GT-820
Clean boost to overdrive, often compared to Klon Centaur
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The GT-820 overdrive rack effect module compares to the Maxon OD-820, a transparent boost and overdrive that some consider a Klon killer, or in GT-speak, a Unicorn killer. Probably less well-known than the Klon Centaur, it sounds very similar and has a similar circuit design.
Description
We choose not to step into any debates about one pedal vs another, but there are plenty of opinions about the relative merits of the Maxon OD-820 and the Klon Centaur. In the end, as it always does, it comes down to preferences, your rig, and what you're doing with the pedal. The Maxon OD-820 has a nice, transparent clean boost that can be dialed up to provide light overdrive tones, or to push a cranked tube amp into overdrive. Perhaps a little less coloring than the competition, which can be good or bad depending on what you want. It was intended to be the next generation Tube Screamer, but didn't really catch on. Some may say that it's touch and transparency expose the player's skill more than the Tube Screamer... The Maxon OD-820 is nearly identical to the Maxon VOP9. The GT-820 allows some modifications, but otherwise stays close to the original circuit.
Configurations
- GT-820 - compares to Maxon OD-820
Options
- Custom Op Amp - The default is the same as the original circuit, JRC4558D. You can choose any pin-compatible op amp. Perhaps a TL072 or OPA2134 might be good alternatives.
- Custom Transistor - The default is the same as the original circuit, the 2SK246 JFET. You can select something else if you prefer, but there's not a lot of reason to choose something other than a JFET or even make a change at all.
- Custom Clipping - The default is the same as the original circuit, 1N914 diodes. You can select something else if you prefer.
- Clipping Switch - Allows you to switch between two clipping diode configurations. A no clipping setting can also be added to the switch. Switching to Ge diodes will make a considerable difference in the drive, although some can be selected to clip nearer to silicon levels. Switching between two different silicon configs will produce subtle differences.
- More Gain - This option isn't fully tested yet, but check with us if you are interested. It sort of runs contrary to the spirit of the circuit (low gain), but rules are meant to be broken, right?
- More Bass - Another option not fully tested. The circuit has little effect on the frequencies it allows through, but we may be able to get a little more bass to go through.
- Crank - This option allow more treble to pass through the gain stage. In addition to allowing more treble through, it adds a bit of gain, with attitude and some presence. Can be subtle with some control settings.
- Custom Components - We use metal film resistors and a selection of capacitors that provide good tone and low noise.
Front Panel
- On/Off indicator LED
- Drive
- Tone
- Level
- (optional) Clipping switch
Rear Panel
- Audio In
- Audio Out
- On/Off Footswitch
- On/Off Override
- DC Power
- DC Power LED
Module Width
- 1.5"
- 2" left wing available
- 1.5" right wing available
Power Consumption (aprox)
35 - 40mA
Base Configurations
| Part # | Description | List Price |
| MOD-GT820 | GT-820 module | $220 |
Options
| Part # | Description | List Price |
| MOPT-GT820-OPAMP | Custom Op Amp | $0 - TBD |
| MOPT-GT820-TRANS | Custom Transistors | $0 - TBD |
| MOPT-GT820-CLIP | Custom Clipping | $0 - TBD |
| MOPT-GT820-SWCLIP | Clipping Switch | $19 - TBD |
| MOPT-GT820-GAIN | More Gain | $0 |
| MOPT-GT820-BASS | More Bass | $0 |
| MOPT-GT820-CC | Component Changes | TBD |