QUAD 33 Audiophile Preamplifier Reviewed

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The interest in nostalgic products from the audiophile world has become quite the phenomenon in the last few years. One need only observe the unexpected resurgence of the previously all-but-dead vinyl format as a prime example. And recently, cassette tapes amazingly are beginning to rise from the ashes of yesterday’s forgotten formats as well. I don’t know about you, but I never would have predicted that one. Vintage audiophile gear also has its enthusiasts as well and those numbers are growing, especially with younger enthusiasts. So, it makes sense that British high-end, hi-fi brand QUAD has decided to resurrect its iconic QUAD 33 preamplifier and QUAD 303 power amplifier, originally made during the 1960s through the early 1980s, but with updated technologies, while maintaining that cool-looking retro industrial vibe of the originals. In fact, QUAD has stated that one of the reasons they decided to revive and update these pieces is the continued strong demand on the secondhand market for the beloved originals.

The QUAD 33 stereo preamplifier, the subject of this review (review of the companion QUAD 303 power amplifier to follow soon), is a compact-sized, all-analog unit with a unique feature set, which I’ll discuss further in a bit. With all of the interest lately in audiophile DACs and DAC/streamers, it’s interesting that QUAD chose to stick with an all-analog design similar to the original. Those wishing to stream digital music files will need a separate external DAC in front of the QUAD 33 preamplifier in order to enjoy them. But QUAD is not alone in manufacturing a compact all-analog preamplifier. They simply are joining the ranks of companies like Benchmark Media, Rogue Audio, SPL and Pass Labs.

The Quad 33 sold like hot cakes when it first came to market.

What Makes the QUAD 33 Preamplifier So Special?

The QUAD 33 preamplifier has a compelling, slightly warm sonic signature that I enjoyed for hours on end without any hint of listener fatigue.
The QUAD 33 preamplifier is “old-school cool” with its retro push buttons, rotary dial tone controls and orange LED display, all nostalgic design nods to the original unit from the 1960s but updated to current standards.
The build quality and heft of the QUAD 33 preamplifier is surprisingly good, given its diminutive size and real-world price point.
The QUAD 33 preamplifier features a unique set of tone controls. In addition to balance and bass-only adjustments (-3dB/+3dB in 1dB increments), the preamplifier also offers a tone control that the company refers to as “tilt control.” When utilized, the tilt control simultaneously increases bass while attenuating treble, or attenuates bass while increasing treble in 1dB steps (+/- 3dB), effectively rotating, or tilting, the audible frequency range on a 700 Hz axis. I found the control to subtly add warmth or coolness to the overall tonal balance. This can be a useful tool when playing recordings that are either too lean or too heavy. To my knowledge, QUAD is the only company utilizing this unique approach to tone control. For the most part, though, I left the tone controls set at their neutral positions for my listening.
The QUAD 33 preamplifier has a phono input that is both Moving Magnet (MM) and Moving Coil (MC) cartridge-compatible with switchable fixed gain settings of 46 dB for the MM and 63.5 dB for the MC. QUAD notes the input stage uses ultra-low noise audio op-amps combined with high slew rates to minimize distortion.
In addition to the phono inputs, there are three sets of RCA single-ended inputs and one set of XLR balanced inputs.
Outputs include one set each of RCA pre-outs, RCA auxiliary outputs, and XLR balanced outputs.
The included remote control has all preamplifier faceplate adjustments available, so all adjustments can be made without getting up from the listening position. Even with all of the included functionality, it’s really easy and intuitive to use, too.
The master volume control is a full-analog precision-motorized ALPS potentiometer for low noise performance. The motorized dial rotates when adjustments are made via the remote control.
There is a 12-volt trigger connection on the back to control the on/off status of an external amplifier from the preamplifier.
The QUAD 33 preamplifier has a very capable dedicated headphone amp with a single full-size 6.3mm jack located on the front faceplate. I found the amplifier to be robust enough to play my 300-ohm impedance-rated Sennheiser HD800 headphones at more than adequate volume levels with full, rich and detailed sound. The slightly warm slant to the sound signature of the QUAD 33 preamp seems to apply to the headphone amplifier as well, giving the Sennheiser HD800 phones a more neutral sound than the typically slightly bright sound they exhibit through many headphone amplifiers. The soundstage wasn’t as wide or three-dimensional as it is with my reference dedicated headphone setup. However, it was better than expected for a preamplifier at this price point. It was obvious that the headphone amplifier designed into the QUAD 33 preamp was much more than just an afterthought. There is no gain adjustment available for the headphone amplifier. QUAD states that the impedance range the amplifier is capable of driving is 20 to 600 ohms, which covers the impedance rating of most consumer headphones.

For $1,599, the Quad 33 preamp is an audiophile value with a whole lot of vintage appeal.

Why Should You Care About the QUAD 33 Preamplifier?

A lot of preamplifiers these days try to be a “jack of all trades,” incorporating as many features as you can imagine, trying to be a one-box solution. That more often than not leads to compromises in design and quality. That’s not what this QUAD 33 preamplifier is about. QUAD is trying to build upon a proven history of a legacy product that did a few things, and did them really well, at a reasonable price point. The new QUAD 33 preamplifier succeeds at that mission while updating its technology to today’s standards. The QUAD 33 preamp puts the music first, delivering a natural, slightly warm sound that is addictive, drawing the listener in with its clarity, accuracy and detail, yet without listener fatigue. The QUAD gets out of the way with its compact form factor and lets the listener just revel in the music they enjoy. But it’s got that retro cool look factor that is appealing at the same time.

A look at the rear of the Quad 33 preamp's inputs and outputs. — A look at the rear of the Quad 33 preamp’s inputs and outputs.

Some Things You Might Not Like About the QUAD 33 Preamplifier

Due to the compact form factor of the QUAD 33 preamplifier, the number of inputs is limited.That means those audiophiles wanting to control a more complicated system with several analog sources will need to either prioritize or look elsewhere.
There is no home theater bypass on the QUAD 33 preamplifier, preventing it from being easily incorporated into an existing home theater system. For those wanting to integrate both a home theater and a separate two-channel audio system, the lack of a bypass could be a deal breaker.

Listening to the QUAD 33 Stereo Preamplifier …

My listening setup started off with the QUAD 33 preamplifier connected to a Classé Delta Series Class-A/B amplifier, feeding Aerial Acoustics 7T floorstanding loudspeakers. After a few weeks of listening passed and I had a good handle on the characteristics of the QUAD 33 preamplifier, I replaced my reference Classé amplifier with the QUAD 303 amplifier, also a Class-A/B design. After all, the QUAD 303 amplifier is intended to be the companion amplifier to the QUAD 33 preamplifier, so I just had to experience them together.

I consistently found the QUAD 33 preamplifier to offer up a laid-back, slightly warm and inviting sound. The preamplifier displayed that signature QUAD sound that became more and more addictive the more I listened. The QUAD 33 preamplifier offered up plenty of small sonic details without any accompanying fatigue. I spent numerous listening sessions that were multiple hours in length without ever growing tired of the sonic signature I was hearing.

To assess treble performance of the QUAD 33 preamplifier, I listened to several familiar tracks, including “When You Say Nothing at All” from the Alison Krauss album Now That I’ve Found You: A Collection (CD, Rounder Records). The QUAD 33 preamplifier reproduced the well-recorded track accurately, portraying Krauss’ breathy soprano vocal with that natural, clear and airy quality that is so distinctively hers. I heard plenty of detail in both her vocal and accompanying instruments, too, but without any of the harshness that can sometimes become evident with less capable electronics. High notes from the fiddle and banjo sounded sharp as they should, but not unnaturally so. The QUAD 33 preamplifier placed both Krauss’ vocals and individual instruments in distinctive, stable positions within a three-dimensional soundstage. The QUAD 33 preamplifier just seemed to get an awful lot right with this track.

To evaluate the QUAD 33 preamplifier’s ability to reproduce bass dynamics accurately, I listened to several tracks I routinely use for that purpose. One of my favorites is Aaron Copland’s “Fanfare for the Common Man,” performed by the Minnesota Orchestra with Eiji Oue conducting, from their album Copland: Fanfare for the Common Man, Appalachian Spring Suite & Symphony No. 3 (Reference Recordings). The QUAD 33 preamplifier delivered a very coherent and stable soundstage throughout the recording. When played at a volume approaching a live performance, the tympani opening provided chest-thumping bass. Instruments were well-defined within that space throughout the track. With the track’s increased clarity when played through the QUAD 33 preamplifier, I found myself hearing additional details and turning up the volume louder than normal to fully immerse myself within all that pulsating bass.

Will the QUAD 33 Preamplifier Hold Its Value?

Based on the fact that the original QUAD 33 preamplifiers are still in demand in the secondary market and commanding a decent price, I would anticipate that the newly-designed QUAD 33 preamplifier will likely follow suit and be similarly desired. That is, if you can find one in the secondary market. These units are likely to remain with their purchasers for quite some time and there are only so many made at this point.

What is the Competition for the QUAD 33 Preamplifier?

The Rogue Audio RP-1 tube preamplifier ($1,695) is an analog preamplifier with an MM/MC phono stage with user-adjustable gain settings of 43 dB and 58 dB to accommodate most cartridges and a full-sized headphone output. It has two sets of variable RCA outputs and one set of fixed RCA outputs. However, it lacks balanced connections. While not a full-sized component, I wouldn’t classify it as a truly compact unit either, given its 15.25-inch width, compared to the more diminutive 10.2-inch width of the QUAD 33.

The SPL Elector stereo preamplifier ($2,695 – read the review) was very favorably reviewed by publisher Jerry Del Colliano, and is another compact stereo preamp built in a similarly retro style with traditional analog topography. It’s retro as in dual mechanical VU meters and a tape monitor circuitry, but has no DAC, phonostage, or headphone amplifier. German manufacturer SPL instead opts to offer a separate, matching MM/MC phonestage . For the extra coin, compared to the QUAD 33 preamp, you get three sets of balanced XLR inputs and three standard RCA inputs, as well as home theater bypass capability.

The Benchmark Media LA-4 preamplifier ($3,050 – read the review) is another compact, analog design preamplifier with two sets of balanced XLR inputs, two sets of single-ended RCA inputs, and one set each of XLR and RCA outputs. There is no built-in DAC, phonostage or headphone amplifier. Benchmark does offer their HPA-4 model preamp if a built-in headphone amplifier is desired. The bare-bones Benchmark LA-4 preamp is known for ultra-clean sound that is musically accurate and natural, something ardent audiophiles will appreciate.

A look at the Quad 33 with the matching 303 power amp at Bob Barrett's home. — A look at the Quad 33 with the matching 303 power amp at Bob Barrett’s home.

Final Thoughts on the QUAD 33 Preamplifier …

The compact-sized, analog-only QUAD 33 stereo preamplifier will appeal to discerning audiophiles on a realistic budget, who prefer a clean, accurate sound that is on the slightly warm side of neutral. These are also people who prefer to keep their digital sources (i.e., DAC) external to the preamplifier. The form factor of the QUAD 33 preamplifier will especially appeal to the minimalist who’d rather listen to their music without a bunch of full-sized components getting in the way. Also, those living in apartments or condominiums where space can be at a premium will be attracted to the compact form factor of the QUAD 33 preamplifier.