The Truth About Digital (Class D) Amplifiers

[Peter Nielsen]

I eagerly await all new TACT products... but yes, I did know about the TCS MKIII. Im not sure how SACD and DVD-A is going to be run digital all the way unless Denon iLink is also incorporated.

It will be possibile as soon as Denon or some other manufacturer releases a player that outputs the SACD bitstream over HDMI. The HDMI v1.2a standard supports SACD (v1.1 is sufficient for DVD-A). One manufacturer (was it Samsung?) was supposed to release a player with HDMI v1.2 support in August, but the US release was cancelled. However, I'm sure Denon will have one sooner or later...

Nevertheless, make use of your ADC6 for now, b/c listening to 5.1 audio through that setup is already amazing.

Didn't get an ADC6, since I don't have a need to do SACD yet. (I'm still using an old Sony 7700 DVD). Instead, I negotiated a deal that allows me to trade in the TCS Mk II towards the Mk III when released. (I only pay the difference in price, if any). Once I get the TCS Mk III, I will upgrade my DVD to a HDMI v1.2 capable player (most likely a Denon 39xx series player, provided that they make a HDMI v1.2 model) .

Thanks for letting me know about the mistakes you made. As you say, reading the manual will probably help you avoid them. I already knew about those pitfalls (especially the amp setting which definitely may destroy things if set incorrectly). Being careful with the gain is of course something that applies to all processors that have automatic calibration...

Peter

 

[Sleestack]

You are a more patient man than me. I'm not sure that could sit around waiting for SACD and DVD-A over HDMI. The ADC6 will give you all the sound quality and channel management you want without the wait. With the speaker setup you have now and the addition of the TCS/BOZ setup, I think an investment in a soild SACD/DVD-A source and the marginal cost of the ADC6 would be well worth it, but the again, I do have a significant collection of multichannel material.

I am anxious to see what BOZ implements in the TCS MKIII. I think he'll have to wait a bit longer to implement high-rez audio over HDMI and fully implement dynamic room correction for multi-channel. Dynamic room correction and the more advanced DSP has been a great upgrade in the 2.2 series and will certainly require a whole new board on the TCS series.

One thing to keep in mind during setup.... while you can use the auto calibration, you get better results when you fix the mic. gain and impulse response level manually. Figuring out the appropriate values can require some testing, but it is well worth the trouble. Also remember that you will be drawing your own target curves, so it is important to understand what you are seeing in the programming screen.

Do separate measurements for your 2 channel and multi-channel setups. You can store a total of 9setups, so dedicating a few to 2 channel should be no problem. Multi-channel benefits from pointing the mic straight up and 2 channel from pinting the mic straight at the front speakers. Also, because the TCS does not have the "dynamic" (i.e fletcher-munson based corrections) part of room correction, I would use 2 setups per curve, with one for low volume and the other for normal volume listening.

It will be possibile as soon as Denon or some other manufacturer releases a player that outputs the SACD bitstream over HDMI. The HDMI v1.2a standard supports SACD (v1.1 is sufficient for DVD-A). One manufacturer (was it Samsung?) was supposed to release a player with HDMI v1.2 support in August, but the US release was cancelled. However, I'm sure Denon will have one sooner or later...

Didn't get an ADC6, since I don't have a need to do SACD yet. (I'm still using an old Sony 7700 DVD). Instead, I negotiated a deal that allows me to trade in the TCS Mk II towards the Mk III when released. (I only pay the difference in price, if any). Once I get the TCS Mk III, I will upgrade my DVD to a HDMI v1.2 capable player (most likely a Denon 39xx series player, provided that they make a HDMI v1.2 model) .

Thanks for letting me know about the mistakes you made. As you say, reading the manual will probably help you avoid them. I already knew about those pitfalls (especially the amp setting which definitely may destroy things if set incorrectly). Being careful with the gain is of course something that applies to all processors that have automatic calibration...

Peter

 

[Peter Nielsen]

Well, a brief follow-up:

I got my TCS, Boz 216, and five Boz 2200s a month ago.

2 of the 2200s are functionally bad
2 of the 2200s are cosmetically bad
1 of the 2200s is in good conditon.

I got one of the 2200s replaced. Three are still bad. I'm struggling with TacT's slow service...

Peter

 

[AdrianMills]

If it really is load sensitive, that would mean it has a high output impedance. I have no idea if it does or doesn't. If it doesn't but is similar to SS amps output impedance, then it cannot be load sensitive. If it has a high impedance, then it will follow the speaker's FR response and most likely be audible, but that would depend on the speakers FR as most would be.

This is going back a bit but I thought I should report back on these B&O ASP modules.

Today I spent 6 hours or so wandering around a HiFi exhibition here in Norway (http://www.hifimessen.no/) and Midgard Audio (http://www.midgardaudio.no/) were installed in a relatively large room. They were driving some home grown 3-way speakers with a pair of ASP1000 monoblocks. The speakers sounded impressive (even if the finish wasn't what you'd expect from a commercial model - which of course they weren't) - I think they were 6 or 8 ohm nominal with a min impedance of 3ohm but according to the guy that built them there were some fairly large swings. Sensitivity was a pitiful 82dB!

I honestly couldn't hear anything wrong with these amps drivng these speakers - any high freq rolloff was inaudible as far as I’m concerned. The amps could drive these insensitive speakers to levels that I found painful - I was impressed.

One thing I was told was that B&O will probably be increasing the price of the ASP modules and it's possible that small scale amp builders that use the modules may have to increase their price by up to 80% when this happens.

I hope the prices stay as low as they currently are for a few more months yet as my finances are pretty tied up until after xmas!

 

[Sleestack]

Well, a brief follow-up:

I got my TCS, Boz 216, and five Boz 2200s a month ago.

2 of the 2200s are functionally bad
2 of the 2200s are cosmetically bad
1 of the 2200s is in good conditon.

I got one of the 2200s replaced. Three are still bad. I'm struggling with TacT's slow service...

Peter

Who is your dealer? My problems always get resolved within days.

 

[Sleestack]

This is going back a bit but I thought I should report back on these B&O ASP modules.

Today I spent 6 hours or so wandering around a HiFi exhibition here in Norway (http://www.hifimessen.no/) and Midgard Audio (http://www.midgardaudio.no/) were installed in a relatively large room. They were driving some home grown 3-way speakers with a pair of ASP1000 monoblocks. The speakers sounded impressive (even if the finish wasn't what you'd expect from a commercial model - which of course they weren't) - I think they were 6 or 8 ohm nominal with a min impedance of 3ohm but according to the guy that built them there were some fairly large swings. Sensitivity was a pitiful 82dB!

I honestly couldn't hear anything wrong with these amps drivng these speakers - any high freq rolloff was inaudible as far as I’m concerned. The amps could drive these insensitive speakers to levels that I found painful - I was impressed.

One thing I was told was that B&O will probably be increasing the price of the ASP modules and it's possible that small scale amp builders that use the modules may have to increase their price by up to 80% when this happens.

I hope the prices stay as low as they currently are for a few more months yet as my finances are pretty tied up until after xmas!

I have been using the Icepower in the Bel Cantos in my system for months now and can't really think of a reason why I would ever replace them.

 

[AdrianMills]

I asked the guy that made the Midgard Oberon 6.1 amps if he had ordered them with mods or if he'd tweaked anything before/after the modules and he said no, the only thing they'd done is mount the modules upside down in their latest amps - which apparently "softened" the sound a little compared to the first amps they made because the new ones ran warmer. I asked if this was because it introduced some distortion or...? And I was told no, it was because it was warm and he started on about amps sounding better when warm - I think he even used a car engine analogy.

Okay, I'll admit I almost laughed at that.

But what the heck, they are nice amps and fairly cheap too for now.

 

[silversurfer]

Adrian,

Thanks for your thoughts on the ICEpower based amp and the possible price increase.

Did you happen to get any info on new or improved modules?

 

[AdrianMills]

Adrian,

Thanks for your thoughts on the ICEpower based amp and the possible price increase.

Did you happen to get any info on new or improved modules?

The guy that built these (I really should have got his name) was interested in selling so I don't think he would have volunteered any info on improved modules even if they were just around the corner.

He did seem to think that B&O were deliberately trying to make it difficult for the small amp outfits though - I'm not entirely sure how B&O would benefit from pricing the small guys out of business but that's what he said.

So I guess you haven’t bought a couple of Beasts from Denmark yet?

 

[silversurfer]

The guy that built these (I really should have got his name) was interested in selling so I don't think he would have volunteered any info on improved modules even if they were just around the corner.

He did seem to think that B&O were deliberately trying to make it difficult for the small amp outfits though - I'm not entirely sure how B&O would benefit from pricing the small guys out of business but that's what he said.

So I guess you haven’t bought a couple of Beasts from Denmark yet?

Thanks Adrian.

I have not bought the Beasts yet. I have a friend travelling to Denmark early next year, so I am wondering if it might be less expensive and safer to have him pick the amps up for me.

I did find someone on AVS that bought a two-channel 1000asp based Beast. He is quite happy with it, but did have some shipping damage. For his trouble, he has been offered a nice discount on another purchase.

 

[ar-t]

He did seem to think that B&O were deliberately trying to make it difficult for the small amp outfits though - I'm not entirely sure how B&O would benefit from pricing the small guys out of business but that's what he said.

I do not think it is fair to say that they deliberately make it hard for small outfits. Their way of doing business, is.....well.......a bit different. No one that I know is wild about their way of donig business. It just happens to be a style that makes it harder for smaller firms.

I don't think they will miss any meals if all of us smaller outfits stopped buying from them. The modules were designed as a commercial product, to be sold in large OEM quantities. While they would never admit it publicly, some of the foibles of their modules are explained by that. They rushed to shove them into production, as fast as they could, as inexpensively as they could. Their genesis of was industrial motor control, and with some tweaking, they turned out to be a decent amp module.

Bottom line is, if they had started out in the beginning to make a really great amp module, I have good reason to believe that some things would have been done differently.

Pat

 

[AdrianMills]

Bottom line is, if they had started out in the beginning to make a really great amp module, I have good reason to believe that some things would have been done differently.

Pat

Maybe they aren't as good as they could be (what is?) but in that demo room they drove those bespoke speakers extremely well indeed. During that day in the expo I listened to numerous setups some costing well in excess of 100,000 US$ and not many impressed me as much; after the show a friend an I compared notes and came to similar conclusions about the speakers being demoed there - the Midgard Audio room was in the top half dozen for both of us along with some Martin Logan Summits and Focal JMlab Electra 1007 Be and some others I can't remember the name of now. Admittedly the Midgard speakers cost almost 6,000 US$ to build or so I was told and of course there are other factors involved here such as different rooms and set up issues etc but still, I doubt that anyone would complain if they could get their home system sounding as good.

 

[ar-t]

In case anyone wants to know.......

We are now at "dot net", instead of "dot com". Long story.......don't ask.

Working on some new stuff. In between the horror of changing domain names.

Pat