- Written by Rick Schmidt
- Published on 24 March 2008
My reference phono stage is from a kit (the Pearl) promoted by the Pass Labs DIY web site. As is the bent of Nelson Pass, this design features a single ended, single transistor gain stage. I haven't the means to measure what types of distortion might come from this sort of design but we can presume a fair amount of the second order harmonic. This is thought to be a good thing by some. I certainly am enamored with this phono stage.
The GCPH had a distinctly different sound that I would attribute to the absence of such a distortion. Indeed, balanced circuits reduce even-ordered harmonic distortion. So coming from this reference my initial impression of the GCPH was that it was on the bright side, perhaps a little brash even. This is the kind of thing that could mellow after a break-in period, but I was not expecting much of a break-in since the unit I was using was a well travelled review sample. And in fact, I did not detect too much change after a couple of weeks of listening. After a time, I placed three Boston Audio TuneBlocks underneath the GCPH. and PS Audio's user's manual recommends careful placement as well as aftermarket vibration isolation such as that provided by Boston Audio. The difference was not slight, not subtle, and not unwelcome. Gone was any hint of harshness or excessive brightness. The sound opened up remarkably. Treble still seemed to be the specialty of the GCPH, but only in that it sounded great. The soundstage was more forward than with my reference. Bass was tight and controlled and tuneful, although I'm not sure it reached the same depths of absolute gravity as with the Pearl. I kept this arrangement for the rest of my listening in my main system.
I'm starting to wonder if it's possible to figure out what sorts of hi-fi equipment manufacturers are listening to as they voice their products. If I had to guess, I'd say that the folks at PS Audio are favoring Jazz. Trumpets, snare drums, pianos were all stellar through the GCPH, as were women's voices.
My reference phono stage prefers the lower frequencies and is more laid back. One of my favorite songs ever is Massive Attack's "Tear Drop", with melt-in-you-mind vocals from the incomparable Elizabeth Fraser (Cocteau Twins). With about half of the melody occurring below 40 Hz its great for repeated listening and great for comparing bass in audio equipment. With my reference, there was a bit more 'thunder', and with the GCPH there was more articulation of those deep notes, and the brilliance of Massive Attack's mixing board fiddling was more evident.
However, the more I listened to the GCPH, the less difference I heard between the two phono stages, I attribute this more to my ears breaking in than the GCPH because this particular unit has been well traveled. The control and authority of the GCPH really grew on me over time and as should be expected with vinyl, without a hint of fatigue (if I want fatigue I listen to CD's).
Boston Audio makes a variety of vibration isolation products from carbon graphite (not fiber). For this review I tried the MAT1, a record mat replacement for most any turntable, and I also got some TuneBlocks which are cylinders made of the same stuff, designed to be placed under components. I tried the TuneBlocks Series 2 XT which are cylinders 2" in diameter and 1.5" high. In addition, the XT's have a recessed cup, about ½" diameter, carved into the top to hold a small ball bearing. Here is where the component rests. This height can be a little off-putting, as the GCPH on TuneBlocks looks a little bit like a monster truck, raised too high for its own good.
Besides the aesthetics, there's the issue of macro stability to think about. Will your component roll away when placed on the TuneBlocks? The recessed cup for the ball bearing means it's not going to roll very far. I tried pushing the GCPH in the horizontal direction while it was on blocks as it were, and the feeling was similar to pushing on foam. The ball bearings would roll only a small amount before hitting resistance as they tried to roll up the side of the cup. However, the GCPH was not as stable in the horizontal direction as it would have been standing on its own feet, or some sort of spikes. The ball bearings are not at all sticky, and if I kept pushing, the GCPH would simply slide along the top of them. This is not anything that concerns me, but if you or a pet or some other creature were to bump a Tuneblock-suspended component, it would move a more than if it were on rubber feet.
Since replacing the mat on a turntable is about the easiest audio equipment installation imaginable, I tried the MAT1 first. Replacing the foam (read 'cheap foam') mat that came standard with my Nottingham Space Deck and still using my reference phono stage while the TuneBlocks and GCPH were safely tucked away in their boxes. There was an immediate improvement; all tones from bass to treble were more clear, less muddled, especially treble. And I didn't think there was any muddling before. The effect was not subtle and it was entirely enjoyable.
Usually, when someone describes an audio improvement as 'clarity' the thing to watch out for is 'grain', that etched, annoying quality most evident these days in cheap CD players but also found in playback from turntables that suffer from vibration problems – such as a direct drive turntable. Replacing the standard soft foam that came with the Nottingham with the stiff MAT1 had me worrying that some grain, some vibration that was formally absorbed by this foam would now be revealed. I worry no more. In fact, I didn't even think of the word 'grain' until I started to write this review. I could not discern any tradeoffs in going to the MAT1.