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Line stage/phono stage
Convergent Audio Technology
SL1 Legend

79.000 PLN (with phono stage) or 69.000 PLN (line stage only)

Distributor: SoundClub

ul. Skrzetuskiego 42, 02-726 Warszawa
tel.: 22 586 32 70, fax: 22 586 32 71


Manufacturer's website: brak

Text: Wojciech Pacuła
Photos: Wojciech Pacuła

Both SL1 preamplifier, and its manufacturer - Convergent Audio Technology, are some kind of „phenomenons”. You won't find CAT's advertisements, they don't try to maximize their sales, they don't tempt you in any way. They don't even have their own web site! All company's activities are in contrary to rules of running an effective business in contemporary (post)capitalistic world. CAT has though something in common with some other, very special also American company like Spectral – it is a specific philosophy, that might be called „soft power”. Ken Stevens, the owner of Convergent, assumes, that what he does at the moment is the best he can do and to keep it that way he must supervise every single stage of production, listen personally to each manufactured piece of equipment, and he also personally assembles most of the pieces. That surely limits company's capacity. That means he doesn't have to try to find buyers – they have to wait for him to deliver, and they have to be very patient. It is a very interesting approach because most of the manufacturers want to move passed this phase of business to become a company of Krell's or Audio Research's size. I really appreciate these companies and admire many of their products, but still in my opinion the ultimate high-end must be custom made with limited supplies. And „custom” means also that the Master himself has to give his personal touch to each and every device that's made. I'm quite sure about that because I can observe it almost every day watching Ancient Audio devices – the approach of Mr Waszczyszyn, company's Owner, is exactly as described above.

The very foundation of such activity and such business approach is PRODUCT. Product, isn't that always the case of running manufacturing busines? Yes, but there is a huge difference between product and PRODUCT. The latter is something really finished, done, that can be only slightly polished but not really improved, or its core character doesn't change even with some minor improvements. And that's what SL1 is. It's a first product Ken Stevens introduced to the market 26 years ago. Sure there were some small changes, minor improvements – but these were only „cosmetic” changes, nothing substantial. To keep it simple manufacturer added „Reference”, „Renaissance” or „Legend” to preamp's name. But the primary name has never been changed, officially there was never any Mk. add-on to the name – it was used only in company's materials for internal use, to make it easier for them to distinguish one version from another. Just to be clear – everybody who tested different versions of SL1, claimed that the newer sounded better, some aspects of sound got improved (which only proves that Stevens worked really hard to improve what already had been almost perfect), but they all also claimed that the general character of SL1's sound did not change.

Recordings used during listening sessions:

  • HiQualityCD. Jazz Selection, EMI Music Japan, TOCJ-90010, HQCD + CD; review HERE.
  • Musik wie von einem anderen Stern, Manger Products, MANG-2010, 2 x 180 g LP.
  • Ben Heit Quartet, Magnetism, Acousence Records, ACO80108, 24/192, FLAC.
  • Billie Holliday, Songs For Distingue Lovers, Verve/Classic Records, One-sided, 2 x 180 g, 45 rpm LP.
  • Buck Clayton, How Hi The Fi, Columbia/Pure Pleasure, PPAN CL567, 2 x 180 g LP; review HERE.
  • Clifford Brown and Max Roach, Study In Brown, EmArcy/Universal Music Japan, UCJU-9072, 180 g LP (mono).
  • Depeche Mode, Fragile Tension/Hole to Feed, Mute Records, 12BONG42, 2 x 180 g, maxi-SP LP.
  • Depeche Mode, World in My Eyes/Happiest Girl/Sea of Sin, Mute/Sire, 21735, maxi-single LP.
  • Don Friedman Trio, Circle Waltz, Riverside/JVC, VICJ-60258, XRCD².
  • Frank Sinatra, Sinatra&Strings, Warner Music/Mobile Fidelity, MFSL 1-313, No. 199, 180 g LP; review HERE.
  • Jim Hall, Live!, Horizon/A&M Records/Universal Music Japan, UCCM-9225, CD.
  • John Coltrane, Giant Steps, Atlantic/Rhino, R1 512581, 2 x 45 rpm LP.
  • John Coltrane, The John Coltrane Plays, Impulse, IMP 12142, CD.
  • Julie London, Julie is her name. Vol.1, Liberty, LRP 3006, LP.
  • King Crimson In The Court Of The Crimson King, Discipline/Universal Music Japan, UICE-9051, HDCD.
  • Kraftwerk, Tour The France Soundtracks, EMI Records, 591 708 1, 2 x 180 g, LP; review HERE.
  • Laurie Anderson, Homeland, Nonesuch, 524055-2, CD+DVD.
  • Lionel Richie, Can’t Slow Down [DeLuxe Edition], Motown/Universal, 181202, 2 x CD.
  • Marty Paich, I Get a Boot Out of You!, Warner Bros./Warner Music Japan, WPCR-13187, SHM-CD.
  • Michael Jackson, Thriller. 25th Anniversary, Epic/Sony Music Japan, EICP-963-4, CD+DVD.
  • Pery Como, Como Sings, RCA/BMG Japan, BVCJ-37258, K2 CD.
  • Robert Plant & Alison Krauss, Raising Sand, Rounder, 478020, 24/96, FLAC.
  • Tori Amos, Abnormally Attracted To Sin, Universal Republic Records, B0012906-01, 2 x 180 g LP; review HERE.

Readers sometimes ask me how was it possible that when testing say an amplifier costing 4.000 PLN I wrote that „treble was simply amazing” and when testing another costing 50.000 PLN I described its treble as „bit gentle, not so rich as in the reference system”. „It's pure nonsense” some say, pointing out that either they should buy cheaper amp forgetting about the high-end one, or I wasn't really telling the truth. Well – maybe it doesn't happen that often but still some Readers ask this kind of questions because they understand my texts too literally. I think I should try to make my intentions more clear for everyone which will also come handy when you read this review. The right word is “relativity” which is a necessary term when reviewing audio equipment. When testing any device I try to compare it first with my reference one of the same kind, regardless of this device's price. The bigger the price and performance difference the better – always when making some comparison you have to assume that there is a difference between your reference point and what you try to compare to it and that the reference point is at least one class better. Same principle is in force on university – dissertations are always assessed by someone with higher academic degree. And only after that I try to cross-reference this device with its competitors at similar price level. When writing a review I don't distinguish one result from the other – I treat them as a whole. So it's on the Readers side to draw proper conclusions – when I say „treble was simply amazing” when testing and amp costing 4.000 PLN I mean „at its price level”, „comparing to similar devices”, and I base my opinion on both – knowledge of direct competitors but also on how it compares to my reference point.

I needed this introduction to make sure you will read this particular review properly. I wanted to remind you that when it comes to high-end devices differences between them are usually really tiny, much smaller than between hi-fi devices. But to describe these tiny differences I still need to use the same words, phrases, expressions. So please keep that in mind when reading this text – same words but less weight to them. CAT SL1 Legend is a member of a very small group of the best preamplifiers I know. Sure – there are still a lot of ingenious devices that I haven't been able to listen to yet, but the list of those I have, is also already not so short. Again so that we are all on the same page here - CAT SL1 is one of the best preamplifiers I've ever heard. What's more is that equally brilliant are both: line stage and phono stage, which makes it a very unique device even among those best ones. Usually when line stage is great phono stage isn't that fabulous or the other way around. Lets start with general description. The sound can be described partially as “tube-like” but in some aspects as “solid-state-like”. In a perfect world there wouldn't be a need of using such descriptions as it wouldn't matter what's the technology behind the device. But the perfect world doesn't exist.

„Tube-like” is mostly CAT's timbre. It offers a very smooth, rich, complex sound. Transient attack is a bit softened to make it sound more “analogue”. It is most obvious at the top end and at the bottom end of frequency range – that reminds me of a sound of Nagra PL-P (HERE and HERE). The lowest bass is not so rich and complex as offered by my own Ayon Polaris II, but on the other hand Luxman C-1000f, and Accuphase C-2810 offered similar sound even though these were solid state devices. These are not significant differences and if you use a tube amplifier then the final sound will be defined rather by power tubes. Surely I couldn't complain about the quantity of bass tones. Lets listen to the opening piece from latest recording of Laurie Anderson Homeland called Transitory Life – a wonderful tune with a very low bass which can be properly handled only by very few devices. CAT presented these in a very nice way – full, extended with good timbre. It wasn't perfect as Polaris did it better, but it was very, very good. Later I listened to many recordings from 50s and 60s, mainly to listen to double bass and there were no significant differences between both preamps. During Circle Waltz by Don Friedman Trio, I Get a Boot Out of You! by Marty Paich, and even during powerful big-band piece Como Swings by Pery Como presentation was perfect. Wonderful timbre, richness and control. Higher up the frequency range it should get even better not because of any weakness of bass range but because of how remarkable is the midrange. But I should talk about it bit later. Important thing is that bass range offered by CAT is at least as good as from competitors like Luxman, Accuphase or Art Audio Conductor or maybe even better.

The way of treble presentation is (no judging yet if it is better or worse) similar to all three above mentioned devices in terms of richness and transient attack. The closest match is Accuphase, than ArtAudio and Nagra. Transient attack is bit rounded so more vibrant than the one from Polaris or for example VTL 5.5. It sounds also very alike transient attack offered by Audio Research Reference 3 (I haven't heard Reference 5 so far), and somehow also like tube module of McIntosh C-500. Same level of performance, and very similar way of presentation – rich and strong. Because one thing is sure - CAT doesn't roll off treble. Some of you would probably prefer me to begin with this last information pointing it out as its main advantage.

But I think that it has even more meaning for you now after reading the rest of the description. SL1 Legend offers strong treble and upper midrange. On one hand sound is not so direct as offered by the best passive preamps and my reference one, but on the other CAT's sound is richer and more … communicative than this of passive preamps and differentiates sound better than Polaris does. Yes, CAT is unbeatable when it comes to differentiation of treble and upper midrange. The only system I know that is capable of even more in this aspect is Ancient Audio without preamplifier, or in fact with preamp integrated into CD player. All I needed was to listen to King Crimson's In The Court Of The Crimson King - ingenious recording of cymbals to have a prove of my opinion: CAT was able to much better differentiate how each cymbal was hit, with how much power, where exactly, etc. It was much easier to admire and follow drummers technique. Same impressions came from John Coltrane's The John Coltrane Quartet Plays - this material was not so perfectly recorded which made it even more difficult to verify my theory but it was still possible. The American preamplifier was also better than Polaris when it came to presenting own noise of master-tape. Surely nobody listens to this noise but it shows you very well the quality of the high frequency range presentation. Basing on it I could clearly tell how fabulous was the resolution and the ability to differentiate high tones.

This particular character of the sound is a result of preamplifier's designer intentions who obviously wanted to achieve some particular kind of sound. The most important is surely the midrange but it's not as warm as in Nagra, ArtAudio or Accuphase nor in any way boosted. I could just simply tell that midrange was the most important part in designer's intention. Sound is not warm (nor warmed up) and because treble and upper midrange are presented in a strong way you can't really tell that it is a tube device playing. A „tube” feature might be a slight rounding of transient attack but nowadays lot of top solid state preamplifiers does same thing. The mid-bass is deep and full and only the lowest part of the range sounds bit more like a tube device. Apart from this last element the most part of frequency range, how it is designed (not the sound itself), reminds me of (better in my opinion) solid state module of already mentioned C-500. So far I presented only the midrange but that's the part that really decides if this particular device could fit into your system. The sound as a whole is bit thinner than sound from Polaris, not to mention much more “tube-sounding” devices like Art Audio and Nagra, but also Luxman (not talking about technology but about sound character). From my point of view, from the point of view of my system in my room Polaris fits better. But it is of course only some choice I made, or to be more exact something that fits my preferences better. Most likely in a bigger room with bigger loudspeakers I might chose CAT over Polaris as more proper device in regard of tonal balance. In such big room there is a space to build a large sound and than you need to have as good control over all aspects of the sound as possible. Polaris might in such case be bit too “warm”, too massive sounding. But in my opinion in smaller rooms this slight enlargement of sound offered by Austrian preamplifier defines sound better. One thing I really love about Polaris is how rich is the midrange. It is not about boosting this range but about how rich it is. I prefer to hear each instrument “here and now” with very rich, full sound even if it's not 100% true sound. CAT creates the sound not so close to the listener – rather in some distance. As I say it is a question of personal preferences because after all you will never have exactly the same sound at home that you can hear at live concert regardless if you use CAT or Polaris.

Line stage is one thing but the phono stage is the other, separate one. If you take a look inside the device you will surely notice how similar topology of both stages look like. They take even same amount of space. In other words – they were both treated with the same care and attention when designing whole device. Usually the line stage is obviously the key part and phono stage is only an addition. The only known to me exception is Polaris II. Its phono stage includes twice as much tubes as the line stage. But somehow I wasn't convinced with the sound of this phono stage so I ordered only a line stage and kept RCM Audio Sensor Prelude IC as external phono stage. During three years only very few other phonos could match Prelude in terms of speed, precision but also surprisingly richness of the sound. The only clearly better device was Manley Steelhead v2. When I saw how CAT was built I became anxious to listen to some records.

At first I listened to CAT with my own phono stage. The surprise was a difference between sound CAT delivered with digital player and with analogue one. With turntable sound became richer, deeper, fuller. But at the same time treble became somehow weaker, and bass not so well controlled. I got same result in every case – I started with comparing same mixes issued on CD and on vinyl, like Kind Of Blue (50th Anniversary Collector's Edition) Miles Davis (HERE) or one of my latest buys – wonderful edition from Vinyl Factory - Massive Attack album Helligoland. I was really surprised because that meant that CAT was able to differentiate the signal depending on the source in an extraordinary way. The characters of both: turntable – Avid Acutus Reference, and cartridge – Miyajima Waza were easily recognizable. When I switched to CAT's phono stage listening became nothing but pure pleasure. I couldn't compare it head to head to Steelhead, but since I listened to the latter every now and then in different systems I knew very well differences between it and my Sensor Prelude. So I could make a bold statement - CAT was one of the best of the best phono stages I knew. And clearly the best phono stage inside integrated device. Its sound was deep, rich but also very precise. In my system CAT offered better control of low range and more vibrant treble than external phono. I didn't have that much time to listen to records as I had for CDs as I left this part of a test to be the last one. I could only regret this decision. The sound was extremely emotional. Maybe it wasn't that precise as with CD Player or hi-res files player (with CEC DA1N DAC ), but it had this “something” that made listening to records more pleasant than listening to digital recordings. BRAVO! Additional advantages - you don't need additional interconnects, power cables – all in one box and the final effect absolutely outstanding, better than anything I've heard before. The line stage offered incredible precision and phono stage made sound richer, fuller which was the only weakness of line stage itself. The final effect – absolutely wonderful, amazing, one of the kind!


Model SL1 Legend is top of the line preamplifier from American company Convergent Audio Technology. There are some significant differences between this one and Renaissance model. Here they use two separate 46-positions shunts, with lots of resistors soldered on creating a resistor ladder to control volume. There are two pots – separately for the left and right channel, instead of one and a balance used for Renaissance. For Legend they also use very expensive Rubycon's Black Gate capacitors (twenty two times more expensive than other also high quality models), that feature extremely solid housing which makes them also much heavier than most other ones. Also Circuit board material is much better than usually used. Before it was G200, now it is made of Teflon.

SL1 Legend is both: line stage and phono stage. The main unit sports amplifying elements and the smaller enclosure power supply. Front panel is a thick aluminum plate with two slots cut out – each of them holds three toggle switches. The ones on the left side serve as input selectors, and functions of these on the right side are as follows: play/record, standby and mute. There are two small knobs in the middle - they serve as volume control, one for each channel. There is no remote control and both knobs are not coupled in any way. It can be done – I know such solutions from some Tascam and Studer tape recorders. But obviously CAT's owner can get used to this solution as I haven't heard any of them complaining about it. Back panel holds RCA inputs and power cables that is not detachable connecting main unit with power supply. Spaces between all RCA sockets are big enough so the use of them is comfortable. Starting from the right the first one is for turntable connection. There are also optional RCA jacks with resistors allowing to use different cartridge loadings. Standard loading is 47 kΩ (no additional jack required). Exactly the same solution was used for Ayon's Polaris II (to be honest I think that Gerhard from Ayon Audio somehow looked up to SL1 when designing his device). Next to it there is another phono stage input as SL1 works with both: MM and MC cartridges. Next three are line inputs including one with Tape loop, Direct – which is output to power amp, and an output marked as ‘AV’ - another loop allowing SL1 Legend to be connected to home cinema system. If the preamp is turned off than signal from ‘Line 1’ input is driven directly to ‘AV’ output. I couldn't find much about it in the manual but I think it can also be used to connect Head Amp to CAT (unfortunately you can use only one input but it is better than none, and I miss such solution in Polaris).

The inside of the device is really filled up from bottom to the top. It is clear that there are two very similar parts – line stage and phono stage. Both are based on tubes – two 6922 in input, two 12AX7 and single 6922 in the output. 6922 tubes come from Electro-Harmonix, and 12AX7 are NOS tubes from Yugoslavian Ei. The Legend's phono stage uses in the input section a special low-gain step-up transformer with CAT's logo on it (MCM-1) that in conjunction with an initial moving-magnet stage delivers 58dB of gain. The transformer can be set for an additional 6dB of gain, but this is only recommended by CAT's designer for cartridges whose internal impedance is under 10 ohms – so my Air Tight PC-1 Supreme could benefit from it. Because of its low gain, the transformer's response is much flatter than that of others - drifting less than 0.02dB from 20Hz to 20kHz. The whole circuit board is filled with polypropylene capacitors marked with CAT's logo. Line stage looks similar but it doesn't include RIAA circuit and input transformer. Its gain is lower though – it's just 26 dB. Gain is adjustable via a switch inside the control unit, which reduces it to 15dB, which allows to better adjust it to particular amplifier and loudspeakers. I used 15 dB gain during my test. Input selector is based on toggle switches. The whole interior is tiled with damping material.

Power supply has its own enclosure built with steel plates. It's not too big and it's connected with the main unit with a very stiff cable. Therefore moving the device and installing it in the system isn't easy. You can find a huge EI transformer and Black Gate capacitors inside the enclosure. On/off switch is also placed in power supply's enclosure. Together with the device Customer gets proprietary power cable called MusicCordPro. Ken states it clearly in the manual that it is highly recommendable to keep it and not to exchange it for any other because it could make the preamp sound worse. My own Polaris was coupled with Acrolink 7N-PC9300 though.

Manufacturer's details:
Convergent Audio Technology
85 High Tech Drive
Rush, NY 14543
tel.: (585) 359-2700

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  • CD player: Ancient Audio Lektor Prime (tested HERE)
  • Phono preamp: RCM Audio Sensor Prelude IC (tested HERE)
  • Preamp: Leben RS-28CX (tested HERE; soon to be changed to Polaris II, tested HERE)
  • Power amp: Luxman M-800A (tested HERE)
  • Integrated amp: Leben CS300 (reviewed HERE)
  • Loudspeakers: Harpia Acoustics Dobermann (tested HERE)
  • headphones: AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, 600 Ω version (reviewed HERE, HERE, and HERE)
  • interconnects: CD-preamp: Wireworld Gold Eclipse 52 (tested HERE; soon to be changed to Acrolink Mexcel 7N-DA6300, article HERE), preamp-power amp: Velum NF-G SE (tested HERE)
  • speaker cable: Velum LS-G (tested HERE)
  • power cables: Acrolink Mexcel 7N-PC9100 (CD; reviewed HERE) and 2 x Acrolink Mexcel 7N-PC7100 (preamp, power amp (reviewed HERE)
  • power conditioning: Gigawatt PF-2 Filtering Power Strip (reviewed HERE)
  • audio stand Base
  • resonance control: Finite Elemente Ceraball under the CD (article HERE ) Turntables change continuously, as do cartridges. My dream setup: SME 30 with Series V tone-arm and Air Tight PC-1 cartridge (also in the PC-1 Mono version).