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Details on internal settings
The Crossfeed effect is mainly defined by the filter frequency and the amount of crossfeed, here
given as damping factor:
1: 650 Hz, -13.5 dB (just a touch)
2: 650 Hz, -9.5 dB (Jan Meier emulation)
3: 700 Hz, -6 dB (Chu Moy emulation)
4: 700 Hz, -4.5 dB (30° 3 meter emulation)
5: 700 Hz, -3 dB (example how even stronger would sound)
8.8 Nostalgia – the RIAA Mode
Shortly after the release of the original ADI-2 Pro we received requests for digitizing vinyl records.
If you want to archive your old treasures on a hard disk then you should do it with one of the best
AD converters - full agreement! However, a record player cannot be connected directly to the ADI
for technical reasons. The most used MM pickups (Moving Magnet) are designed for an input
impedance of 47 kOhm and 100 pF capacitance. In addition, they deliver a much too low level,
and the signal of the record is provided with a so-called RIAA pre-equalization, thus has hardly
any bass, but a lot of treble. This needs to be compensated. The ADI-2 Pro can't do this, but
external RIAA preamplifiers can, which can be connected in front of the ADI-2 Pro to digitize
records.
Thanks to MM compatibility, the ADI-2/4 Pro SE does not require an external preamplifier any-
more. It has suitable input impedance, RIAA equalization, and the necessary preamplification.
This can be activated in the menu I/O, Analog Input, Settings, RIAA Mode, and you can choose
between different gains. The horizontal level meters in the analyzer show if the selected gain is
sufficient or if the input tends to overload.
The RIAA mode of the ADI-2/4 Pro SE is unusual in that gain and RIAA equalization is done in
the digital domain. We wouldn't have included this at all if this concept didn't actually have some
interesting advantages in both theory and practice. Namely:
very low channel deviation across the gain stages
very accurate RIAA compensation
perfect frequency response
super low distortion
user selectable headroom for high overload immunity
In addition, there are the well-known advantages of the DSP in the ADI: The frequency response
of a cartridge in the high frequency range, which is typically influenced by capacitance changes,
can be corrected much more flexibly and effectively with Band 5 of the Analog Input PEQ. The
PEQ optionally cuts all low-frequency oscillations below 20 Hz. And with the RIAA Mono Bass
Mode, acoustic feedback as well as rumble and groove noise is suppressed most efficiently. For
this purpose, only the bass frequencies below 150 Hz are summed to mono. These frequencies
are mono on vinyl anyway (a limitation of the cutting system). Due to the stereo encoding tech-
nique, however, the acoustic feedback signal is phase-shifted on the left and right channels. Mono
summing cancels out this signal component.
Further notes and information is found in chapter 34.27.
16
User's Guide ADI-2/4 Pro SE - v 1.0
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