[jhm731]

A few quick notes, then back to a schematic I'm working on...

The amp jhm731 shows is open loop.  Two of my patents are on open loop (groundbreaking at the time, 1999), and my design for that (processing done originally in an FPGA) eventually became the property of ST Microsystems.  Open loop is just not capable of the kind of performance we are talking about with the DAC4800A and Cherry amps.  Open loop is OK for 100W and lower A/V Receiver type products, but not a 1000W+ high end amp.

Regarding NuForce, I heard it's actually a decent amp, but the specs aren't as good as DAC4800A or Cherry.  Nuforce's ref9-v2 (their top of the line unit?) puts out less than half the output power of DAC4800A, higher THD+N (0.03% versus our <0.009%), and much lower SNR (by more than 12 db!).  Plus, you have the same old thing about paying for trade shows and advertising.

Regarding price, although the list price for the DAC4800A is $3600 and the Cherry is $6000, we frequently discount them to our newsletter subscribers (nearly half price), and we also offer a demo unit here and there.  The price on Amazon for the DAC4800A refurb unit is $2799, and that's upgraded to new modules and fully tested!  Very clean.  Very nice.

Our amps are built with OUR OWN TECHNOLOGY, not some off-the-shelf chip set or module.  We build in the USA as well in case that matters to you.

More later...

The amp in the picture is rated at 150watts at 8ohms and 300watts at 4ohms, other versions from this manufacture have higher ratings.

From pictures of your amps, I see nothing in parts or build quality to justify your asking or half off pricing.

[bummrush]

what a waste of time

[cab]

Are you familiar with the UCD design from Bruno Putskey (my apologies in advance for mis-spelling Bruno's name)???? I understand it is a simple, elegant solution with excellent specs and exceptional sound....

[AmpDesigner333]

what a waste of time

Why do you say this?  A comment like that is better left unsaid.  Being negative like that can only do you harm.

[AmpDesigner333]

Are you familiar with the UCD design from Bruno Putskey (my apologies in advance for mis-spelling Bruno's name)???? I understand it is a simple, elegant solution with excellent specs and exceptional sound....

Yes, I've known Bruno since 2001 or so (he worked for Philips then).  We corresponded often, and I think he's pretty much a genius!

DAC's design differs in several ways, most notably the feedback design.  He now sells modules to DIY individuals and companies.  I did hear that his designs sound great, but I'm not too familiar with his work over the last year or so.  I liked his direct digital stuff better than the analog stuff.  He had a really neat design for medium power way back, but it was pretty expensive.  There was an AES paper on it years ago.  We're both AES members.

I'll write him and ask him to check this topic...  Thanks for your kind post.

[AmpDesigner333]

The amp in the picture is rated at 150watts at 8ohms and 300watts at 4ohms, other versions from this manufacture have higher ratings.

From pictures of you amps, I see nothing in parts or build quality to justify your asking or half off pricing.

jhm731,

Our customers TOTALLY disagree with you, and they put their hard earned money on it!

You can't tell from the picture that the DAC4800A has 6 boards in it, stuffed with premium (expensive) components.  Wire, connectors, transformer, all premium parts, and some costly custom stuff as well.  We believe in quality-in, quality-out.  The chassis is 16 gauge steel.  The Cherry has a faceplate that costs more to make than many complete high end amps!

You can't judge sound quality from a picture, but you can compare measurements, and that's what I did.  Plus, we receive LOTS of compliments on the build quality of the DAC4800A and Cherry.  People have said "like a tank", "super sturdy", and similar accolades.  Thanks for your post.

Regards,
AmpDesigner333
www.DigitalAmp.com

[AmpDesigner333]

Please post a picture of the inside of your product, so we can see that it's more than just another repackaged Ice amp.

Based on what I see on your website, if I wanted a high power Class D amp, I'd pay the extra $1200. to get a Spectron MIII Signature MK.2.

The Spectron unit has pretty respectable specs, but THD is about 5x the DAC amps.  Also, I concluded that the outputs are bridged (the "black" binding post is not GND), so the two channels can't be bridged.  This means twice the output filter components --- the audio goes through more before getting to the speaker.  FYI, a DAC4800A can be bridged for 1000W into 8 ohms (killer amp for a passive sub).

I consulted for Harris Semiconductor back in the mid 90s.  They went back to being Intersil shortly after that.  At the time they were marketing their MOSFET drivers to Class-D amplifier makers.  Spectron came out with a 500W x 2 amp a few years later (correct me on the time line if I'm wrong).  It used the old fashioned triangle wave and comparator type modulation.  Based on the text that Spectron has on their site, it looks like they still use this technique.  We built amps like that in the 1980s and early 1990s (before DAC was officially founded) but abandoned the technique for more advanced methods.  I'm not saying that the old way can't be done well, however, and the specs prove that it can.

The same comment I had earlier about paying for trade shows and advertising applies to any mass market amp.  We prefer not to call our products "mass market" --- they are specialty products.

[jhm731]

Please post a picture of the inside of your product, so we can see that it's more than just another repackaged Ice amp.

Based on what I see on your website, if I wanted a high power Class D amp, I'd pay the extra $1200. to get a Spectron MIII Signature MK.2.

The Spectron unit has pretty respectable specs, but THD is about 5x the DAC amps.  Also, I concluded that the outputs are bridged (the "black" binding post is not GND), so the two channels can't be bridged.  This means twice the output filter components --- the audio goes through more before getting to the speaker.  FYI, a DAC4800A can be bridged for 1000W into 8 ohms (killer amp for a passive sub).

I consulted for Harris Semiconductor back in the mid 90s.  They went back to being Intersil shortly after that.  At the time they were marketing their MOSFET drivers to Class-D amplifier makers.  Spectron came out with a 500W x 2 amp a few years later (correct me on the time line if I'm wrong).  It used the old fashioned triangle wave and comparator type modulation.  Based on the text that Spectron has on their site, it looks like they still use this technique.  We built amps like that in the 1980s and early 1990s (before DAC was officially founded) but abandoned the technique for more advanced methods.  I'm not saying that the old way can't be done well, however, and the specs prove that it can.

The same comment I had earlier about paying for trade shows and advertising applies to any mass market amp.  We prefer not to call our products "mass market" --- they are specialty products.

You can't judge sound quality from measurements or specs either.

If you think your amps can outperform the Spectron MIII Signature MK.2, I can put you in touch with a reviewer that has Spectron MIII Signature MK.2 monos(http://www.spectronaudio.com/monoblocks.htm) and stereo amps.

Good luck for your products.

[bummrush]

Because i've listened to quite a few and despite all the hype that went with them,was quite disappointing,thats all.

[pbrstreetgang]

http://www.iceh2oaudio.com/index_htm.html

Here is a pic of a 2K H20 100x2 based on a modified B&O module. I would like to hear yours of course but ones with huge PS and dual transformers are hard to pass up. Also I raised a brow a bit on the suggestion of a 6K amp on a sub 

[AmpDesigner333]

Because i've listened to quite a few and despite all the hype that went with them,was quite disappointing,thats all.

Sorry, I was a little strong in my tone.  Here's something I wrote recently to an audio magazine...

We have relied on word of mouth (or word-of-web) to spread the news of our products.  Many of our competitors are well established companies that have come out with similar products (functionally) despite a serious lack of design experience in this very difficult field.  I have been designing digital amps (and some analog ones too) for 20 years, and believe me when I say that there is no substitute for experience.  However, these competitors put the bulk of their sales revenue into elaborate marketing campaigns, not into their hardware or technology development.  As a result, there are a bunch of underwhelming digital amps on the market, giving a bad name to an amplifier technology that can yield the ultimate in audio when done just right.  We put the cash into our products and treat our customers like gold, but the crowded market sometimes buries us in the noise.


Thanks very much for your kind reply.

[2bigears]

 these digie amps sure are comin' at us from all sides now....they say it's in the name of dynamics which is also headroom, or stand-by power....3500w for 0.5 second ready for music peaks.would a conventional amp with 600 or 1kw wpc also do this ??

[AmpDesigner333]

http://www.iceh2oaudio.com/index_htm.html

Here is a pic of a 2K H20 100x2 based on a modified B&O module. I would like to hear yours of course but ones with huge PS and dual transformers are hard to pass up. Also I raised a brow a bit on the suggestion of a 6K amp on a sub 

The DAC4800A is $3600 list and there's one on Ebay for $1499!
The Cherry is $6000 list, but no web deals on that just yet.  If you're interested, write to dacsales@DigitalAmp.com and maybe you can get an "early adopter" special.  Subscribers of the private DAC newsletter get a few deals, too.

I did listening tests and measurements on a PS Audio amp based on "customized" B&O modules, and the DAC4800A blew it away in every respect.  Hands down.  Thanks.

[AmpDesigner333]

 these digie amps sure are comin' at us from all sides now....they say it's in the name of dynamics which is also headroom, or stand-by power....3500w for 0.5 second ready for music peaks.would a conventional amp with 600 or 1kw wpc also do this ??

Our amps are not "typical" Class-D due to a large body of work in the field over decades.

The low level detail is actually what customers rave about the most.  Sure, having lots of power doesn't hurt, but the DAC4800A and especially Cherry use a patented modulation technique that allows minimal feedback, high speed, and extremely linear response through the critical crossover (positive to negative output current transition) region.  THD is below 0.01% down to milliwatts and up to hundreds of watts.  These specs are superior, but the sound is the "proof in the pudding".

Thank you for your great post!

[tvyankee]

hello

you seem like a guy who knows what he is talking about and seem to be very much a part of this crazy hobby.  if i were you and don't take this the wrong way but i would re-think your price structure. if your and early bird and you can find it on amazon referb and stuff like this people here are not going to take you seriously.  come up with a price that works for you and stick with it.  any other way makes it seem like your not sure of yourself.

[lonewolfny42]

AmpDesigner333 ....

.....and there's one on Ebay for $1499...

Link....

[art]

Sorry, I was a little strong in my tone.  Here's something I wrote recently to an audio magazine...

We have relied on word of mouth (or word-of-web) to spread the news of our products.  Many of our competitors are well established companies that have come out with similar products (functionally) despite a serious lack of design experience in this very difficult field.  I have been designing digital amps (and some analog ones too) for 20 years, and believe me when I say that there is no substitute for experience.  However, these competitors put the bulk of their sales revenue into elaborate marketing campaigns, not into their hardware or technology development.  As a result, there are a bunch of underwhelming digital amps on the market, giving a bad name to an amplifier technology that can yield the ultimate in audio when done just right.  We put the cash into our products and treat our customers like gold, but the crowded market sometimes buries us in the noise.


Thanks very much for your kind reply.

If you have been designing amps for that long (and I have no reason to think otherwise), then you should accurately state that they are Class D and not digital. They are, in fact, analog. Ask our mutual friend Bruno if you don't believe me.

BTW......we don't go to trade shows either. Might be all that we agree on. I have worked on amps without feedback after the filter that have peaking problems. I prefer amps with feedback after the filter. (Ask Bruno why!)

Best wishes on your product line.

Pat

[AmpDesigner333]

Sorry, I was a little strong in my tone.  Here's something I wrote recently to an audio magazine...

We have relied on word of mouth (or word-of-web) to spread the news of our products.  Many of our competitors are well established companies that have come out with similar products (functionally) despite a serious lack of design experience in this very difficult field.  I have been designing digital amps (and some analog ones too) for 20 years, and believe me when I say that there is no substitute for experience.  However, these competitors put the bulk of their sales revenue into elaborate marketing campaigns, not into their hardware or technology development.  As a result, there are a bunch of underwhelming digital amps on the market, giving a bad name to an amplifier technology that can yield the ultimate in audio when done just right.  We put the cash into our products and treat our customers like gold, but the crowded market sometimes buries us in the noise.


Thanks very much for your kind reply.

If you have been designing amps for that long (and I have no reason to think otherwise), then you should accurately state that they are Class D and not digital. They are, in fact, analog. Ask our mutual friend Bruno if you don't believe me.

BTW......we don't go to trade shows either. Might be all that we agree on. I have worked on amps without feedback after the filter that have peaking problems. I prefer amps with feedback after the filter. (Ask Bruno why!)

Best wishes on your product line.

Pat

Haven't heard back from Bruno yet, but I did email him today...

I have designed many open loop "true digital amps".  This is why I had to learn VHDL in the 90s.  At one point, I designed cell phone ASICs, so learning VHDL came in handy!  I'm actually a "Computer and Electrical Engineer", officially.

Yes, I agree that analog input switching amps sound best (for now).  I'm working on a new approach to fix that!

Here's something I wrote with a little background on amp technology in general.  It explains misuse of the term "digital amp":

Audio amplifiers are used in a variety of products from MP3 players to concert sound systems. Historically, these amplifiers are based on an inefficient circuit topology known as Class-AB, which wastes nearly half the power it consumes as heat. During the last decade, an alternate approach to amplifier circuit design, Class-D, has enjoyed steadily increasing commercial success. The reasons for the shift to Class-D are simple, near 100% power efficiency and the availability of power devices capably of satisfying the speed and current carrying requirements of Class-D amplification. However, Class-D amplifiers, also known as “digital amplifiers”, are difficult to design for low noise and low distortion. Very few Class-D amplifiers on the market are considered to have good enough audio performance to be referred to as “high end”. There are other topologies popular in the high end audio market, such as tube based and Class-A (even more inefficient than Class-AB). The subject of amplifier topology and design is rather involved, so it is only touched upon here to provide a background to those not seasoned in the field.

An amplifier that uses its output devices as switches is a Class-D amplifier. Therefore, a “switching amplifier” is a Class-D amplifier. The term “digital amplifier” is actually a misnomer, but has undeniable traction in the industry. There are other ongoing nomenclature debates regarding “digital amplifiers”. Some industry players wish to differentiate digital input Class-D amplifiers from analog input Class-D amplifiers by calling digital input Class-D amplifiers “true digital amplifiers”. Several companies have also introduced amplifier products (mostly chip level) with fictitious class designations such as “Class-Z”. This is a marketing tactic only and looked down upon by industry professionals in recent years.

You may wonder why we called our company "Digital Amplifier Company"...  Well, at the time, we were selling only open loop amps which were truly digital up to the output stage.  Actually, we did analog input, then digital input, then analog input.  Now we are working on a combo that can do both!

Thanks for your kind post!

[denjo]

Dennis,
Do you have an audio company or a company of some other type?  Sounds like you know a little about business...

Best Regards,
AmpDesigner333 / www.DigitalAmp.com

AmpDesigner 333

No, I am not in business but just thinking out loud, coupled with some bad experiences I have had with audio manufacturers in the 15 odd years that I have been in this hobby.

I think you will find that with a company or product name that incorporates the acronym "DAC", some might be misled to think that you were offering a Digital Analogue Converter or an amplifier with DAC within. At least that was my initial impression before I visited your website. Just a thought!

Best Regards
Dennis

[THE_ANSWERS]

hello

you seem like a guy who knows what he is talking about and seem to be very much a part of this crazy hobby.  if i were you and don't take this the wrong way but i would re-think your price structure. if your and early bird and you can find it on amazon referb and stuff like this people here are not going to take you seriously.  come up with a price that works for you and stick with it.  any other way makes it seem like your not sure of yourself.

I agree . what is the   r e a l   price?  do you get sized up ?  my buddy told me his was 1500 but why is it 3600 on the web site and 2700 (?) on amazon and what the hell is it doing on amazon .  nobody buys serious gear there!!!!!!     why not audiogon



still the product is good like I said before.    just being devils advocate