! Of course, I have speakers with an SPL of 98dB @ 1W-meter.

I could design you a class AB amp... the difficulty will be getting transistors that handle that kind of power... becuase the type of amp I know of right off hand uses BJT's... NOT FET's. So, they are less efficient and burn more power (huge heatsinks, etc).

I used to always want to build a massive amp... but it just isn't worth it. I'm an EE, and I've realized... 100-W is enuff unless you are running a nightclub.

My $0.02... hope it helped.
 
thanks for the replies..

nevermind the above post, I confused myself.

I am planning to build two amps, a 1000W single channel amp for subwoofers that can drive loads down to 2 Ohms or even 1, and another 20W - 30W low THD for midrange/tweeters..

For the sub amp, I just want it to put out as much power as possible.

As for the mr/tw amp, I am more concerned about sound quality and THD rather than efficiency as I am leaning towards a class A or class AB amp and the transistors used WILL BE bjts, no MOS.

Any schematics?

(I only have access to a pcb lab for another two quarters b4 i graduate so i wanna make full use of it 😉 )
 
Like I said... with a 1000W amp.... I really don't think you'll be able to make it class A. It will just burn too much power. Class AB would work... and for a sub... if I remember correctly, you don't need the cleanest (THD wise) of all amps in the world. When your windows shake and your lights rattle, that'll gain you a bunch of THD right there. 😉

The 30W deals for the midrange... EASY. In fact, there are some totally integrated solutinos from TI/Burr Brown, Maxim, or Linear Tech, or Analog Devices... it is a one chip, single channel or stereo, 20W+ amp. I think they may have higher wattage. Discrete component designs are fairly easy too.

What do you plan on powering this thing with? You are going to have to design a CLEAN supply with a huge (and expensive) capacitors to support your subwoofer amp. You are just getting yourslef into some major expense, and you'll probably not be overly impressed with your results -- IMHO.
 
A company called maplin electronics, in the UK, used to sell a build-it-yourself kit featuring a 1000 W RMS (1 channel) audio amp.

It was, apparently, quite a good design based on a class AB push-pull system - A friend of mine's brother built one and claimed that it worked very well, although I never had a chance to see it myself. Unfortunately, this kit has now been discontinued, however you may be able to get back issues of their magazine, which featured detailed descriptions of the circuits, PCB layouts, and potential modifications that you could make to them as well as potential problems faced during construction.

If I remember rightly it used 4 BJTs in parallel for each of the push/pull drivers, mounted on a heatsink a foot long and 6 inches tall and wide.

 
I checked that site but couldn't find any kiy kits.

but most of the kiy kits are designed from simple amp designs (differntial amp at input, a single vas stage, and a push-pull class b output stage) that results in a THD of around 0.2-0.5% @ 1khz.

I want to build an amp that rivals most high-end amplifiers out in the market 🙂
 
i just found a 50W schematic in that book I mentioned.

50W @ 8Ohms THD 0.0006% @ 20khz WOW.

Gonna build it and see how it sounds. ill let yall know.
 


<< i just found a 50W schematic in that book I mentioned.

50W @ 8Ohms THD 0.0006% @ 20khz WOW.

Gonna build it and see how it sounds. ill let yall know. >>


how much does that cost and how much time would it take?
 
well, building the single channel amp (drawing it up on a layout program, going to my lab to develop/etch, drill it, populate it) is not going to cost much, maybe less than $40-$50 for parts, but building a clean power supply for this sucker is going to be expensive.

I just want to prototype the circuit and try it out on a bench supply first to see how it sounds. If it is significantly better, I'll spend that extra $150 on a nice toroid an some big caps.
 
blahblah99, do you really need an elaborate power supply? Amplifiers are very good at rejecting hum, and it's usually enough to regulate only the input sections.
 
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