1. Choice of Timber: select between Vacuum Tube and Solid State timber on the faceplate. This is no doubt the most attractive, most discussed, and most sought after feature of C9.
2. State-of-the-Art analogue amplification: C9 is probably the most sophisticated portable headphone amplifier for both earphones and headphones in the market. Cayin firmly believe that when the amplifier excels in control and equipped with appropriate volume management, there is no such thing as over-powered. Even IEMs will perform at a different level when we have ample power. Unfortunately, from what we observed, most, if not all, high-end headphone amplifiers are designed with full size headphone in mind, portable amplifiers are mostly DAC/Amp with emphasis on the digital audio technologies. Given the rapid development of high-end IEMs in recent years, Cayin believes there is a market for ultimate portable headphone amplifier that can bring out the best of these high-end IEMs, especially when they are equipped with demanding dynamic, planar magnetic and/or EST drivers, and yet versatile enough to cover a lot of full-size headphones in portable scenarios.
3. Dual input mode: on top of regular LINE input mode, C9 can also operate in PRE-amp input mode (or known as pure power amplifier mode), with volume control disabled and all stages operate at full capacity.
• When operate in LINE input mode, which we presume will be the primary input mode of C9, it will receive audio signal from the line level output of DAP, DAC, or from any reliable audio source.
• The PRE-amp input mode is designed to work with variable level inputs (e.g PRE-amp or DAC with variable-level line out).
• Alternatively, if you have a DAP with high quality low distortion phone out but no line out, you can use the phone out as PRE-amp output. Switching between Line input and PRE-amp input is an unique feature, the first of its kind to the best of our knowledge.
4. Versatile input and output options: C9 supports 3.5mm single-ended and 4.4mm balanced for both input and output, the amplifier will also optimize balanced inputs to single-ended headphones, and from single-end input to balanced headphones. The following interconnects are bundled in the C9 package:
5. Replaceable battery: the removable battery module houses 4 x Sony US18650VTC6 (3000mAh 3.7V) lithium batteries. You can charge the 18650 batteries while the battery module is attached to C9 or after you detached it from the amplifier. The battery module supports standard, PD and QC3.0 battery charging through USB-C connector.