by Kevin OBrien on February 1, 2015
YFS CUSTOM HEADPHONE CABLES
Since we're not busy enough with 2 channel custom HiFi gear, we figured why not give the headphone market a shot? Well, we're kidding of course but seriously, YFS is now in the custom headphone cable market. I recently moved into a new residence here in Boulder. That means I have neighbors all around me. Neighbors do not mix with loud music. Especially when that loud music never seems to fully go away but rather have its output level slightly altered depending on the time of day. This isn't going to work out...
That is how the concept of using headphones even came about for me. At first I did not want to admit that I needed to use headphones or that I even had a "noise level problem" with my new neighbors. I put so much time, effort, and more importantly, money, into my 2 channel system that it seemed counterintuitive to even think about something like that. Reality finally set in and I had to find a solution fast or get evicted at some point down the road. My solution is to now use headphones during those sensitive times of the day and night. I mainly play my 2 channel rig on Saturday and Sunday during the day and stick to cans during the week. This has solved my current problem and opened my ears and my mind up to other ways to enjoy my favorite thing to do: listen to HiFi.
After buying a few pair of headphones, I realized quickly that each set of phones had a different sound and an associated set of properties unique to that particular set of phones. I am specifically referring to properties such as output impedance, sensitivity, weight and fit, driver type, etc. All these factors come into play and need to be addressed when making a decision on what amp to match with what headphone. With each set of phones comes a need for a different headphone amp. At first I figured I could get away with using the headphone output on a McIntosh C2300 preamp and that would be sufficient. I quickly realized this was not the case. All it took was one listen to a friend's headphone amp and I was sold right then and there. Unfortunately for me, that required a new set of gear specifically focused on making my headphones sound better which required more spending than I wanted to do. Such is the life of an audiophile I suppose? Nothing we can do really...
So, I bought a pair of Audeze LCD-2's and a pair of Sennheiser HD800's as well as a pair of Sennheiser HD650's and HD700's. I then picked up a Schiit Vahlhalla 2, Lyr 2, Asgard 2, and a Mjolnir Balanced amp to pair with the different phones. This is what ultimately led me to making a cable for each set of phones and testing them out with each amp. Looking at the stock cables that came with each set of phones, clearly there was room for improvement. That is how we got into this 'headphone mess' and I am so excited we did.
There are some basic things I've learned in a short time that should be mentioned about pairing amps and cans. A cool site to check out, Audiobot9000, helps the user with amp and headphone matching. Select your headphone and your amp from the drop-down menus and it will tell you if the combination will work. It provides invaluable information on amplifier impedance as well as headphone sensitivity and headphone impedance. Unfortunately, it cannot tell you how things will sound when paired or if there will be good synergy between components. The site tells you whether or not the amp has enough power to power the headphones sufficiently based on calculations from product specs. It can also tell you if you've tried to pair a flat out mismatch. It will suggest to "try a headphone with a higher impedance" if your phones you've chosen are a blatant mismatch with the amp you want which is nice. The above statement is just one of several examples.
That's where the spending comes in again and things can get painful. Let us do the spending and hopefully our readers can do more reading and less spending. That is the ultimate goal of this article. I hope we can help make things a little less confusing and make that purchase a little easier for somebody looking to purchase things once or twice, not ten times.
Cables can have a drastic effect on sound quality and they are never something to ignore or pass over, just as in 2 channel audio. The stock headphone cables, in some instances, are not satisfactory in terms of quality and should be replaced. Others are better but we still feel that replacing the headphone cable, equivalent to replacing speaker cable in 2 channel audio, is paramount to getting the last bit of performance out of those expensive headphones.
Replacing the stock cable also allows you to personalize the sound signature of your phones. Silver coated copper, pure silver, and copper Litz are available for our custom headphone cable conductors. You get to decide what length and what type of conductor you want based on the sound you tell us you are looking for. Each cable material has an effect on how the headphone will sound. It reminds me of voicing a 2 channel rig by using different interconnects and speaker cables. The finishing touches can be made to take your system to the next level if you so desire.
Now let's talk about headphone impedance and amp impedance matching. I have heard it said that the output impedance of your amp should be at minimum 1/8 the impedance of your headphones. This will help ensure a proper match for your amp and phones. Here's another cool site, Headphone & Amp Impedance, that goes deeper into this subject if you're interested. (We're not in entire agreement with all of the author's statements but it is a great reference none the less)
So, as an example, the Audeze LCD-2 has an impedance of 50 Ohms. The Schiit Valhalla 2 has an output impedance of 3.5 Ohms and 14 Ohms in low and high gain mode respectively. That means if we match the LCD-2 with the Valhalla 2, we're looking at (1/8)*(50 Ohms) which equals 6.25 Ohms. This is the highest impedance value we want to see when pairing these two by this rule of thumb above. This tells us that in low gain mode (3.5 Ohms) the Valhalla 2 will be able to mate with the LCD-2 but in high gain mode, the LCD-2 will most likely not match up with the Valhalla 2 and create good synergy. I indeed tried this second scenario and it did not pair well in my opinion. In fact, even though the Audiobot9000 site told me the Valhalla 2 could power the LCD-2, it did not sound 'right' to me compared to the Asgard 2, Lyr 2, or Mjolnir. Those 3 amps are a much better match and have better synergy together. Sound is a matter of taste so one listener's 'bright' is another listener's 'detailed' and so on and so forth. Without hearing for yourself, there is no way to know for sure if your gear will mate well together but at least we can get somewhat close. 
The sensitivity (or commonly referred to as efficiency) of the headphone must be taken into account in the above scenario as well. Just because your impedance rules of thumb are followed, does not guarantee a good match. A very sensitive headphone may not work well with a very powerful amp and vice versa. In the case above, the Valhalla 2 is not a great match for the relatively power hungry LCD-2 (~90 db efficiency) no matter which gain setting is selected. I feel the Schiit Lyr 2 sounds the best and is the most versatile sounding with planar magnetics such as the LCD-2, LCD-3, and LCD-X / XC. On the contrary, the Audeze LCD-XC and Sennheiser HD800 are too sensitive for amps such as the Schiit Mjolnir which is very powerful and is designed for use with low efficiency headphones. The Mjolnir / LCD-XC combination still works but does not provide great synergy.
Other factors such as damping, driver type (planar magnetic vs. dynamic for example) and amplifier topology (solid state vs. tubes) also come into play when matching gear. Tubes always give the listener a chance to change the sonic signature of the headphone amp simply by rolling tubes. I prefer tubes myself just for this reason. Check with the amp manufacturer if different variants of the stock tubes will be compatible with that amp's topology. It is inadvisable to drop in replacement tubes blindly and hope for the best.
Unfortunately, sometimes there is no way to know if two components will work well after doing your homework without hearing them for yourself. That's where we come in handy to help you make those important decisions. We have experience with the Schiit line of amplifiers as well as the Sennheiser and Audeze lines. Drop us a line and we'll try to answer any synergy questions you have as far as matching components, etc. Don't hesitate to ask about different cable combinations with different headphone models. As always, let us know what you have in mind for a headphone cable and we're sure we can make it happen. Or at least we'll die trying... Thanks for reading and enjoy that music (but make sure your neighbors don't hate you for it).
- YFS Design Team