Using HK MAIN INs connection with Elite receiver

[KEW]

I know there have been some especially poor implementations of Class D that have tainted their reputation (Panasonic, in particular). In this case, the differences were obvious on the test bench as well. I doubt HK is making gear that has bad measurements, they are a company with a deep background of research, engineering, and science; and they know their gear will likely see an independent test bench (though I do believe their own published specs are accurate).
My Focal Solo6 pro audio monitors have a class D (BASH) amp for the mid-woof and class AB for the tweeter. These are very popular professional recording studio monitors and designed for people who are focusing on the sound quality. What I am getting at is they decided to use Class D for mid&lows, but not for highs. I don't know what was the reason. Does AB perform better at high frequencies? Maybe AB cost less in this particular application? I don't know, but I do feel it is safe to say that Class D gives up nothing audible in the low&mid frequencies.

 

[slipperybidness]

I know there have been some especially poor implementations of Class D that have tainted their reputation (Panasonic, in particular). In this case, the differences were obvious on the test bench as well. I doubt HK is making gear that has bad measurements, they are a company with a deep background of research, engineering, and science; and they know their gear will likely see an independent test bench (though I do believe their own published specs are accurate).
My Focal Solo6 pro audio monitors have a class D (BASH) amp for the mid-woof and class AB for the tweeter. These are very popular professional recording studio monitors and designed for people who are focusing on the sound quality. What I am getting at is they decided to use Class D for mid&lows, but not for highs. I don't know what was the reason. Does AB perform better at high frequencies? Maybe AB cost less in this particular application? I don't know, but I do feel it is safe to say that Class D gives up nothing audible in the low&mid frequencies.

Yup.

Modern Class D is pretty much at the same SQ level as AB. Many generations ago, class D had problems at the higher frequencies, it's just an inherent problem of the design that took a few generations to engineer out. But, damage was done, and Class D got a bad reputation due to the original problems.

Kind of like today when you get questions about "Plasma Burn In". Modern plasmas have pretty much engineered that problem out of existence.

Wiki gives you an idea of why high freqs can be problematic for class D:
A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices (transistors, usually MOSFETs) operate as electronic switches, instead of as linear gain devices as in other amplifiers. The signal to be amplified is a train of constant amplitude pulses, so the active devices switch rapidly back and forth between a fully conductive and nonconductive state.

If your devices can't switch on/off fast enough, the high freqs suffer. Modern class D, the disadvantage is that they don't have the headroom that you can get with class AB.

Now, as I mentioned, Class D and SMPS typically go hand-in-hand. My opinion is that SMPS has no place in Hi-Fi audio! There are many experts and several books that agree on this. The BEST PS for an amp is a simple unregulated linear supply. There are several reasons that SMPS are inferior for Hi-Fi applications.

BTW--The HK in question is Class AB. It is the Pio that is class D.

 

[videopete]

Thanks for all the responses!! I appreciate all the help.
I'm learning lots on this forum.

 

[RichB]

Yup.

Modern Class D is pretty much at the same SQ level as AB. Many generations ago, class D had problems at the higher frequencies, it's just an inherent problem of the design that took a few generations to engineer out. But, damage was done, and Class D got a bad reputation due to the original problems.

Kind of like today when you get questions about "Plasma Burn In". Modern plasmas have pretty much engineered that problem out of existence.

Wiki gives you an idea of why high freqs can be problematic for class D:
A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices (transistors, usually MOSFETs) operate as electronic switches, instead of as linear gain devices as in other amplifiers. The signal to be amplified is a train of constant amplitude pulses, so the active devices switch rapidly back and forth between a fully conductive and nonconductive state.

If your devices can't switch on/off fast enough, the high freqs suffer. Modern class D, the disadvantage is that they don't have the headroom that you can get with class AB.

Now, as I mentioned, Class D and SMPS typically go hand-in-hand. My opinion is that SMPS has no place in Hi-Fi audio! There are many experts and several books that agree on this. The BEST PS for an amp is a simple unregulated linear supply. There are several reasons that SMPS are inferior for Hi-Fi applications.

BTW--The HK in question is Class AB. It is the Pio that is class D.

Speakers are reactive loads and there have been measurements where Class-D performed well but there were issues driving low impedance loads. I was not at all happy with the performance of the old ICE amps, but that was a while ago.

For the record, Plasmas can suffer from image retention which many confuse with burn it. However, since they do age and are emissive, they will burn in, depending on the use. OLED will also "burn-in". This is not a problem for most video applications, but a Plasma or OLED may not be an ideal computer display.

- Rich