THERE's those beautiful risers under the R500 & 210 extension! Woo hoo! Love that splash of color. Thanks for sharing Ms. Maple!!
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THERE's those beautiful risers under the R500 & 210 extension! Woo hoo! Love that splash of color. Thanks for sharing Ms. Maple!!
Right, but two transistors as the only SS components are not going to be a Class D amp. I believe that was the original point.
Thanks! It's become my number one bass.
I know. But while class AB may come in discrete forms, class D virtually never does.
All the high powered class D amps I have seen use discrete mosfets as power transistors. Which point are you trying to make?
My little Fender corner. Still love that Rumble 40. Best practice amp!
Interesting. I haven't checked any 1,000+ W amplifiers, so I presume you're right about them. But I've seen class D amps up to several hundred watts and they all had single IC amplifiers, which is why I assumed it's more likely that all class D amplifiers are implemented as ICs.
I asked GrokAI about it, (because I'm lazy) and here's what it said:
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In modern (2020s-era) high-power power amplifiersāmeaning those typically rated from several hundred watts per channel upward, especially in professional/pro audio (touring, installed sound, large PA systems), high-end home theater, or serious hi-fi applicationsāthe output power stages overwhelmingly use discrete transistors rather than integrated circuit (IC) implementations. Here's the breakdown by category and why.
Professional / High-Power Pro Audio Amplifiers (e.g. 1,000ā10,000+ W total, bridged/parallel configs common)
- Almost all use discrete power transistors (usually MOSFETs, sometimes high-power BJTs) in the output stage.
- Examples include flagship lines from Crown (many Macro-Tech and I-Tech series models), Lab Gruppen, Powersoft, QSC, Powersoft, and others.
- Even when modern high-efficiency technologies appear (Crown's DriveCore in some lines integrates drive/modulation into a small chip), the actual high-current output power devices remain discrete for thermal handling, current delivery, and power scaling.
- Very high power requires effective heat spreading across multiple large devices mounted on big heatsinks or with forced-air coolingāimpossible to achieve in a single IC package without severe thermal limits.
- The vast majority use discrete output transistors (often paralleled MOSFETs or bipolar devices).
- Brands like Pass Labs, McIntosh, Bryston, Anthem, Rotel (higher models), Accuphase, and many Class A/AB purists stick with discrete designs.
- Even many Class D amplifiers that achieve very high power (e.g. Hypex Ncore/Purifi modules, ICEpower modules used in brands like Jeff Rowland, NAD high-end models, or Devialet) rely on discrete power MOSFETs or GaN FETs in the output stage, not a monolithic IC power op-amp style construction.
- Here IC-based power amplifiers dominate (e.g. Texas Instruments TPA32xx series Class D chips, Infineon MERUS, older LM3886-style Class AB chips).
- These typically top out at 50ā300 W per channel (often bridged or paralleled for more), and are common in compact AV receivers, soundbars, mini amps, and budget/mid-fi integrated amps.
- Thermal and power density constraints make discrete impractical or uneconomical at modest power levels.
- Thermal dissipation ā High-power Class AB or even efficient Class D dissipates tens to hundreds of watts of heat in the output devices. Discrete transistors spread this across many large packages on big heatsinks; a monolithic IC cannot handle that without catastrophic overheating.
- Current and voltage handling ā Discrete allows higher rail voltages, massive peak current delivery (important for speaker control and 2ā4 Ī© loads), and easy paralleling of many devices.
- Scalability and customization ā Easier to scale to kilowatt levels or optimize for specific loads/impedances.
- IC power amps exist (some Class D controllers + discrete output FETs are hybrid), but pure "power op-amp" ICs (like LM3886 descendants) are rarely used above ~200ā300 W due to these limits.
~~~~
Given the specific examples, I think this is probably "fairly" trustworthy info.
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Dunno what Grok smokes, but...
like: QSC KS118 or RCF SUB 8008-AS (or basically any high power application in recent years)
Lighter, more efficient, simpler circuits... It has basically only pluses.
- Sound reinforcement systems. For very high-power amplification, the power loss of class-AB amplifiers is unacceptable. Amplifiers with several kilowatts of output power are available as class D. Class-D power amplifiers are available that are rated at 3000 W total output, yet weigh only 3.6 kilograms (7.9 lb). Class-D amplifier - Wikipedia
like: QSC KS118 or RCF SUB 8008-AS (or basically any high power application in recent years)
Lighter, more efficient, simpler circuits... It has basically only pluses.
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Most of the examples given by GrokAI in my comment were class D.Dunno what Grok smokes, but...
class D has taken over big PA systems long before it made it's way to mainstream bass amps/combos.
- Sound reinforcement systems. For very high-power amplification, the power loss of class-AB amplifiers is unacceptable. Amplifiers with several kilowatts of output power are available as class D. Class-D power amplifiers are available that are rated at 3000 W total output, yet weigh only 3.6 kilograms (7.9 lb). Class-D amplifier - Wikipedia
like: QSC KS118 or RCF SUB 8008-AS (or basically any high power application in recent years)
Lighter, more efficient, simpler circuits... It has basically only pluses.
So I'm not sure what provoked your above response.
Grok's madeup hallucination
You will not find any calss AB at any recently made high power application.
There are multi-stage high power "class AB" amps (amp stage after amp stage, with power switching), but those aren't even called class AB anymore. (class G/H/etc.)
a class D chip is NOT a transistor... or mosfet... or...
We could call them ICs, but they are analog, that could be misleading as IC is mostly used for digital integrated circuits these days. (and a lot of class D designs also integrate signal processing - DSP)
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Operational amplifiers, DACs and ADCs are ICs and analog (well, half-analog in case of ADC/DAC).
As for the answer by Grok, it said that power loss of class AB amplifiers is unacceptable, which is absolutely true, I don't know what the problem is?
Before class D became a solved problem, high power PA amplifiers would commonly be implemented as class G or class H, but class D took the market by storm.
I'd say that the watershed moment came about 20 years ago, even though class D amplifiers were being developed for at least two decades prior to that, but my EE classes in the late nineties (secondary/vocational school level) never even mentioned class D, not even as a curiosity, while my nephew, twenty years younger, in the same kind of school already had them covered.
PS: I've no idea why I thought that class D amps wouldn't use discrete components and everything would be realized in the IC, aside perhaps from the LC filtering.
As for the answer by Grok, it said that power loss of class AB amplifiers is unacceptable, which is absolutely true, I don't know what the problem is?
Before class D became a solved problem, high power PA amplifiers would commonly be implemented as class G or class H, but class D took the market by storm.
I'd say that the watershed moment came about 20 years ago, even though class D amplifiers were being developed for at least two decades prior to that, but my EE classes in the late nineties (secondary/vocational school level) never even mentioned class D, not even as a curiosity, while my nephew, twenty years younger, in the same kind of school already had them covered.
PS: I've no idea why I thought that class D amps wouldn't use discrete components and everything would be realized in the IC, aside perhaps from the LC filtering.
It is. Look at a class D specsheet. For example rumble100s
It's quite self-contained. Needs power, signal and a couple of components for filtering and control. That's all.Grok is wishwashing info. Like "Almost all use discrete power transistors (usually MOSFETs, sometimes high-power BJTs) in the output stage." Class D uses none of those usually...
Just think about it, even a computer CPU/GPU is able to use 5-600Watts+ in a couple of cm^2 chip package. And those are not outputting power, but burning it all converting to heat. So it's not that hard to do with silicon.
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Please Please, take this class D stuff to it's own thread?
The way I asked the question may have excluded class G & H.Grok's madeup hallucination
You will not find any calss AB at any recently made high power application.
There are multi-stage high power "class AB" amps (amp stage after amp stage, with power switching), but those aren't even called class AB anymore. (class G/H/etc.)
a class D chip is NOT a transistor... or mosfet... or...
We could call them ICs, but they are analog, that could be misleading as IC is mostly used for digital integrated circuits these days. (and a lot of class D designs also integrate signal processing - DSP)
Let's refer to the part of the amplifier circuit that does the heavy lifting of amplifying the signal as a power output device(s).
I asked GPT-OSS 120B, "how common is the use of discrete mosfet's in the power section of class d consumer high power amplifiers?".
Its answer:
## Use of Discrete MOSFETs in ClassāD Power Stages
**Very common** ā most highāpower consumer ClassāD amplifiers (ā„100āÆW per channel) rely on discrete MOSFETs rather than integrated driver chips for the final output stage.
### Why Designers Choose Discrete MOSFETs
The very latest technology used in class D amplifiers is using GaN MOSFET's or GaN HEMT's and they can be in either discrete or IC implementations.
I'm not sure if the IC versions of the GaN's are used in high power applications or not.
mosfets are just linear gain devices. until You implement class D switching.... and so You've implemented the Integrated Circuit.
I'm pretty sure there must be implementations where switching is not integrated, as for why the hack would anyone do that, dunno. Makes no sense to me.
(see the same pattern as class AB vs class G/H?)
You could go down to atomic levels or beyond and find out that everything is just the same in our world
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