15IPS mkIII Tape Saturation Colour


The compression, saturation, and tone of analog tape. (Everything but the hiss.)

For decades analog tape was the sound of records. Then the technology changed, but our ears didn't. Things tracked on tape just sound fuller, warmer, and more "finished" by default than things tracked digitally. Bring the sound of tape back to your recordings with the 15IPS Colour.

The sound of tape comes from three things—compression, harmonic saturation, and filtering—and the 15IPS does all three.


Tape has a "built-in" compressor; that is, it can only take so much signal and anything above that limit is compressed. The 15IPS' ladder of diodes recreates this soft clipping, making sounds fuller and more present in the mix without adding more volume.


The "warmth" of tape comes from the harmonic saturation of both the tape itself and the electronics of the tape machine. The 15IPS' diodes emulate the harmonics generated by the tape, while the discrete transistor circuitry creates the complex harmonics of a vintage tape machine.

Tone Filtering

Part of tape's distinctive sound is its non-linear frequency response: a low-end roll off with a "bump" at the cutoff frequency. The 15IPS features a 40Hz resonant high-pass filter that simultaneously makes the low-end tighter and larger-than-life.


  • Tape-like soft limiting with NOS germanium diodes
  • Multiple class-A transistor stages for richer, more complex harmonic saturation
  • Resonant high-pass filter simultaneously clarifies and magnifies low end
  • Compatible with the Colour format
  • Yellow PCB
  • Full, step-by-step assembly instructions and support

Note on Revisions

The 15IPS is currently on its third revision. The 15IPS mkI, (2014-2019), featured an IC opamp and a relatively high clipping resistor for more saturation. The mkII (2019-2023) replaced the IC with a discrete, class-A transistor circuit and reduced the clipping resistor to widen the sweet spot of the Colour. The current version, mkIII, is identical to the mkII but with schottky diodes instead of germanium. An additional resistor in the clipping circuit replicates the character of the original diodes exactly. However, because the gain staging is slightly different between each one, two 15IPS from different revisions will not make a stereo pair.

What the Pros are Saying

"Even a little bit of the 15IPS adds a warm vibe and a huge low end. Just switching it in can thicken up a kick drum, bass or even a whole mix. With more drive, 15IPS gives a great saturated tape-like squash."

-Paul "Willie Green" Womack
Wiz Khalifa, The Roots, Donnie McClurkin, Billy Woods

Customer Reviews

Based on 20 reviews
Jacob Seal
Finally built mine and I love them

After having them for almost a year I finally got around to building my pair of mkii's.

All I can say is wow. This is probably my most favorite module. It does something very pleasing on everything you send through it.

I ran kick and snare through it, then the whole drum bus as a stereo send, then the master mix. It made a noticeable difference.

I am learning with the colour modules when to use it thick and rough and when to use just a pinch. There is a learning curve. Just a pinch of 15ips on each bus plus master bus is a good start.

Robert Skelton
You kidding

I love this stuff. Versatility

Theodore Cook
DIYRE 15IPS - not tape.

Didn’t like it after listening, and after some measurements I know why. Even at the lowest setting, harmonics are too present and stretch way too high.

A tape simulator should have a little 2nd harmonic, a little more 3rd, then a little less on the rest up to maybe the 6th or so where they should start to taper into the noise floor.

UAD’s tape emulations, u-He Satin, and the Anamod ATS-1 all get this right. The 15IPS does not, with dozens of audible harmonics.

In a setup with multiple subtle stages of saturation, it’s best for them all to be subtle and relatively low-order. Otherwise you’re putting too many harmonics on the harmonics you already generated - it quickly becomes an unmusical fractal mess.

The head bump is also a little exaggerated and high, and the HPF a bit steep and also high for 15IPS. Looks more like a 30IPS head bump.

For the record I like the CP5, and I’m building an OLA5 tonight. But I think the 15IPS needs some revision.

Hi, thanks for taking the time to dig into the 15IPS and write a review. I'm glad you're enjoying the CP5 and I'm sorry the 15IPS isn't to your liking. I just wanted to reply with a bit more context and point you to our 15IPS mods. You may be able to customize the 15IPS to work better for you via the resonant filter and distortion mods here:

Now, onto a couple specifics from your comment that I think warrant more discussion. (These points aren't meant to change your impression of the 15IPS's sound. Rather, they're to provide more context about why the 15IPS is designed the way it is.)

Regarding the head bump, it's a 3dB bump with a corner frequency of 47Hz. This is right about in the middle of measured head bumps on machines running at 15IPS. You can see a bunch of sweeps here: If you want less that 3dB you can mod it by changing the value of R7 (Mod here:

Regarding the harmonic content, the number of visible and audible harmonics is related to the amount of distortion. Like real tape or vacuum tubes, the 15IPS uses soft clipping to emphasize lower harmonics. But any piece of analog gear will introduce higher harmonics as it reaches it's limit. I think what you are noticing is more the amount rather than the character of the distortion. The 15IPS is dialed in to be a bit hotter than a high-quality tape machine so that those who want it for aggressive tone shaping have that available. But depending on your goals and the levels of your equipment, it can be too much. If you'd like it to be more subtle just reduce the value of R6. (Mod here:

Thanks again for your feedback. I hope this reply was helpful.

Greg Samuel
A Delightful Way to Warm Up Your Tracks

The 15 IPS definitely adds the smooth warmth and the low end bump reminiscent of analog tape, but with the added flexibility of dialing in only as much as you need. Unlike most tape emulation plugins, which I've found don't add very much, this actually makes an audible difference. Plus, you can dial in even more to dirty up your sound in a not-so-pleasant way if that's what you want to do. Great module. Just like analog tape channels, the effects are cumulative as channel count increases. We use five of them in our DIYRE preamps. Be careful when building this one because the NOS glass diodes are fragile. We found a couple defective ones in one of the modules we built. But you can be sure that Peterson always makes it good and if anything is amiss, he will make it right and send out the parts you need.


Using pretty much always on to track through. Sounds not exactly like real tape (only real tape does) but does what I expect it to. Similar to fatso tape sim. Compresses very naturally and nicely. Pretty much always on at least a little for tracking so far, have a stereo pair for busses. Love it!

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