Driving Headphones

There are two ways to drive a set of headphones on a Naim system. The conventional solution is the Headline headphone amp, connected to a tape loop on your pre-amp. Points to consider:

• The Headline is designed to drive headphones.
  
• It's a load on the tape output loop, which may affect the pre-amp's performance.
  
• It's got its own volume control, which can be convenient. For example, your significant other can be watching TV, while you listen to tunes on the cans. Each of you can set your own volume.
  

The other method for driving headphones is to create a custom cable from 4-pin to 1/4" phono socket. This connects to a spare output on your *-cap. Points to consider:

• You can only do this if you have a Flat-Cap, Hi-Cap or Super-Cap, and it has to have a spare power-amp output socket.
  
• You need a custom cable.
  
• You must turn off the power amp while listening to headphones. Although warm-up tends to be pretty quick with Naim power-amps, some listeners are more sensitive to this than others.
  
• You must unplug the headphones when using the power-amp, or regular performance is compromised.
  
• The volume control on your pre-amp controls the volume, and it may be set much differently for headphones compared to normal use. If you're not careful, you may leave it set very loud when you switch from headphones to speakers, or vice versa
  
• An expensive pre-amp, instead of a cheaper Headline, is driving your headphones, which could sound better.
  
• The pre-amp is designed to drive a power-amp, not headphones, which may negate the previous point. It may also be detrimental to drive headphones over an extended period, so your pre-amp might be damaged.
  

I’m testing with two sets of headphones: AKG K240-DF and Sennheiser HD330. Although the price of the AKGs is only marginally more than the Sennheisers, the differences are significant. In general the AKGs, have much more clarity, speed and definition, although they can sound a tad bright, lean and fatiguing. In contrast, the Senns have more bottom-end and warmth, but it sometimes seems a bit like "one note bass". Curiously, the differences between the headphones was less obvious when being driven directly from the pre-amp. I enjoy switching back and forth, depending on what my ears want at the moment.

I hooked up the Headline a couple of weeks ago. When I first tried it, it was harsh, edgy, lacking in bass, and generally awful. Since the Headline was new and it was powered by a newly recapped SNAPS2, I figured that it probably needed to be broken in. After running for about 50 hours, it was much more comfortable and natural sounding. Just for good measure, I left the headphones connected and running for another week, (whenever the CD was used). The sound rounded out a touch more, but it wasn’t a significant change compared to the initial 50 hours.

As expected, the Headline sounds better than my speakers, although the headphone listening is little strange compared to speakers. The biggest difference is the detail and finesse that the headphones proffer.

After two weeks of run-in, I finally got around to hooking up the custom "direct drive" cable to my Super-Cap. When I'm driving the Sennheisers, the volume on my pre-amp needs to be about the same as for non-headphone listening, compared to double for the AKGs. (The AKGs are lower impedance than the Senns.) I tried to match the levels between Headline and custom cable as closely as possible, as well as when comparing the two sets of headphones.

The first thing I noticed was how similar the performance was between the Headline and custom cable. After further listening, though, some differences were noticed. Curiously, the differences between the two methods were similar to the differences between the two sets of headphones. The Headline had more bass and body, while the custom cable had more definition and clarity. Both sounded quite acceptable, and I don't know whether either would be considered "better".

Also, my pre-amp is an 82/Super. This affects the Headline to some extent, because the pre-amp feeds it. However, it has an even greater impact on the directly driven headphones. Depending on the quality of the pre-amp and its power supply compared to the Headline and its power supply, we might see variations in relative performance. For example, keeping the Headline+PS constant, a 72/Hi might sound better with the Headline than driving the phones directly. Direct drive from a 52/Super might sound better than the Headline. Or this could be completely switched. I would have to do more testing with different pre-amps and power supplies.

Since headphones provide such a personal interface to the music, I suspect the final decision as to which was "better' would be based very much on personal preference. It's that old adage of "Try before you buy".

This whole thing ends on a rather ironic note. It was four months from the time I initially ordered my new Headline until I had the necessary SNAPS and SLIC to drive it. Although I was somewhat eager to get it up and running, I wasn't going crazy without it. Even after I did get the necessary ancillaries (including the custom cable for direct drive), it took me a few weeks to get around to comparing the various configurations. Now that I've had the ability to use headphones for a few weeks, I haven't felt compelled to use them. In almost all situations I would prefer to listen with speakers, and I realize now that I'm not a big fan of headphones. Consequently, I think the direct driven solution is probably sufficient for my occasional headphone use, and I'll be putting the Headline up for sale.

-=> Mike Hanson <=-