DOD FX13 Gonkulator Modulator

Collector's Notes

Due to its short production run, and popularity among experimental noise artists, original units have become highly sought-after collector's items. Originally retailing between $149 and $199, they now routinely sell in the aftermarket between $200 and $400. The higher priced units are typically the rarer "2nd" series with the actual pot functions labelled on top of the control knobs. Of course, condition, original box, box condition, and having the original paperwork all play a part in value.

There were a total of 18 DOD pedals (coined by Josh Scott as the Lamb Series) that Jason and Roger Johnsen, VP of Engineering at DOD/DigiTech, created together. (See section below)

On December 26, 2025, Roger sent me an email that helped clear up some misinformation out there and gave the real back story behind Jason, the Gonkulator Modulator, Dale and the Deadheads, and so much more:

Roger's story

"As a kid, growing up in the Avenues area of Salt Lake City, I was a fan of Hogan's Heroes and got a kick out of the Gonculator episode, so I filed that Gonculator name in the back of my mind. A few years later, as young teenagers, my younger brother and I formed a fictitious, at first, band that we called 'Dale & the Deadheads', incidentally with no real connection or interest in the Grateful Dead band. We came up with stage names - I became Dale Fender, and my brother became Righteous Nelsen, later Righteous Scott Nelsen. (Huh?) We also concocted fictional stories and facts about the band, one of which was that our band's music was regularly played on the KRAP radio station located in St. George, Utah by the station's popular DJ, Ron Lemmon. KRAP, we decided, was neither an AM (Amplitude Modulation) station, nor an FM (Frequency Modulation) station. No, it was a station broadcast using the newest RF technology called Gonculated Modulation (GM) and, naturally, only the newer stereos and car radios were equipped with the GM band. (What nerds!)

Fast forward a couple of years to high school at East High in Salt Lake City. Yes, that East High School of Disney 'High School Musical' fame. We had added a few additional band members who were classmates, also with aliases, and actually became a 'real' band: Hondo Afterburner, Del Rey Thunderang, Idget Silvertone, and others down the line. While we were now an actual band, we were still (intentionally) a bit of an inside joke. Some key hallmarks of our band included distorted 'lead bass' lines, and fuzzy guitar distortions into cheap amps (such as the Checkmate brand). In an attempt to be counter-culture to the then-current punk rock counter culture, we dubbed our brand of music 'Gunk Rock', implying particularly raw and distorted 'gunky' bass and guitar sounds.

Sometime around 1979-1980, Hondo and I were joking around and 'riffing on' fictional guitar gear, and I mentioned the Gonculator name, reminding him of the old Hogan's Heroes episode. Knowing that I had conceived of the Gonculated Modulation radio band, Hondo immediately blurted out 'Gonculator Modulator' as a fictional piece of gear. I immediately latched onto that name but stated that we had to spell it 'Gonkulator' with a 'k' because that was more like 'Gunk'. Then, once again, I filed that name in the back of my mind.

For years afterward, I would periodically think about that name. Related to that, in 1983, I built a homemade pedal (that I still have to this day) that plugged directly into the 1/4" guitar jack and 'rode' on the guitar. I dubbed it the Piggyback Gunk Box. I used decals from hobby model building for the markings on the pedal. Long before I had even heard of 'Spinal Tap', I labeled the sole control, the gain/distortion knob, such that it maxed out at '38'. Not 10. Not 11. But 38.

While finishing my Electrical Engineering degree at the University of Utah, I started working part-time at DOD in February of 1987 on the production line testing and repairing DigiTech, DOD, and Audio Logic pedals and rack-mount equipment. Jason Lamb was hired shortly thereafter. And shortly after that, Dale Curtis as well, who went on to work as an engineer on dbx and DigiTech products, followed by a more-than 15-year stint as VP of Engineering for Fender. He also played keyboards in my band for a bit, including when we played at a 1988 DOD company party.

On Monday, January 2, 1989, I was hired as an engineer and, along with another engineer (Von Parker) hired near the same time, we essentially picked up where David O. DiFrancesco left off, as he had moved on from the company one week earlier. Von had also worked with Jason and me as a production line tech prior to this. He and I continued designing products for the DOD product line.

Enter Jason Lamb:

Roger Johnsen continues: If my memory serves me correctly, about a year into the DOD engineering gig, we snagged Jason Lamb from the production line, to be an Engineering Associate to help get new DOD pedals to production. I was quickly promoted to Engineering Manager over DOD products and started working more closely with and relying on Jason to get pedals defined and designed and to market. In early 1993, Jason came to me with an idea to really capitalize on the burgeoning 'Seattle Sound' of Nirvana, etc. With Jason, it was never as much about the sales potential as it was about his passion for what he wanted to build. He had been modifying distortion circuits to try to get that 'grunge' sound. I have to admit that I was not plugged into the grunge movement at that point, but Jason quickly brought me up to speed.

I was TOTALLY on board when Jason proposed doing a Grunge pedal as it resonated with my Gunk Rock sensibilities and reminded me of my Piggyback Gunk Box. I excitedly told him I know exactly the paint process that we should use on it. The head of our Paint and Silkscreen Department, Mike Nelson, had recently showed me a happy accident where a topcoat was painted over an incompatible undercoat, which caused the topcoat to pull away from the undercoat, leaving a cracked look to the topcoat and revealing the undercoat in the cracks. Jason loved the idea and said he wanted the topcoat to be metallic purple. After a few minutes of thought, I suggested we should give the control names a bit more attitude: Loud for level, Butt for low EQ, Face for mid-high EQ, and Grunge for gain/distortion. And we HAD to sequentially order the knobs such that it read as a coherent sentence fragment: Loud-Butt-Face-Grunge! Such began our practice of the wacky control names, of which I named probably about 80% of them, Jason naming the other 20%.

We knew we were pushing boundaries, and we secretly hoped that upper management would not squash our Grunge idea. Fortunately, they didn't. Although management didn't always understand this particular market, they gave us a little rope with which to experiment (or to hang ourselves). But the Grunge became a smash hit! This bolstered Jason and me, and so we felt like we had a little more leeway to continue to get crazy. So, then came Death Metal, the Meat Box, and the Gonkulator Modulator! This was my chance to bring to life this pedal that I had envisioned (but in name only) for more than 15 years, but...

Now I had to figure out what the heck a Gonkulator Modulator would actually do. It didn't take much thinking as the name practically laid it out for me. It had to be a 'gunky' (or 'grungy') distortion combined with a ring modulator! I finally brought that idea to Jason and he was all over it! I drew out a block diagram and I pointed him to available multiplier chips that we could use for a ring modulator design and tasked him to go try to draw out the whole schematic. I let him have a lot of freedom to design and try things and make mistakes, and I would review his schematics and make suggestions and changes, and over the years he became more capable as a self-taught engineer.

Upon suggesting the 'Gonk' to Jason, my mind immediately shifted to what the controls would be and what would we name them. I had long wanted to make a pedal with a 'Suck' knob, thinking back to a Gary Larson Far Side comic strip showing a front-of-house sound engineer foolishly reaching for a knob on the console labeled 'Suck' and the caption reading 'Raymond's last day as a sound engineer', or something to that effect. Ultimately, I couldn't come up with a completely coherent sentence fragment that included the control names I wanted, so I settled on names that at least somewhat flowed as you read them from left to right: Suck-Smear-Gunk-Heave.

Further, the pedal HAD to be purple and yellow. My band had recorded a song called 'The Purple and Yellow Dress' that Righteous Nelsen and I had essentially written in 1981 in about 10 minutes when he and I were 'freestyle jamming'. This song was a blatant ripoff of The Cars, and I did my best to imitate Ric Ocasek's vocal style, as well as throwing in a DEVO 'Mr. B's Ballroom' vocal outro at the end of the song. We later recorded a more polished version in 1987 which was part of a demo tape we sent to Dr. Demento, along with 'Gumby and Pokey Ride Again' which Dr. Demento featured in April of 1987, mentioned in the same breath as the Beatles, Frank Zappa, and other famous artists on his show! The pedal also HAD to be dubbed the FX13, as 13 was our band's lucky number."

Thank you Roger for sharing this important slice of DOD history!

When I posted the link to this page on Facebook on 12-28-25, Gregory Barreto read it over and asked the question: "The internal trim pot in the new one (2015 reissue) controls bias, I suspect this one is the same? I'm sure someone will confirm." I thought that was right but Tom Cram commented with the following correction: "The new Gonk has an ADDITIONAL Freq control that controls the carrier frequency in order to tune the ring modulation. The internal trim pot on both the old and new controls the Null, this controls the bleed of the carrrier. The Freq control does not exist on the old Gonkulator." Thanks Tom!

And speaking of the Gonkulator reissue, here are some Notable Artists Using the FX13:

    ● John Dwyer (Guitarist/Singer, Thee Oh Sees): Dwyer has been seen using the 2015 DOD Gonkulator reissue on his pedalboard during a 2019 live session with KEXP, indicating its use in his psychedelic/garage rock sound.

    ● Brian Ray (Singer/Guitarist, Paul McCartney's live band): Ray has used the Gonkulator reissue, even sharing the specific settings he used for a guitar lick for his band, The Bayonets, on social media.

    ● Geordie Greep (Bassist/Keyboardist, Black Midi): The pedal can be seen on Greep's pedalboard in photos, suggesting its use in the band's experimental and avant-garde sound.

    ● Masahiko Ohno (Guitarist/Music Producer, Solmania): Ohno's gear setup has been documented to include the DOD FX13 Gonkulator, contributing to his noise music and experimental soundscapes.

    ● Nick Reinhart (Composer/Guitarist, Death Grips): Reinhart has used the pedal as part of his experimental work and has also produced a demo of the reissue.

    ● Tommy Meehan (Guitarist/Bassist, Gwar, Deaf Club): The pedal has been spotted on Meehan's pedalboard in live performance videos with Deaf Club.

While many of the most famous examples of the Gonkulator are from the 90s original (e.g., Mike Einziger of Incubus on "Glass" or Larry LaLonde of Primus), these modern artists are continuing to use the unique sonic possibilities of the reissue.

Videos

Here's a really cool video of Tom Cram interviewing Roger about Jason, those crazy pedals, what really happened with the DFX6, DFX7, and a whole lot more. Video starts at 6:10 with Jason's story. Entire video is (20 minutes, 1 second)

Here's Josh Scott's excellent video on these incredible pedals (24 minutes, 59 seconds)

TheSuperFunAwesomeHappyTimePedalShow does a cool sounds demo, no talking (4 minutes, 2 seconds)

The SoCal Riff Ranch does a sounds demo, with commentary (5 minutes, 11 seconds)

Jim Crye does a sound demo, no talking (6 minutes, 7 seconds)

Anarchy Audio sound demo, no talking (1 minute, 6 seconds)

Both cosmetic variants of the FX13, from early (left) and
late 1996 with the "real" control names above the knobs.

Technical info