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.
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!