I will be moving soon and will need to pack my system away for a few months. I’ve never been much into headphones but am thinking of listening via headphones in this period. Ideally, I would like to use my Linn KDS for streaming and buy some high quality headphones (possibly Meze Empyrian). The KDS has a volume control. What do I need to put between the KDS and the headphones?
Many headphone amplifiers include DACs, volume controls and even switching (doubling up as pre-amps). I am interested in sound quality but not keen to pay for things I do not need.
Hi Hans, it’s unlikely you’ll find a headphone amplifier that doesn’t include at least one or more features you don’t need. Even the most basic headphone amp is going to include a volume control. However, there are plenty of headphone amps that don’t include a DAC, so need to worry about that aspect.
Not sure what your budget is, but the Schiit Jotunheim and Schiit Lyr amps are both very good. In your position, I’d be tempted to get the Jotunheim. You’ll be able to use the balanced output from the KDS and XLR balanced to your headphones with a suitable cable. In my experience with various Sennheiser headphones I’ve always liked the improvements that balanced drive to headphones brings. I’ve done very much this sort of thing in the past with an Akurate DS/3 and the amps recommended above.
A question that will really show my ignorance; why can’t I plug headphones directly into the pre-amp outputs of the KDS? Why is a headphone amp needed at all?
Someone will probably be able to demonstrate the mathematics around this but basically the output from the KDS is designed to be connected to a much higher impedance load (e.g tens of thousands of ohms) than a pair of headphones (tens or a few hundred ohms). The high impedance of a preamp or power amp input means very little current will be drawn, whereas to drive a pair of headphones will need significantly larger amounts of current than the KDS output stage can provide.
The KDS output stage uses a balanced transformer so I expect what will happen in this case is that the voltage at the output terminals will simply collapse and the headphones will be far quieter than required. Where an output stage is driven directly by an op-amp or transistor, there’s a danger that it might over-heat with prolonged use as it won’t have the heat sinking necessary to deliver the wattage needed.
I know there are exceptions to this, like the various Chord Hugos or the Dave, where the output stage is designed to drive high impedance devices or headphones directly. But the KDS and most other DAC’s or streamers don’t fit into this category.