Originally Posted by dahlgren
On the 8801 spec sheet it lists:
Hybrid PLL jitter reducer for accurate audio clock
M-DAX (Marantz Dynamic Audio eXpander)
Is this the Marantz equivalent to Denon Link and AL32?
No. A PLL (Phase-Look Loop) is an electronic circuit that can have various applications in electronics. It's often used for signal synchronization and clocking purposes. While this Hybrid PPL circuit it is located inside the Altera MAX V CPLD chip for both the Denon 4520 and the Marantz 8801 and inside the Altera FPGA for the Denon AVP-A1HDCI processor (See the AVP-A1HDCI audio block diagram on figure 2 of my AL32 post
), in this case it's used to reduce jitter, which is a time deviation error in the transmission of bits and can have various negative effects on sound when fairly high, one of the most notable being a reduced sense of localization of discrete sounds. As JimP, joerod and I were reporting yesterday and other have remarked before, we've observed a more accurate localization and focus of instruments and sounds over the soundstage as well as the improved intelligibility of dialog and vocals. This can probably be attributed in part to the reduction of jitter provided by the hybrid PLL circuit.
This is how Denon explains the hybrid PLL in that 13-page brochure I mentioned on my AL32 post: "In addition by regenerating the master clock with a high-accuracy phase-locked loop (PLL) near the D/A converter, residual jitter is minimized, enabling playback of high-quality sound with clear sound images and contours."
The AV8801 owner's manual mentions the following about the hybrid PLL on page 2:
"Equipped with “Hybrid PLL Jitter Reducer” capable of reducing jitter and phase noise that negatively affect sound quality
“Hybrid PLL Jitter Reducer” provided with this unit improves the sound localization, reproducing a natural sound field."
The Denon Link is Denon's trademark name for what other audio gear manufacturers call a "master clock" or "word clock input". Some Marantz Reference CD/SACD and higher-end universal players have been equipped with a word clock input. This mechanism allows the Denon AVRs equipped with this feature, the 4520 for instance, to send a reference clock signal to a Denon Link equipped player through the Denon Link RCA jack and cable to synchronize the transmission of data and almost completely eliminate jitter. This represents a fairly high step above the aforementioned hybrid PLL approach. The Denon Link master clock is most likely located inside the Altera CPLD on the 4520 since this chip provides the general master clock duties. The 8801 quite possibly has the circuit inside it's Altera CPLD but since it lacks the Denon Link RCA jack and it doesn't have the option on the firmware to allow activation through the menu, we're out of luck on this one.
The M-DAX (Marantz Dynamic Audio eXpander) is not AL32. It's intended to partially reverse the negative effects of compression on lossy audio codecs such as MP3. I haven't tested this feature yet as I don't really listen to MP3s but I eventually will out of curiosity and to evaluate how successful it is at the task it's intended to address. The Denon 4520 has the same feature but it's called the "Restorer". Sounds like something Arnold Schwarzenegger could be advertising.
Again more brand differentiation. I actually like the name of the feature on the Marantz better.
M-DAX description on page 122 of the AV8801 owner's manual :
"Compressed audio formats such as MP3, WMA (Windows Media Audio) and MPEG-4 AAC reduce the
amount of data by eliminating signal components that are hard for the human ear to hear. The M-DAX
function generates the signals eliminated upon compression, restoring the sound to conditions near those
of the original sound before compression. It also corrects the sense of volume of the bass to obtain richer
sound with compressed audio signals."