{"id":4850,"date":"2013-08-18T17:04:13","date_gmt":"2013-08-18T15:04:13","guid":{"rendered":"http:\/\/www.hifi-advice.com\/blog\/?p=4850"},"modified":"2021-04-19T21:00:15","modified_gmt":"2021-04-19T19:00:15","slug":"jeff-rowland-725-mono-power-amplifiers-part-1","status":"publish","type":"post","link":"https:\/\/www.hifi-advice.com\/blog\/amplifier-reviews\/power-amplifier-reviews\/jeff-rowland-725-mono-power-amplifiers-part-1\/","title":{"rendered":"Jeff Rowland 725 mono power amplifiers"},"content":{"rendered":"

Reference class,\u00a0Class AB Mono Power Amplifiers<\/h2>\n

Review sample supplied by HVP Audio<\/a>
\nRetail price: 35.500 euro per pair<\/h4>\n

After the recent crop of ICE-power-equipped power amps, Jeff Rowland has now returned to the classic, proven class AB principle, but with a twist.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

Above: Sophisticated and immaculately finished but brutally powerful.\u00a0Company logo not on the front but engraved on the heavy top panel – quite stylish!<\/em><\/p>\n

A little background information<\/strong><\/p>\n

Regular readers know that I am very fond of Jeff Rowland. I guess it is fair to say that I am more than a little biased toward the brand. But I frequently give other amps a chance and if something better comes along, I will not be too proud to admit it. Interestingly though, I have never come across an amp that has entirely beaten my model sixes. Of course, there is the matter of personal taste, and Rowland amps do happen to cater to my taste, but Rowlands, also the sixes, can be beaten in certain areas. Luckily for me, this is always in the areas that are, for me, less important than others. There were too many amps to list but a few come to mind because they stick out above the rest that I tried.<\/p>\n

There were the Bryston 7B ST’s, with much more power and drive and fantastic bass but only average resolution, focus,\u00a0and refinement. Depth layering and treble extension were even below par. One could be forgiven to think that these PA amps would have coarse or harsh treble. This is absolutely not the case. Their treble is fluid and entirely free from edginess. It is just less well-resolved and doesn’t extend as far. But all that didn’t stop me from enjoying the 7B ST’s: they were immense fun. In the longer run though, the sixes catered more to my taste and made me consistently happy. In a perfect world, I would have several setups with several key areas of strengths but if forced to choose it would always be Rowlands.<\/p>\n

A friend brought along a Levinson no.29. While certainly neutral and very powerful in the bass, it was also very dark in balance and lacked subtlety and sparkle.<\/p>\n

I’ve also had a McIntosh (not MacIntosh!) MA-6900 integrated amp. That was when I thought my setup could be simplified without penalty. Of course, I was wrong about that but suffice to say that the MA-6900 does sound very compelling. It was like a mix between Bryston and Pass with a shot of Tube Sound mixed in: very powerful and dynamic yet highly emotionally engaging because of its mellifluous, even slightly rich midrange. However, it didn’t pass my standards for resolution and treble air. What’s more: the MA-6900 not only had less air and extension, it was really dull in the treble, and that weighs heavily for me.<\/p>\n

The Dutch Array Quartz amps came close to sounding like a model 6 at a fraction of the cost. But the longer I listened, the more I realized that they lacked musicality, they were simply too stripped of color and body.<\/p>\n

There were a couple of Krell amps that I compared my sixes to in other people’s setups. KS250’s and KS350’s. The funny thing is that these amps have a reputation for being powerful bass champs but in direct comparisons to the sixes, they only had mildly fatter upper bass and besides being able to play louder, at normal volume levels they really weren’t very much more powerful. The Krells did, however, have more slam but they consistently sounded quite ragged through the upper midrange and treble, and they were darkish and ill-resolved, also having little in the way of soundstage layering.<\/p>\n

Then there was the Pass Labs X250.5. Also lots of fun and again better than the sixes in the bass and drive department, however less so than the Brystons. But another area of the Rowlands was now being challenged: that of midbass bloom and midrange believability. The latter is difficult to explain but Rowland amps, for all their naturalness, can be ever so slightly thin through the upper bass and lower midrange. Call them overly clean or call other amps overly colored. Doesn’t matter. The point is that if you need some extra color and substance through the midrange (as I do with my Magnepans) then you can do better than the sixes, as evidenced by the Pass. But the latter, again just like the Brystons, has less overall resolution and articulation across the frequency band, and, most important to me: treble was a bit coarse, even ever so slightly brittle and also didn’t extend as the Rowlands do.<\/p>\n

Various Musical Fidelity amps came and went. All were very musical and appealing but most were too bloomy, just too rich through upper bass and lower midrange, and lacking PRAT. This was pre-2010 and I haven’t heard the latest crop of amps, however.<\/p>\n

Of course, there were a couple of ICE-power amps: both Rowland-branded (model 201’s, model 102) and some OEM products, and even switching amps using proprietary techniques like the Audio Physic Stradas. While at least the ICE variants were remarkable for achieving such high quality at such models prices, invariably they failed to really stir me. ICE amps always sound fresh, agile and open, even the key area of treble air is almost up to model 6 standards. Technically it is all fine, if for a subdued, almost unconscious, lack of resolution. While some are better than others, it is always almost as if you can hear the holes between the power pulses, much like being able to hear (or see) MPEG compression.<\/p>\n

I’ve also listened to a variety of tube amps, even highly exotic ones, all of them challenging the Rowlands in the midrange (convincing vocals) and sometimes the lower treble but never were they as finely resolved, as well-layered in the depth plane, as nimble in the bass or even as fluid and airy in the treble. The latter was interesting to find out because it is still said that transistor amps have a distinct transistor sound. It is also said that Rowlands mimic tube sound. Well, they don’t, but they do avoid all the usual transistor problems. Which is why I find them so compelling.<\/p>\n

I think I’ve heard a fair share of amps and there might well still be a real challenger for my trusty sixes, but I haven’t heard it yet. That’s why they have been part of my system for so long. Another reason is their reliability: Rowlands are built for life it seems. They always work without a glitch, never hiss or hum and behave utterly predictably. Where tube amps need frequent tube swaps and need to be carefully placed to prevent hum or other noises, Rowland is care-free. Tube fans will point out that transistors also age and that you can’t simply swap them out like tubes. If that is the case, then I’ve certainly never noticed. I frequently put my amps up for comparisons to much younger specimens and I think I would’ve definitely noticed if they had started aging.<\/p>\n

Which brings me to the last point in this introduction: operational life. I’d mentioned above that Rowlands are made for life and while that will certainly hold true for their pre-amps, I can imagine that their power amplifiers might not have eternal life simply because all capacitors (as word has it) will ultimately age. My sixes are anywhere between 14 – 20 years old now. It is because I like them so much that I am always aware of the fact that it is said that capacitors will only last around 20 years. Luckily I have engineers amongst my friends and they reassure me by saying that capacitor aging is very much coupled to warmth. And Rowlands have very good heat dissipation and also carefully place capacitors there where the least heat is developed inside the amp’s housing. Still, one can imagine that I’d be hesitant of having to recap the amps if the need arises.<\/p>\n

I was very happy to see that Jeff Rowland haven’t stopped development with the range of ICE-power models and have recently added a whole range of newly designed Class AB models (625, 725, 825 and 925), because if I were to finally replace my trusty model sixes, a natural successor would have to have a badge saying “Jeff Rowland” again.<\/p>\n

The subjects of this review, the new model 725’s, look to be the perfect candidates as replacements for the sixes, although their hefty price tag will be prohibitive for me, as well as the majority of audiophiles. But the good thing about reviewing equipment is that I don’t have to worry about that… until I want them of course!<\/p>\n

Enter the brand new Jeff Rowland Model 725 mono power amps.<\/strong><\/p>\n

\"JRDG_m725_550pix<\/p>\n

Above:\u00a0Model 725 inside – top section, housing the actual amplifier<\/em><\/p>\n

\"JRDG_m725_550pix<\/p>\n

Above:\u00a0Model 725 inside – bottom section, housing the power supply<\/em><\/p>\n

Just look at these pictures… is that superb engineering or what! And apart from the switching power supply, this is genuine Jeff Rowland class A\/B linear amplification technology. No ICE components in sight. The 725’s put out 330 watts into 8 ohms and almost double that to 650 watts into 4 ohms. Going by the looks and specs, the 725’s are very, very promising indeed. But how do they sound?<\/p>\n

<\/p>\n

\u00a0\"JRDG-Corus_550pix<\/h4>\n

Above:\u00a0Review setup – The Jeff Rowland Corus is reviewed separately<\/em><\/p>\n

725 sound, right after unpacking<\/strong><\/p>\n

Although this pair is privately used by Hans and has supposedly been in use long enough to be run in, they did arrive cold from their boxes. Naturally, I couldn’t control myself and did have a listen straight after connecting them up. After initial connection, they sounded powerful, dynamic, fast and lively. But what was missing was refinement and coherence and musical flow. They were only impressive for my mind, not sounding very emotional. They were somewhat reminiscent of the 201 ICE power units that way. I listened to them for a few hours but the sound did not improve so I just left them powered on and found something else to do. Their aluminum housing was cold to the touch and remained cold the entire evening. I was worried that they were now so eco-friendly that they wouldn’t warm up at all but those fears were unnecessary: the next morning, after having been switched on all night, they felt nicely warm and are at about the same temperature as my model sixes.<\/p>\n

Adrenaline<\/strong><\/p>\n

Before heading off to work I briefly listened to them again and was happy to find that they now sounded completely different: much more Rowland-like in terms of continuity, fluidity and charm. What remained was their massive bass control and explosive dynamics. These amps really invite to play the hardest, meanest audio tracks while increasing volume again and again. I selected a CD by Yoshinori Sunahara, filled with bass-loops and hard-hitting synthesizer sounds and the 725’s just gobbled up the deep and powerful bass stabs. At some point, my windows were rattling but the 725’s did not cave: on the contrary, they seemed to ask for more and more and it seemed they were just incapable of ever running out of steam. I found it electrifying beyond belief. It was like having Brystons yet with transparency they can only dream of. I couldn’t suppress a continuously growing grin throughout track selection and concluded: these 725’s are Rowlands on steroids! And after putting a CD on repeat, off I went for work. Lesson learned: Rowlands, like Wadias, should not be switched off for extended periods.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

\"JRDG_m725_550pix<\/p>\n

\"JRDG_m725_550pix<\/p>\n

Continued listening<\/strong><\/p>\n

After coming home from work and having had one of my indestructible spare swing-arm Philips CD players on repeat all day, the 725’s were still nicely warm, seemingly not any warmer than in the morning, when they had only been switched on but not playing any music. It seems that the aluminum housing takes longer to warm up than the more hollow model sixes but is also more stable in temperature.<\/p>\n

After playing more music I was still in love with their bass and very content with their dynamic abilities but depending on the CD that was played now became a little worried that although they definitely carried the Rowland sound signature, the 725’s weren’t quite as fluid and continuous, or as finely resolved as the sixes. But their bass power and superb control more than made up for it. This is what people are on about when they talk about authority and the 725’s have it in spades.<\/p>\n

Less fluidity or continuity is a matter of balance but less resolving power? Surely the 725’s would be just as detailed as the sixes? I couldn’t believe it and carried on testing. But the more CD’s I played, the surer I became: the 725’s trump the sixes as well as several powerhouses out there in terms of bass power, bass pitch and definition, dynamic expression and all-out stability and authority. A friend is using a Krell FPB600 on the bass panels of his Apogee Full Range speakers and swears by it, but I’d bet that the 725’s can show the Krell a thing or two in the field of bass definition and power. But at the same time, some CD’s that were previously lush and lovely using the model sixes, now were a little dry and business-like, less analog if you will. But was this really a matter of resolution? And would that classify the sixes as better than the 725’s? Of course not. But the sixes do sound more fluid and lush and more continuous. Decay goes on longer. But after some more listening, it became clear that that’s a function of their being less controlled. Bass control on the sixes is definitely not bad at all, but compared to the 725’s the sixes are more blurry and less powerful in the bass. This relative lack of control carries on through the midrange to the treble, which is, therefore, more continuous and less damped, which I like in treble when using highly accurate ribbon speakers.<\/p>\n

So, on balance, the 725’s have just as much resolution as the sixes, but more easily show dry recordings for what they are, and they certainly cannot be blamed for that. The sixes, with their more romantic view, tend to make less than stellar recordings still enjoyable but this is very much a matter of context, not of absolute quality.<\/p>\n

The more I listened to the 725’s and compared them to the sixes, the more difficult it became for me to choose between the two. I would classify them as being of equal quality, both possessing the Jeff Rowland house sound, but with shifted perspectives. Both the 725’s and the model sixes have the same superb soundstage layering, provoke emotions in the same manner and are both blessed with a perfect combination of transparency and lushness, the sixes tilting more toward a rosy forgiveness and the 725’s tilting more towards honest and dynamic portrayal. In short: the sixes are more romantic and the 725’s are more live, more life-like.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

\"JRDG_m725_550pix<\/p>\n

I have only 3 small observations regarding design choices that I was not entirely happy with, of which 2 have been addressed in a mail I received from Jeff via Hans.<\/p>\n

First, the XLR input on the rear is reversed in position compared to all connectors I have and have had in my system, less the Rowland Aeris<\/a>. This is particularly inconvenient when using stiff cables such as the Cardas Hexlink Golden 5C. In the case of the 725’s and my Transparent Reference interlink, this results in reversed network boxes, showing their screw-hole and hiding their gold nameplates from view.<\/p>\n

Jeff responded to this: “The jack can simply be rotated 180 degrees, from the back of the unit without removing any covers. Just remove the two small supporting screws on the XLR with a small Phillips screwdriver and gently rotate the connector half a turn. The input wire connected to the connector internally is flexible enough that the connector can be repositioned without any strain on the wire.<\/p>\n

Second, the blue power indicator lamp avoids being beamy on a direct axis like the blue LEDs on the ICE power models were, but all the same is beamy at an angle and overall less lovely than the very refined, candle-light-like lamps on the model sixes. The blue LEDs used in the 725 also seem to be chopped and blink at a very high rate. This is definitely not noticeable to everyone but if you are bothered by DLP flashes and the chopping frequency of the surrounding light of Philips Ambilight TV’s, you’re likely to notice this too. Jeff responded to this: “There is an internal small PC board switch which can be adjusted for faceplate lamp brilliance or even off. The switch is located on the power supply PC board and has 4 slides. Slide 1 and 2 adjust brightness. Bright is 2 on, dim is 1 on, both 1 and 2 off make light off when the amp is on. Some like bright and some prefer dim so I made the option to choose.” However, Hans indicated that the lamps were already in their lowest setting.<\/p>\n

Finally, I think that the choice of the power button is somewhat detrimental to the amp’s overall design. The casing really is a work of art and I wished they had chosen a more refined power button, like the one used on the model 10, 12 and 112.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

\"JRDG_m725_550pix<\/p>\n

The above comparisons were all done using restored Apogee Duetta Signature magnetostatics. For the final touch, I reconnected my usual Magnepan MG 3.6R magnetostatics (at first without the REL Strata subs) and re-evaluated the sixes and 725’s.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

While the Apogees were happy with both amps, the Magnepans had clearer preferences. Where the Apogees were all too happy with the added bass control and dynamic grip of the 725’s, the Magnepans became a little too controlled and did not seem to benefit from the 725’s superb bass quality. Never mind that, as this is clearly something to blame the Maggies for, because their bass panels are much more restricted in movement than the Apogees’ ribbons are. It is just the nature of these beasts. The sixes however, even if their midrange was clearly less communicative and the overall balance now seemed a little bit more boxed in, seemed to be more synergistic. They just balance out better. But after having listened to the Apogees for over a month and also having gotten used to the 725’s fantastic life-like sound, I wasn’t entirely happy with the Magnepan-model 6 sound either, mostly being discontent with the slower pace. You should know that the Maggies have always been driven using Transparent Reference XL speaker cables and while these cables always matched perfectly when I still used Spider equipment racks, ever since I started using an Artesania Exoteryc rack, the sound was admittedly a little slow.<\/p>\n

Before the 725’s arrived, the Apogees were also connected with the same Transparent cable but even if this made them more forgiving and sweeter in tonality, I couldn’t get over the slower pace and dynamic compression. The Apogees are connected using very cheap Van Den Hul cable but somehow, the combination works. So, for the Magnepans, I now also pulled out some basic speaker wire (brand unknown) and substituted it for the Transparent. Yup, back was the pace and at the same time the midrange became more open and communicative. But what remains very obvious is the Magnepan’s lack of bass power. Dynamics seem to be very constrained in the bass region. Curiously enough, reconnecting the subs not only provided better extension, more colorful sound and a larger soundstage but also greatly improved the sense of dynamics and attack. Clearly the Maggies’ midrange doesn’t lack slam or expression and is in fact very well-controlled. And that goes some way toward explaining why they match less well with the 725’s, the combination simply making for too much control. The remainder of this story is more something for the upcoming Magnepan versus Apogee review so I won’t write much more about it here. But suffice to say that because of the Magnepans’ character and flaws, the match with the model sixes (and stock speaker wire) works better for me than the match with the 725’s (using either stock or Transparent speaker cables).<\/p>\n

This is once again not a complaint at the address of the 725’s, merely an indication of what has become something of a personal mantra, which is that balance is everything. Some components work synergistically with each other while others seem to work against each other. That’s only natural.<\/p>\n

Postscript september 2013<\/strong><\/p>\n

The sixes were listened to both with and without BPSses attached. Their sound is influenced as soon as the BPS is connected. Switching them on then makes for the last mile. The sixes sound more like 725’s without the BPSses in terms of bass articulation and power, but they then also sound less charismatic, charming and less colorful. For the purpose of this review, the sixes were judged with BPSses attached, but not switched on.<\/p>\n

\"JRDG_m725_550pix<\/p>\n

Conclusion<\/h2>\n

Regardless of the different results using Magnepans or Apogees, my opinion of the 725’s remains utterly positive: they are simply fantastic amplifiers and a more than worthy addition to the Rowland Repertoire. They do not betray their legacy but manage to add more power, better dynamics, a more life-like sound and a heretofore unheard midrange purity while avoiding to slip into clinicality or leanness. What’s more: while the midrange can be slightly forward (compared to the slightly recessed model sixes) it is never shouty or aggressive. That sums up what I have become to know as the Rowland House Sound: all the transparency, tonal richness and delicacy one can wish for, combined with life-like dynamics and an utter lack of aggression. Oh, and even if the model sixes, with their 150 watts, already show big Krell KSA250’s a thing or two about bass quality and articulation, the 725’s, I suspect, will simply wipe the floor with many so-called bass champs. By the way: I’m sure that I could tweak my system in such a way that the Magnepans would work well together with the 725’s. This would involve relocating the speakers and using different powercables, interlinks and speakercables. But that was well beyond the scope for this review. I can’t afford the 725’s, not even at second hand prices. But finances aside, I would not know of a better candidate to replace my sixes with, than the 725’s. I can only dream of what the 925’s would be capable of. Scary stuff…<\/p>\n

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

External Links<\/h3>\n

Manufacturer: Jeffrowlandgroup<\/a><\/p>\n

DISTRIBUTOR BENELUX:<\/p>\n

HVP Audio
\nPrinses Irenelaan 218
\n2285GB Rijswijk
\nNederland
\nTelephone: +31 61 492 69 47
\nWebsite : www.hvpaudio.com<\/a><\/p>\n

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