i browse around these boards almost everyday and know that many of the members are adamant and very knowledgable about their H/K equipment and was wondering what the exact advantages (if any) are of the DPR line over their AVR product line? are there any advantages or disadvantages overall and what about sound quality? On the H/K website it says that "it uses digital path topology to link your program sources directly to a powerful amplifier without analog interference"(direst quote from H/K website). is this technology that much better than a receiver that handles both analog and digital signals. i guess i do not understand how this receiver is any better than analog receivers. the reason i am wondering about this receiver is that i can pick one up for under $500 and was wondering if it would be worth replacing my onkyo-801. since i have the ever dreaded disease that everyone one on here talks about "upgraditis". thanks in advance for any help or input that anyone might have.

I think the big thing is the use of a digital power amp, which lets the receiver be smaller, lighter, cooler. From what I remember most of a modern receiver is digital anyways... with the possible exception of the volume control

It looks like early in 2006, Axiom will offer their own Digital Power Amplifiers. It looks like digitial is the way the technology is headed for the most part. Lighter, smaller, cooler, and cheaper to manufacture. Does it sound better? I don't know. Hopefully if a company that is passionate about great sound like Axiom is getting into digital amps, they will sound as good or better than existing amps or they wouldn't do it.

Lighter and smaller are probably the main things. I have heard others mention that the digital amps do run warm. I thought I remember Alan mentioning this as well.

Hi Frenche,

I haven't listened to H/K's "digital-path" line, so I just don't know. There are unquestionable advantages to digital amplifiers if the design is done right (a big IF...). First, they are much lighter and smaller and much more efficient than analog power amps. For instance, the Axiom's unique digital amplifier design for the EP500 and EP600 subs (it has an analog power supply, unlike many digital amplifers) has more than 90% efficiency vs. about 50% or less for a conventional ananlog solid-state amplifier. So you can get a lot of power with much less wasted energy in heat, and you don't have to include elaborate heavy heat sinks and cooling fans because digital amplifiers are barely warm, even at very high output.

But, because the switching frequencies of digital amplifiers are very high-frequency, you have to be very careful about preventing a digital amplifier from operating like a small radio transmitter, causing RF interference in nearby equipment.

Digital amplifier technology isn't that new. I recall reviewing a very small, powerful, lightweight car-audio digital amplifier about the size of a hard-cover book, which Infinity introduced back in the 1980s. Even when it was isolated in the trunk of a car, it still produced interference with AM and FM reception in the car's in-dash tuner. But shielding designs have greatly improved since then. Another potential liability, like any digital device, is preventing clipping. A digital amp will clip instantly in very nasty fashion if driven past its output limit. But there are ways of avoiding this.

Another advantage is a digital amplifier's ability to drive very low impedances-- to 1 ohm or less-- with none of the problems of analog amplifiers. Axiom's EP500 and EP600 subwoofer digital power amp handles the very low impedance of its 3-inch dual-voice-coil driver with no problems.

I will be doing some listening tests in upcoming months to a digital amplifier intended for full-range reproduction, so in time I shall report.

Regards,

Gee, I wonder who the manufacturer of said amplifier is...

kcarlile:

How clever of you, ha, ha (I really must learn how to do those smiley faces. . .).

Regards,

Distortion on Harman Kardon DPR 1005



Distortion on Denon 3805



Distortion on Harman Kardon 630



There are probably other factors involved that could make a digitally amped receiver superior to an analog one, yet the biggest one touted is lower distortion since everything is kept digital. However, the digital amps seem to have much more distortion.

Also, check these measurements that compare some flying mole amp to a bryston 4st.

From this I'd gather that digital amps are far less pure to the signal than solid state amps now. Perhaps because they are a very new technology. Yet not something I'd want to use just yet.