ultra-high precision TCR25 low temperature coefficient thin film resistors support up to PCM 384kHz and DSD 64/128/256 Detail retrieval is exceptional; pair RU6 with a highly resolving IEM or headphone and you’ll find every micro-detail present and accounted for. This device miraculously blends transparency with smoothness, unlike some sigma-delta DACs. The 1-Bit ladder DAC is a purposively designed micro-miniaturized 1-bit DAC circuit from discrete components. It converts the digital signal to an analogue signal through a fully differentiate 4-ch DAC architecture. The 1-Bit DAC circuit is a resistor network composed of 128 pcs (4 x32) high precision Thin Film Resistors, and it closely resembles to the discrete DAC of Cayin’s N7 DAP. It wasn't a straight up double-blind A/B-switch test setup, but spread out across the table for a few hours, this was overall a fun experiment and I enjoyed the time spent. It was also interesting to take notes on the items BEFORE seeing price or specs -- the inherent biases that I know I have get taken out of play.

This deactivates the digital filters and the signal is retained in perfect timing. That is, the phase distortion and jitter remain at a very low level with no artifacts in the output signal. The RU6 has digital volume control, which overrides that of the connected mobile phone or PC. This means that you can’t use the phone or PC to adjust the sound; that’s done with the buttons on the RU6. The percentage scored by RU6 is truly mind blowing. Comparing this against Luxury & Precision W2, that W2 only managed to score 70% (with Fostex T40RP MK3) at the very best. Clearly RU6 is a much better device for hard to drive partners.The additional balanced output power, the technical capability, and several All-To-DSD modes are just some of the key features that elevate and differentiate the RU7 from its peers and the competition. Cayin RU7 Technical Specifications The RU7 will sound relatively wet and analog in tone on DSD64 mode but even then, it’s a more balanced performance both in terms of bass weight and midrange timbre. The DAC itself is power efficient so you don't have to worry about draining the host device battery. Without hesitation is one of the best sounding and most powerful USB DAC dongles available right now.

Digital Audio Bridge: convert DSD to PCM; convert all audio signals to the left and right channels of 24 Bit/384kHz serial audio data signal. The RU7 is the second portable DAC/Amp dongle from Cayin. The reason why they got into the dongle market – according to Cayin – is because they were not satisfied with the highly integrated off-the-shelf solutions available out there. By the time Cayin completed the R01 Audio Motherboard for the N6ii DAP, they noticed that the R-2R resistor ladder network c ould be implemented as a low power consumption DAC circuit that offers outstanding audio performance. Natural is the word to use again, not only to define the timbre but also for expressing the decay, the notes are born and then fade away with the perfect timing.The RU7 has dual-headphone outputs: a 3.5mm single-ended and a 4.4mm balanced one. With a properly designed balanced headphone amplification section, the RU7 (@32Ohm) produces a powerful output of up to 400mW on the go. In SE mode you get 160mW. The Cayin RU7 also has line-out support with fixed voltage output, allowing you to set the outputs as LO, feeding a portable or desktop amp of your choice. The output of the resistor network will go through a 3-level active LPF and then converted to a single-ended signal for volume adjustment.

Like the RU6, the FC6 is another R-2R dongle so we will not really into the differences once again between the 1-BIT architecture and traditional R-2R. I’ve posted impressions elsewhere from a previous loaner tour, and my ambivalent feelings about this dongle haven’t really changed, which is why I didn’t buy one. I prefer the tonality of NOS but find it constrained, closed in, and dull; OS, by contrast, is less congested and constrained but has a thinner and weedier tonality. It’s still somewhat lifeless and flat. I'm not an IEM guy, so I basically ran through the headphone stands against all four units at least for a few minutes before settling into evaluation mode. Obviously throwing every headphone I had into a detailed accounting would have taken way longer than my allotment, but all four units seemed to manage everything I threw at them: HD280, HD558, HD650, HE5XX, OG Clear, even Atrium. Eventually I landed on the HD280 (v2016) for testing, as it's probably the most flat headphone in my kit right now. The additional resolution and treble extension from the DSD256 RU7 mode also injected some improved clarity and improved separation over the more analog and slightly less resolving RU6. Cayin RU6 has both 3.5mm unbalanced and 4.4mm balanced output. (Photo: Geir Gråbein Nordby) As an amplifierThere is a different emphasis in the design approach regarding temperature and precision tolerance being much more exacting for R-2R compared to 1-BIT which switches its focus more on noise shaping and achieving a clean power supply. The OLED screen will display sampling rate, volume level, gain H/L and whether you are using NOS or OS mode. The RU7 features a discreteresistor network volume control with a 100 steps volume control through3 segments of resistors andswitching relays. It offers a precise control overa wide volume range, making it ideal for sensitive IEM users. (Segment 1: 1-49, Segment 2: 50-79, Segment 3: 80-100)