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conrad-johnson ET7 line preamplifier

conrad-johnson ET7 line preamplifier

One of the foundation stones of American high-end, conrad-johnson has returned to its core recently. The company built its reputation on high-performance tube (valve) amplification, and although subsequent diversions into solid-state, and digital audio have often been greatly received, it’s those deceptively simple, high-performance tube line-stages, phono stages, and power amplifiers that are first to pop into your head when the c-j name is uttered, and it’s those products – and those products alone – that form the company’s 2018 line.

The new ET7 line preamplifier is central to that line, doubly so in fact. It’s the middle out of three preamplifiers from the brand, and as a control amplifier represents the nerve centre or hub of any multi-source system. On the other hand, it owes so much to the flagship GAT preamplifier, I’m probably not the first to think of it as ‘baby GAT’.

That ‘ET’ prefix to the name means ‘Enhanced Triode’, in that the circuit uses a single 6922 double triode tube, acting as a single-ended triode for each channel. This provides voltage gain, and sends the signal to a similarly minimal high-current MOSFET buffer, which helps provide a very low output impedance. This makes the single-ended only ET7 extremely flexible in terms of interconnect cable design and length. DC voltage is provided by a discrete voltage regulator that isolates the audio circuit from the power line by maintaining negligible impedance across the audio frequency band. In addition, infra-sonic noise is minimised by operating the tube heaters on a DC voltage supplied by a separate regulated power supply. All of which is a direct ‘trickle down’ from the design developments that took place in moving from the original GAT to the GAT Series 2.

The ET7 retains the microprocessor-controlled relay system and network of metal-foil resistors as its gain control, allowing one hundred 0.7dB steps in volume and balance. The preamplifier has five single-ended line inputs, and two external processor loop input/outputs, the second of which puts the preamp into ‘Theater’ mode and automatically switches the ET7 to unity gain. Unlike the entry-level ET3, there is no optional built-in phono stage, but there are two standalone phono stages in the range. Also unlike the ET3, the ‘balance’ control on the remote control actually works, even if there is no replication of that balance control on the ET7’s front panel! As ever with c-j, volume is displayed by a pair of two-digit yellow LEDs in the centre of the front panel, and these are flanked by yellow LEDs to denote source and function. Power up puts the ET7 into soft-start heat-up mode, and the blinking mute switch is a reminder of that.


We have been critical of c-j’s build quality of late. The products had exceptional circuit design, good – if distinctive – aesthetics, but were not built to the same high standards. The fit and finish were good, but not exceptional, and in some cases not commensurate with the kind of prices modern c-j commands. It was little things like folded top plates with rough edges, small, uneven gaps between the front panel and the top-plate, and slightly thinner casework than we have come to expect from modern high-end audio. The argument was that you pay money for the performance, not the box it comes in… but this sometimes becomes a bitter pill for consumers to swallow. Fortunately, those days seem to be coming to an end, and the ET7 is not just one of the best built c-j products of recent years, but puts the company back on a level constructional playing-field with its peers. It retains the gold front and black crackle side and rear, but that gold front panel has a subtle two-tone look that is extremely elegant, and those top, rear, and side panels are more solid than we’ve seen in years. This is doubly good, in that the build quality now matches the sound quality, and that the step up does not come with radical design changes meaning existing c-j owners will find the product looks very much in line with existing conrad-johnson products.

There remain three points to note, however. The microprocessor-controlled relays used to change inputs and control the volume still have that distinctive – and quite loud – ‘clacka, clacka, clacka’ sound when adjusting the level. The Teflon capacitors used in the circuit take a long time to come on song, so the sound of the ET7 at the first hour of use has little in common with the sound of the ET7 a hundred hours later. It’s good right out of the box, but it’s a lot, lot better with some mileage on the clock. Then, as with all c-j preamps, the simplicity of the circuit means the output is not in absolute phase. Most companies put a phase inverter in the circuit, but c-j maintains that is extraneous and deleterious to the sound. So, use your loudspeaker terminals as phase inverters instead! None of these things are new to the ET7, more they are standard c-j preamp housekeeping.

This is not a preamplifier for those who view high-end audio as some kind of larger-than-life IMAX interpretation of audio, with a huge soundstage and large, impressive instrument voices. Neither is the ET7 the preamplifier for those who want their electronics to impose a tonal or rhythmic imprint on the music. Or even the preamplifier for those who crave cranking up the volume; even if coupled to an amplifier with the sort of power delivery that could turn loudspeaker cones into smoking ruins, the gain structure of the amplifier tends toward a more measured approach.

All of which means the ET7 is the preamplifier for more developed, grown-up listeners. If you have achieved that degree of musical maturity, the conrad-johnson ET7 is an outstanding performer because in absolute terms, the ET7 makes little impact on the music. As with any such product, the realisation of just how little impact it makes comes at you slowly. You begin to hear sounds as they were intended, where most other preamplifiers irrespective of price add in an electronic-sounding remastering of the original. You begin to perceive other preamplifiers as providing brightness masquerading as detail, where the ET7 instead conveys the true structure of the instrument, the texture of the playing, and the flow of the music itself. This naturally leads the listener to well-recorded acoustic music (at least at first) because the differences in performance stand out so well here.

If you have both versions of Gould playing Bach’s Goldberg Variations [Sony Classical], the differences in interpretation stand out as far as the recording quality. And yet, at all times, what becomes really obvious is both the mastery of Gould playing Bach, and Bach effectively creating modern tempered music. With that nailed, the rest of the presentation falls into place perfectly, with the kind of dynamic range and shading that could well be the envy of other preamplifiers, a tonal balance that is consummately true to the recording, a sense of holographic soundstaging, sublime vocal articulation… the works. That these elements don’t draw attention to themselves individually, but act as a musical gestalt, just shows how outstanding the ET7’s performance really is, and how rare that kind of truly effortlessly natural and cohesive presentation is out in the world of preamplifiers.


The performance of the ET7 stands alone. At its price or below, the only way to get its extraordinarily unforced, natural presentation is to go with passive preamplification, and in many cases that causes its own issues regarding gain and cable length limitations. And to improve upon the ET7’s performance without changing the mix, there are few other options aside from the GAT itself. It’s not the only game in town that does ‘natural’ well, but there are few that do the job so thoroughly or so benignly.

ET7’s ‘baby GAT’ nickname is both deserved and entirely the wrong way of thinking about the preamplifier. Yes, the circuitry is fundamentally a GAT Series 2 writ a little smaller and with perhaps slightly less extension to the lowest and highest notes, and you might expect that more than halving the price of the GAT would sacrifice much to the Discount Gods. In fact, what you get is a level of performance so close to that of the GAT that unless you have an absolute top-of-the-line system with the kind of resolution that few can attain, the differences between the two become harder to justify. Those differences are not mere nuance, but the fundamental performance of the GAT is replicated in the ET7 and at less than half the cost. That alone would make it highly recommended, but the conrad-johnson ET7’s performance in and of itself makes it, quite simply, one of the best preamps money can buy at this time.


  • Type: single-ended valve line preamplifier
  • Inputs: 5×single-ended RCA stereo line‑level inputs, 2×single-ended RCA processor loop inputs
  • Outputs: 2×single-ended RCA stereo variable outputs, 2×single-ended RCA processor loop outputs
  • Tube complement: 1 ×6922
  • Gain: 25 db
  • Maximum output: 20 vrms
  • Output impedance: 100 ohms
  • Distortion: less than .15% THD at 1.0 V
  • Frequency response: 2 Hz to more than 100Khz
  • Hum and noise: 100 db below 2.5 v
  • phase: inverts phase of all inputs at main out
  • Dimensions (W×D×H): 48.3 ×  39 ×11cm
  • Weight: 8.62kg
  • Price: £10,000

Manufactured by: conrad-johnson design, inc.

URL: conradjohnson.com

Distributed in the UK by: Audiofreaks

URL: audiofreaks.co.uk

Tel: +44(0)208 948 4153

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