The Truth About Digital (Class D) Amplifiers

S

Sleestack

Senior Audioholic
Peter Nielsen said:
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).
Boz and Peter Lyngdorf had some differences and split the company. Lyngdorf is its own company in Europe and has its own amps. Even though they have the same form factor, they are no longer a part of TACT, which is now Boz's company. Lyngdorf has had some trouble getting his own room correction implemented, as the cutting edge TACT room correction hardware and software was retained by Boz at TACT. A recent review of Lyngdorf's released room correction was not very flattering.

Personally, I would stick with TACT (i.e. Boz). His room correction is very well developed and I don't feel Lyngdorf offers anything else that TACT can't.

I do not think the TACT amps will have sufficient power for your Maggies. They are wonderful amps, but I think the ICEpower amps are better suited for your application. I use the TACT Boz amps in my 5.1 setup, where I am bi-amping and externally setting crossovers for each of my Andra IIs, so I don't need as much power as you.

You have some really great gear there, but if I were you, I would replace those heat monsters with 1000w monos like the Bel Cantos. I don't think you will have anything to worry about. As for the pre/pro, IMO, if you care about sound, there is nothing better than the TACT TCS MKII. I think the TCS MKII coupled with any monoblock of your choice would truly transform your listening experience. It would be the single biggest improvement you could make to your system, as advanced room correction applied to a multichannel system can truly produce "night & day" differences.

The only reason I would tell you to wait is b/c there will inevitably be a TCS MKIII. Personally, I wouldn't wait. It could be years, and there is no pre/pro available that can do what the TCS MKII does.

I have spent a ton of money buying all sorts of gear to figure out what really matters to me. You already have great speakers. I think you are getting too wrapped up in amplification, as your room is probably affecting your sound more than any amp could. Using a TCS MKII will make you realize that all you need out of your amplification is sufficient power and transparency. Trust me, the Bel Cantos give you that in spades. Add the TCS MKII to your system, and I believe you will have an aural revelation.
 
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mtrycrafts

mtrycrafts

Seriously, I have no life.
Peter Nielsen said:
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

Perhaps what he was trying to say is that confidence in a company that sells such voodoo products may suffer because of this practice on their part?
The CD producer Mapleshade has the same issues; they also are in the voodoo business:D
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
Sleestack said:
I have spent a ton of money buying all sorts of gear to figure out what really matters to me. .

Is that a ton of pennies or $100 bills:D Or a mix;)
 
S

Sleestack

Senior Audioholic
mtrycrafts said:
Perhaps what he was trying to say is that confidence in a company that sells such voodoo products may suffer because of this practice on their part?
The CD producer Mapleshade has the same issues; they also are in the voodoo business:D
Don't you think comparing PS Audio to Mapleshades is a bit of a stretch? Would you discredit every company that has engaged in marketing hyperbole and created products that didn't do what they were said to do? I'm not sure that you would be left with much.
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
Sleestack said:
Don't you think comparing PS Audio to Mapleshades is a bit of a stretch? Would you discredit every company that has engaged in marketing hyperbole and created products that didn't do what they were said to do? I'm not sure that you would be left with much.

I don't find Bryton doing that, do you? Marantz? Yamaha? Denon? or a whole lot of others? PSB? Mirage?

When a company does what PS Audio or Mapleshade does, more than marketing, they are marketing voodoo products, one has to think hard, do I really need their amps when there are lots of others to pick from? I would.
 
A

AdrianMills

Full Audioholic
mtrycrafts said:
I don't find Bryton doing that, do you? Marantz? Yamaha? Denon? or a whole lot of others? PSB? Mirage?

When a company does what PS Audio or Mapleshade does, more than marketing, they are marketing voodoo products, one has to think hard, do I really need their amps when there are lots of others to pick from? I would.
I agree totally.

Sometimes the indifference to the cons that are being perpetrated daily really get my goat particularly when previously reputable companies give in to the temptation of making a quick buck off of the gullible. :mad: Probably beyond rationality sometimes but hey, I never said I was perfect.

SilverSurfer and I have had an interesting exchange on another thread about ICEPower modules and Scandinavian amps - I mailed Søren Bertrams about his "Beast" amp to get details too... but he's also a snake oil merchant selling exotic cables. :rolleyes:

It's a pity no one has performed an ABX test on the ICEPower 1000ASP too... I'd really like to know if this roll off above 2kHz is audible. :confused:

I'm starting to get more interested in the UCD amps though... But is anyone building amps from the 700 module yet? The thought of buying all the bits and hunting around for a decent housing before putting it together myself really doesn't appeal to me that much – call me lazy.
 
S

Sleestack

Senior Audioholic
AdrianMills said:
It's a pity no one has performed an ABX test on the ICEPower 1000ASP too... I'd really like to know if this roll off above 2kHz is audible. :confused:

.
If anything, I find that I have to roll off the high end further when i use these amps.
 
S

Sleestack

Senior Audioholic
mtrycrafts said:
I don't find Bryton doing that, do you? Marantz? Yamaha? Denon? or a whole lot of others? PSB? Mirage?

When a company does what PS Audio or Mapleshade does, more than marketing, they are marketing voodoo products, one has to think hard, do I really need their amps when there are lots of others to pick from? I would.
Well, I can't argue with your position as it relates to your choices. Although I have no experience with any PS Audio products, I would prefer to keep my options open and use my own judment and some research when buying any product.
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
Sleestack said:
I do not think the TACT amps will have sufficient power for your Maggies. They are wonderful amps, but I think the ICEpower amps are better suited for your application. I use the TACT Boz amps in my 5.1 setup, where I am bi-amping and externally setting crossovers for each of my Andra IIs, so I don't need as much power as you.
If I go the Boz route, I will be bi-amping and using the Boz crossovers.

My Maggies are 86dB/1W/1M. Your Andra IIs are 88.5dB/1W/1M. That's only a 2.5 dB difference.

Without bi-amping, you're definitely right that the power probably won't suffice. However, with bi-amping I think I'll be Ok.

Sleestack said:
I think the TCS MKII coupled with any monoblock of your choice would truly transform your listening experience.
I have mixed feelings about the analog outputs of the TCS. The TCS MKII DACs apparently don't incorporate analog volume control. Instead, the volume control is done in the digital domain if the builtin DACs are used. (This is supposedly not a good thing to do since resolution is lost at lower listening levels). This problem of course goes away when the TCS is mated with another TacT digital amp and the output is driven at full level and the volume is controlled by the amp.

Sleestack said:
The only reason I would tell you to wait is b/c there will inevitably be a TCS MKIII. Personally, I wouldn't wait. It could be years, and there is no pre/pro available that can do what the TCS MKII does.
The thought has crossed my mind, but you're right. It's impossible to know if the update is going to be in two months or two years...

Do you know how good TacT has been with offering upgrades? Was there an upgrade from the original TCS to the MKII ?

Sleestack said:
I have spent a ton of money buying all sorts of gear to figure out what really matters to me. You already have great speakers. I think you are getting too wrapped up in amplification, as your room is probably affecting your sound more than any amp could. Using a TCS MKII will make you realize that all you need out of your amplification is sufficient power and transparency. Trust me, the Bel Cantos give you that in spades. Add the TCS MKII to your system, and I believe you will have an aural revelation.
I know I'm probably getting "wrapped up". That's simply because I want to be 100% sure that I make the right choice since I plan to keep the amps for many years.

I am not questioning the Bel Cantos, but I am questioning the sound of the analog outputs of the TCS.

To further complicate my choices, I stumbled onto the Lexicon MC12 that now has room correction too, and pretty much any other feature you could dream of. If I decide to go with amps with traditional analog input (e.g. the Bel Canto), this might be just as good a choice as the TCS...

Peter
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
mtrycrafts said:
IWhen a company does what PS Audio or Mapleshade does, more than marketing, they are marketing voodoo products, one has to think hard, do I really need their amps when there are lots of others to pick from? I would.
There are two sides to the stories. PS Audio belongs to those few companies where the CEO himself takes the time to discuss on do-it-yourself electronics forums like diyAudio.com.

One of their truely unique products is the HUMBUSTER, a device that can eliminate the mechanical humming sound of toroidal transformers. In the DIY forum he openly describes how their unit works, and confirms that you can probably build the device yourself for a fraction of what they're charging for the unit ($300 MSRP).

Have a look at this thread

Also, the PS Audio power cables have a unique feature: The ground pin is removable (it unscrews). This is a fantastic feature to have if you experience ground loops. Those that frequently swap around gear must love this feature.

Now, again, I don't believe in the Noise Harvester (I pretty much ignored it), but PS Audio does have products like the Humbuster that does work. Some people think this is a voodoo product too, but it's really not since its function can easily be proven with a little bit of knowledge in electronics. I think it's great that they're offering this since even most of us electronics geeks try to stay away from messing around building stuff that is connected directly to the mains without transformer or other sort of protection. (A lot of precaution needs to be taken since the voltage is lethal and you're dealing with current in the 15/20 ampere range).

Peter
 

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N

Nick250

Audioholic Samurai
Peter Nielsen said:
Also, the PS Audio power cables have a unique feature: The ground pin is removable (it unscrews). This is a fantastic feature to have if you experience ground loops.
Peter
Electronics is not my strong suit, but is this not a fancy cheater plug?

Nick
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
Nick250 said:
Electronics is not my strong suit, but is this not a fancy cheater plug?
Correct, but since it's "built in" to the cord you will avoid one extra connection layer.

Also, those $.99 cheater plugs are possibly a fire hazard if you try to use them with a big amp. Personally I would not use them in a permanent installation...

Peter
 
gene

gene

Audioholics Master Chief
Administrator
Whoa! I just stumbled onto something that is totally new to me. Sunfire apparently makes a new breed of amps that run cool, yet appear NOT to be Class-D amps:

7x400/800W: http://www.sunfire.com/TGA7400.html
2x600/1200W: http://www.sunfire.com/Signature600FrontPR.htm

This looks like a winner! Does anybody here have experience with this technology
Just so you know, those aren't continous ACD ratings. They use a class H type topology which modulates the rail voltage depending on input signal. Its more efficient than traditional linear a/b's and slightly more than Class G. The penalty is however a higher noise floor which can be an issue if you have high efficient speakers and/or sit close to your rear speakers.

Remember, more power is NOT always better!
 
S

Sleestack

Senior Audioholic
Couple of things. First, whoever is telling you that you lose resolution at lower volumes with the TCS has no idea what they are talking about and is probably just stuck on the idea that digital attenuation is a bad thing. The TACT preamps are far more resolving at lower volumes than traditional preamp I have used. The analog outs should not be your concern with the TCS.

Second, I don't know much about the Lexicon system, but keep in mind that not all room correction is created the same and that TACT has been integrating their room correction software/hardware for almost 10 years now. Denon also offeres Audyssey "room correction," but it is a far cry from what the TACT room correction does. Just make sure the Lexicon system incorporates automatic time, level and frequency correction and isn't just auto eq.

As for the upgrade path for the TCS MKII, I really don't have much info. I know it is being developed, but it could be far down the road.

Other than speakers, the 2 most significant pieces of audio equipment I have ever purchased are the TCS MKII and RCS 2.2.XP. I think your setups would benefit tremendously.


Peter Nielsen said:
If I go the Boz route, I will be bi-amping and using the Boz crossovers.

My Maggies are 86dB/1W/1M. Your Andra IIs are 88.5dB/1W/1M. That's only a 2.5 dB difference.

Without bi-amping, you're definitely right that the power probably won't suffice. However, with bi-amping I think I'll be Ok.

I have mixed feelings about the analog outputs of the TCS. The TCS MKII DACs apparently don't incorporate analog volume control. Instead, the volume control is done in the digital domain if the builtin DACs are used. (This is supposedly not a good thing to do since resolution is lost at lower listening levels). This problem of course goes away when the TCS is mated with another TacT digital amp and the output is driven at full level and the volume is controlled by the amp.

Do you know how good TacT has been with offering upgrades? Was there an upgrade from the original TCS to the MKII ?

To further complicate my choices, I stumbled onto the Lexicon MC12 that now has room correction too, and pretty much any other feature you could dream of. If I decide to go with amps with traditional analog input (e.g. the Bel Canto), this might be just as good a choice as the TCS...

Peter
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
Sleestack said:
Couple of things. First, whoever is telling you that you lose resolution at lower volumes with the TCS has no idea what they are talking about and is probably just stuck on the idea that digital attenuation is a bad thing. The TACT preamps are far more resolving at lower volumes than traditional preamp I have used. The analog outs should not be your concern with the TCS.
Hmm... It was Agnes Nizborski at TacT that told me the volume control of the analogue outputs on the TCS is controlled in the digital domain. (Instead of running the DAC at full resolution with volume control in the analogue domain).

Maybe she misunderstood my question. I will send TacT another e-mail about this issue.

Peter
 
S

Sleestack

Senior Audioholic
Peter Nielsen said:
Hmm... It was Agnes Nizborski at TacT that told me the volume control of the analogue outputs on the TCS is controlled in the digital domain. (Instead of running the DAC at full resolution with volume control in the analogue domain).

Maybe she misunderstood my question. I will send TacT another e-mail about this issue.

Peter
It is controlled in the digital domain, but there is no adverse affect on the output.
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
gene said:
The penalty is however a higher noise floor which can be an issue if you have high efficient speakers and/or sit close to your rear speakers.
Thanks Gene. The noise floor should not be a problem since my Maggies are very inefficient, but it sure sounds this may be a major issue with efficient speakers.

Are there any other peculiarities with the Sunfires that I should know of? It's hard to find any info about them. Strangely enough, my Parasound dealer didn't seem to regard them very highly, although he also sells Sunfire. He tells me that the New Classic (entry level) Parasound is better than the Sunfire amps... Maybe I will get burnt by the Sunfire and better stay away? :rolleyes:

Peter
 
Peter Nielsen

Peter Nielsen

Audioholic Intern
Sleestack said:
It is controlled in the digital domain, but there is no adverse affect on the output.
I guess TacT is probably doing the volume control in the 24-bit domain. This should indeed produce excellent results. I'll try to find out if this is the case.

Peter
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
AdrianMills said:
It's a pity no one has performed an ABX test on the ICEPower 1000ASP too... I'd really like to know if this roll off above 2kHz is audible. :confused:
.

I am not familiar with those products, so how much is that roll off? This link shows how audible some roll off is compared to bandwidth:

http://www.provide.net/~djcarlst/abx_crit.htm

A broad bandwidth roll off is more audible than a fraction of an octave.
 
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