{"id":16913,"date":"2019-01-03T21:38:52","date_gmt":"2019-01-03T19:38:52","guid":{"rendered":"https:\/\/www.hifi-advice.com\/blog\/?p=16913"},"modified":"2021-04-19T20:52:52","modified_gmt":"2021-04-19T18:52:52","slug":"ch-precision-a1-5-part1","status":"publish","type":"post","link":"https:\/\/www.hifi-advice.com\/blog\/amplifier-reviews\/power-amplifier-reviews\/ch-precision-a1-5-part1\/","title":{"rendered":"CH Precision A1.5 Power Amp"},"content":{"rendered":"

Miracles do exist!<\/h2>\n

Review sample supplied by CH Precision<\/a><\/p>\n

Retail Prices in the EU, incl 20% VAT:<\/strong>
\nA1.5: 34.600 euro
\nA1 to A1.5 upgrade: 15.200 euro<\/h4>\n

When reviewing the CH Precision C1 and A1<\/a> earlier this year, the C1 quickly established itself as the absolute best DAC that I had ever heard.\u00a0Likewise, the A1 was the first amplifier that I heard to combine incredible speed, dynamics, articulation, and transparency with amazing fluidity, naturalness and overall finesse. In my book, all of these attributes just could not be combined in a single amp, but CH Precision made it happen. While it can be argued that tube amplifiers have a different set of virtues that can also be very appealing, such as richer harmonics or a more fluid presentation, none of the amps that I tried so far have been able to match the A1 on all accounts. The Zanden 8120<\/a>, for example, quite uniquely combines the desirable aspects of tubes with traditional transistor strengths. While it comes closer than any tube amp I tried before, the A1 retained the lead position in terms of speed, articulation and bass control. But that\u2019s the way that it is: tubes and transistors remain in opposing camps, even if they are getting closer to one another. In the transistor camp, it’s certainly possible to find an amp that sounds more sonorous than the A1, or one that has a richer midrange, for example, but invariably these amps perform less well in one or more other parameters. So, while it is all relative and there is no single “best” product for all tastes, it is its superb balance of virtues that, for me, makes the A1 so difficult to beat. And then, along comes the A1.5, which actually does beat the A1 at its own game, and then some! But before I proceed to the listening sessions, let me explain the differences between the A1 and the A1.5.<\/p>\n

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What’s new?<\/h3>\n

The most obvious difference is the size: the A1.5 has the same width and depth as the A1 but is considerably taller, 50% taller, in fact.\u00a0The input- and output stages have not changed from those in the A1. The output stages have always been more powerful than required by the application and they were ultimately limited only by the power supply. The A1 already had a very large toroidal transformer and a bigger one would not fit within the existing casing. But simply upping the power was not what drove the decision to upgrade the A1, rather it was the realization of how much improvement the new “Red Caps” upgrade brought to the company’s biggest amplifier, the M1 which turned it into the M1.1. The name “Red Caps”, incidentally, stems from their color. They were\u00a0ordered in red and referred to as “the red caps” internally and it has somehow become their name.\u00a0When the technicians at CH tried these same “Red” capacitors\u00a0in the A1, the improvement was staggering and that’s what initiated the decision to build an improved version of the A1, which would become the A1.5.<\/p>\n

Below is the company’s official statement regarding the A1.5’s new capacitors:<\/p>\n

As part of the A1.5’s development, CH Precision has recently compared top of the line electrolytic power capacitors from several of the most renowned component manufacturers. Voltage rail ripple measurement, amplifier output noise measurement, and most importantly direct listening comparison allowed us to easily rank the tested models in terms of micro and macro dynamics, noise floor and low-frequency control. After further refinement and customization with the manufacturer of the best model that we tested, we were able to finalize the A1’s bigger brother, the A1.5.<\/em><\/p>\n

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Left: A1, Right: A1.5. It took me literally no time at all to appreciate the new form factor. I think the new amp has even nicer proportions than the A1.<\/em><\/p>\n

The new 1700VA toroidal transformer, along with the aforementioned new “Red” capacitors that increase the output rating from 100 to 150 watts into 8 ohms, combined with the new internal layout, makes for a leap in quality. According to CH Precision, the A1.5 now comes closer to the performance of their flagship, the M1.1. As I know CH Precision to be a company that is not at all in the business of making hollow statements, you better believe it! Oh, and the best part? Any existing A1 can be upgraded to an A1.5.<\/p>\n

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Another difference is in the transport screws, or rather, the lack thereof. For all CH products, the power supply sits on a metal plate that is supported by flexible Silent Blocks and with\u00a0the A1 this plate needed to be fastened from the bottom using 3 big thumb screws for transport. Thanks to a smart system that restricts excessive movement but at the same time allows the required movement for the Silent Blocks to work their magic, there is no more need to flip the amp upside down and insert or remove any screws. And given its weight, that’s a very good thing!<\/p>\n

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Finally, after hearing from multiple M1 customers that they preferred using the 10% global feedback setting, it was decided to add this value to the A1.5 as well. So, now its global feedback can be set to 0, 10, 20, 40, 70 and 100 %. I quickly found that I also have a preference for the 10% setting but wherever comparisons with the A1 were in order, I used the closest setting that both amps offer, which is 20%.<\/p>\n

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Above: Settings tab, Amplifier Mode setting pop up window. This is only one of the tens of screens with settings. It’s a tweakers’ dream come true! This amp works right out of the box, though, and should you “mess up” then you can always restore the default settings very easily.<\/em><\/p>\n

Features<\/h3>\n

All the features of the A1 remain the same: the front panel OLED display still displays a selection of modes containing every possible aspect of the amp’s status, the amp’s entire setup menu can still be controlled via its front panel buttons or via the CH Control Android app and all the clever amplification schemes are still there. For its extensive connectivity and superb\u00a0configurability, CH Precision amplifiers truly are one of a kind. For a full description of all the features, please refer to the original A1 + C1 review<\/a>.<\/p>\n

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Not only a matter of power<\/h3>\n

The 100-watt A1 may not appear to be a powerhouse but I am absolutely confident that it drives virtually any loudspeaker in the world. The only limitation, ultimately, would be absolute power, which originates from its power supply. Theoretically, if you crank the volume up to earsplitting levels while using inefficient speakers, then the limitations could become clear. But in my room, with the Wilson WP8, this never happened, not even with the volume control at “are you crazy” level. So, one could wonder if any extra power is needed or even desirable. In my situation, honestly, I did not think so. But boy am I glad that I got the chance to hear this new amp in my system!<\/p>\n

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Traditionally, when comparing a medium-powered amplifier with a more powerful amplifier of the same brand, obviously, you get more power. And often, for better or for worse, the amp will “sound” more powerful, too. But any amplifier’s sound is the result of a delicate balance of internal circuits and decision making that is easily offset. in my experience, the increase in power usually has a detrimental effect in one or more other aspects of the amp’s sound. Speed, articulation, refinement, transient purity, airiness, fluidity… usually at least some of these areas take a step back whenever the transformer size increases or output transistors are added.\u00a0It’s only logical and in some cases, the change in the amp’s sonic balance can actually have an effect that is desired by many. Oftentimes, what you get in return, along with the extra power, is a richer, fuller, more sonorous sound. Take Bryston, for example. All their amplifiers follow the same principle and are marketed as being of the same quality, differing only in power output. Still, the\u00a03B Cubed<\/a>, for example, sounds faster and more articulate than the more powerful 4B Cubed. The latter, however, has a more sonorous, creamier, richer sound that is preferred by many. I have a lot of sympathy for Bryston and am using this brand as an example only because I have reviewed a bunch of them at the same time not too long ago but, in my experience, this principle holds true for many class A or AB amplifiers.<\/p>\n

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Personally, I like my amps to be fast and articulate but I would absolutely choose the aforementioned richer sound over the alternative. You see, the other thing that can happen\u00a0as the amplifier power increases is that the sound becomes ever more controlled and you start to lose the sense of life and natural flow. What I’m trying to illustrate is that, usually, the balance of virtues is shifted when going from a medium power amp to a higher power amp, even if the circuits are pretty much identical. In my case, even if the extra power would be beneficial, I did not want my A1 sound to change. For me, it already had a perfect balance. And so, rather than swapping my A1 for the A1.5 immediately, I first opted to do a comparative listening test. But I needn’t have bothered…<\/p>\n

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Miracles do exist!<\/h2>\n

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The sound<\/h3>\n

The A1 was already state of the art in my book, so I was a bit skeptical of the claimed improvements, but the difference is immediately clear and it’s really not subtle! The A1.5 has increased power while not only retaining all the other aspects of its sound that are so precious to me but it actually further improved on each and every one of them!<\/p>\n

Ok, so get this: the A1.5 has a more authoritative sound with a fuller, more solid bass that also has more impact but at the same time is even more precise and articulate than that of the A1. Further, it has a richer, more full-bodied midrange that is also more transparent and even more communicative. Finally, its treble is even more fluid and refined while fully retaining its already superb air and resolution. Add to this the overwhelming sense of a more free-flowing, more lyrical presentation that is actually more organic and natural and one has to wonder if miracles do in fact exist.<\/p>\n

Probably because both brands come from Switzerland, the natural inclination is to compare CH Precision with Soulution, even if the two brands don’t share any similarities in design. Or maybe it’s because they both strive for precision. Be that as it may, some time ago I’ve had a Soulution 711 in my system very briefly, courtesy of audio buddy Niels.\u00a0So, any comparisons at this time can only be done rather globally and from memory. But since I have compared the 711 directly to the A1’s<\/a>\u00a0and also have\u00a0compared the 711 to various other amps<\/a> using Apogees and the Wilsons only months ago,\u00a0I think I have a reasonably good handle on its sound, relative to the A1, and by extension, to the A1.5. As I already detailed in the C1 + A1 review<\/a>, these two amps really sound quite different, with unique, and largely mutually exclusive, virtues. Without going into this too deeply, the main aspects of the 711 that stood out for me were its immense bass solidity, its rich midrange, and its 3D soundstaging but the A1 at that time countered with higher resolution and a more fluid, more refined sound.<\/p>\n

Coming from a long history with Martin Logan, Magnepan, and Apogee speakers with Jeff Rowland amplification, I guess I will forever remain a sucker for low-level resolution and refinement, even if solidity, neutrality, speed, and dynamics have become ever more important to me in the last few years. That’s why I think so highly of CH Precision: the brand combines all the sonic aspects that I find important, into a single amp.<\/p>\n

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Because the A1.5 is more solid and sonorous in the bass, richer and more organic in the midrange and also has a more enveloping soundstage than the A1 did, one could deduct that the amp has gained more of what made the 711 so endearing to me while becoming even better at the things that it already did so well. It’s like having two cakes, and eating both! Despite having moved closer to each other, however, I think they still remain different amps that cater to different tastes but only a direct comparison would provide any definitive answers. What’s\u00a0unequivocally true for me, in any event, is that the upgrade from A1 to A1.5 has turned an amp that I already loved into an absolute champion, and it is absolutely a keeper!<\/p>\n

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Above: the Status tab, only one of the many possible display settings via the CH Control App.<\/em><\/p>\n

Matters of Feedback<\/h3>\n

I mentioned the new 10% feedback setting. The A1 goes from 0% straight to the 20% mark and indeed I found myself wandering between these two settings a lot, with the Wilsons as well as the Kroma Audio Carmens<\/a>. 0% gave a beautifully fluid and free-flowing presentation but at the expense of bass tightness and articulation. Vice versa, the 20% setting made for excellent bass but reduced the fluidity in the midrange and treble. With the new A1.5 and the Wilsons, at 20% global feedback, the sound is fluid and free-flowing, yet at the same time tight and super-articulate and it becomes even more lyrical and the soundstage even more enveloping at a setting of 10%, which is the setting that I prefer with these speakers.<\/p>\n

And the A1? Even at a setting of 0%, it does not reach the same level of free-flowing fluidity as the A1.5 (at any of its settings) and just the same, even at a setting of 40 or higher, the A1 cannot reach the same level of bass control and explosive dynamics as the A1 even at its lowest setting. Go figure.<\/p>\n

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Conclusion<\/h2>\n

CH precision has not only succeeded in boosting the power of an existing already superb amp design while leaving all its delicate attributes intact but actually significantly improved its performance across the board. Importantly, the improvements are not only of a technical nature but also result in a more musically engaging delivery. the A1.5 is nothing short of a\u00a0giant killer amp.<\/p>\n

Yup: miracles do exist! Even at 3 minutes into the listening session, I already knew that there was no way back! Owners of the A1 should not hesitate to contact their dealers for specifics about the upgrade. I promise: you will be astounded, or your money back! Well, actually, I cannot really make that promise on behalf of CH, but I can<\/em> promise that you will not be sorry!<\/p>\n

This concludes the main part of the review. Continue reading the next page (see button below) for the Technical Side Notes.<\/p>\n

<\/p>\n

technical Side Notes<\/h2>\n

Below are screenshots of all the interesting settings that can be made via the tablet, or via the amp’s front panel.\u00a0The individual snapshots below are, in reality, a single, long, scroll page. All the options below\u00a0can be switched on the fly, from the comfort of the listening seat, using an Android tablet.<\/p>\n

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Above: the main Status tab, showing the same info as the front panel, when the latter has been set to Status mode.\u00a0<\/em><\/div>\n
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Above: even the amplifier mode can be switched on the fly.<\/em><\/div>\n
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Above: the physical inputs, as well as several loading options.<\/em><\/div>\n
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Display color is fully configurable.<\/em><\/div>\n
<\/div>\n
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Above: a bunch of network-related info that you normally do not need to worry about.<\/em><\/div>\n
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Above: more network settings that are normally set just fine by default but there is the option to change a component’s name or to change which is the master and which is the\u00a0slave, which dictates which component can be used to switch on or off the other components.<\/p>\n

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Associated Equipment<\/a><\/p>\n<\/div>\n

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Read Also<\/h3>\n

CH Precision C1 and A1 Extensive Review<\/a>
\nCH Precision A1.5 compared to Soulution 711<\/a>
\nCH Precision L1<\/a>
\nAn Interview with Raphael Pasche of CH Precision<\/a>
\nCH Precision P1 Extensive Review<\/a><\/p>\n

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External Links<\/h3>\n<\/div>\n

Manufacturer: CH Precision<\/a><\/p>\n<\/div>\n

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