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An AVR with Class A/B or Class D Amps? Which one is one better?

post #1 of 22
Thread Starter 
What really is the big difference between the Class A/B or D amps? I have been looking at some of the new Pioneer Elite A/V receivers and have been wondering about those Class D Amps they are using in them. Are they any good? One of the first things I noticed is that when they give the power specs on them they are only rated at the 1kz level. What's up with that, are those Class D Amps a little weak, are they trying to hide something there? I heard read that the class A/B Amps run the signal straight through but they do get hot. And also that the Class D Amps usually have more THD. I am setting up a HT in the bedroom.
So what the heck, I am pretty new to this technology but I definitely know when something sounds good. Trying to make an informed decision is not so easy now a days. It seems like the more I learn, the less I know... rolleyes.gif
post #2 of 22
Compared to class AB ampfliers, class D amplifiers use less power and run cooler, but apparently cost more to make. That is assuming the goal is to make a class D equivilent in quality to a decent class AB amp. Cheap class D amplifiers are used in certain low end equipment where size and low power usage is important, but sound quality is not.
post #3 of 22
I just did an A/B comparison of my Onkyo TX-NR 809 receiver and a newly aquired Pioneer SC-1222-K. Well........the Onkyo (that I just bought 3 months ago) is going to eBay or Craigslist today. The power, clean sound and clarity is unmatched in "class A/B" amps to my ears. I've always loved "class D", and finally Pioneer comes along and does it right.
post #4 of 22
Quote:
Originally Posted by spacecowboy View Post

I just did an A/B comparison of my Onkyo TX-NR 809 receiver and a newly aquired Pioneer SC-1222-K. Well........the Onkyo (that I just bought 3 months ago) is going to eBay or Craigslist today. The power, clean sound and clarity is unmatched in "class A/B" amps to my ears. I've always loved "class D", and finally Pioneer comes along and does it right.

I am currently an Onkyo 809 owner. I'm running all Polk Rti's and wondering if I should make switch to the 1222? Will I notice a significant improvement or just keep what I have?

Thx
post #5 of 22
Quote:
Originally Posted by Ross Ridge View Post

Compared to class AB ampfliers, class D amplifiers use less power and run cooler, but apparently cost more to make. That is assuming the goal is to make a class D equivilent in quality to a decent class AB amp. Cheap class D amplifiers are used in certain low end equipment where size and low power usage is important, but sound quality is not.

Lets clear the air...
Higher power Class D amplifiers (>50W) are significantly less expensive to build than Class A-B amplifiers..
Thats why 90% of the home theater subwoofers utilize Class D amplification.. And now Class D solutions are dominating car audio (both OE and aftermarket), portable, multi-media and all-in-1 Blu-ray systems. Earlier Class D solutions did have some serious audio sonic drawbacks but these have been solved...
A couple of AVR brands have done Class D solutions with some sucess:
  • HK did a couple of models a few years back that were actually THX approved
  • Pansonic & Sherwood both sold platforms designed by TI
  • Pioneer has done (2) generations the 1st being ICE and the 2nd being IR

IMHO...
Within the next 3 years, the majority of AVRs will be Class D as they run cooler, more green friendly, smaller foot print and more cost effective...

Just my $0.02... wink.gif
post #6 of 22
If it Class D amps were both cheaper and more power efficient while still maintaining the same level of quality then all AV receivers would be using them. Not three years from now. Not just in Pioneer's more expensive receivers. All receivers. Today.
post #7 of 22
Quote:
Originally Posted by Ross Ridge View Post

If it Class D amps were both cheaper and more power efficient while still maintaining the same level of quality then all AV receivers would be using them.

Only true if the above three items were always true.

They haven't been always true, Switchmode amplifiers represent an evolving technology.

Switchmode amplifiers have been used in commercial audio amplifiers for several decades.

Historically, switchmode amps have not always been cheaper and maintained the same level of SQ.

I am unaware of any time where they did not have an efficiency advantage.
Quote:
Not three years from now. Not just in Pioneer's more expensive receivers. All receivers. Today.

The evolution of switchmode amplifiers has been riding on the back of the development of solid state devices that could switch enough power fast enough and have low enough cost. This has taken time and will be ongoing for some time yet.

Would I buy a swtichmode amp today? Probably. So far my purchasing activity in this area has included Class G amps with switchmode power supplies. They have been a success for me on all grounds.

I suspect that the HK 1700 may be the turning point for swtichmode technology in the mainstream market. It appears to win on all three points. I'd like to ABX one to settle the SQ issue.
post #8 of 22
Quote:
Originally Posted by Ross Ridge View Post

Compared to class AB ampfliers, class D amplifiers use less power and run cooler, but apparently cost more to make. That is assuming the goal is to make a class D equivilent in quality to a decent class AB amp. Cheap class D amplifiers are used in certain low end equipment where size and low power usage is important, but sound quality is not.

They're also used in high end gear where sound quality is important. And I think your concept of cost might be off a bit as well, it's been a fast moving technology. For an example a relatively old technology ICEpower 1000ASP module which is the guts of the Bel Canto Ref e1000's (1000w @ 4ohms), probably wholesales for $300/$400 depending on volume purchased.

I know Pioneer worked with ICE to create their initial amp sections, I have to assume they use the same technology now, and they're basically multiple mono-block channels on a single circuit board which should yield a bit of an advantage over a conventional multi-channel amp with a single shared power supply. How much is debateable, and how much actual sound quality difference you'd get is probably debatable too, it's not likely there would be much if any if both are operating within tolerances.
Personlly I like the idea of less real-estate being taken up by power supplies in these swiss army knife receivers since they get pretty cramped and component isolation can become an issue.
I'm not familiar with Pioneers' room correction and that would be my only concern when compared to Anthems ARC or Audyssey's XT & XT32 offerings.
post #9 of 22
Quote:
Originally Posted by Ross Ridge View Post

If it Class D amps were both cheaper and more power efficient while still maintaining the same level of quality then all AV receivers would be using them. Not three years from now. Not just in Pioneer's more expensive receivers. All receivers. Today.

That would seem to be the case, but there's a market driven anomily where the consumer equates weight and size with quality. It's been a tough sell for Class D because inevitably the consumer will buy the big heavy box with the advertised "toriodal transformer" without really understanding what's in play.

I have a PS Audio GCA, which is a dual ICEpower ASP amp and they acutally welded a 10lb steel plate to the top of the chassis, for no other purpose than to add the precious "weight".
Edited by rnrgagne - 2/26/13 at 12:21pm
post #10 of 22
Quote:
Originally Posted by arnyk View Post

Only true if the above three items were always true.

No, I'm only talking about the state of technology today. I thought that would've been made clear when I used the word "today" alone as a sentence.

If it's possible today to make a Class D amp that is both cheaper and more power efficent, then all AV receivers being manufactured today would be using them.

Saying that this could change in the future isn't all that relevent to anyone looking to buy an AV receiver today in the present.
post #11 of 22
Quote:
Originally Posted by Ross Ridge View Post


If it's possible today to make a Class D amp that is both cheaper and more power efficent, then all AV receivers being manufactured today would be using them.

Oh, it is the "Repeat it until everybody gets tired of debunking it and arguing with it" approach.

Since the technology is evolving and not yet at steady state, it is unfair to expect 100% market penetration now even if it is cheaper, more efficient, and has equal SQ today.

It takes the market a little while to respond to such changes.
Quote:
Saying that this could change in the future isn't all that relevant to anyone looking to buy an AV receiver today in the present.

I'm saying that there is a good chance that all three criteria are met today, but it will take the market a little while (like 3 years) to more fully respond. Even if a technology is fully perfected, it doesn't go 100% instantly. In 3 years, maybe 60-70 percent penetration presuming I'm right and its good enough.

BTW you forgot to count reliability. ;-)

The market is very interested in that.! Only time will tell that.
post #12 of 22
Quote:
Originally Posted by rnrgagne View Post

They're also used in high end gear where sound quality is important. And I think your concept of cost might be off a bit as well, it's been a fast moving technology. For an example a relatively old technology module which is the guts of the Bel Canto Ref e1000's (1000w @ 4ohms), probably wholesales for $300/$400 depending on volume purchased.

That's a lot more more expensive than I would assume a company like Pioneer would've payed for a single channel of amplification in their AV receivers.
Quote:
I know Pioneer worked with ICE to create their initial amp sections, I have to assume they use the same technology now, and they're basically multiple mono-block channels on a single circuit board which should yield a bit of an advantage over a conventional multi-channel amp with a single shared power supply.

They no longer buy ICE modules for their receivers and supposely came up with thier own completly new less expensive design, but I don't know how much the technology has actually changed. Still it wasn't cheap enough to convince them that it would be a good idea to use them in their high-volume low-margin models, where any reduction in the cost of components would have its greatest benefit.

According to M Code, Pioneer receivers use linear power supplies, I assume a single one is shared by all the amps.
Quote:
That would seem to be the case, but there's a market driven anomily where the consumer equates weight and size with quality. It's been a tough sell for Class D because inevitably the consumer will buy the big heavy box with the advertised "toriodal transformer" without really understanding what's in play.

There's some merit to this, as Pioneer doesn't seem to use the technology to make thier AV receivers any smaller. However, even in my Class AB receiver only about a 1/4 of the internal volume, including space for cooling, is taken up by the power amps. Shrinking these wouldn't allow the receiver to get much smaller, especially since all the jacks on the back limit how much you can reduce the height.

Removing the non-toroidal transformer would save more space and wieght, but that apparently isn't practical in AV receivers today.
Edited by Ross Ridge - 2/26/13 at 1:59pm
post #13 of 22
Quote:
Originally Posted by arnyk View Post

Oh, it is the "Repeat it until everybody gets tired of debunking it and arguing with it" approach.

No, you argued against something I didn't actually say.
Quote:
Since the technology is evolving and not yet at steady state, it is unfair to expect 100% market penetration now even if it is cheaper, more efficient, and has equal SQ today.

It's at not all unfair. It's a very competive business, manufacturers don't wait three years to introduce new technologies that cost them more money, they're certianly no going to wait that long to introduce technologies that save them money. If we were in the middle a transition then this technology would much more widespread, and it would be first seen in the cheapest highest volume models where saving even $5 would make it worthwhile.
Quote:
BTW you forgot to count reliability. ;-)

The market is very interested in that.! Only time will tell that.

Sure, but that ultimately figures into the cost. If Class D amplifiers are cheaper to make but have more reliability problems then that could be what effectively makes them more expensive. Even just uncertainty about their reliabilty could make them effectively more expensive to manufacturers as they'd have to put aside more money for potential waranty claims.
post #14 of 22
Quote:
Originally Posted by Ross Ridge View Post

That's a lot more more expensive than I would assume a company like Pioneer would've payed for a single channel of amplification in their AV receivers.

Oh for sure, but I was referring to comparable monoblock A/B costing.
post #15 of 22
Quote:
Originally Posted by arnyk View Post



I suspect that the HK 1700 may be the turning point for swtichmode technology in the mainstream market. It appears to win on all three points. I'd like to ABX one to settle the SQ issue.

The 1700 uses a Switch-Mode-Power-Supply, however its amplfier is Class A-B..

Just my $0.02... wink.gif
post #16 of 22
Quote:
Originally Posted by spacecowboy View Post

I just did an A/B comparison of my Onkyo TX-NR 809 receiver and a newly aquired Pioneer SC-1222-K. Well........the Onkyo (that I just bought 3 months ago) is going to eBay or Craigslist today. The power, clean sound and clarity is unmatched in "class A/B" amps to my ears. I've always loved "class D", and finally Pioneer comes along and does it right.


+1
post #17 of 22
Quote:
Originally Posted by M Code View Post

Quote:
Originally Posted by arnyk View Post



I suspect that the HK 1700 may be the turning point for swtichmode technology in the mainstream market. It appears to win on all three points. I'd like to ABX one to settle the SQ issue.

The 1700 uses a Switch-Mode-Power-Supply, however its amplifier is Class A-B..

Just my $0.02... wink.gif

Just checked the SM and it confirms that the HK 1700 output stages are indeed Class AB. You are right and I was wrong!

Output devices are 2SD2390 and 2SB1560 150 v 10a devices. Typical fare for AVRs in the 100 wpc range.

What was I thinking?
post #18 of 22
Quote:
Originally Posted by arnyk View Post

Just checked the SM and it confirms that the HK 1700 output stages are indeed Class AB. You are right and I was wrong!

Output devices are 2SD2390 and 2SB1560 150 v 10a devices. Typical fare for AVRs in the 100 wpc range.

What was I thinking?

No biggee..biggrin.gif
I knew what was in it as I did the initial product definition and prototype validation for HK. Primary reason was to have world-wide AC voltage compatibility, as well as using the same basic SMPS design in the 2700/3700..

Just my $0.02... wink.gif
post #19 of 22
Quote:
Originally Posted by bad1550 View Post

I am currently an Onkyo 809 owner. I'm running all Polk Rti's and wondering if I should make switch to the 1222? Will I notice a significant improvement or just keep what I have?

Thx
Only you can make that decision after listening to both. With the Pioneer, I don't have to crank the knob to get good sound. I started to get distortion a liitle more than half way on the Onkyo. I get no distortion on the Pioneer - a sign of stronger amps. Honestly, I miss the ease of Audessey. MCACC is just as great, but you have to work a little harder to get the sub dialed in where you want it. Some may consider that NOT a negative at all though. If I were you, if you are happy with the Onkyo 809, which is a great receiver, keep it. To me, the sound quality was a significant improvement. To you it may not be to warrant an upgrade from the 809, but class d amps do sound different from the class a/b counterparts. Go to Best Buy and listen to a Pioneer SC-61. It is essentially the same. Hope this helps a little.
post #20 of 22
Quote:
Originally Posted by M Code View Post

Lets clear the air...
Higher power Class D amplifiers (>50W) are significantly less expensive to build than Class A-B amplifiers..
Thats why 90% of the home theater subwoofers utilize Class D amplification.. And now Class D solutions are dominating car audio (both OE and aftermarket), portable, multi-media and all-in-1 Blu-ray systems. Earlier Class D solutions did have some serious audio sonic drawbacks but these have been solved...
A couple of AVR brands have done Class D solutions with some sucess:
  • HK did a couple of models a few years back that were actually THX approved
  • Pansonic & Sherwood both sold platforms designed by TI
  • Pioneer has done (2) generations the 1st being ICE and the 2nd being IR

IMHO...
Within the next 3 years, the majority of AVRs will be Class D as they run cooler, more green friendly, smaller foot print and more cost effective...

Just my $0.02... wink.gif
Don't forget that Sony had some class D receiver offerings several years ago , and although sounding nice, I don't think they were received very well.
post #21 of 22
Quote:
Originally Posted by spacecowboy View Post

Only you can make that decision after listening to both. With the Pioneer, I don't have to crank the knob to get good sound. I started to get distortion a liitle more than half way on the Onkyo. I get no distortion on the Pioneer - a sign of stronger amps. Honestly, I miss the ease of Audessey. MCACC is just as great, but you have to work a little harder to get the sub dialed in where you want it. Some may consider that NOT a negative at all though. If I were you, if you are happy with the Onkyo 809, which is a great receiver, keep it. To me, the sound quality was a significant improvement. To you it may not be to warrant an upgrade from the 809, but class d amps do sound different from the class a/b counterparts. Go to Best Buy and listen to a Pioneer SC-61. It is essentially the same. Hope this helps a little.

I ordered the 1222 from Newegg. I hope to sell my 809 on CL. I've only had it for 8 months but very interested in 1222 based on all of the comments. Just received my 2nd Klipsch RW-12D. How exactly do I set up 2 subs with the Pio as I am used to the Audessey?

Thanks
post #22 of 22
Quote:
Originally Posted by bad1550 View Post

I ordered the 1222 from Newegg. I hope to sell my 809 on CL. I've only had it for 8 months but very interested in 1222 based on all of the comments. Just received my 2nd Klipsch RW-12D. How exactly do I set up 2 subs with the Pio as I am used to the Audessey?

Thanks
Wow. Way to go! I think you will like the difference. The Pioneer is 7.2 which has 2 sub outputs. I have a Klipsch RW-12D as well as an SVS PB-10. The Onkyo sells on eBay quite well too.
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