conrad-johnson CA150 integrated amplifier

In conrad-johnson parlance, there is no such thing as an integrated amplifier. Of course, integrated amplifiers exist, but c-j doesn’t make them. Instead the company makes ‘control’ amplifiers. This is a power amplifier with basic source switching and volume adjustment of a solid-state line preamplifier in the same box. Just to make things even more confusing, many audio companies used to call a preamplifier the ‘control unit’ or even the ‘control amplifier’. The new CA150 integrated, er, control amplifier is the first such design from c-j since the CA200 of 10 years ago.

Delve deeper into the concept of the control amplifier, c-j style, and there is a distinction between a device like the CA150 and most integrated amplifiers. The company suggests most integrated amps throw the baby out with the bathwater, eliminating key features and better quality components just to make a cheaper product. Instead, the CA150 is more an exercise in high-performance space-saving, essentially combining the company’s solid-state stereo power amplifier with a solid-state variant of one of c-j’s preamplifiers in one chassis. In the process, rather than paring down the quality too far, the CA150 eliminates the need for potentially sonically deleterious long interconnect cables between preamp and power amplifier. Eliminating the line stage – especially a c-j tube line stage – also has a direct benefit in that the output at the loudspeaker terminals is in absolute phase (c-j preamps typically invert phase).

In fact, the amplifier is so ‘two amplifiers, alike in dignity’ that happen to share the same case, the pull to separate the sections in description is incredibly strong. Normally we’d describe this as a six/seven line input amplifier that is capable of delivering 135W into eight ohms, but that seems too reductionist. The six/seven input stage (six line inputs, plus one extra line input that is also a theatre by-pass input if required) bears a striking similarity to the ET3 preamp from the brand, with a Burr-Brown level control and the removal of the single 6922 tube for voltage gain (and unlike the ET3, there is also no provision for adding an optional phono stage). Instead, the CA150 uses the FET-based voltage gain stage of the power amplifier, which is coupled to a bi-polar output stage. As with all c-j designs, this is a low feedback design. Eagle-eyed c-j amp spotters may notice the FET-in/bi-polar out design is remarkably similar to that found in the company’s recent return to solid-state power amplification, the MF2550 and MF2775, and given the power output and size of the chassis, it’s fair to conclude this is basically most of an ET3 meets all of a MF2775 in one box.

The CA150 shares another key design element with the MF2775 power amplifier – it takes forever to come on song. We had this amp happily working away on a low gas for the longest time, and judging by the performance upgrades delivered by running in the power amp, there’s still a way to go. It’s already sounding pretty much great, though, but we know that a month longer down the line and this amp will continue to give up more. Deadlines trump extended burn‑in, however.

In fairness to the CA150, it started well and just keeps getting a little better with every turn. Sounds that were already free and natural sounding are becoming just that bit more free and natural sounding over time. We know where this is going though, and it’s already got about 85% of the way there.

As with all things, there are trends in audio amplification. The current vogue in audio amps is to make things brighter and more forward sounding than previous generations. There are exceptions of course, but many of them are not solid-state designs. In fact, c-j makes many of those exceptions, and the CA150 tonally fits right in with the rest of the range.

There is a sense of unforced linearity and balance to the CA150’s sound and it bestows that sound upon everything it touches. And in the process, it doesn’t just challenge the received wisdom of going for forward sounding electronics, it presents the loyal but unshakable opposition. I can imagine those who think all music should be fast and forward will probably find alternative amplifiers, but there’s something intrinsically musical about the CA150’s sound that reminds you of listening to live concerts that few of those more forward sounding amplifiers can deliver to the same extent.

Musical examples here are legion. The CA150 lends itself towards jazz like the two were made for one another. ‘Bluesnik’ by Jackie McLean [Bluesnik, Blue Note] is a perfect example; McLean’s alto playing interplays with Freddie Hubbard’s outstanding trumpet work like the two were in the room with you. You hear how the two were at the top of their game, how jazz was undergoing massive change in the early 1960s and yet still retaining its melodic roots. This hard bop track is exhausting (horn players are especially fond of Hubbard’s extraordinary solo, knowing they’d struggle to ever replicate anything like that, let alone improvise that kind of musical dynamism), but through the CA150 it manages to retain that energy yet not prove in any way fatiguing. This is a sign of an amplifier that is delivering an accurate harmonic structure to the music played, but is not adding its own signature.

In a way, this amplifier represents the best of both worlds. It’s got the sinew and control over the music expected of a good solid-state amplifier, yet has a lot of the sensual flow and lyricism of a good valve amplifier. It doesn’t gloss over transients in the way too much harmonic distortion can sometimes, but it also isn’t so bleeding edge that it turns music into a stream of brash musical attacks. In other words, it’s a levelheaded performer. Once again, this is best highlighted by acoustic music, especially piano: Uchida playing Beethoven’s sonatas [Philips] can be too ‘clean’ for some, but the amplifier tempers this without suppressing it: the delivery is cut-glass perfect to match her playing style, bringing out the passion and energy she puts into her playing to such an extent you start to think the critic who once said, “she plays like a Japanese sewing machine” was not listening through good enough equipment. The sound this amplifier produces is so effortless, so unforced that it just gets out of the way of the music it is reproducing.

The tonal balance, however, is distinctly old-school in approach. This, to my mind, is a good thing – the tonal balance being distinctly honest next to more immediately exciting and crowd-pleasing presentations. However, this doesn’t necessarily make the best of a bad job and anyone listening to ‘Some Might Say’ from Oasis’ (What’s the Story) Morning Glory? [Creation] will find it sounding shouty, flat, and uneven. More forward sounding amplifiers make this forward and compressed sounding recording seem exciting and vibrant, but the pivotal word is ‘seem’. The reality is the track is shouty, flat, and uneven, and the c-j tells it like it is because it’s not presenting an artificially forward sound.

Let’s not get carried away by the unforced, ‘unforward’ aspects. This is an energetic, dynamic, and detailed amplifier with outstanding imaging properties, and more than a little punch to its performance. It’s not governed by its beat, but neither is it unrhythmic in its presentation. But basically the CA150 is honest enough with its musical wards that not very well recorded music has nowhere to hide. Not in an exposed, etched top end detail way, but simply that well recorded music sounds so damn great through the c-j amplifier, you are disappointed when recordings not so hot don’t sound anywhere near as good as you’d expect. And yet, this amplifier is not stark in its portrayal of sound; it’s just so great on acoustic sounds, you want the same throughout.

I’ve listened to a lot of different amplifier designs this issue: some solid-state, some hollow-state, and some undergoing some kind of identity crisis. None have been quite so approachable, so listenable, and just so damn enjoyable as the conrad-johnson CA150. It’s a grown up amplifier for grown up listeners. It’s a refined, civilised design in an age that has forgotten what refinement and civility mean. It’s a lot more than that, too; powerful, dynamic, potent, and even rhythmic in outlook. In short, it’s a delight to play music through this amplifier. Firmly recommended.

Technical Specifications

Type: Integrated ‘control’ amplifier

Inputs: 6× single-ended RCA, 1× Processor/tape pass‑through

Power: 135 watts per channel RMS both channels driven into 8 ohms from 20Hz to 20KHz at no more than 1% total harmonic distortion or intermodulation distortion

Small Signal Distortion: less than .1% at mid-band

Sensitivity: 2.0 Volts rms to rated power

Frequency Response (at 10 watts): 20 Hz to 20 kHz, +/– .5 dB

Hum and Noise: 100 dB below rated power

Input Impedance: 10k Ohms

Phase: speaker output is phase correct, sub-woofer output is phase correct

Dimensions (W×H×D): 48.3×11×37.2cm

Weight: 15kg

Price: £4,995

Manufacturered by: conrad-johnson

URL: www.conradjohnson.com

Distributed by: Audiofreaks

URL: www.audiofreaks.co.uk

Tel: +44(0)208 948 4153