Line Out of Cayin N8
Line out is a commonly available feature in DAP, but not all line out are the same. Traditionally line out is mean to be an analogue audio interface between source and amplifier, and you won’t confused it with Pre-out our something else because they are very straight-forward at the good old days.
In simple term, line out is a fixed voltage signal without volume control while pre-out is a variable output with volume control, but in reality, the real issue is whether the audio signal is “clean” enough to feed into an amplifier, and yet meeting the “standards” and can work with a variety of amplifiers.
Line Out in DAP is a bit more complicated because it is an all-in-one unit with source and amplifier packed into one chassis. We have noticed, but not limited to, the following Line-out implementation:
- Share with Phone out circuit with Volume set to Maximum
- Share with Phone out circuit with fixed voltage output
- Direct output from DAC (by-pass volume control and headphone amp.)
- Dedicated line out circuit (by-pass volume control and headphone amp.)
The line out of Cayin N5 and N3 are based on (2), and that line out of N6, N5ii/N5iiS and N8 are based on (4). Now let’s take a look on the Line out function of Cayin N8:
First of all, the Line out of N8 skipped the headphone amplification stage completely, so it is as clean as it should be. Contrast to the general believe that line out is simply a direct output from the DAC chip, we have developed a line out circuit to 3.5mm single-ended and 4.4mm balanced line out independently. We want to make sure the line out from N8 will work with very wide range of amplifiers, not just portable products. The following table provides the technical detail of the Line out:
The single-ended line out of N8 is dedicated 3.5mm TRS port and it is rated at 2.1V. The Balanced line out of N8 is a 4.4mm TRRRS port shared with phone out, and it is rated at 4.3V. Both line out are fit for audio equipment with input impedance higher than 10 kΩ, which is not uncommon in desktop systems. Some of our previous DAPs are designed with 3.5mm line out from 1V, 1.5V to 1.7V (from N3, i5 and N6) respectively, these line out work with portable amplifier alright, including our C5 which is high-gain based, but they tends to lean sounding when connect to desktop amplifier, mainly because of lower than regular output level and output impedance. With a proper line amplifier circuit, we can regulate the output level and impedance of N8 line out to the commonly practice of desktop amplifier, that’s why we described these as desktop grade line out,
Plug IEM into line out accidentally
Since line out use the same connector s as phone out (shared or dedicated) and it does not facilitate volume control, there is a common worry that if we plug a pair of IEM into line out accidentally, it will blow the IEM at very high volume, or even damage our hearing if we are wearing the IEM.
Well, this can happen if the line out didn’t by pass the headphone amplifier circuit. In other word, if the line out is implemented under option (1) and (2) in the list I stated earlier on, then you better be careful to avoid this mistake. Cayin is fully aware of this risk and that’s why we always reset the player back to phone output whenever we detect the line out connector has been unplugged or the player has powered on.
However, if the line out has by-passed the headphone circuit (i.e., option (3) and (4) in my previous list), it won’t pose the same threat to the users. It can get very loud with efficient IEMs but it won’t blast like the line out from (1) and (2). Even with a dedicated line out circuit and rated at 4.3V on the N8 balanced line out, the accident won’t cause any damage to your IEM or your hearing. That’s because the line out circuit only involve voltage gain, it doesn’t involve current amplification. Give it a try starting with your less efficient IEM and you’ll notice the different completely.
Accessories and Connectivity
With the correct cable and accessories, you should be able to connect N8 to vast variety of amplifier in the market, I’ll listed the options briefly for your reference, if you need further information, please refer to the Connectivity of N8 in
this post. Before we move on, I must remind you to turn the volume down before you make the connection, and turn up the volume after you completed the connection. If you are using the balanced line out, remember to set the N8 Balanced output to LO from the pull down menu after you completed the connection.
- 3.5mm single-end line out to desktop amplifier: 3.5mm to 2xRCA interconnect.
- 3.5mm single-end line out to portable amplifier: 3.5mm to 3.5mm interconnect.
- 4.4mm balanced Line out to desktop amplifier: 4.4mm to dual XLR male adapter and standard XLR interconnect.
- 4.4mm balanced Line out to an amplifier with 4.4mm analogue input: 4.4mm to 4.4mm interconnect.
- 4.4mm balanced Line out to an amplifier with 2.5mm analogue input: 4.4mm to 2.5mm adapter and 2.5mm to 2.5mm interconnect.
This has concluded the Audio Design elaboration of Cayin N8 DAP, and now we can merge the headphone amplifier, digital interface and line out features into one set of functional diagram: