The Audio Path In Consumer-Grade Products

[PENG]

You've lost me. The definition of a Class AB amp is that it runs in Class A up to a certain voltage level, the so-called bias voltage, and then operates in Class B. Yes, it's always in Class AB, but at 0.1 watts I would guess that every Class AB amp is operating in Class A.

0.005% is about -86db, so I suspect those graphs rise at low power levels because you can't measure the distortion through the noise.

Yes, I agree with you, noise was the issue

 

[PENG]

Well, PENG, I've never heard of any definition or explanation like that. In a push-pull transistor pair there's a so-called "bias" current applied to the transistors that is usually constant. (Some amps, like some Krells and older Levinsons, to name two, have a feature called "sliding" or "dynamic" bias, where the bias level is adjusted in some increment in real time depending on the voltage of the input signal. But let's stick to constant bias for this discussion.) When the input signal is at a voltage that only requires current less than or equal to bias current for amplification, both transistors in the pair are powered to fully amplify the signal. As the current demand exceeds the bias current, one transistor gets a higher current than the other, depending on the phase of the input signal that is being amplified (since it's a differential pair), the current asymmetry between the two devices is my understanding of Class AB mode.

Do you think this explanation is incorrect?

Your conduction angle explanation seems like another way to describe the transition between symmetry and asymmetry in the current flowing through the transistors, but for some reason we seem to be talking past one another.

I think we both know how class AB work. The point I am trying to make is that by definition if you have the transistor pair biased to conduct even just 181 degrees, just for argument sake, it will be considered class AB and you will have symmetry and linearity, but barely. That barely class AB bias will not make the amp class A at even a low output level of 0.01W. Again this is just for argument sake, I have not done any calculations (will have to revisit my textbooks first if I try) to guesstimate what bias level will be needed to produce 0.01W in class A, when both transistors will be conducting for the full 360 degrees, i.e. full time.

 

[Irvrobinson]

You've lost me. The definition of a Class AB amp is that it runs in Class A up to a certain voltage level, the so-called bias voltage, and then operates in Class B. Yes, it's always in Class AB, but at 0.1 watts I would guess that every Class AB amp is operating in Class A.

I think my brain was running in Class B when I wrote this explanation. A Class AB amplifier never operates in Class B, since a Class B amplifier has no bias current and a Class AB amp always does. Duh. I can't remember what I was thinking. I think this low-carb diet I'm on is causing sugar withdrawal symptoms.

 

[PENG]

I think my brain was running in Class B when I wrote this explanation. A Class AB amplifier never operates in Class B, since a Class B amplifier has no bias current and a Class AB amp always does. Duh. I can't remember what I was thinking. I think this low-carb diet I'm on is causing sugar withdrawal symptoms.

Yep, now try telling that to Johnny2bad.

 

[Irvrobinson]

Yep, now try telling that to Johnny2bad.

That's the great thing about the internet, every brain fart you've ever had captured forever. It keeps one humble.

 

[AcuDefTechGuy]

...since most here seem to rely on science and measurable facts, I was wondering if anyone was in disagreement...

Again, I emphasize the measurable facts, not the VERBIAGE and superfluous writing flavors.

Measurable facts is NOT bias opinions or your own personal experience.

The FACT is that all these AVRs and PrePros (like the Denon, Yamaha, Marantz) MEASURE EXTREMELY WELL.

Now if the Marantz, Denon, Yamaha, etc., measure poorly, the article by Benchmark would have a solid point.

Better engineering, better quality, better PATHWAY = better measurements.

But the FACT is, why waste the money if you can't produce a product that measure significantly better than all these other products?

Science and measurable facts means you look at the MEASUREMENTS, not DISMISS the measurements!!!!

 

[AcuDefTechGuy]

As already mentioned, when you take into consideration the measurements of everything else in the pathway, like the speakers and room acoustics, etc., the measurements of the electronics mean even less!

And this is exactly the reason why experienced people in this hobby will focus most of the money on the speakers and room acoustics.

What good is having an amp or DAC with SNR of -100dB if your speakers have > 1% THD and +7dB boost at 10kHz, etc.?

 

[AcuDefTechGuy]

Now getting into personal experience, I have not tried every DAC. But when I was much younger and less experienced, I have owned some DACs that cost more than most AVRs.

When I was much younger and more ignorant, I have also owned cables and interconnects that cost more than some AVRs!!!

But extremely costly experience have taught me that DACs don't make a lick of difference compared to speakers, room acoustics, processors, and the original source.

 

[PENG]

Again, I emphasize the measurable facts, not the VERBIAGE and superfluous writing flavors.

Measurable facts is NOT bias opinions or your own personal experience.

The FACT is that all these AVRs and PrePros (like the Denon, Yamaha, Marantz) MEASURE EXTREMELY WELL.

Now if the Marantz, Denon, Yamaha, etc., measure poorly, the article by Benchmark would have a solid point.

Better engineering, better quality, better PATHWAY = better measurements.

But the FACT is, why waste the money if you can't produce a product that measure significantly better than all these other products?

Science and measurable facts means you look at the MEASUREMENTS, not DISMISS the measurements!!!!

Right on! Measurements are key as it is the objective way to validate the published specs and other claims. People often argue that there are things that cannot be measured but that does not apply to electronic products such as just an audio amplifier that is entirely designed and build based on science and engineering know how that is nowhere near the complexity involved in the design and build of a supersonic jet, let alone rocket science.

 

[PENG]

Now getting into personal experience, I have not tried every DAC. But when I was much younger and less experienced, I have owned some DACs that cost more than most AVRs.

When I was much younger and more ignorant, I have also owned cables and interconnects that cost more than some AVRs!!!

But extremely costly experience have taught me that DACs don't make a lick of difference compared to speakers, room acoustics, processors, and the original source.

That's the point I supposed the OP maybe missing, that some of us have been there, done that and now want to share our experience with potential newcomers. I think he wants to do the same, and that he believes others will benefit from "better" electronics such as external amps, based on his own experience.

I suspect those who's been there, done that, tend more likely to have validated their beliefs not just from experience, but also by over time, realizing what the specs and measurements are telling us.

 

[Pogre]

That's the point I supposed the OP maybe missing, that some of us have been there, done that and now want to share our experience with potential newcomers. I think he wants to do the same, and that he believes others will benefit from "better" electronics such as external amps, based on his own experience.

I suspect those who's been there, done that, tend more likely to have validated their beliefs not just from experience, but also by over time, realizing what the specs and measurements are telling us.

I've had 3 different receivers ranging from entry level to mid tier to my SR6011 and now a separate amplifier. No receiver stood out as "sounding better", nor did my amplifier. I'm getting the same sq from my Monolith as I had with my Denon AVR S510BT, which now resides in my son's bedroom.

I think it's safe to say my personal experiences correlate with the objective data I've been reading over the past year. With a separate amplifier there's little, if any difference at all in sq. I would never recommend separates or a boutique amplifier to improve sq.

 

[AcuDefTechGuy]

That's the point I supposed the OP maybe missing, that some of us have been there, done that and now want to share our experience with potential newcomers. I think he wants to do the same, and that he believes others will benefit from "better" electronics such as external amps, based on his own experience.

I suspect those who's been there, done that, tend more likely to have validated their beliefs not just from experience, but also by over time, realizing what the specs and measurements are telling us.

I suppose it's okay for everyone to try it out and mark it off their bucket list.

Exotic wires, cables, plugs - check
Expensive DACs - check
Expensive CD players and turntables - check
Expensive Amps - check
Expensive Preamps - check
Expensive AVR - check
Expensive Speakers & subs - check
RAAL, AMT, Silk, Aluminum, Magnesium, Titanium, Beryllium, Diamond tweeters - check
Active/Passive/Bi-amp/Tri-amp/Quad-amp - check

 

[Bucknekked]

I think it's safe to say my personal experiences correlate with the objective data I've been reading over the past year. With a separate amplifier there's little, if any difference at all in sq. I would never recommend separates or a boutique amplifier to improve sq.

Pogre
My only quibble with your post is the absolute : never. Absolutes are almost always porous.
While I agree with the sentiment, its not a brick wall.
For instance, @TLS Guy is going to be able to make a legitimate case for separates if someone is a serious classical listening buff with a serious budget to go along with the desire. What TLS Guy has assembled, and others like him, are systems that deliver and meet their standard for audio. Having seen him describe and defend the choices, I am going to nod my head and agree with him because I don't have the chops or the ears to disagree.

You and I may live a long time yet and not get around to recommending separates to anyone. I will wager than the classic music buffs that TLS Guy listens with would probably find it their first choice.

 

[Bucknekked]

I suppose it's okay for everyone to try it out and mark it off their bucket list.

Exotic wires, cables, plugs - check
Expensive DACs - check
Expensive CD players and turntables - check
Expensive Amps - check
Expensive Preamps - check
Expensive AVR - check
Expensive Speakers & subs - check
RAAL, AMT, Silk, Aluminum, Magnesium, Titanium, Beryllium, Diamond tweeters - check
Active/Passive/Bi-amp/Tri-amp/Quad-amp - check

I know you said that halfway in jest, but the sentiment is close to the mark for many.
There are a number of folks who have an image set in their heads what "great hifi" looks like on a shelf.
Everything else is not going to be satisfactory until they give it a whirl.

My only comparison point is watches: there are 1,000's of men this year who will hit a milestone or a bonus or something like that. They've had the itch for a Rolex since they were pups. They will spend the extra and strap it on and be ecstatic. After a while, and after seeing it on 100's of other wrists, the shine wears off and reality sets in.

There's no real loss. The Rolex is still a great watch and it will hold its value. Same with separates. No real audio loss. They will hold up. The owners just spent more than they probably needed to.

 

[Pogre]

Pogre
My only quibble with your post is the absolute : never. Absolutes are almost always porous.
While I agree with the sentiment, its not a brick wall.
For instance, @TLS Guy is going to be able to make a legitimate case for separates if someone is a serious classical listening buff with a serious budget to go along with the desire. What TLS Guy has assembled, and others like him, are systems that deliver and meet their standard for audio. Having seen him describe and defend the choices, I am going to nod my head and agree with him because I don't have the chops or the ears to disagree.

You and I may live a long time yet and not get around to recommending separates to anyone. I will wager than the classic music buffs that TLS Guy listens with would probably find it their first choice.

Well, I said that I would never recommend an amplifier to improve sq and thus far that statement has been true. Once a person has their speakers, room and positioning worked out and still have an itch, sure. Get separates.

I can't imagine a scenario where I would recommend a separate amp outside of difficult to drive speakers. Then there is also my lack of experience. The only amp I'm familiar with is my Monolith. I really don't know what to recommend!

 

[AcuDefTechGuy]

Pogre
My only quibble with your post is the absolute : never. Absolutes are almost always porous.
While I agree with the sentiment, its not a brick wall.
For instance, @TLS Guy is going to be able to make a legitimate case for separates if someone is a serious classical listening buff with a serious budget to go along with the desire. What TLS Guy has assembled, and others like him, are systems that deliver and meet their standard for audio. Having seen him describe and defend the choices, I am going to nod my head and agree with him because I don't have the chops or the ears to disagree.

You and I may live a long time yet and not get around to recommending separates to anyone. I will wager than the classic music buffs that TLS Guy listens with would probably find it their first choice.

Separates vs AVR is just as popular of a debate topic as any.

We've even debated which classical music composers (Mozart, Beethoven, Back) was the BEST. We all know Mozart was the best.

I think many people who listen to all types of music (classical, rock, pop, jazz, folk, etc.) would say that it doesn't matter which type of music you listen to when it comes to separates vs AVR; it doesn't matter if you watch movies, TV shows, or listen to music.

Great sounding systems will sound great with all types of materials as long as the original source is great.

IMO saying that separates will sound better than AVR for classical music is just as untrue as saying external DACs sound better than the DACs inside PrePro and AVR.

With that being said, I will continue to use my separates (Denon AVP-A1HDCI and ATI 3000 amps) for everything in my HT room.

 

[Pogre]

Separates vs AVR is just as popular of a debate topic as any.

We've even debated which classical music composers (Mozart, Beethoven, Back) was the BEST. We all know Mozart was the best.

I think many people who listen to all types of music (classical, rock, pop, jazz, folk, etc.) would say that it doesn't matter which type of music you listen to when it comes to separates vs AVR; it doesn't matter if you watch movies, TV shows, or listen to music.

Great sounding systems will sound great with all types of materials as long as the original source is great.

IMO saying that separates will sound better than AVR for classical music is just as ridiculous as saying external DACs sound better than the DACs inside PrePro and AVR.

With that being said, I will continue to use my separates (Denon AVP-A1HDCI and ATI 3000 amps) for everything in my HT room.

I bought my amp as a want, not a need. Did it improve anything? Well, my stuff runs cooler and it just looks plain badass sitting on my stand. I have plenty of power on tap and I feel good knowing that my amplification needs for now and well into the future are taken care of. I could add a half dozen speakers for full blown Atmos glory if I choose to down the road.

When the new big "must have" comes down the road I can replace my receiver and be good for the next 5-6 years again.

 

[AcuDefTechGuy]

I know you said that halfway in jest, but the sentiment is close to the mark for many.
There are a number of folks who have an image set in their heads what "great hifi" looks like on a shelf.
Everything else is not going to be satisfactory until they give it a whirl.

My only comparison point is watches: there are 1,000's of men this year who will hit a milestone or a bonus or something like that. They've had the itch for a Rolex since they were pups. They will spend the extra and strap it on and be ecstatic. After a while, and after seeing it on 100's of other wrists, the shine wears off and reality sets in.

There's no real loss. The Rolex is still a great watch and it will hold its value. Same with separates. No real audio loss. They will hold up. The owners just spent more than they probably needed to.

I would own Rolex watches just for the heck of it if I were a billionaire.

There's nothing wrong with owning expensive DAC or separates vs AVR. Whatever makes you happy. You don't need to justify it. Just do it.

We are sharing our personal experiences.

But if we're relying on science (double-blind testing) and measurements, you're not going to win the debate.

If the speakers (tweeters of Al, Mg, Ti, Be, Diamond, Silk, RAAL, AMT, etc.) and electronics measure superbly, how can people debate that one type is better?

Or better ONLY for certain venues (classical music, rock, pop, jazz, etc.) ?

 

[AcuDefTechGuy]

I bought my amp as a want, not a need. Did it improve anything? Well, my stuff runs cooler and it just looks plain badass sitting on my stand. I have plenty of power on tap and I feel good knowing that my amplification needs for now and well into the future are taken care of. I could add a half dozen speakers for full blown Atmos glory if I choose to down the road.

When the new big "must have" comes down the road I can replace my receiver and be good for the next 5-6 years again.

That's absolutely right.

It's about desires, not needs. We don't even have to justify it. We are not hurting ourselves or anyone financially or any other way. We do it because we can afford it, because feel like it, because we can, and because we deserve it!!!

 

[Irvrobinson]

But if we're depending on science (double-blind testing) and measurements, you're not going to win the debate.

Yeah, but you've got to know enough about measurements to put them in context. I'm as big a fan as anyone here of measurements, but when I see a review with one-line statements with a few unqualified measurements, especially on electronics, I pretty much disregard them as I do with subjective prose.

After I purchased the Outlaw 975 pre-pro I've had some performance issues with I saw some rave reviews for it, complete with measurements. It's not enough to quote simple numbers; it takes understanding to know what they mean, and in some cases I know that I don't know enough to know what they mean.