RME ADI-2 DAC is a popular DAC among many HiFi interested. I do not know if the following has been noticed elsewhere in the forum, but I have searched but not found anything.
RME has replaced the DAC chip in ADI-2 with a chip from ESS. This, of course, as a result of the fire that affected AKM. Here is information. I have copied the following information from RMS's forum. As usual, RME's information and communication with users is top notch.
"At the end of 2020 a fire destroyed AKM's production facilities for AD and DA converter chips. A resumption of production and thus availability of these components is not expected before 2022. Therefore, many manufacturers - like RME - are forced to either discontinue products based on AKM chips, or to use other chips for the foreseeable future.
The ADI-2 DAC was initially based on an AK4490, later on the AK4493. The current unit uses an ES9028Q2M for its high-quality DA conversion. This chip is very similar to the AK4493 in features and technical specifications, which allows RME to continue offering the ADI-2 DAC in its well-known supreme quality, and with a nearly identical feature set.
Even though this chip is a central (sometimes sole) quality determining element, the ADI-2 DAC is just not a normal DAC. Tech specs and features are based on RME technologies, and they are available unchanged also with the ESS chip:
- Complete DSP functionality (PEQ, Bass/Treble, Loudness etc.).
- All sample rates, PCM as well as DSD
- All digital formats (SPDIF/AES/ADAT)
- Analog input and output circuitry, including Auto Ref and 2.5 dB digital headroom
- Extreme Power headphone output stage
- SteadyClock FS, including the latest 1 Hz filter technology
- Lightning fast sample rate change on playback
- Remote, display, general behavior, operation and handling....
ADI-2 DACs with AK4493 and ES9028Q2M are neither sonically nor visually easily distinguishable. However, the ESS version is recognized by a small C at the end of the serial number sticker (B stood for AKM 4493). Furthermore, the units differ in the available filters. The unit with AKM has a filter called Short Delay Low Dispersion, while the one with ESS has a filter called Brickwall (the other filters, SD Sharp, SD Slow, Sharp, Slow, NOS, are identical). Further Chip dependent differences are mentioned in this manual.
------------------
Regarding Tech Specs: forget the data sheet tech specs. AKM and ESS both have their pros and cons, a simple THD+N comparison won't do it. Additionally we needed to reserve 2.5 dB headroom as that feature of the 4493 DAC should be there as well, and - even more important - the ESS chips do not handle intersample overs as gracefully as AKM chips do. So that headroom is a must - and naturally already steals 2.5 dB of SNR and THD+N.
Reading the manual you might notice the new Loopback feature (mainly for Mac DIGICheck to show playback data) - it will come to all DAC and Pro, don't worry.
And yes, we added all missing filters ourselves by loading them into the ESS chip in real-time."
RME has replaced the DAC chip in ADI-2 with a chip from ESS. This, of course, as a result of the fire that affected AKM. Here is information. I have copied the following information from RMS's forum. As usual, RME's information and communication with users is top notch.
"At the end of 2020 a fire destroyed AKM's production facilities for AD and DA converter chips. A resumption of production and thus availability of these components is not expected before 2022. Therefore, many manufacturers - like RME - are forced to either discontinue products based on AKM chips, or to use other chips for the foreseeable future.
The ADI-2 DAC was initially based on an AK4490, later on the AK4493. The current unit uses an ES9028Q2M for its high-quality DA conversion. This chip is very similar to the AK4493 in features and technical specifications, which allows RME to continue offering the ADI-2 DAC in its well-known supreme quality, and with a nearly identical feature set.
Even though this chip is a central (sometimes sole) quality determining element, the ADI-2 DAC is just not a normal DAC. Tech specs and features are based on RME technologies, and they are available unchanged also with the ESS chip:
- Complete DSP functionality (PEQ, Bass/Treble, Loudness etc.).
- All sample rates, PCM as well as DSD
- All digital formats (SPDIF/AES/ADAT)
- Analog input and output circuitry, including Auto Ref and 2.5 dB digital headroom
- Extreme Power headphone output stage
- SteadyClock FS, including the latest 1 Hz filter technology
- Lightning fast sample rate change on playback
- Remote, display, general behavior, operation and handling....
ADI-2 DACs with AK4493 and ES9028Q2M are neither sonically nor visually easily distinguishable. However, the ESS version is recognized by a small C at the end of the serial number sticker (B stood for AKM 4493). Furthermore, the units differ in the available filters. The unit with AKM has a filter called Short Delay Low Dispersion, while the one with ESS has a filter called Brickwall (the other filters, SD Sharp, SD Slow, Sharp, Slow, NOS, are identical). Further Chip dependent differences are mentioned in this manual.
------------------
Regarding Tech Specs: forget the data sheet tech specs. AKM and ESS both have their pros and cons, a simple THD+N comparison won't do it. Additionally we needed to reserve 2.5 dB headroom as that feature of the 4493 DAC should be there as well, and - even more important - the ESS chips do not handle intersample overs as gracefully as AKM chips do. So that headroom is a must - and naturally already steals 2.5 dB of SNR and THD+N.
Reading the manual you might notice the new Loopback feature (mainly for Mac DIGICheck to show playback data) - it will come to all DAC and Pro, don't worry.
And yes, we added all missing filters ourselves by loading them into the ESS chip in real-time."