Your Preferred Amplifier Topology

[forss]

Plain and simple I would like to know your Preferred Amplifier Topology

mine is Class A/B ......... BUT I am starting to lean toward the Class "D" now .....with the Crown and Hypex

 

[tomtoo]

Class D couse its the most efficient. And does what it should do.

 

[Tom C]

The plainest and simplest I can say it is
lowest possible distortion at highest possible output

 

[iMickey503]

Class a/b for mids and highs. Class D for Bass.

 

[TheBatsEar]

I say A/B or D, but i would prefer regular A/B for it's repairability. Top ten amps are A/B or D.

Not a fan of tubes (distortion) or A (idle heat).

 

[somebodyelse]

I'm less bothered by amp class and more by implementation. AB isn't inherently any more repairable than D.

 

[Killingbeans]

What ever, as long as it's small, reliable and efficient. Preferably built into the speakers.

If I had the skills and experience to make one from scratch, I'd go for an ampliverter with i2s input and a super fast ADC for global feedback.

Four FETs working as both rectifiers, switchers (SMPS/PWM amp) and DAC at the same time. That would be the dream... but probably not easy to get stable, or profitable.

 

[Katji]

Class a/b for mids and highs. Class D for Bass.

I know an extreme horn fanatic who does it like that. Although mid or high might be Class A.

 

[DVDdoug]

Class-D. But I'd also consider the cost. It's really the specs/performance/cost that counts. I'm not overly-concerned with what's inside.

IMO class-A is "dumb". It's inefficient, you can't get much power out of it, and even though it's basically one-less transistor or MOSFET it's usually more expensive (certainly more expensive per-watt), and they can make a "transparent" A/B or D.

Class-A is OK for a preamp, but If I was building a preamp I'd use a low-noise op-amp which would (probably) be class A/B internally.

AB isn't inherently any more repairable than D.

A class-D amp is more difficult to troubleshoot and its going to have special high-density fine-pitch chips that are very difficult to replace. A repair shop (or the factory) would probably replace the whole board (if it's still available). The main-chip will usually be specialized and single-source so it may eventually become unavailable too.

A class A/B might use discrete components and/or easier to replace chips (chips than can be replaced with a basic soldering iron) and there are usually substitute components for transistors FETs, MOSFETs, and op-amps.

 

[Bleib]

Only used A/B and D. Varied quality in both, I'm unlikely to ever purchase A because of wasted energy.

 

[boXem]

A, B, AB, D, G, ... are amplifier classes
Amplifiers topologies define the way an amplification class is implemented.
In example, my preferred topology to implement a class D amplifier is self oscillating post filter feedback.

 

[AdamG]

I was very hesitant to dive into the Class D amp pool. As a life long (the heavier the better) room heater Amp guy. But now going on 15 months driving 12 separate channels of my sound system @ 12 hours per day (Average) for an estimated total run time of 5,400 hours. Without a single problem or hint of distortion or clipping going as loud as I want and occasionally beyond. I am firmly transplanted to the Class D camp. Small footprint, light, cool running and gobs of headroom and efficiency. I needed a forklift to lift my old 5 channel amp. I can carry (2) Six channel amps in one arm. It defies my Subjective Brain that something this small and light can have the chops to drive 12 channels. But they do and they measure well under the Amir hammer. I highly doubt I will be going back.

 

[TheBatsEar]

AB isn't inherently any more repairable than D.

I don't think that's true. Sure, there are probably very esoteric A/B constructs, but every class D is essentially always proprietary, closed firmware, darkware. Also, you probably need a large investment in diagnostics and special tools.

I know an extreme horn fanatic who does it like that. Although mid or high might be Class A.

I think the KEF LS60 has two 100W class D (bass and mid) and one (i think 100W as well) A/B for the tweeter.

 

[Vacceo]

I love class A! I can grill some steaks while I listen to Teitanblood all on the same device!

Now, in seriousness, Hypex and Purifi are life changers.

 

[AwesomeSauce2015]

I think the KEF LS60 has two 100W class D (bass and mid) and one (i think 100W as well) A/B for the tweeter.

Kef quotes the amps for the ls60 as follows:

"Amplifier output power (per speaker) LF: 500W MF: 100W HF: 100W"
and
"Amplifier class (per speaker) LF: Class D MF: Class D HF: Class AB"

-Source: KEF's website

So the bass and mid drivers are powered with 500w and 100w class d amps. The tweeter has a 100w A/B amp.
They most likely used the A/B Amp for the tweeter b/c it doesn't require as much attenuation of the UHF (from what I understand), which would allow them to run the tweeter up higher in frequency, getting that "36khz" UHF extension.

But it is interesting that they decided to use class A/B for the tweeter as we know that class D is just as good or better. Class A/B uses more power and I know that they want to get power consumption down... They probably turn off the amps in "standby mode", to get the low idle power draw.

Additionally, they quote the "operating power" at 450w. So I would be willing to bet that those amplifier power numbers are probably peak. (This is also backed up by other KEF speakers which probably can't handle 100w to the midrange or tweeter driver...)


But my favorite amp topology is the one that gets the job done. Class A has its place in very low-power high-sensitivity setups, tubes are good for looking cool (subjective) and adding distortion... Right now I'm firmly in the good class D camp for the low cost, and high efficiency.

 

[TK750]

I was very hesitant to dive into the Class D amp pool. As a life long (the heavier the better) room heater Amp guy. But now going on 15 months driving 12 separate channels of my sound system @ 12 hours per day (Average) for an estimated total run time of 5,400 hours. Without a single problem or hint of distortion or clipping going as loud as I want and occasionally beyond. I am firmly transplanted to the Class D camp. Small footprint, light, cool running and gobs of headroom and efficiency. I needed a forklift to lift my old 5 channel amp. I can carry (2) Six channel amps in one arm. It defies my Subjective Brain that something this small and light can have the chops to drive 12 channels. But they do and they measure well under the Amir hammer. I highly doubt I will be going back.

I hope you don't mind me asking but I'm curious as to what you have playing 12 hours a day through 12 channels? Are these routed to different areas or some kind of crazy surround setup? Maybe just music for some kind of office/workshop setup?

 

[TheBatsEar]

So the bass and mid drivers are powered with 500w and 100w class d amps. The tweeter has a 100w A/B amp.

Right.

But it is interesting that they decided to use class A/B for the tweeter as we know that class D is just as good or better.

Lots of Audiophools out there that don't like Class D because it sucked 20 years ago. Maybe it was a marketing decision after all?

 

[somebodyelse]

I don't think that's true. Sure, there are probably very esoteric A/B constructs, but every class D is essentially always proprietary, closed firmware, darkware. Also, you probably need a large investment in diagnostics and special tools.

That sounds like assumptions from someone who's never actually repaired them, or has skill for one but not the other. It certainly wasn't true of the only class D amp I've had cause to fix, which turned out to be pretty close to International Rectifier's datasheet. A discreet output transistor had failed short and was easily replaced. There wasn't a microcontroller in the whole thing. Conversely the similarly failed but not discreet output transistor in a class AB amp couldn't be. The AB one had many more proprietary/unobtanium components in than the class D one, and needed a combination of buttons pressing at power up to stop the supervisory part turning it off again immediately.

If there is any firmware it tends to be in supervisory processors and control rather than the core amplification, so is independent of the amp class question as you can find similar stuff in both.

 

[AdamG]

I hope you don't mind me asking but I'm curious as to what you have playing 12 hours a day through 12 channels? Are these routed to different areas or some kind of crazy surround setup? Maybe just music for some kind of office/workshop setup?

Hi TK750,

I don’t mind and realize my above statement sounds like I am exaggerating. I have a 9.2.6 Atmos/DTS:X/Auro setup. I alike multichannel music in the morning and most of the day. Followed by Movies/Tv in the evening. So from about 0800 thru 2200 hrs my system is on and something is playing. Damn near every day 24/7/365. I am retired so this may make more sense. I use the hell out of my kit and apparently (reading what I just typed) I don’t get out much. In bed at night I use IEM’s to sleep with.

Other than the occasional headphone use and the IEM’s in bed. The above is all in one room. I hope this helps further explain my sickness…….

 

[TK750]

Hi TK750,

I don’t mind and realize my above statement sounds like I am exaggerating. I have a 9.2.6 Atmos/DTS:X/Auro setup. I alike multichannel music in the morning and most of the day. Followed by Movies/Tv in the evening. So from about 0800 thru 2200 hrs my system is on and something is playing. Damn near every day 24/7/365. I am retired so this may make more sense. I use the hell out of my kit and apparently (reading what I just typed) I don’t get out much. In bed at night I use IEM’s to sleep with.

Other than the occasional headphone use and the IEM’s in bed. The above is all in one room. I hope this helps further explain my sickness…….

Ah very interesting! Thanks for the response, it sounds like you are making the most of your retirement which can only be a good thing. I hope one day I will be able to report similar numbers!