The Pettyjohn Electronics CoreX GLASS is a low to medium gain overdrive pedal in the blues breaker tradition, built for high headroom and touch sensitivity. Pettyjohn describes it as a classic blues breaker inspired overdrive, great for players who want the pedal to respond to their picking rather than flatten it1. It sits in the overdrive family alongside pedals like the Pettyjohn CHIME and ODI, and it shares the CoreX platform with the CoreX ODI and CoreX FIVE.
Pettyjohn Electronics describes the CoreX GLASS as a classic low to medium gain blues breaker inspired overdrive, voiced to be more "transparent" than others1.
What it does
The GLASS is voiced to be more "transparent" than other overdrives, according to Pettyjohn, meaning the pedal is designed to add gain without imposing its own character on the guitar and amp1. With its low to medium gain range and high headroom, it is aimed at players who push an already working amp rather than replace its tone, in the way blues breaker style circuits are typically used. For context on how this approach compares to a more compressed, mid focused drive, see Boss SD-1 vs Ibanez TS9 Tube Screamer.
The maker's product page lists Blue Knobs among the pedal's features1. Other CoreX series pedals and Pettyjohn's Foundry line, such as the GOLD and IRON V3, carry the company's broader design language of extended controls beyond a simple three knob drive.
Questions
Is the Pettyjohn CoreX GLASS still in production?
No. Pettyjohn Electronics discontinued the CoreX series as of October 2026. The company explained that the power supply the series is designed around is being discontinued, and that the CoreX line will stay out of production until a suitable replacement is found.
What kind of overdrive is the CoreX GLASS?
Pettyjohn describes it as a classic low to medium gain overdrive inspired by the blues breaker circuit, with high headroom and touch sensitivity. The maker voices it to be more transparent than other overdrives, so it is aimed at players who want their amp's character to come through.
Sources (1)
- CoreX | Pettyjohn Elec, Pettyjohn Electronics
