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Line preamplifier

Price: 8500 zł

Distributor: MJ Audio Lab

ul. Belwederska 20/22 (wejście od ul. Sułkowickiej), 00-762 Warszawa

phone: 22 397 79 08, 888 693 711, 506 063 857

WWW: Conrad-Jonhso

Text: Wojciech Pacuła
Translation: Krzysztof Kalinkowski

Classic is the cheapest preamplifier from the American company Conrad-Johnson. In this case cheapest does not mean cheap – CJ products are part of the hi-end world and this – despite that, what I wrote a moment ago, but also due to their sound. It’s just that quality has its price… Even in this ‘entry-level’ preamplifier we can find most of the solutions, which make the CJ have its own, developed during its thirty years of history, sound aesthetics. Three solutions are most important for CJ: the preamplifiers have only one gain stage and work in class A, there is no negative feedback loop, and in the sound path as well as in the power supply all the capacitors are polypropylene or polyester ones, manufactured by the company itself. Each of those elements can be found in preamplifiers from other manufacturers (although finding units without any electrolytic capacitors will not be easy), but all of those in one device – this is extremely rare. It is easiest – against appearances – to explain lack of feedback. As it is known, NFL is a technology, that connects the input of a circuit with its output (a part of the signal from the output goes to the input). This allows for a wider frequency response, lowers distortion and improves the stability of the circuit. But there is one big problem with this solution, while it looks perfect on paper – it introduces phase discrepancies (the electric signal has a finite speed). And introducing a signal which has a shifted phase – by a small amount, but still – with regard to the base signal, means blurred and less precise sound. Resigning from the feedback is a way to get around phase shifts. This is possible under a certain condition: because the circuit is in no way corrected, it has to be of a very good quality on its own. Simple, but so difficult to achieve.

No electrolytic capacitors is also well justified – electrolytes have a very non-linear characteristic and are often accused for bad sound. The problem is, that high capacities can only be reached in that technology. CJ circumvents that to some extent, by manufacturing very big polyester and polypropylene capacitors, which work together with very worked out, active, stabilization circuits. In the CJ company materials, we can read, that the Classic has one gain stage, but it contains also a buffer on the output, which lowers the output impedance. Also because each gain stage changes absolute phase by 180°, having only one results in absolute phase being reversed. This can be corrected by using the function in a CD player (if available), or reversing the plus and minus poles in the loudspeakers (both, not only in one!). For the test, except my system, I used also the turntable Dr Feickert Woodpecker with the cartridge Ortofon SPU Synergy A.


Discs used for testing:

  • Al Di Meola, John McLaughlin, Paco De Lucia, Friday Night in San Francisco, Philips/Hi-Q Records, 6302137, 180 g LP.
  • Art Garfunkel, Fate For Breakfast, CBS, 86090. LP.
  • Bill Evans Trio, Waltz For Debby, Riverside/Analogue Productions, 9399, No. 773, 2 x 45 rpm LP.
  • Clifford Brown and Max Roach, Study in Brown, EmArcy/Warner Music Japan, UCJU-9072, 180 g LP.
  • Count Basie&Tony Bennett, Basie/Benett, Roulette/Classic Records, SR 25072, 4 x 45 rpm, special one-sided pressing, 180 g LP.
  • Depeche Mode, Wrong, Mute Records, 12BONG40, maxi-SP.
  • Enya, Watermark, Warner Communications Company, 243875-1, LP.
  • J. S. Bach, The Works of Johann Sebastian Bach. IX. Research Period, Archive Production, ARC 3162, LP.
  • John Coltrane, Giant Steps, Atlantic/Rhino, R1 512581, 2 x 45 rpm LP.
  • Kraftwerk, Tour De France, EMI, 591 708 1, 2 x 180 g LP.

Japanese editions of the CDs can be found on CDJapan.

Listening to discs using the Conrad-Johnson preamplifier in the system is pure fun. But you have to forget about one thing, that turns some audiophiles on, and is mostly ignored by music lovers – about analyzing the sound in hi-fi terms. Because how would you perceive the words: “The Classic sounds with a full, warm sound, in which the main role is played by the midrange and slightly rounded mid-bass.”? Those are the words I noted in the beginning of the listening session and underlined when finishing it. And this statement is true, from the beginning to the end, in my opinion, and is the quintessence of the basic preamplifier CJ offers. So from the hi-fi point of view, meaning some way of looking at the sound, implying achieving the musical truth from the accurate way, not adding any elements, even at the cost of omitting some elements, this sound is not “correct”. And in this context correct sound means good (not bad). And this is something else than “accurate”.

And the Classic, in general, sounds in an absolutely correct way, it fulfills its basic purpose, an audio device has to perform: it plays music in a way, that it makes joy. I am not forcing this statement at all expense, because a top performing device has to be based on an objective master, as widely accepted. Even then, the choices made by listeners are as important, as the sound quality, but their “weight” is lower. But it is different in the price category the Classic is in. This is quite an expensive preamplifier, but not the priciest one. This is why there is a large margin, where one proposition is equal to another, while keeping the basic suppositions valid. In case of the tested preamp this is especially important, because it does not prone with detail, resolution and frequency extension. Without any shame, the most important sub-range is here the midrange. This is quite common in devices without a feedback loop. This is the reason, that the CJ preamplifier reminds a bit that, what was inherent to the integrated DM-10 from Densen. This kind of sound is incredibly fluent, smooth, although it lacks resolution, the latter is achievable without a feedback loop only in top offerings, and we have to become reconciled with that.

But when we accept those limitations, then we can continue… The American preamplifier has an incredibly pleasant timbre. I tested it with a few power amplifiers, mostly solid state, and it turned out, that the Classic brilliantly “fitted” with expensive loudspeakers. Although earlier, when I connected cheaper solid state preamplifiers to my system, the Dobermann from Harpia Acoustics sounded a bit nervous, showing the flaws of the solid state technology more, than they should (this is just how those loudspeakers are). Changing from those preamps to the Classic all this sanding up disappeared. Instantly. The American device sounds with such a saturated sound, that it imposes it on the whole system. The mid bass is so intensive, that even flat, bass shy loudspeakers, start to sound as if their bass sections would be exchanged to a bigger one. But this is no “subwoofer” effect (in the bad meaning of that word). This is a splendidly coherent sound, there is no place for any holes. Just everything in a system gains sense, becomes live. Listening to music employing such a “filter” is fantastically relaxing and joyful.

A “filter” is a cursed word in the audiophile vocabulary. It implies sound processing, distorting it, and this is just bad. And true – every modification of the sound is something bad, this is not the way to go. But when we look at any device, then it will turn out, that each one of it, is actually a worked out, complicated filter: the sound on the output is always a bit different to the sound at the input. The changes done to it, their extent and their correlations are key to the sound we get. And in this context, the modification of the signal as introduced by the Conrad-Johnson preamplifier, it is completely “normal”, conform to that, what happens in other devices. But I must confess, that it is extremely rare, to find a device, for the given money, coming from a known company, which sound would be as mature, as thought through, as “digested” during long listening sessions, as is the sound of the Classic. It is not possible to create a device with such a beautiful timbre, soft, but not rubbery attack, based only on measurements. This can only be achieved by thorough listening, having a vision, of what we want to achieve. Each disc played with the CJ sounds, as if this would be a bit “bettered”, as if its weaker sides would evaporate. This happens due to the softening of the sound attack, and the slight softening of a part of the treble and upper midrange. Now because the latter is not limited to a narrow band, but has an even distribution, we do not see it as an error, but like a “quality”. At the same time the dynamics of the device is surprisingly good, what should be hard to achieve with a rounded attack. So the guitars from the Doors box sounded very well, similar to the accompanying Hammond organ. The instruments had their own micro-spaces, were “bold”, and did not flow together more, than the price of the device would suggest. Voices, like Frank Sinatra or Art Garfunkel were shown to the front, had a full body, and were well connected to the rest of the sound stage. The latter is closer to the listener than from the Polaris II or the Polish Absolutor, and the instruments are not so focused on the stage.

Whatever I could write, how would I not try to explain this sound, I will stay within a few statements and words: full, warm, organic, vivid, connecting everything in one symbiotic whole, etc. This is how the Classis is, and how it probably was meant to be. The power amplifiers from this price range usually sound a bit light and lack “spirit”. And the CJ can provide them with that spirit. It pays a price for it, because it is not an “analytical” device, it cannot be used to analyze a system or a recording. It sounds resolved and detailed enough, for the money, but we can hear, that those are only supportive elements, and not something equal to the timbre. Vividness is an additional key word, that can be used when listening to the Conrad-Johnson. Every time we will get everything I described above, but also something in addition, the musical spectacle. If this is what you are looking for, if you do not want to kick-in open doors, then please give the Classic a listen. The lack of a remote can pose a problem, but this is something, no one can solve.


Classic SE Factory Export Edition is the cheapest preamplifier from the American company Conrad-Johnson. Yet it employs all the key technologies more expensive products have, as well as the characteristic, for this company, external design. The front panel is made from aluminum anodized gold. The same color is used for the knurled knobs – one for volume control, the other for changing inputs. Also the big, yet stylish, power switch is also golden. The knobs resemble those used in the 70-ties. There are six inputs, one of which, named “Aux1/PH” can be converted to a MM cartridge phono input. According to the company materials, this is achieved by installing an additional PCB inside the unit, containing a RIAA preamplifier based on three double triodes 12AX7. This is the reason, that next to this input a grounding terminal was installed. There are two variable outputs, parallel, based on RCA sockets. Classic is not balanced. There is also a fixed output that can be used for a recorder or headphone amp. All those sockets are of mediocre quality and are placed close to each other. This was the reason I could not use the Acrolink Mexcel 7N-DA6300 interconnects, which features thick, carbon plugs. To the side we have also an IEC power socket. The enclosure is made very well, because the side and top plates are made from thick aluminum plates. The Classic is supported by four rubber feet.

Conrad-Johnson splits their products in two groups: FET based devices and tube based ones. The Classic is a member of the second group. The amplifying circuit is based on small power triodes M8080 with damping rings, one for each channel. We deal here with only one amplifying stage. This means that the absolute phase is reversed and – usually – there is no output buffer lowering the output impedance. In the first case, when our CD player does not have a phase inversion switch built in, we need to reverse the connections of the plus and minus leads in both loudspeakers. The second case requires thorough choice of accompanying devices – the amplifier should have the input impedance as high as possible, and the source as low as possible. The frequency response will depend on those parameters. But as the Classic was designed to match a variety of devices, it was equipped with a suitable output buffer.
The whole circuit was mounted on a single, big PCB. It turns out, that the gramophone preamplifier is not mounted on a separate PCB, but empty places on the main PCB are populated. From the markings it can be seen, that this circuitry takes more space than the line preamplifier section. I already mentioned the active elements – the passive ones are of a very high quality: a splendid potentiometer from Noble and an equally solid, mechanical input selector, Dale resistors, and polyester and polypropylene capacitors made by CJ. The transformer, of classic EI type, has two secondary windings – one for the heater and the second one for the anode voltage. Both are initially filtered in… electrolytic capacitors. Visibly some cost cutting must have been done, and high capacity capacitors, other than electrolytic, are very expensive. But later the voltage is filtered many times in expensive, dry capacitors and stabilized. Finally the output is keyed with relays.

Technical data (according to manufacturer):
Gain: 22dB
Maximum output voltage: 9.5V Rms
Distortion: <0.15% THD
Frequency response: 2Hz – 100kHz
Noise: -98dB (at 2.5V on output)
Tubes: 2 x M8080
Weight: 7kg

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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).