There is a good reason why I titled this review as Dr. Jekyll, Mr. Hyde. While many daps are relying on a sound signature of the DAC and solid state opamps used in phone amplifier section, here Cayin gives you a choice of two audio signatures based on amplifier section, Solid State and Vacuum Tube. And on top of that, you get HIGH2 (High Output, High Impedance) mode where thanks to their two-stage power supply control used with line driver and internal headphone amplifier circuit you can change the sound characteristics further when increasing the supply voltage of all OPA1622 SoundPlus HiFi OpAmps from TI.
Even with all these variables, it’s clear that 3.5mm Solid State (SS) output has a typical Cayin house sound signature with a fuller body sound and a more neutral resolving tonality. This neutral tonality leaves more headroom for warmer “changes” when switching to Tube output. It has a very precise layering and separation of the sounds, typical of AK4497 DAC performance I’m used to, and a very good soundstage expansion and decent imaging even for a single ended output.
When switching from 3.5mm SS to Tube, soundstage perception widens (becomes more holographic) and the sound becomes a little more laid back. Tube sound change is not very drastic, but it’s noticeable enough with addition of a more analog flavor to the sound where the tonality becomes more organic, more natural, a little warmer and smoother, especially in mids where I hear a fuller body with a more forward presentation, and treble where I hear a little less sparkle. The change in the sound here is more of a refinement by taking the edge off the digital colder tonality. At the same time, the sound is still very dynamic and resolving, and the blackness of the background is not affected too much.
In a summary, the tube output adds warmth and analog texture to the sound and brings mids a little more upfront without adding a distortion or taking away resolution. But don’t expect Tube output to have a more pronounced “tubey” sound associated with desktop vacuum tube amps.
When you compare 3.5mm SS (single ended) to 4.4mm SS (balanced), you can hear more power where I had to turn the volume down. Soundstage is wider, and it sounds to me like it has the same width and holographic expansion as Tube output. Other than that, these Solid-State outputs are very close in tonality and presentation. The only difference I hear is soundstage expansion and output power.
In some pair ups, going from Standard (P) output to HIGH2 (P+) gives you an improvement in bass response with a deeper lifted sub-bass rumble and a stronger mid-bass slam. Plus, I hear more body in the lower mids. In some cases, it even improved the soundstage expansion. For more details please read my Pair Up section of the review. As I mentioned already, this mode boosts the voltage of headphone amplifier stage which changes the characteristics of opamps. While this mode was implemented specifically to drive more demanding higher impedance headphones, surprisingly I also hear improvements with average and low sensitivity IEMs.
During this test I was using 64audio U18t w/EA Leo II cable, volume matched in every comparison. I will only focus on sound characteristics which is still the most important factor, but you must factor in all the features. At the flagship level many manufacturers have DAPs with excellent sound performance, but there are still variations due to a difference in sound signature and soundstage expansion. And of course, you need to figure out your requirements regarding the internal/external storage capacity, battery life, support of hi-res formats, output power, direct or remote streaming, access to apps, Bluetooth protocols, etc. In the comparison below, I noted if I was using N8 in either Solid State (SS) Balanced (4.4mm) or Tube Single ended (SE). And the same with a DAP of comparison, either SE or BAL.
N8 (SS, BAL) vs A&K SP1000 SS (BAL) – In this comparison N8 soundstage is a little wider and the sound is more holographic. In terms of the performance, these are very close, everything from layering of the sounds to their separation and dynamic expansion, but there is a difference in tonality. SPK is a little smoother and has a little fuller body sound, while N8 is a little leaner in comparison and has a more reference tonality with a little stronger mid-bass punch. SPK SS with its earlier fw1.06 used to be on par with N8 (or maybe even brighter), but A&K follow up fw updates (at fw1.11 now) made the sound smoother, especially with a warmer upper end. With Tube output, N8 becomes smoother and warmer, adding a little more body in lower mids than even SPK CU.
N8 (Tube, SE) vs Sony WM1Z (BAL, direct source) – In this comparison I still hear N8 having a little wider soundstage. Tonality/signature is close, but N8 is a little warmer, smoother, and has more analog flavor, especially with a little more laid-back presentation of the sound. With N8 having more analog flavor and warmer sound, in comparison to that I hear 1Z having better separation and more precise layering, just keep in mind when comparing N8 with solid state – the performance is close. But under the original test conditions, they both aim for a smoother, fuller body, more analog sound, but NuTube gives it additional dimension and pushes it further. Though, when you enable Vinyl Processor digital effect on WM1Z, you get the tonality closer to smoother-analog flavor of N8. Maybe it’s not totally the same, but it’s closer in tonality.
N8 (SS, BAL) vs iBasso DX200Ti (amp8, BAL) – In this comparison N8 soundstage is a little wider with a more holographic perception. Technically they have a very similar performance, perhaps with N8 having an upper hand in layering of the sounds, but I think it’s due to N8 having more revealing tonality in this comparison, where DX200Ti w/amp8 is warmer and smoother. Of course, you tip the scale in the other direction when you use N8 with Tube output where the sound is smoother and warmer in comparison to amp8.
N8 (SS, BAL) vs L&P L6 (3.5mm) – with an exception of N8 soundstage being a touch wider, in this comparison I hear nearly identical sound, both in terms of tonality and technical performance. As expected, Tube output will change the sound, but when you compare the solid state N8 output to a lower impedance single ended output of L6 (it’s balanced output has high impedance) – I hear way too much similarities in tonality and technicality.
N8 (SS, BAL) vs N6 (3.5mm) – It has been a long time since I re-visited N6, and I was surprised to hear how wide and expanded its soundstage is, almost on par with N8. N6 sound tonality is brighter and more revealing, while N8 has a more natural tonality with a fuller body sound. In terms of technical performance, I hear N8 as having an edge with better layering and separation of the sounds, plus N8 sounds a little more dynamic. Another difference, which is hard to ignore, a higher level of hissing in N6 when tested with sensitive IEMs.