The Hagerman Amplification Gamma Radiatiøn Transistor Distortion is a four-knob distortion pedal built entirely from discrete transistors: seven of them do all the amplification and buffering, with no opamps in the circuit1. It is based on Jim Hagerman's "gamma" patent from 1995 and comes from the maker's newly re-released silicon lineup of pedals1. Pedal of the Day describes it as "the powerful and versatile Gamma Radiatiøn Transistor Distortion," and it is available both as a finished pedal and as a pedal kit1.
How the circuit works
Instead of a single clipping block, the Gamma Radiatiøn runs two clipping stages in series with an Energy (tone) control in between, which Pedal of the Day says gives "more control of voicing"1. That arrangement is the heart of the pedal's flexibility: the Energy control shapes the character of the signal between the two clipping stages rather than only after them.
The pedal carries four knobs in total1. Two are named in the review:
| Control | What it does |
|---|---|
| Drive | Adjusts the amount of drive; turned down with the guitar's volume rolled off, it gives what the reviewer calls "spooky clean, warm tones"1 |
| Energy | A tone control sitting between the two clipping stages, for voicing control1 |
What it sounds like
The maker's and reviewers' accounts agree that this is a wide-ranging distortion rather than one fixed voice. Pedal of the Day's reviewer writes that "the extreme flexibility of this pedal allows it to mimic a wide range of flavors, from Blues Breaker to Rat to Screamer," and adds: "Crank it for radiant joy"1. On the circuit type generally, Stefan Karlsson of Guitar Pedal X said:
"I'm a huge fan of discrete transistor overdrives and distortions - they tend to deliver some of the most richly textured"2
Stefan Karlsson, Guitar Pedal X2
Karlsson places the Gamma Radiatiøn in that discrete-transistor family, calling it "a unique variant of that type circuit character"2. Pedal of the Day's verdict on the range of the pedal: "The range here is amazing, and these tones will leave your amp and your audience in a state of sonic bliss"1.
Power and practicalities
The pedal runs on a -9V to -15V DC supply at 4mA, center negative1. The 4mA draw is low enough that any standard pedalboard supply should handle it, and the center-negative polarity matches the common boss-style standard. Bypass is true bypass1.
The pedal is part of Hagerman Amplification's newly re-released silicon lineup1, and it is offered as a pedal kit as well as a finished unit1.
Price
Pedal of the Day, reviewing in September 2026, lists the pedal at $99.00 and calls it "a steal at just $99.00"1. Guitar Pedal X's earlier coverage, from February 2026, gives the price as $1292. The two reviews disagree, and the price may have changed between the two dates.
For where this pedal sits among its neighbors, see the site's pages on Distortion Pedals, Overdrive Pedals and Fuzz Pedals, or the fuller listing at Hagerman Amplification Hagerman Gamma Radiation.
Videos
Pedal of the Day
Questions
Who designed the Hagerman Gamma Radiation?
The pedal is based on Jim Hagerman's "gamma" patent from 1995, and it comes from Hagerman Amplification, the company run by Jim Hagerman. Pedal of the Day reviewed it in September 2026 as part of the maker's newly re-released silicon lineup of pedals.
Is the Gamma Radiation pedal true bypass?
Yes. Pedal of the Day lists the Gamma Radiatiøn Transistor Distortion as true bypass, so the pedal takes itself out of the signal path entirely when switched off.
What polarity does the Gamma Radiation pedal use?
It runs on a center-negative supply, from -9V to -15V at 4mA. That is a standard boss-style center-negative input, and the low 4mA draw means even a modest shared supply should handle it.
Does the Gamma Radiation use opamps?
No. According to Pedal of the Day, seven transistors do all the amplification and buffering in the circuit, with no opamps anywhere. That discrete design is what Guitar Pedal X's Stefan Karlsson points to when he describes the pedal's richly textured character.
Is the Gamma Radiation available as a kit?
Yes. Pedal of the Day notes it is offered as a pedal kit as well as a finished pedal, so builders can assemble the circuit themselves.
What is the maximum gain of the Gamma Radiation?
Pedal of the Day gives the maximum gain as 43dB, with a bandwidth of 55Hz to 7kHz and a 100k input impedance.
Sources (2)
- Hagerman Amplification Gamma Radiatiøn Transistor Distortion, Pedal of the Day, 2026-09-04
- Guitar Pedal X, Guitar Pedal X, 2026-02-12
