Graham Slee Voyager

If an amplifier is supposed to amplify the signal feed to it while preserving its sound as pure as possible, Mr. Graham Slee for sure don’t hold that belief. The Graham Slee Voyager amplifier is one warm sounding amplifier with a very thick and lush sound. It definitely does not qualify to be called “neutral”, but at the same time its sound signature can be very addictive to people who wants analog and tube like sound.

The first thing that comes to mind when I listened to the Voyager is its smooth treble, smoother than even the highly acclaimed Corda 3Move amplifier. After more listening, I beginning to notice that the low bass frequencies also have more punch on the Voyager than it does on the 3Move. As much as I like the smooth treble, and the low bass of the Voyager, the midrange is actually its biggest strength. The Voyager has a very smooth, very thick midrange. Think vacuum-tube thick, something that analog lover would die for in this age of Digital Audio Players.

While the midrange is thick, it is also quite dominant, sometimes eclipsing the bass and the treble, and this can be a really good thing or a really bad thing depending on taste and application. For example, people who are used to tube amps with a thick midrange will definitely find the Voyager at home. However, if you are used to a solid state, or your music doesn’t revolve around the midrange (i.e Rock, Classical), then the really thick mids muddies everything, and all the frequencies seem to be sucked out by this thick midrange blackhole.

Again, depending on the application: A run of the mill Grado (ie the John Grado kind) has always maintained a very strong treble presence, (with the Grado HF2 being an exception). After a while, people get tired of the strong treble, and they started to feel the other frequencies missing. The Graham Slee Voyager amp would work nicely with these bright cans, filling in the mids, and making it more lovable like the Grado HF2.

On the other hand, the Westone UM3X has a warm sound signature with a relatively flat frequency curve and a fairly good body. When paired with the Voyager, I find that the sound becomes muddy and congested, the thick midrange taking all the roles, and I can’t seem to enjoy this combination no matter what genre I throw at it.

Power wise, the Voyager is actually pretty good, driving the Sennheiser HD650 with enough punch behind it. It is still no SR-71a, but I have a feeling that a 24V DC power supply can really turn the table around. (Too bad that’ll be for another article, as I can’t find a suitable 24V power supply for this review).

One thing about the Voyager that bothers me is its black ABS plastic enclosure. Compared to the offerings from RSA, Headamp, and Meier, the Voyager falls short both in material and build quality. What’s more, it is way too big too be competitive in this age of super tiny amps like the RSA Shadow and Pico Slim. The biggest size I can tolerate these days is the RSA SR-71a, and that’s only because the SR-71a has a superb build quality and just as superb sound quality. Even the Triad Audio LISA 3, though mighty sounding, has often been referred to transportable duties due to its size.

The Graham Slee also has 3 options for power: through 5V USB, a 9V battery, and a 12/24V external DC power supply. The DC power supply that came with the Voyager is 12V, but I’m really curious on what 24V would do. Switching between the 9V batttery to the 12V DC power supply yields no significant change, except that I don’t have to worry about recharging my 9Vs. Last on the feature want list is a DAC and a crossfeed.

What it does have that many other amps don’t have is a contour switch. Basically it’s a fixed equalizer setting, except that Graham Slee wisely reworded the dreaded e-word to read “contour”. The flat setting is not actually flat, but rather, midrange-is-the-superhero presentation that I described above.  When you flick the switch to “contour”, it boosts the bass and the treble, bringing the much needed treble back to the music, and actually sounding more neutral than “flat”. This can be a good feature, as you now have two sound presentations to choose from, and you can still boast to your friends that you don’t use an equalizer because you’re an audiophile.

At the end of the day, what’s the verdict on the Voyager? Yes, it has a nice analog sound that can be a love affair for a lot of people. Personally for me, the music works better for me with the contour switch on. Size and build quality is not the best, so this can be an area of improvement for future products. All packaging issues aside, however, you do get a solid performing amp with a great analog sound in this age of digital. Moreover, the reputation that Mr. Slee has gained worldwide over his amplifier is rightly deserved, as he dedicates a lot of time answering people’s enquiries, patiently answering my questions over email. So you can buy his products with confidence, knowing that he will quickly respond should any problems arise.

Very analog sound. Smooth treble. Thick and smooth midrange. Contour switch gives a more exciting sound.

DIY grade packaging and size.

System for auditioning:

Headphones: Sennheiser HD650, Westone UM3X
Source: Ipod Touch 2nd Gen
Amplifier: Graham Slee Voyager, Corda 3 Move.

Big thanks to Alvon and Diboy for making this review possible.

4.3/5 - (3 votes)


  • Reply October 29, 2009


    Very nice review…comprehensive and detailed….For me GS Voyager would be my choice among my other amps for audiophile female song…It really shines…

  • Reply November 4, 2011


    would this amp actually be suitable for hip hop/electronica?

    • Reply November 4, 2011


      It would be okay I guess.

  • Reply April 25, 2013

    Roy BonJovi

    How does it pair with the beyerdynamic dt880?

    • Reply April 25, 2013


      I don’t remember if I ever tried that particular pairing. Maybe I have, maybe with the dt770, but the voyager should help smooth out the Beyer and make the Beyer warmer and more analog. It would also rob some speed out of the Beyer.

      • Reply April 26, 2013

        Roy BonJovi

        Thanks for the quick reply! What amp would you reccomend for the dt880? I am looking for a reference and i listen to classical and a bit of rock

        • Reply April 26, 2013


          The Graham Slee Solo is nice and pairs well.

  • Reply March 4, 2014

    Chong Keat

    Will this Graham Slee Voyager improve HD598 soundstage? I mean wider
    I like HD598 because of it’s dark sound. Will this amp make it a over-warm sound? Is that bad?
    i usually listen to Paramore and Coldplay some alternative rock music
    HD598 will do better with this amp on rock music?

  • Reply February 15, 2015

    Marcin Andrukajtys

    Been using the contour a lot with AKG K401 and personally think that it much improves the overall sound quality. It really depends what headset you’re using and keep in mind that none of them is perfectly linear. K401 is heavily lacking bass and I also could hear that other K series eg. K601 sound similiar like the K401 with activated contour. K601 with no improvers has more bass and treble. Beyerdynamic has such the amount of bass (or even more) like AKG’s + the contour. K501 got more treble. One can say that using an EQ is somewhat artificial, but I was impressed with the way Voyager brought into the sound; still natural and more dynamic with proper bass punch, perfectly placed and never overdrawn. Slightly more treble like K501 and the scene is same huge and spatial as before. I found the marriage better than other K series, including the flagships! And have to mention that I’m more into acoustic/classical music than electro. Simply a great solution for AKG headsets.

  • Reply May 4, 2016


    “the Voyager falls short both in material and build quality.”

    This has got to be a joke. My Voyager has been used and tossed without a casing for many years now and it still looks effin fresh out the BOX! Not a single scratch, not even on the beautiful metal front plate. The material and build quality is stellar and unlike any product I’ve ever used.

    • Reply May 4, 2016


      It’s a 7 year old review, so probably impossible to know if the case was the same as yours. It’s a good amp, not to worry. But if I had an extra $700 now, I would order myself a Lehmann Traveler amp.

  • Reply May 7, 2016


    Agree totally. The case is the same as it always was. Handmade in the UK to last a lifetime. the reviewer obviously doesn’t know real quality from bling. Bought mine second hand 6 years ago and it’s like new.The use of a standard 9v battery that lasts for months at a time is a genius decision. Great match with HD25

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