The Truth About Digital (Class D) Amplifiers

[silversurfer]

Ok, let me clarify: What I tried to convey is a metaphor.

Class-D amps are evolving at a rate comparable to computers at the 80286 stage... Clear enough? (Significant breakthroughs are yet to come, and the ASP modules of today will be fossiles of tomorrow -- just like a 286 or 386 computer is a fossile...)

Peter

I am not too worried about the rate of advancement. As of now, they compete with the best of traditional amps.

Will they get better? I think so, but it will be all "gravy".

 

[Sleestack]

Ok, let me clarify: What I tried to convey is a metaphor.

Class-D amps are evolving at a rate comparable to computers at the 80286 stage... Clear enough? (Significant breakthroughs are yet to come, and the ASP modules of today will be fossiles of tomorrow -- just like a 286 or 386 computer is a fossile...)

Peter

I understood you very clearly, but don't think it is a good comparison. If Class D amps had no dynamic range, high noise floors and only came in 20 watt monoblocks that were bigger than a rack space, I'd say we were at the 286 stage. But, given that some current Class D amps have superior technical specifications and can achieve effortless transparency, I'm not sure what you want them to improve. Certainly the technology will advance and as with SS and tube gear, there will always be people developing better implementations, but a good amp is a good amp and will drive tomorrow's speakers as well as any current SS amp. If speaker technology changes, all bets are off, but that would apply to SS as well. On the other hand, a 286 won't run today's programs.

 

[Peter Nielsen]

I understood you very clearly, but don't think it is a good comparison.

I was referring to the bang-for-the-buck ratio. Within 2 years, you can most likely buy a D-class amp for $500 that sounds just as good as the $2000 offerings today...

Peter

 

[ar-t]

No, I haven't heard about that. However, one year is a lifetime for a computer. Digital amps are evolving like computers... Hence, one year can be considered a lifetime for a digital amp (if you want to stay on the leading edge of technology).

I do not see how there will be so many changes to make an ASP obsolete in one year. Other than to make them smaller and probably cheaper.

If you base all your purchases on that assumption, you will spend your entire lifetime standing on the sidelines.

I have been doing this stuff for over 25 years. You are the first person I have heard fret about whether or not their amp will be cutting edge or not. Unless they start putting high-power DACs in speakers, my bet is any digital amp will function for quite a long time. (Translation: don't count on speakers with built-in DACs happening anytime soon.)

BTW......I still use a '386. Anything faster will not talk to our "fossil" D-size plotter. Which still works, >15 years later.

The "leading edge" ink jet plotters only cost more. The plot looks just the same, only it takes less time to produce. If we had waited all these years to buy one, we would have not been able to design PCBs in the interim.

Take your pick: sit around and wait for a constantly evolving field to stop evolving, or decide it is time to get in gear.

 

[highfihoney]

I was referring to the bang-for-the-buck ratio. Within 2 years, you can most likely buy a D-class amp for $500 that sounds just as good as the $2000 offerings today...

Peter

I agree with that philosophy on buying alot of things,especially audio gear.

Alot of audiophiles are so caught up in having the latest & greatest whatever that they pracitally give away gear that is only a year old & in mint condition to fund their new gear.

For savings of 60% or more i'll gladly wait on the sidelines for a year or two

 

[krabapple]

Well, PS Audio is very highly regarded...

er....if you think that, you might want to read this thread about their 'Noise Harvester' for another perspective...

http://www.avsforum.com/avs-vb/showthread.php?p=8182906#post8182906

pay particular attention to recent posts from 'speco2003', who bought one, tested it, and took a look inside it.

 

[silversurfer]

I was referring to the bang-for-the-buck ratio. Within 2 years, you can most likely buy a D-class amp for $500 that sounds just as good as the $2000 offerings today...

Peter

I don't think there is anything that supports that arguement. Can you show us an example?

Also, just about everything that is used and 2 years old is not going to be anywhere close to its original cost.

 

[Peter Nielsen]

I don't think there is anything that supports that arguement. Can you show us an example?

Many of the highly regarded amps out there (PS Audio, Bel Canto, etc.) are based on the generic ICEpower modules.

Now, if ICE can stay without competition for 2 more years, fine. Then the modules will probably cost the same, and nothing happens.

However, what about if ICE gets more tough competition. What will they do? They will either drop the prices, or create even better modules...

This can't be done in the classic solid state area where the amps are based on expensive heavy parts like toriods and big heat sinks. Shipping costs go up with fuel prices, so we can forget about the price dropping in this area...

If heat wasn't such a big problem, I would have kept all my nine Parasound JC-1 monoblocks...

Peter

 

[Peter Nielsen]

IAlot of audiophiles are so caught up in having the latest & greatest whatever that they pracitally give away gear that is only a year old & in mint condition to fund their new gear.

Very true. I got myself 9 Parasound JC-1 monoblocks that I planned to keep for at least 10 years, if not 20.

However, I didn't count on the heat all these blocks created, and to make things worse, the air conditioning in my media room is mediocre. Since I plan on moving in a few years, I did not want to waste a lot of time and energy on totally revamping my AC, and decided to try digital amps instead.

Now I am facing a conundrum. What about if the digital amp is not as good as the JC-1 monoblocks? I can't afford to lose thousands of dollars going from one digital amp to another... Also, I'd really hate spending $12,000 on generic ICEpower ASP500 amps and see them sold for a fraction of the cost in a year...

TacT Boz is an interesting choice. 10-channels MSRP at $21,000 - a lot more expensive than ASP. However, at least I know the proprietary TacT technology is not going to be sold for half the price in 2 years...

Maybe I'm too paranoid about ICEpower to drop in price, or maybe not. Massproduction usually brings prices down, and ICE is mass produced...

Peter

 

[Peter Nielsen]

I have been doing this stuff for over 25 years. You are the first person I have heard fret about whether or not their amp will be cutting edge or not.

I'm not looking for cutting edge. What I am looking for is multi channel amplification that runs cool and sounds as good as the Parasound JC-1 monoblocks.

I plan to keep the amps for 10 years or more, so I want to be sure that I make a good choice. (Soundwise I made an excellent choice with the JC-1s. It's just the practicalities that stops me from keeping them...)

Unless they start putting high-power DACs in speakers, my bet is any digital amp will function for quite a long time. (Translation: don't count on speakers with built-in DACs happening anytime soon.)

They already exist. Did you forget that Meridian has a whole range of speakers with digital inputs.

Take your pick: sit around and wait for a constantly evolving field to stop evolving, or decide it is time to get in gear.

I agree. But what would you do if somebody told you that you can buy any amplifier you want with the condition that you must keep it for at least 10 years ? (And you must be able to use it without modifying your air conditioning, etc.)

Peter

 

[Sleestack]

I'm not really sure why you are so wrapped up in dropping values. Even the solid state gear I have bought, I have sold for between 50-60% of retail value. Furthermore, I sold my 2nd BOZ/216/2200 set for 50% of what I paid for them.... and that was 2 months after i bought them. I can tell you from experience with the JC-1s, that you won't suffer any performance loss going to Bel Cantos or the TACT amps. You will get less power with the BOZ amps if that is a concern. Personally, I wasn't very impressed with the JC-1s, as they created ay too much heat and didn't sound any different than their A51. The bottom line is that the Bel Canto amps will give you all the performance you want. If you were not so wrapped up in "value, " you could replace your JC-1s with the Bel Cantos or something similar right now, and have exactly what you are looking for.

Very true. I got myself 9 Parasound JC-1 monoblocks that I planned to keep for at least 10 years, if not 20.

However, I didn't count on the heat all these blocks created, and to make things worse, the air conditioning in my media room is mediocre. Since I plan on moving in a few years, I did not want to waste a lot of time and energy on totally revamping my AC, and decided to try digital amps instead.

Now I am facing a conundrum. What about if the digital amp is not as good as the JC-1 monoblocks? I can't afford to lose thousands of dollars going from one digital amp to another... Also, I'd really hate spending $12,000 on generic ICEpower ASP500 amps and see them sold for a fraction of the cost in a year...

TacT Boz is an interesting choice. 10-channels MSRP at $21,000 - a lot more expensive than ASP. However, at least I know the proprietary TacT technology is not going to be sold for half the price in 2 years...

Maybe I'm too paranoid about ICEpower to drop in price, or maybe not. Massproduction usually brings prices down, and ICE is mass produced...

Peter

 

[silversurfer]

And it would not cost you $12K on nine generic ICEpower 500ASP amps.

You could also buy one or two just to see if you like what they do.

 

[Peter Nielsen]

And it would not cost you $12K on nine generic ICEpower 500ASP amps.

You could also buy one or two just to see if you like what they do.

Here are a few ICEpower ASP alternatives I've been considering:

ASP1000:
#1) Nine Bel Canto ref 1000 ($1995 each) = $18k
#2) PS Audio GCA-MC-500 5channel ($7995) + pair of GCA-MC-500 stereo amp ($3995 each) = $16k
#3) One Rotel RB-1091 ($1499) + four Rotel RB-1092 ($2499 each) = $11.5k

ASP500:
#1) PS Audio GCA-MC-250 5channel ($5995) + pair of GCA-MC-250 stereo amp ($2995 each) = $12k

As you can see, they are all priced around $12k.

I know that I could get some not-so-fancy generic amps for around $6k or less, but aesthetics are important to me so this is not an option.

Peter

 

[Peter Nielsen]

Personally, I wasn't very impressed with the JC-1s, as they created ay too much heat and didn't sound any different than their A51

Oh, there is a HUGE difference in sound between the JC-1 and A51. Night and day if you ask me!

At first I had an A51, but it was just "powerless" and unable to deliver clean power to my Maggies. When I brought the A51 to clipping, it blew the midrange fuse in one of my speakers. Ouch! Also, the A51 does not have enough capacitors in its power supply. At first, when I had the A51 connected to a general outlet, the light in the room started flickering when I pushed the A51. The JC-1s don't exhibit any of these problems. The JC-1 has enough capacitors to deliver reserve power and keep the power consumption smooth instead of pulsing. Also, I have never seen the JC-1 clip. It has enough power to cause my Maggies to bottom out...

I sold my A51 a year ago and replaced it with five more JC-1s, ending up with a total of nine JC-1s...

Did you give the JC-1 the full break in it needed (3 months minumum)? A new JC-1 indeed sounds lifeless. They are notorious for requiring a looong break in time. Also, the JC-1s can also be tricky when it comes to grounding. I've heard about users that thought the JC-1 sounded bad until they discovered they had a grounding problem, and when corrected the sound changed dramatically... (FWIW, the ground lift switch on the back is worthless!)

Peter

 

[silversurfer]

OK...you want them to look good too.

Also checkout
http://acoustic-reality.com
http://www.iceh2oaudio.com
http://www.jjaz.dk

 

[Sleestack]

Oh, there is a HUGE difference in sound between the JC-1 and A51. Night and day if you ask me!

At first I had an A51, but it was just "powerless" and unable to deliver clean power to my Maggies. When I brought the A51 to clipping, it blew the midrange fuse in one of my speakers. Ouch! Also, the A51 does not have enough capacitors in its power supply. At first, when I had the A51 connected to a general outlet, the light in the room started flickering when I pushed the A51. The JC-1s don't exhibit any of these problems. The JC-1 has enough capacitors to deliver reserve power and keep the power consumption smooth instead of pulsing. Also, I have never seen the JC-1 clip. It has enough power to cause my Maggies to bottom out...

I sold my A51 a year ago and replaced it with five more JC-1s, ending up with a total of nine JC-1s...

Did you give the JC-1 the full break in it needed (3 months minumum)? A new JC-1 indeed sounds lifeless. They are notorious for requiring a looong break in time. Also, the JC-1s can also be tricky when it comes to grounding. I've heard about users that thought the JC-1 sounded bad until they discovered they had a grounding problem, and when corrected the sound changed dramatically... (FWIW, the ground lift switch on the back is worthless!)

Peter

That's not a sound issue. That's a power issue. Your Maggies require more power than the A51 can deliver. I don't think the TACT amps will have sufficient power for your speakers either. On the other hand, I think the Bel Cantos will more effortlessly do what the JC-1s are doing for you, with minimal heat. IMO, for more efficient speakers, the JC-1s don't really offer and identifiable sonic difference. I really haven't heard break-in with any solid state gear I have ever used. Nevertheless, the JC-1s had a previous owner and moderate hours. They are great amps, as is the A51, and I certainly don't think you should change anything if you are happy. But, if sound is your primary concern, go with the Bel Cantos or something similar without concern about the value 2 years from now. With both balanced and single ended inputs and 1000w (at 4 ohms) of transparency, some thing like the BCs should be plenty for your Maggies and anything to come. Plus, you'll feel much cooler.

Perhaps I've gone of the digital deep end, but I also like the way they look:

 

[Peter Nielsen]

That's not a sound issue. That's a power issue.

Yes, it's a power issue, but it's NOT a "maximum output power in watts" issue. The 250/450 watts of the A51 would in principle be enough. The problem is that the power supply in the A51 does not have enough reserve power.

The A21 has the exact same output transistor configuration as the A51, but a better power supply (almost double the capacitance; 50,000uF vs 32,000uF). It did not run out of steam as easily as the A51 did, although the power specifications are the same on paper. Finally, the JC1 doubles on the per-channel-capacitance of the A21 (and quadruples on the A51). It never runs out of steam...

The Boz 216 and 2200 seem to have a lot of capacitors in the power supply. They may well have all the power reserves that I need... This raises the question of the ICEpower and its power reserves. It's so small that there is no room for a lot of capacitors...

As somebody said, the best thing I could do is probably to pick up an ICEpower based amp and give it a try. That's probably the only way to find out if I like it or not. The same goes for TacT, but that's a rather costly experiment if I decide that I don't like it.

And, yes, you're right about the value issues. If I'm concerned about that, then my best bet is to pick up a used digital amp on Audiogon. (I only missed your BOZ setup by a few days. When I saw it, it was already sold).

I also realize that if I go the TCS/Boz216/Boz2200 route, I am pretty much painting myself into a corner because of the digital only inputs and the proprietary volume control via RS-232. If I want to upgrade the preprocessor in the future, I have to rely on a future TCS Mk III upgrade or a Boz preprocessor. (I would be running my two Martin Logan Descent powered subwoofers directly off the preprocessor, so it is necessary to be able to keep the Boz216 volume synchronized with the preprocessor volume. Because of this, I could not rely on the Boz216 volume control alone. The preprocessor and amp volume will have to be syncronized).

What's your take on this? I vaguely remember reading that you had some more details about the split between the TacT founders Boz and Lynggård... Is the TacT/Boz split that something to be concerned about? (Feel free to PM me if you have info that you don't want to post here).

Thanks,
Peter

P.S. Here are a few pictures of my Parasound setup with 9 JC1s:

 

[davelee98]

Room Treatments?

At the $$ level you're spending at, perhaps it might help to invest in some room treatments? For example, realtraps. At first I thought those tall black objects were Gobotraps, but then I noticed the electronics poking out the back, so I guess they're electrostatics...

Might I also suggest a better set of chairs and a replacement for the hideous ceiling fixture... (WAF)

Yes, it's a power issue, but it's NOT a "maximum output power in watts" issue. The 250/450 watts of the A51 would in principle be enough. The problem is that the power supply in the A51 does not have enough reserve power.

The A21 has the exact same output transistor configuration as the A51, but a better power supply (almost double the capacitance; 50,000uF vs 32,000uF). It did not run out of steam as easily as the A51 did, although the power specifications are the same on paper. Finally, the JC1 doubles on the per-channel-capacitance of the A21 (and quadruples on the A51). It never runs out of steam...

The Boz 216 and 2200 seem to have a lot of capacitors in the power supply. They may well have all the power reserves that I need... This raises the question of the ICEpower and its power reserves. It's so small that there is no room for a lot of capacitors...

As somebody said, the best thing I could do is probably to pick up an ICEpower based amp and give it a try. That's probably the only way to find out if I like it or not. The same goes for TacT, but that's a rather costly experiment if I decide that I don't like it.

And, yes, you're right about the value issues. If I'm concerned about that, then my best bet is to pick up a used digital amp on Audiogon. (I only missed your BOZ setup by a few days. When I saw it, it was already sold).

I also realize that if I go the TCS/Boz216/Boz2200 route, I am pretty much painting myself into a corner because of the digital only inputs and the proprietary volume control via RS-232. If I want to upgrade the preprocessor in the future, I have to rely on a future TCS Mk III upgrade or a Boz preprocessor. (I would be running my two Martin Logan Descent powered subwoofers directly off the preprocessor, so it is necessary to be able to keep the Boz216 volume synchronized with the preprocessor volume. Because of this, I could not rely on the Boz216 volume control alone. The preprocessor and amp volume will have to be syncronized).

What's your take on this? I vaguely remember reading that you had some more details about the split between the TacT founders Boz and Lynggård... Is the TacT/Boz split that something to be concerned about? (Feel free to PM me if you have info that you don't want to post here).

Thanks,
Peter

P.S. Here are a few pictures of my Parasound setup with 9 JC1s:

 

[Peter Nielsen]

At the $$ level you're spending at, perhaps it might help to invest in some room treatments?

The TacT TCS has room correction software so I'm not so sure how important this is.

At first I thought those tall black objects were Gobotraps, but then I noticed the electronics poking out the back, so I guess they're electrostatics

They're magnetic planars made by Magnepan in Minnesota.

Might I also suggest a better set of chairs

Yes, the chairs will be replaced at some point. Those are of course temporary, but work well...

and a replacement for the hideous ceiling fixture...

You mean the projector? That would probably imply a projector upgrade, which I don't plan to do at this time (no cash for that expensive upgrade).

Currently I'm using a JVC G15 D-ILA. It is VERY NOISY due to all the fans to extract the 700W of heat. The enclosure needs to be that big & bulky to handle the silencing task and heat removal (heat is pumped up in the attic).
Behind the wall is a hallway with the staircase down to the 1st floor, so I cannot really cut a hole in the wall either. Well, I guess I could, but it would not look pretty on the other side. I'd also like to avoid major modifications to my home since I plan to move in a few years anyway...

The enclosure may be ugly, but performs its task EXTREMELY well. BTW, what difference does the enclosure make with all those big Maggies in the room? They're not excatly offering high WAF factor either. Fortunately I have an understanding wife, so my setup has all the WAF it needs

Peter

 

[Peter Nielsen]

Well, PS Audio is very highly regarded...

er....if you think that, you might want to read this thread about their 'Noise Harvester' for another perspective...

http://www.avsforum.com/avs-vb/showthread.php?p=8182906#post8182906

pay particular attention to recent posts from 'speco2003', who bought one, tested it, and took a look inside it.

I don't see what you're trying to prove here. Their new "Noise Harvester" product belongs in the very controversial product category "power cables and power filters". We all know that there is usually no magic to be performed here. A $5 power cable usually measures and sounds the same as a $500 power cable, yet some people claim there is a night and day difference. A lot of hokey-pokey going on in the cable world.... Unidirectional power and speaker cables, etc... LOL!

I was referring to the higly regarded PS Audio amplifiers and Power Plants. There are thousands of happy Power Plant users out there, and I have yet to read a review from somebody that thinks the power plant sucks or is not useful...

Peter