ADI-2 DAC FS
Extreme Power
6.35 mm TRS
High power. Lowest noise. Ultra precise.
Advanced IEM
3.5 mm mini-TRS
Record low noise. Ultra precise.
Maximum output level is -0.5 dBu (with Volume set to +2.5 dB), equalling 0.73 Vrms. The noise floor at extremely low -124 dBu(A) stays inaudible even with the most sensitive In-Ears. At full output level and loaded with16 Ohms, distortion is lower than -110 dB or 0.00039 %.
The rear RCA and XLR outputs and the front outputs Phones and IEM are fed from the same DAC, hence carry the same signal. They all have individual driver stages with different output levels.
All outputs feature mute components to suppress power on/off noise, even when power fails in-stead of switching the unit off via its standby button.
SNR and THD values as well as frequency response are nearly identical on all analog outputs(!).
Worldwide unique ear and headphones protection features
Both phone outputs provide a unique over-current detection, DC protection and plug detection. The integrated DSP delivers auto assigning volume and once you plug your phones in, a slow volume ramp up (!) to protect your ears and phones!
On top of it: the DAC warns you automatically, when an overload and potential harmful noise or volume is detected. Your ears are perfectly safe!
Worldwide unique ear and headphones protection features
Both phone outputs provide a unique over-current detection, DC protection and plug detection. The integrated DSP delivers auto assigning volume and once you plug your phones in, a slow volume ramp up (!) to protect your ears and phones!
On top of it: the DAC warns you automatically, when an overload and potential harmful noise or volume is detected. Your ears are perfectly safe!
Headphone Magic
During the development of the ADI-2 Pro an extensive research on today’s headphone amp technology as well as headphones has been carried out. Many (many!) headphones later a maximum output level of +22 dBu (10 Volt) was set as development goal, as it will drive even insensitive headphones sufficiently, while a maximum output current of around 260 mA per channel will result in lots of power for lower impedance phones (1.5 Watts @ 32 Ohm).
Limiting the current makes a lot of sense. It is needed to control the internal power supply, to not fully overdrive (and destroy) weaker headphones, and prevents malfunction at short-circuit state. The Extreme Power output stage acts like a small power amplifier, so it got a similar feature set: a relay that mutes and interrupts the connection to the phones, a DC sensing circuit to prevent DC at the output (DC destroys your precious phones already when the rated watts are not even closely reached!), and an over-current protection circuit that will notice when a short-circuit causes too high current, preventing the output stage to get destroyed. In light of the malicious treatment of this output stage during development it needs to be mentioned that it can not be destroyed by a short-circuit at the output nor by overheating. Still some extra safety won’t hurt, and the over-current protection circuit got in.
A goal during development was to build a headphone amp that not only reaches very low THD un-loaded (the typical way of measuring it), but very low THD values with a 32 or 16 ohm real-world load. This was achieved in the new Extreme Power headphone driver output stage. It uses 6-fold spread power technology, improved thermal conductivity and a special super-low distortion driver design. The result is THD below -110 dB at 32 Ohm load even near full output level (clipping), the same SNR as the DAC provides (120 dBA), an output impedance of only 0.1 Ohms, totally stable operation, and a frequency response from 0 Hz up to 80 kHz, with just 0.5 dB decrease at the top end.
No audible hum, noise or distortion, fully transparent and crystal clear sound at any volume setting, for any personal taste in any application!
And there is more. The headphone sockets of the ADI-2 DAC have sensor contacts. The unit always knows when a headphone jack is inserted or removed. The DSP uses this information for several superior, partly never-seen before features. For example the ADI-2 DAC activates the mute relay half a second after the phones plug has been plugged in, then the DSP ramps up the volume slowly from lower level to the last used state. Comfortable? Luxurious? Yes, but the main reason for it was to give the user a chance to react.
Extreme Power headphone outputs set to full output level, music already playing at full level, inserting the phones, and the moment the relay switches on the doctor is called, diagnosing sudden deafness – this should and can not happen with the ADI-2 DAC. When the volume is ramped up one has the time to either quickly set the phones off, unplug the phones again, or to grab the Volume knob to quickly turn it down. To guarantee that the Volume knob will be set to control the correct outputs in that moment, the DSP also sets the Volume knob automatically to the output where phones had been plugged in. And even returns the setting when the phones are unplugged again.
But isn’t +22 dBu, or Hi-Power as it is called in the menu, much too loud for modern phones? That depends. There are still phones that need higher levels. Music can be low in volume but consume a lot of power, especially with lots of sub-bass. And lots of headroom is always nice to have. Typically with Hi-Power off, which equals +7 dBu maximum output level, modern music and mod-ern headphones, Hi-Power is mostly not needed. But you will notice that even with Hi-Power active, which requires to use a volume setting 15 dB lower as usual, the sound stays the same, and there is no audible noise or hum at the phones output (provided the source is clean, of course). So even at a Volume setting of -40 dB the ADI-2 DAC delivers perfect sound quality, being a no-brainer in daily use as how to set it.
In Low Power mode, the Extreme Power design of the ADI-2 DAC turns it into one of the world’s lowest noise headphone outputs. However, a few IEMs are so incredibly sensitive (means loud) that, despite all the technical super specs, a faint noise could become audible (current example: Campfire Andromeda, at least 20 dB louder as modern, already as loud categorized headphones). The usual remedy is the use of an external, passive voltage divider 16 Ohm to 1 Ohm, either self-built, or bought as a pre-made product.
Since IEMs are not only increasingly popular, but are generally more sensitive than normal head-phones, and a powerful Extreme Power output stage always entails the risk of destruction of the IEM with wrong settings, the ADI-2 DAC has been equipped with an additional output stage opti-mized for IEMs. Here, there is no Extreme Power, but extreme noise freedom, with the same sensational low distortion as at the big phones output, but a maximum output level of only -3 dBu. For most users this will suffice even for ordinary headphones, in particular portable ones with the mini TRS connector. This output with < 0.1 Ohms impedance turns the ADI-2 DAC into a reference for all types of headphones, from over-ear planar up to in-ear multi-drivers.
But the awesomeness doesn’t just end here, because all of the different outputs on the RME DAC can have their own equalizer settings, so I can only have this EQ enabled on the headphone out, and you can have different EQs enabled or disabled for your IEMs, headphones, and speakers.
Sound On Sound Magazine
Learn More about the ADI-2 DAC FS
Overview
The Sound
The DSP
