Not all class A schemes need five watt resistors or so, and there are class B schemes as well wth common components. So why we never saw class A or B integrated circuits as chips. When valve to silicon transition happened, class A was quite mainstream too, unlike now when it's for enthusiasts and custom builders.
"So why we never saw class A or B integrated circuits "---- class AB integrated circuits are available .
As far as class A IC,s are concerned and we are talking --non-digital /switching check out the design parameters required for even a 10 watt or 20 watt class A IC .
I am talking standard class A not one of those switching into class AB types .
A DIY class A power amp requires a lot of design work due to heat for one and cost in high current analog/linear power supplies -- non switching.
If this is not what you are getting at then let me know ?
As far as class A IC,s are concerned and we are talking --non-digital /switching check out the design parameters required for even a 10 watt or 20 watt class A IC .
I am talking standard class A not one of those switching into class AB types .
A DIY class A power amp requires a lot of design work due to heat for one and cost in high current analog/linear power supplies -- non switching.
If this is not what you are getting at then let me know ?
If the LM317 (stabilizer) is connected to the TDA2030 (AB class) output, we will get a 5W class A amplifier 🙂
Yes that's what I was talking, standard class A.
Take as example, say, lineup s latest class A iteration, albeit of little output at four watt, but four watts of class A is in different league than four watts of any AB venture. Or why not the original '69 version of JLH. They need common one fourth wattage resistors along with other common components.
There are other designs of much simpler I've come across though.
So packing everything in an IC was not of a tough challenge as many AB class IC has more complex architecture. In my opinion.
I think more than fabrication it's the business marketing caveats those played a role.
Complexity costs nothing with IC's where the manufacturing is done with photographic (1st generation) masks. Heat removal costs a lot. Class A provides no bulk distortion minimization. It does provide a certain group of distortion overtones, that some like.
If some bright boy suggested this Class A IC at a meeting, marketing would soon kill the idea because so few people would pay for the expensive heat removal features. Especielly for an IC that put out such low output wattage, compared to contemporary class AB IC's.
We're lucky to still be able to buy class AB amp IC's and probably won't be able to very long. The whole packaged amp business is moving to class D, which modern processing techniques make very cheap. So cheap, the supply of class AB IC's with their heat removal features will go the way of the dodo bird. If fact, I loaded up on transistors with leads because those are headed to extinction too. Unfortunately, some bright boy hauled them all off to the copper scrap yard. I'm doomed to a class D amp in my future, I'm afraid. I turned a class D "400 w/ch" amp down last week. Really upset the guy that sold me the speakers. Use once & send to the landfill, buy again, repeat. That is the lifestyle pushed by the business owners.
I've heard class B in early transistor radios with germanium transistors. I was not impressed. I don't know why you want to talk about class B, crossover distortion sounds horrid. My ST120 had too much crossover distortion cold, one reason it was criticized as "the worst amp ever made". Now tamed.
Last edited:
In a class A amplifier, the main cost is formed by a suitable power supply and massive heatsinks. Large continuous power consumption.
One channel JLH1969 mini is placed on PCB 50 * 50 mm. You can do less with DSM. Costs $2.
You will not get any obvious benefits using IC. PCB and additional parts will be required.
One channel JLH1969 mini is placed on PCB 50 * 50 mm. You can do less with DSM. Costs $2.
You will not get any obvious benefits using IC. PCB and additional parts will be required.
Last edited:
Firstly there are loads of class B ICs, although many are becoming obsolete - they are the standard analog integrated amp chips. Note I use Doug Self's take on class B.
Class A for power is usually a (very) poor engineering choice in commercially manufactured equipment, basically no demand for it - if you want to sell chips you make chips people will buy in the 100,000's.
Class A for power is usually a (very) poor engineering choice in commercially manufactured equipment, basically no demand for it - if you want to sell chips you make chips people will buy in the 100,000's.