CH Precision A1.5 compared to the Soulution 711 – Mini Review
Two of the finest transistor amps that I have heard
In the CH Precision A1 + C1 review, I made a brief comparison with the Soulution 711 and I also listened to the 711 using the Apogee Duettas in the Analog Domain M75/P75 review. When I reviewed the new CH Precision A1.5 I was amazed to find that it took all of the A1’s qualities and added to this significantly. In that review, I also briefly referenced the 711, speculating that the new A1.5 had attained “more of what made the 711 so endearing to me while becoming even better at the things that it already did so well.” Well, now it is time to put that speculation to the test.
Above: the 711 during an earlier as part of the Analog Domain M75D/M75P review
Above: the A1’s flanking the 711 as part of the CH Precision A1 + C1 review
Audio buddy Niels was not really looking forward to hauling his very heavy 711 over to me again so we decided to do it the other way around this time and carry out the comparison in his system.
The core of Niels’ system that we used for this comparison consists of a Spectral 30SV preamp, Aurender S10 music server, connected to the Zanden 5000 Signature DAC via an MIT Oracle MAX digital interlink, Soulution 711 power amp, and Magico Q5 loudspeakers. Cables are MIT Oracle MA cinch between Zanden DAC and preamp, MIT Oracle MA XLR interlinks between pre- and power amp and MIT Shotgun Evo speaker cables. Power cables used in both cases are Belden 19364, with Oyaide 079 connectors for the CH A1.5 and with molded-on standard connectors for the Soulution 711. Alas, we could not swap these cables because the A1.5 uses a 20A connector and the 711 does not. At a later stage, we did experiment with the interlinks and used Cardas Clear and CH Precision Balanced Link, both XLR cables.
We used a playlist on the Aurender with diverse but familiar 44/16 material and started with Niels’ own setup so that I could accustom myself to his sound. A very nice aspect of both the CH and the Soulution amps is that they seem to require no warm-up time, or at least, they don’t change very noticeably with while warming up. This enables very easy comparisons but just to make sure, we swapped from a warm Soulution to a cold CH as well as from a warm CH to a cold Soulution. If there was an effect, I could not detect it.
The CH A1.5 has an adjustable Local/Global Feedback ratio. After some experimentation with this, we all felt that 10% was the best setting, which is the same setting that I use at home with the Wilsons.
Coming from the Soulution 711 to the CH Precision A1.5, the latter was tighter in the bass and the 711 was bigger and fuller but less articulate and differentiated. The same relative difference was also evident in the treble which with the A1.5 was more refined and more clearly hi-res. Some recordings that contained edgy sounds which became a little bit too loud and forward with the 711 were more delicate with the A1.5 while retaining all the expression. We later found that the MIT cables were also doing these recordings no favors and that the Cardas provided a milder, friendlier presentation. Although the Cardas also rounded everything a bit, especially compared to the CH Precision Balanced Links, it seemed to provide the most even-handed and well-balanced presentation.
The 711’s bass is very different from the A1.5’s, or the A1’s, for that matter and I have to say that I really like both presentations but for different reasons. To me, the A1.5 is the most accurate as well as the most nimble, making basslines crystal-clear and easy to follow. On the other hand, the bass-lover in me also cannot resist the voluptuous, full-bodied V12-like goodness of the 711. While the A1.5 is indeed quicker on its feet, the 711 is still on the fast side and definitely not too slow.
Another area in which the amps really differentiate themselves from one another is in the midrange. Judged by themselves, I find both amps to be clean and even-handed even if they are voiced quite differently. Whereas I would regard the A1.5 as being super-neutral, I find the 711 to be richer in color, smoother, and fuller. Midrange tonality aside, the A1.5 tended to be more agile and liquid as well as more revealing while the 711 was creamier and richer, painting images in a big and generous manner, albeit in broader strokes.
Although my objective was only to compare the two amplifiers by themselves, I think we all feared that the combination of CH Precision and Magico could accumulate in an overly clinical sound but we were surprised to find that this was not the case. What I found interesting to hear is that the A1.5 revealed more low-level details without foreshortening the notes and leaving subtle decays intact. The Q5’s clearly have an extremely good resolution and transparency and for that, one has to respect them. That said, with speakers that are so clean and precise, in a room that contributes very little of its own, on balance, I felt that the Soulution’s fullness and warmth were ultimately preferable to the A1.5’s agility and refinement. Likewise, with my bolder and more sonorous Wilsons, I prefer the tightness and extra delicacy of the A1.5. The best matching amps with the Magico Q5’s in Niels’ setup, for me, ultimately are not Swiss-made or even transistor-based. Indeed, I am talking about tubes. The tube amp to take up the task to drive Q5’s sure needs to be very potent but at a rated power of 200 watts, the French Jadis JA200 Gold’s have no issues with this at all. Granted, they do not sound as detailed, extended, or as articulate as either Swiss amp but they add that unmistakable tube magic, that I feel these speakers crave, while retaining the drive and dynamic slam.