Strymon Iridium VS Walrus Audio ACS1 (Comparison)
Our pick: The Strymon Iridium
Between these two extremely similar preamps, we like the Iridium slightly better because it has a more versatile tone profile and better gain (distortion sound). Otherwise, there aren't many features (or tones) that separate the two.

In this comparison we have two amp and cab simulator pedals, the Strymon Iridium and the Walrus Audio ACS1.
And if you're trying to decide between the two, it's going to be a bit of a coin toss because both of these units are extremely similar.
Not only do they house a similar feature and control set, but the amp and cab models they simulate create comparable clean tones. It's the distortion and heavier settings where the two start to separate.

This pretty much sums up the entire comparison.
On both pedals you get a roster of digitally-simulated vintage amp models and cabs in the style of Fender, VOX, and Marshall amplifiers.
From a style perspective both lean vintage and seem to match the profile more of a single coil Stratocaster than a modern Ibanez or PRS with dual humbuckers. Because neither preamp is particularly aggressive, so we would definitely recommend it for a limited scope of musical genres.
Again, the Iridium is the more flexible and "heavier" of the two.
But in either case we'd recommend thinking in terms of bluesy breakup and classic rock.
If that's what you're looking for, these are both solid preamps that you'd have a hard time going wrong with.
Just don't buy them to replace your Mesa Boogie or Diezel amp.
Read the full review: Walrus Audio ACS1
Strymon Iridium VS Walrus Audio ACS1 Comparison Tool
If you want to do a brief comparison of these two preamps, use the tool below to view pricing, features, and audio demos of both. You can shop for them and browse product descriptions via the orange Sweetwater buttons which help support our work at no extra cost to you.
Preamp | Title | Rated | Browse |
---|---|---|---|
![]() | Strymon Iridium | n/a | |
![]() | Walrus Audio ACS1 | n/a |
If you listen to both demos, you can pretty clearly hear (and see via the labeling) that these two pedals sound incredibly similar. Personally, we like the Iridium a little better, especially with gain higher, but it's purely an issue of taste and preference.
Detailed Specs
While there's some flexibility with a USB connection and external Impulse Responses (cab simulating), there are basically three amp models and three cabs that can be combined with each model. Despite some differences in language and lingo, the rest of the feature set is essentially the same in both devices.
Header | Iridium ![]() | ACS1 ![]() |
---|---|---|
Effect Type | Amp Emulation, Impulse Response Cabinets | Amp & Cab Simulator |
Analog/Digital | Analog/Digital Hybrid | Digital |
Features | 9 x Pre-loaded IR Cabs, 3 x Amp Models, Reverb/Ambience Settings | 3-Band EQ, Room, Boost |
Presets | Single (favorite switch) | Three (hold both switches) |
Knobs | Drive, Level, Bass, Middle, Treble, Room | Bass, Mid, Treb, Vol, Gain, Room |
Switches | Amp (Round, Chime, Punch), Cab (A, B, C) | Cab (A, B, C), L/R, Fullerton, London, Dartford |
Inputs | 1 x 1/4" TRS (mono, stereo via adapter) | 2 x 1/4" (stereo/mono) |
Outputs | 2 x 1/4" (L/mono, R), 1 x 1/8" (headphones) | 2 x 1/4" (stereo/mono) |
MIDI | 1 x 1/4" TRS (expression/MIDI) | In/Thru |
Height | 1.75" | 2.64" |
Width | 4" | 2.52" |
Depth | 4.5" | 4.9" |
Weight | Not listed | Not listed |

Distortion and high gain settings in the Iridium make all the difference.
Strymon Iridium Details

The gain profile and overall tone flexibility is better in the Iridium.
The Iridium does have a preset switch, though it's only a single "favorite" button compared to the three presets in the ACS1.
Otherwise, a three-band EQ, room control, gain, and level are all in the Iridium and mirrored in the ACS1.
MIDI control in the Iridium is available via TRS through an expression jack, while the ACS1 has physical MIDI ports for in and thru control.
Walrus Audio ACS1 Details

Boost control but no "fav" button.
In the ACS1 you have a BOOST button, which also functions as the preset switch when you press both bypasses at one time.
If you prefer the boost button - and the additional presets - the ACS1 is going to be a better option for you.
Another consideration should be MIDI controller users. Do you need the thru connection with physical MIDI ports? If so, the ACS1 has you covered, while the Iridium requires you to go in through the TRS expression jack.
Outside of these two differences, most of the features in the ACS1 are also present in the Iridium:
- 3 amp models
- 3 cab models
- 3-band EQ
- Gain/level control
Comparison Summary
Since both preamps are the same price, we can't say that one is necessarily a better value than the other.
It's actually not often that you get two devices from different companies that are this similar, but the Iridium and ACS1 comparison is truly unique.
And with only a couple nuanced features separating the two, along with a similar tone profile, we'll recommend the one with more versatility and a better-sounding distortion, in the Strymon Iridium.
On the other hand, those wanting the extra presets and boost option should go with the ACS1.
Questions and Comments
Do you have questions about the Strymon Iridium or the Walrus Audio ACS1? If so, drop us a line in the comments section below.
We can continue the discussion about these two preamps there and hopefully be helpful to future readers of this comparison.
We'll talk then.
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Written by GC Editorial on Pedals and Comparisons
Written by GC Editorial on Pedals and Comparisons
You forgot one very important feature of the ACS1: dual amps! Practically it’s entire selling point.
What do you mean dual amps? I don’t see that anywhere on the product page. https://www.walrusaudio.com/products/mako-series-acs1-amp-cab-simulator
Quoting from the product description you so kindly linked to:
“The ACS1 models three vintage amp styles crucial to music industry history designated by their places of origin. When running the ACS1 in stereo, one amp can be used through both channels or mix and match amps and cabinets on the left and right channels with the L + R switch. Simply choose the channel you want it to modify, select your amp and cab model, and set your levels. Then flip over to the other channel and choose your amp and cab settings. If you would like to use the same settings on both channels, set the switch to the middle or “+” and dial in all your settings. They will be duplicated on the left and right outputs.”
Yeah, the “selectable” stereo output, I guess you could call it. Entire selling point? I would disagree with that.
Having said that, I appreciate you detailing this information. Adds substance to the comparison. Thank you.
Acs1 has 3 presets through the bypass switch (long press).
Thanks Sylvain – corrected. Mistake on our end, so I apologize, and appreciate you pointing this out.