Cayin N6iii w/T201

A pair of tubes in your pocket.

PROs: triple timbre output with Solid State, Modern Tube, and Classic Tube modes, different tunings based on the mode selection, 2x Raytheon JAN6418 miniature Tubes, black background, Gen2 module with quick-release latches for faster exchange, excellent battery life (w/N6iii), 3.5mm and 4.4mm PO, Pre-Out, and LO outputs.

CONs: cost of an additional module.

The product was provided to me free of charge for review purposes in exchange for my honest opinion.

The manufacturer’s website: Cayin. It is available for purchase from authorized retailers such as Musicteck, where it can be purchased separately or with the N6iii DAP.

Intro.

In my last review of the N6iii audio cards, covering the R202, I speculated about the next module and would never have guessed it to have two Raytheon JAN6418 miniature tubes. While there were a handful of other DAP releases that used these tubes, including Cayin’s own N3 Ultra DAP, I wasn’t sure it was feasible to fit it inside the compact N6iii Gen2 audio motherboard, given that it’s not just an amp card but a DAC/amp module. I mean, nothing surprises me anymore, considering they were able to squeeze in R2R and 1bit DACs into the R202 module. But still, miniature vacuum tubes require a custom-designed sleeve and damping system, in addition to all other components.

Thanks to its modular design, even over a year after its debut, every new audio card brings N6iii back in the spotlight. Starting with the original N6iii/C201 combo, Cayin users were able to get a new DAP experience without buying a new DAP by upgrading the sound with the E203 card, bringing back memories of the N6ii with the R202 card, and now being treated to a real tube sound experience with the T201. I’m sure some diehard Cayin N6ii/N6iii fans, like in Pokémon, get them all because you Gotta Catch ‘Em All! For others, it’s a decision of what to get to complement what you already have. Either way, here you have options using easy-to-swap on-the-go audio cards.

While I already featured T201 in some of my recent IEM reviews, after spending a few months with this audio motherboard, I’m ready to share my full write-up of this latest addition to the Cayin N6iii DAP.

Unboxing and Accessories.

There’s not much to discuss here, as this is the Gen2 module featuring quick-release latches for faster exchange, eliminating the need for screws or screwdrivers. It arrived in a nice, compact cardboard box, complete with an exterior sleeve, foam padding inside, and a detailed user manual. The only thing to note here is that the board’s mini-PCI Express connector has a rubber cover that you have to remove before plugging the module in.

Design and Under the Hood.

T201 is a Gen2 audio motherboard module that is inserted at the bottom of the N6iii DAP via a quick-release latch mechanism with two buttons easily accessible on the left/right sides. The mechanism seems to be very robust and secure, and I found it very easy to handle with one hand. Once latched in, there is no wiggle room, nothing rattles, and I have never had an issue while pulling on the cable when removing IEMs/headphone plugs. While switching between modules, it worked in a true plug-and-play fashion without the need to power down the DAP.

Cayin implemented a dedicated microcontroller on the card that interacts with the primary 665 MCU whenever a card is inserted, making all necessary custom adjustments and monitoring specific to that card. Since this is not just an amp card but a DAC/amp board, each one requires more interface customization per its corresponding design since each DAC/amp card will be custom not only to its selection of components but also its functionality, related to different ports, like T201 and C201 having separate 3.5mm PO and LO ports and a shared 4.4mm PO/LO port, while R202 and E203 having a separate 3.5mm and 4.4mm PO-only ports.

Unique to the T201 design, Cayin implemented a viewing window (a precision-drilled opening) on the right side that also serves as an auxiliary heat-dissipation channel. Then, to make it look symmetrical, they also added a decorative perforation window on the left side. If you are not aware that the left-sized window is for decoration only, some might assume the tubes are out because the light glow comes only from the right side, but they work as expected. Besides, once inside the case, the tube window will be covered anyway.

According to a new naming convention, the “C” in C201 card corresponds to Cirrus Logic DACs (CS43198), “E” in E203 corresponds to its ESS DAC (ES9039S Pro), “R” corresponds to a discrete DAC (R-2R and 1Bit), and the new card I’m covering today is T201, where “T” corresponds to Tubes, using two Raytheon JAN6418 miniature tubes. Unlike the R202 design, which focuses on pure audio output performance with only PO and no LO, the T201 includes Line Out and Pre-Out as well.

At the heart of T201 audio processing is the AKM AK4497S, the flagship DAC in the upgraded Velvet Sound architecture, which supports up to 768kHz PCM and DSD512. The module design also implements multiple SoundPlus TI OPA1612 audio opamps, as well as four TI INA1620 integrated hi-fi audio high-current headphone opamps. From the block diagram, they also continued to use a quad-channel precision analog volume control, utilizing a well-regarded JRC NJW1195 fully balanced chip with 0.5dB step adjustments.

The triple-timbre tuning was achieved using a selective local negative feedback (NFB) topology at the anode stage to vary the tuning, a design similar to that used by Cayin in their higher-end N8ii/N30LE/C9ii DAPs and amps. Except here, instead of NuTubes, they are using Raytheon JAN6418 miniature tubes. Furthermore, to eliminate microphonics in vacuum tubes on the go, JAN6418 tubes are housed in a custom-designed silicone damping sleeve and integrated with the chassis via a mounting structure that provides multi-directional buffering and vibration absorption.

Also, worth mentioning: timbre choice is easy to select from either the Notification bar (when you swipe it down) or Audio Settings.

The T201 card features a 3.5mm PO (0.5ohm output impedance, 252mW @32 ohm), and a 4.4mm PO (0.8ohm output impedance, 543mW @32ohm). Plus, you have a separate 3.5mm LO/Pre-Out, and the 4.4mm port has a shared LO/Pre-Out. Please keep in mind that LO has a fixed line-level output for connection to amps with a volume control, while Pre-Out has a variable-level output for connection to power amps or active speakers. When it comes to the N6iii’s battery performance with the T201 card, the specs are very impressive. From 3.5mm SE, you get 23.5hrs (Solid-State), 17.8hrs (Tubes); and from 4.4mm BAL, you get 21.1hrs (Solid-State), 16.5hrs (Tubes).