Cayin announced a new DAP N3Pro today. While the Pro suffix suggested that this is an upgrade from our previous N3 DAP back in Q1 2017, the bar of audiophile DAP has been raised significantly over the past 4 years, and Cayin decided to develop a new DAP from scratch instead of refining the very well-received N3. In fact, if you look at the N3pro carefully, you’ll notice Cayin has passed down a lot of technologies from other premium products to N3Pro, making it one of the most sophisticated and powerful dedicated entry level DAP.
The digital part of N3Pro features two AKM AK4493EQ DAC chipsets in mono mode and can natively decode up to DSD256 and 32 Bit/384kHz. The analog audio circuit is fully balanced by design, providing 4.4mm balanced and 3.5mm single-ended phone out. We have also provided a dedicated unamplified 3.5mm single-end line out and a shared 4.4mm balanced line out to connect N3Pro to portable or desktop amplifiers.
Dual Timbre: Vacuum Tube and Solid State
The most attractive part of N3Pro is definitely the Dual Timbre function. This will allow users to select Vacuum Tube or Solid State timbre from the pull down menu. This feature was first seen in Cayin’s desktop iDAC-6, which was pretty straight forward to implement. When the feature was introduced in N8 DAP, it was revolutionary. Vacuum tube suffers from microphonic by nature, and its non-rigid structure also makes it very sensitive to shock and vibration. Cayin has developed a spring-loaded suspension system with custom build shock absorption silicon housing to install a KORG Nutube into the N8. It works beautiful and the innovative technologies become an instant hit back in 2018.
We were excited by the Nutube experience and started to look for opportunity to do this again with other DAPs. The Nutube is definitely the best choice in the market technically in view of its unique form factor and its low-heat, low power consumption nature. Unfortunately it is fairly expensive and limited its application. With our decades of tube amplification experience, we finally identified another candidate JAN6418 and this turned our N3 revision plan to a completely new direction.
When you plug in a 3.5mm headphone, the pull down menu will enable the Timbre selection option and you can select Tube Timbre or Solid-State Timbre. This selection is disabled if you were using 4.4mm headphone or if you didn’t plug in any headphone. The vacuum tube requires 5 seconds to warm up otherwise you’ll hear distortion in playback, that’s why we mute the player for 5 seconds when you enter Tube Timbre. However it takes around 15 seconds to arrive optimum condition, so you might still be able to hear small audio changes in the first 10 seconds.
Raytueon JAN6418 Miniature pentode vacuum tube
The USA made Raytheon JAN6418 used in N3Pro is vintage NOS vacuum tube manufactured back late 70/early 80. It is a miniature vacuum tube originally designated in military communication and hearing-aid applications. The prefix JAN stands for Join Army-Navy and that is a clear designation of military grade products. The tube is inexpensive but please underestimates the audiophile value of this miniature tube because of that. For instance, Audio-Technica installed one JAN 6418 sub-miniature tube in
AT3060, one of the first tube condenser microphones that don’t need an external power supply. The mic is retailed at $600 (USD) and music professionals often describe this microphone as having a warm classic tube sound.
When Cayin decided to use JAN6418 in DAP, the first thing we do is to build up our inventory. NOS vintage vacuum tube is a very volatile market. When a particular tube become popular or new application (and demands) surfaced suddenly, the price will go up and the availability will become unstable. Cayin has spent 3 years to stock up around 40K units of NOS JAN6418 gradually and this is a hefty inventory investment as well as time consuming exercises. We probably will continue our procurement depends whether we have new project using JAN6418 down the road but our customer can rest assured that Cayin has taking care of this important part to safeguard a steady supply of JAN6418 in our production plan.
The JAN6418 is direct-heated tube. Its miniature form factor and long life low power consumption characteristic makes it ideal for portable applications. Max plate and screen grid only require 15-22.5V, its tube filaments are 1.2V and draw just 10mA. It is only slightly warm when you touch it, and you can barely see the tubes glowing in a dark environment.
N3Pro uses a matched pair JAN6418 in its single-ended tube timber circuit. Similar to the Nutube application in N8 DAP, we can’t offer Timbre selection in balanced headphone amp. Circuit because that will required 4 pieces of JAN6418 in total. The cost of extra tube is minimal, but a balanced amplification circuit will required matched quad which is exponentially more difficult than matched pair in mass production. The extra spaces required and shorten playback time are also deal breaker constraints that make this impossible for N3Pro.
The JAN6418 Tube Timber circuit will offer a smooth, liquid and warm sound signature, this will work well with vocal and pop music. Alternatively, the Solid State Timbre circuit will offer stella dynamic and separation and we recommend that for music requires authorities and transparency
Dual Operation Mode: Triode and Ultra-linear
Unlike the KORG Nutube, the JAN6418 is miniature pentodes tube and we can connect the vacuum tube to the audio circuit in standard, triode mode or ultra-linear mode. Wiring the JAN6418 in standard mode will generate serious ringing effect in music playback, making it inappropriate for DAP purpose. The triode mode and ultra-linear mode will generate different amount of feedback, distortion, harmonic and output impedance.
The sound signatures of these two operation modes are noticeably different. In triode Mode, the presentation and soundstage will be tighten up, sounds more sophisticated and elegant, images is focused and the mid-range will be more up-front. This is a good setting for string and vocal-based music, especially with songs that are intimated and refined
When change to Ultra-linear mode, the transient will be enhanced and soundstage will open up. You can feel the space and dimension immediately and the music become lively, clean and energetic. This is good for instrumental, especially for music that requires a lot of punch, dynamics and control
When you plug in a 3.5mm headphone and selected Tube Timbre, the Dual Operation Mode will be enabled and you can select either Triode mode or Ultra-linear mode from the pull down menu. Please be reminded that we use electronic trigger to change between Operation Modes and this will involve a series of electrical adjustments. Please don’t switch between Operation Modes rapidly, wait at least 1 sec before you change mode again. Rapid mode changing will result in loud pop sound.
Microphonic and Shock Treatment
The biggest challenge to implement JAN6418 into a DAP is handling the microphonic and shock treatment the best we could. Unlike our previous experience with KORG Nutube in N8 which use LED technologies, the JAN6418 is a traditional vacuum tube with filament, and the filament will vibrate when the tube encounter even minor shock. This will produce microphonic effect and affect your listening experience.
Cayin has spend months of R&D in this exercise. We have tried out 4 different shock absorption silicon housings and 6 rounds of Flexible PCB design, and we have conducted lot of test in each round to determine the effectiveness against different practical shock and vibration scenario. The R&D difficulties are in proportional to the entry level position of N3Pro.
Our final take is to suspend the shock absorption silicon housings over a specially crafted slot and connect to the main PCB through a flexible PCB. Users can now walk around or place the player in a backpack while listening with nominal detrimental effects. However microphonic effect might be audible when jogging, knocking on DAP, holding the DAP and then place it on table or knocking on table when DAP is placed on it
). Admittedly, I don't like streaming services. The last thing I want to see when I open a music app is that I can't play the 6th song in an album anymore because of rights issues in my country (thanks a lot Apple Music).
