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Harrison 32Cpre+, MR3eq and Comp 500 Series Units — A Mix Real-World Review

Harrison recently released its first 500 Series units ever, aiming to bring the sound of its famed analog desks to racks everywhere. How do they stack up? Mike Levine put them to the test to find out.

Harrison 32Cpre+, MR3eq and Comp 500 Series Units — A Mix Real-World Review
THE TAKEAWAY: “Individually, all three are notable products. Put them together in your 500 Series rack, and you’ll have a powerful and versatile console-style input chain for vocals or instruments.”
COMPANY: Harrison Audio •
PRICE: 32Cpre+ ($699), MR3eq ($399), Comp ($399)
• All three processors use analog technology from Harrison consoles and offer excellent sound quality.
• 32Cpre+’s front-panel combo jack provides connection flexibility in conjunction with the back-panel jack on the 500 Series frame.
• The High and Low-Pass Filters on the 32Cpre+ and the Low-Pass Filter on the MR3eq offer extremely wide frequency ranges.
• Program Dependent Attack on Comp is quite effective.
• 1/4-inch part of front panel combo jack on review unit was stiff.
• Metering lacks detail.
• Hard to tell the status of the buttons on the MR3eq.
• No adjustable attack on Comp.

New York, NY (June 26, 2024)—Harrison Audio recently released three 500 Series processors: the 32Cpre+ preamp, MR3eq three-band equalizer, and Comp, a VCA compressor. All feature technology from the company’s large-format consoles of the ’70s, ’80s and ’90s. The single-slot, mono processors represent the company’s first foray into the 500 Series market.



The 32Cpre+ gets its name from Harrison’s 32Classic console, whose preamps feature similar transformer-coupled technology. The 32Cpre+ is equipped with the same Jensen JT-MB-CPCA transformer used on the console channels, providing low noise and excellent frequency response.

One of the 32Cpre+’s handiest features is a front-panel combo jack that supports mic- and instrument-level sources. Pressing the Hi-Z or XLR button just above the jack activates the combo input and deactivates the back-panel XLR. This arrangement lets you have a default mic connection through the back output but keeps your options open to connect a mic or DI source through the front panel.

One minor issue on my review unit was that the 1/4-inch jack felt “sticky” when unplugging cables. The connector worked fine, but pulling a jack out required more strength than it should. I didn’t have the same issue with XLR cables, which connected and disconnected smoothly and efficiently. I’m guessing that the 1/4-inch tightness was anomalous to my review unit, but not having another to compare it with, I can’t say for sure.

The preamp’s 20 dB to 70 dB gain range is controlled with the conveniently large and redcolored Micpre Gain knob. Three switches to the left activate polarity reverse, 48V phantom power and a -20 dB pad.

Pressing the “In” button at the top turns on the filter section. The High- and Low-Pass Filters have a 12 dB/octave slope and a wide range for setting the corner frequency. The former goes from 25 Hz to 3.1 kHz, and the latter from 160 Hz to 20 kHz. Those ranges are large for a 500 Series preamp (many only offer a fixed-frequency high-pass filter and no low-pass filter) and are likely more expansive than you’ll ever need. Still, it’s better to have too many choices than too few.

The metering is simple: An input LED turns green to show signal activity, deep red for clipping, and lighter red when hot but not fully clipped. In a perfect world, I’d prefer a meter with more detail, as it makes level-setting easier and more precise. However, because of the relatively small size of 500 Series processors, manufacturers often have to compromise design to get everything to fit.

With a price of $699 for one channel, which falls in the middle of the range for 500 Series preamps, I expected quality tone from the 32Cpre+, and it did not disappoint.

I used it when miking vocals, acoustic guitar, mandolin, DI bass and DI electric guitar. The resultant recordings were not only clean and detailed but also had a subtle roundness that yielded a pleasing, natural sound that was free from harshness. I did an A/B comparison with other preamps in my studio, and it held up favorably to them all.



From a control standpoint, the MR3eq is similar to the channel EQs on the 32Classic console. Both feature low and high bands, each with a 6 dB/octave shelving filter, a knob for boosting or cutting by 10 dB, and a button that switches from a shelf to a bell filter.

The low and high bands don’t have useradjustable Q controls, but their bell filters feature proportional-Q circuits, which cause the bandwidth to increase or decrease based on the amount of boost or cut. The choice of shelving or bell filters for those bands makes the EQ more versatile.

The mid-band is not the same as on the 32 Classic’s channel EQ, which has two semi-parametric midbands. The MR3eq features one fully parametric mid-band with controls for Corner Frequency, Boost/Cut and Q. The frequency ranges of the three bands overlap significantly, which provides additional flexibility.

The unit also has a switchable High-Pass Filter with a wide corner frequency range of 25 Hz to 3.15 kHz, as on the 32Cpre+. If you’re using the MR3eq in conjunction with the 32Cpre+, you won’t need the filter, but with the EQ on its own, the HPF is handy.

In addition, the EQ and filter sections have an In button that allows you to switch them in or out of the circuit. These are useful, especially for comparing the sound with and without processing. However, there are no status LEDs to indicate when either of those sections is active, so you have to figure that out based on whether the In button appears to be pressed.

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Overall, I liked the MR3eq a whole lot. For recording vocals and instruments or as a hardware insert when mixing, it always helped to improve the sound. On a strummed acoustic guitar, for example, I used it to beef up the lower-mids while adding extra sparkle on top. Another time, with a DI Fender Precision bass, I boosted slightly at around 130 Hz for added bottom and at about 1 kHz for a more distinct top end.

The controls on any analog EQ aren’t as precise as on a digital equivalent, so you end up using your ears more and your eyes less as you’re dialing in a setting. That’s a good thing, in my estimation. The sound quality, design and workflow of the MR3eq offer similar design, sound and feel to what you’d find on the channel EQ of a large-format analog console, which I presume is what Harrison was going for.



Harrison’s compressor technology was first developed for the company’s broadcast consoles. Dave Harrison, who founded the company in 1975, initially was not a fan of compressors for music, but he relented and included them on his broadcast consoles because of that industry’s need to control levels and prevent clipping. As a result, Harrison compressors were designed first and foremost for leveling purposes.

The compressor in Comp follows a similar design, featuring a THAT 2180 VCA chip and a feed-forward architecture. For those unfamiliar, a feed-forward VCA compressor’s detector gets its signal from the sidechain before it hits the VCA, whereas a feedback-style unit gets it afterward. As a result, feedforward units can better capture transients but aren’t typically as smooth-sounding.

The controls on Comp include an In button (on/off) as well as knobs for Threshold, Release time, Makeup gain and Ratio. Oddly, the latter’s labeling is reversed from normal; for example, 1:2 instead of 2:1. I asked Harrison about this and was told that was how they expressed ratio on the compressor that Comp is based on, so they kept it the same.

You may have noticed I didn’t mention an attack time control. That’s because there isn’t one. The attack is program-dependent—it changes based on the amplitude and frequency of the signal. Although I prefer the control of a dedicated attack knob, I have to admit that Comp’s automatic settings were usually satisfactory.

Harrison suggests setting a fast release and low ratio to use Comp as a leveler. I tried that, and it worked well for reducing peaks and keeping dynamics under control on sources like vocals, snare drum and bass.

Harrison touts Comp as a “vibe compressor,” and, indeed, it can add character with higher gain reduction amounts and slower release times. For example, I used it to soften the transients and lengthen the sustain on a snare, giving it a pumping sound. Perhaps because of the compressor’s feed-forward design, Comp is very sensitive to transients, and I had to be careful not to squash the signal too much. I noticed that it’s not only the Threshold and Ratio controls that impact the amount of compression; so does the input level.

As with the MR3eq, I appreciated dialing in settings mainly by ear without the visual feedback and distractions of a plug-in screen. It made me realize that it’s not just the sound of an analog processor that’s appealing, it’s also the workflow.

As you adjust the sound, there’s no computer between you and the music, and you feel a more direct connection to it.


My overall experience with the new Harrison 500 Series processors was highly positive. They all provide solid performance and excellent sound quality. The MR3eq and Comp, in particular, also offer outstanding value. The 32Cpre+ is pricier but still quite reasonable for the quality it provides.

Individually, all three are notable products. Put them together in your 500 Series rack, and you’ll have a powerful and versatile console-style input chain for vocals or instruments.