4-Channels Analog Volume Control
One of the major different between N8ii and the original N8 is the volume control. N8 relies on the digital volume in DAC chipset, N8ii use a separate quad-channels electronic controlled resistance ladder analog volume before the fully balanced fully discrete head-amp circuit.
So what is the big deal with analog volume control? The advantage of using analog volume is to keep the digital audio circuit in full output all the time. This is particularly important to current mode DAC because we do not want an attenuated input to the IV converters. A properly implemented analog volume control can preserve the dynamic range of the digital audio circuit even when output is attenuated to very low volume. Try to visualize from a very sensitive IEM user perspective. If you turn the digital volume all the way down to single digital (say 9 at 0..99 volume range), what will be the implication to the output stage of the digital audio circuit? Will they still maintain 100% dynamic range?
Cayin uses digitally controlled analog volume in many DAPs and PGA2311A is our most frequently used 2-channls electronic analog volume controller. Our first DAP was N6 back it 2014, it employs dual PCM1792A current mode DAC and that's where we start our venture with PGA2311A electronic controlled volume. When we need a fully balanced volume control for our new portable product, our natural choice will be PGA4311A which is the 4-channels version of PGA2311A. Unfortunately the PGA4311A turns out simply combining two PGA2311A into one chipset, so it has two separate electronic controllers in one chipset, not an ideal design from noise level, power consumption and channel balanced management point of view.
That’s where
JNC NJW1195A comes in. This is a premium grade low noise low distortion electronic controlled analog volume controller. With 4-channel in one integrated controller, we can achieve higher precision, lower noise and lower power consumption than using two stereo volume controllers. One of the biggest advantages of JNC NJW1195A is to ensure channel balanced at low volume level. This has become a significant problem to latest high sensitivity IEMs.
We used this volume controller in A02 Audio Motherboard and we were very pleased with its low noise performance, that's why we used it again in N8ii. For the record, NJW1195A is widely used among audiophile preamp, including the high-end
Esoteric N-05XD Streamer/DAC/Preamp retailed at $11K.
Last but not least, the NJW1195A requried an "encoder", aka volume knob to complete its chain. The original N8 uses an encoder to cover Volume control, on/off and screen on/off feature. As a result of that, the encoder need to rotate and push in (or described as click by some reviewer) on different occasions, that means we need to left a 3mm to 4mm gap behind the knob so that it can be push in. Some users didn't like this "lack of firmness" feeling when turning the volume knob of N8. Although we didn't encounter abnormal repair rate because of this design, we decided to change our design to offer better user experience. So we split the encoder into a dedicated volume knob (aka, encoder for the volume chip) and a push button to facilitate Power on/off and screen on/off button seperately.
The N8ii volume knob is made of brass because it has hard and soft properties that allow it to be strong and flexible enough to repeatedly turning without stressing. We have engraved it with a glamour 3{4} dodecagram and gold-plated it for glamous and elegant presentation. No, it won't improved the audio performance of N8ii, gold plating is mainly for durable consideration.