Warm Audio WA-C1 Mod Review: Classic CE-1 Tone Perfected

The 1976 Boss CE-1 Chorus Ensemble is undisputed guitar royalty. Its thick, syrupy analog modulation—powered by legendary Bucket Brigade Device (BBD) chips—defined decades of guitar tones, from Andy Summers and John Frusciante to Alex Lifeson. However, anyone who has owned or gigged with an original unit knows it comes with significant real-world compromises: a massive footprint, an easily overloaded low-impedance input, a dark preamp that can't be turned off, and a notoriously high noise floor.

Warm Audio WA-C1 Mod

The Warm Audio WA-C1 Mod Chorus & Vibrato directly addresses those vintage quirks. Rather than building a straight clone, Warm Audio engineered a pedalboard-friendly unit with premium all-analog BBD circuitry (Xvive MN3007) while fixing the 1970s original's glaring usability issues.

First Impressions

Warm Audio kindly provided Guitar Bomb with this unit for review. The pedal is solid, feels robust, and the control knobs are smooth and roadworthy.

The mini switches on the rear to engage both the preamp and the Hi-Z are easy enough to engage, but won't get knocked in use. They could be easier to use if they were on the front, but that's a minor niggle at best.

The top-mounted jacks make them easy to use on modern pedalboards, and the standard power supply requirements are exactly what we need in 2026. I've owned a few old CE-1s, and they are a pain to set up, as they're mains-powered and huge!

Warm Audio replicated the style of an old CE-1, with a textured dark green finish and the same style of control knobs (just smaller and more of them). The High/Low switch on the main front panel is also handy, and it's out of the way, so you won't accidentally bump or damage it with a boot.

Once you plug it in and get started, it is easy to get good results, and I was quickly dialing in some classic chorus tones. The effect really shines in stereo, so I would highly recommend that option if you have two amps to hand. I'm really impressed by how quiet this circuit is, which is great for recording (my old '70s units were so noisy).

Switching between chorus and vibrato is simple: hold the footswitch down to smoothly transition between the two effects. Each side has its own flashing LED, so you can see the modulation speed/rate.

Really, it was a joy to use, and the updated preamp bypass via the vintage/modern switch is where it shines over the previous, larger Warm Audio version. If you don't want the preamp coloring your tone, being able to bypass it is a useful feature.

If you like analog modulation but want something more flexible and less noisy, check these out. I found it worked well with all my guitars and a few synths, so it is a handy studio tool, not just a gigging one.

Key Features & Specs Comparison

The Major Upgrades: WA-C1 Mod vs. Vintage Original

1. Ultra-Quiet Noise Floor

One of the most immediate differences when stepping up to the WA-C1 Mod is its quieter background noise. Vintage CE-1 pedals are infamous for introducing noticeable BBD clock hiss and power supply hum into your signal chain.

Warm Audio overhauled the power delivery using an internal dual DC-DC voltage converter. The result is a whisper-quiet noise floor, letting you place the pedal ahead of driven amps or stack it with gain pedals without raising the background hiss.

2. Preamp Bypass (Vintage vs. Modern Switch)

The original CE-1 preamp was designed for keyboards, so electric guitar signals—especially from high-output or humbucker pickups—often pushed the input into unwanted clipping while adding a thick mid-range push.

The WA-C1 Mod introduces a dedicated Vintage / Modern switch:

• Vintage Mode: Retains the full 100% analog preamp circuit, recreating the original unit's subtle harmonic saturation, compression, and dark analog warmth.
• Modern Mode (Preamp Bypass): Completely bypasses the preamp stage, offering pristine, transparent modulation that preserves your guitar's natural tone and headroom.

3. Hi-Z Input Impedance Switch

Because the original CE-1 featured a low 50kΩ input impedance, connecting a guitar directly into it resulted in severe high-frequency loss (tone-suck). The WA-C1 Mod solves this with a back-panel Hi-Z switch:

• Hi-Z Mode (1.1MΩ): Matches modern guitar signal requirements, instantly restoring top-end clarity, upper-mid presence, and dynamic response.
• Low / Vintage Mode (50kΩ): Matches vintage specifications for line-level sources, synthesizer gear, or retro signal chains.

4. Independent Depth & Rate Control

On the 1976 pedal, adjusting chorus intensity meant changing both the delay time and LFO rate simultaneously via a single dial. The WA-C1 Mod features separate Depth and Rate controls for the chorus section, letting you dial in slow, deep liquid sweeps or fast, shallow detune effects with precision.

Sound Quality & Performance

With Vintage Mode and Hi-Z enabled, the pedal instantly delivers that iconic late-70s analog chorus sound—lush, dimensional, and organic, without sacrificing high-end bite. Switching over to Modern Mode clears out the low-mid thickening, producing a pristine, glassy 80s chorus texture that excels on clean rhythmic passages.

Independent Vibrato mode produces a pitch-bending throb, from a subtle amp-style bias wiggle to a wide, rotary-speaker-style swirl. In Stereo, the spatial separation creates an expansive, three-dimensional soundstage. This pedal really excels in a stereo setup, so I'd recommend trying it with two amps whenever possible.

Our Thoughts

This new compact version of Warm Audio's original WA-C1 is a neat update, and I really enjoyed the modulation effects and updated preamp options.

I've owned the original Boss CE-1 (both 110-volt and 240-volt versions), which I always found noisy; it also had a keyboard-focused preamp that was sometimes tricky to dial in with certain guitars, and it's massive and mains-powered!

The Warm Audio WA-C1 Mod retains the tonal magic that made the original Boss CE-1 famous while modernizing every area where the vintage unit struggled. With a drastically reduced noise floor, bypassable preamp, Hi-Z guitar matching, and top-mounted jacks, it stands out as one of the most versatile and practical vintage-voiced BBD chorus/vibrato pedals available.

If you want that dark, syrupy chorus, it can do it, or you can add some high end by engaging the Hi-Z; then it brightens up nicely. Being able to bypass the built-in preamp completely is also a huge win, since not everyone wants that (though I quite liked it) when they are dialing in gain stages on modern pedal setups.

Again, ideally the effects work best in a two-amp setup.

Why the WA-C1 Mod Works as a Modern Gigging & Studio Tool

The preamp is great if you want to do that Frusciante thing, or something similar, so it offers more than just modulation.

Finally, the smaller footprint is great, and I enjoy having dedicated controls for both chorus and vibrato (a big step up from my old Boss CE-1s). So, it is a solid substitute for a vintage pedal, with some nice upgrades for modern players.

Price-wise, it is much more affordable than a vintage 1970s CE-1 and less hassle, so if you want vintage-voiced modulation with plenty of character, it's worth checking out. I also like that it is easy to source (so not highly boutique and hard to find, with a waiting list or limited supply).

I would happily gig with this pedal, and it is also a great studio tool (a few of my mono synths have already run through it in the last week with great results).

Read our review of the Warm Audio Dan Auerbach Peach Fuzz here.

MSRP - $199.00/£199.99

Thank you to Warm Audio for providing the unit for review.

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