Is the Conrad-Johnson ART88 Triode Preamplifier the Right Reference Line Stage for Your System?
The Conrad-Johnson ART88 Triode Preamplifier is a dual-mono valve line stage for listeners who want a zero-feedback triode circuit with remote control and relay switching. Conrad-Johnson designed it to serve as an industry reference standard for line-stage performance, a role its predecessor, the GAT preamplifier, filled for more than a decade. It suits buyers building a separates system around a dedicated power amplifier and external sources, including those who want to add a surround processor without altering their two-channel path.
What makes the ART88 Triode Preamplifier different from other valve line stages?
The ART88 Triode Preamplifier is a true dual-mono design. Its two channels share only the tube power transformer and the chassis. Each channel runs on its own regulated DC power supply with discrete voltage regulators. Those regulators isolate the channels from each other and from the AC mains.
The ART88 uses two high-transconductance PCC88 twin triodes per channel in a zero-feedback circuit. The gain stage is a composite triode formed by paralleling both sections of one NOS Philips PCC88. A second PCC88, again with paralleled sections, forms a high-current buffer between the gain stage and the outputs.
The ART88 runs its tube heaters on DC from a separate regulated supply, which minimises infrasonic noise. Conrad-Johnson rates hum and noise below 50 µV.
The ART88 is built with parts chosen for both sonic performance and durability. The audio path, including the level control, uses precision metal foil resistors and proprietary CJD Teflon capacitors. The power supplies use the same resistors with CJD polypropylene and Teflon capacitors. There are no electrolytic capacitors in the audio circuits or their power supplies.
Where does it sit in the Conrad-Johnson range, and who should choose it?
The ART88 is the line stage Conrad-Johnson positions as its reference. GAT owners considering an upgrade are moving to a design with paralleled PCC88 triode sections, a dedicated buffer stage and per-channel regulated DC supplies.
Before you buy, check three things against your system. The ART88 is line-level only, it runs on tubes that need periodic replacement, and its outputs invert phase. Buyers who need a built-in phono stage for a moving-magnet or moving-coil cartridge should shortlist preamplifiers with an integrated phono section. Buyers who’d rather avoid tube replacement should shortlist solid-state line stages. Choose the ART88 if you want a zero-feedback triode line stage and accept tube care as part of ownership.
Will the ART88 Triode Preamplifier drive my power amplifier and interconnects?
The ART88 Triode Preamplifier is designed to drive a wide range of amplifiers and interconnect cables. Its buffer stage gives an output impedance of 190 ohms, which is what makes that broad compatibility possible. Conrad-Johnson recommends pairing it with a power amplifier that has an input impedance of 20 kilohms or higher.
The ART88 provides 25 dB of gain and up to 10 V rms of output. It has two pairs of main outputs. You can feed two amplifiers in a bi-amplified system, or connect a crossover. Conrad-Johnson notes that the best interconnects depend on the system, and recommends asking your dealer for system-specific matching.
How do turntables, CD players and other sources connect?
The ART88 is fitted with five high-level inputs labelled PH/AUX, TUNER, CD, VIDEO and AUX2. All five are electronically identical. The load they present never drops below 12 kilohms, though it varies with the volume setting. Line-level sources such as CD players and tuners connect directly.
The ART88 takes vinyl through the PH/AUX input once the signal has passed through your phono preamplifier. Your turntable, tonearm and cartridge connect to the phono stage, not to the ART88.
The ART88 gives an EPL1 loop for an external processor, such as a parametric equaliser or tone controls. It doubles as a tape loop: connect EPL OUT to the recorder’s input and EPL IN to its output. Without a processor, EPL IN serves as an extra line-level input.
Can it share a system with a home theatre processor?
The ART88 is set up to add a surround-sound processor without changing the two-channel signal path. Connect the front left and front right outputs of your SSP to the EPL2 input. Selecting THEATER locks the ART88 at unity gain, and the SSP controls level and balance. The same front speakers and power amplifiers serve both stereo and home theatre.
The ART88 offers a THEATER OUT connection that can feed an input on your SSP. The processor can then apply matrix surround decoding to selected two-channel sources. In SOURCE mode, the selected input goes straight to the volume control without passing through either processor loop.
How do I set absolute phase with the ART88 Triode Preamplifier?
The ART88 Triode Preamplifier is easy to bring into correct absolute phase with one wiring change. A system is phase correct when its number of phase inversions is even or zero. If the ART88 is the only inverting component, the system has one inversion. Correct it by swapping the positive and negative speaker leads at both loudspeakers.
In correct absolute phase, the speaker cones move outward on a positive transient. That matches the initial rise in air pressure produced by most musical attacks. If you’re unsure of every component’s phase, Conrad-Johnson suggests checking by ear across several recordings. Some recordings, including some audiophile releases, aren’t phase correct themselves, so one disc isn’t a reliable test.
What does installation and placement require?
The ART88 is designed to sit horizontally on a flat, hard surface. Keep the ventilation holes in its base unobstructed. Leave at least 50 mm of clearance above the unit and keep the back of the cabinet or shelf open. The chassis measures about 476 mm wide, 406 mm deep and 138 mm high, and weighs about 15 kg. Check your rack shelf depth and height before ordering.
The ART88 is supplied in versions configured for specific mains voltages, with the rated voltage and frequency marked on the back panel near the power cord. US units run on 108–126 V at 60 Hz. Contact us before ordering to confirm that your unit is configured for Australian mains. Line voltage should stay within +5/−10% of the rating.
The ART88 avoids heavy-handed RFI filtering, which Conrad-Johnson says would compromise audio performance. Careful installation can often prevent interference problems. Use shielded interconnects of 3 m or less. Place the preamp well away from the power amplifier, and keep mains cables at least 100 mm from signal cables to reduce hum pickup.
How does day-to-day operation work?
The ART88 is controlled by microprocessor-driven relays for both input selection and volume. The level control switches combinations of precision resistors, giving 100 steps of about 0.7 dB each, numbered 0 to 99. You’ll hear a soft click from the relays at each step. Holding a volume button speeds up the change.
The ART88’s wireless remote runs every function. It’s the only way to adjust balance, which lowers one channel at a time. It gives direct access to each input and to the EPL loops. Holding the remote’s mute button for three seconds puts the preamp into standby with the tube circuits switched off.
The ART88 grounds its outputs for about 60 seconds at switch-on while the tubes warm up. The mute LED flashes during this period and the controls are disabled. The same relays ground the outputs immediately at switch-off or during a power interruption. This suppresses the transients that tubes generate as they warm up and cool down. The preamp remembers the last input and volume setting unless mains power is lost, in which case it returns to CD at level 20.
What does tube ownership involve with the ART88 Triode Preamplifier?
The ART88 Triode Preamplifier is fitted with four PCC88 tubes in total. Conrad-Johnson states that the PCC88 offers low noise, low microphonics and gain well suited to a zero-feedback line stage. The supplied tubes are burnt in under a controlled procedure and selected for minimum residual noise. Replacement sets go through the same preparation, so Conrad-Johnson recommends buying them directly from the company.
The ART88 typically gets two to three years of normal use from a set of tubes if it’s switched off when you’re not listening. Left on continuously, a set can wear out within a few months. The remote’s standby function makes switching off easy.
The ART88 needs about 15 minutes to warm up before critical listening. Conrad-Johnson specifies this period because performance improves as the unit warms up.
How does the build reduce noise, crosstalk and vibration?
The ART88 is built to keep signal paths short and to isolate its circuits from vibration. Its switching relays sit right at the input connectors, which reduces crosstalk between channels and between inputs. These sealed relays are designed specifically for signal switching and use gold-plated silver contacts.
The ART88 isolates its audio circuits from microphonics, the noise valve circuits pick up from mechanical vibration. The level control and the audio circuits sit on separate, shock-mounted daughter boards. This keeps vibration from the level-control relays and from outside sources away from the audio circuits. Heavy-gauge aluminium casework helps minimise microphonics.
