Aleph Null
Well-known member
The Spork is a mid-focused overdrive with a wide gain range and a powerful EQ.
This is not a Tube Screamer. If anything it's more in the lineage of the Distortion +.
The Filter and Contour controls are lifted almost directly from my Clever Hans circuit. The mode switch does a few different things at once. Fork mode has a little extra poke. Spoon mode has an extra dollop of gain.
The signal first hits a non-inverting opamp stage. The Gain control is set up so that, as it is turned up, the upper-mid content is emphasized. This helps retain clarity. Bass is progressively rolled off, up to about 723Hz at the highest Gain setting. The 100pF capacitor in parallel with the 1M resistor set a low pass filter with a corner frequency of 1.6kHz. The non-inverting arrangement means nothing ever gets attenuated, the mids just get amplified more than everything else. Lower gain settings sound transparent. As again is increased, the mids saturate first, keeping everything tight and articulate.
The gain stage then feeds one of two sets of hard clipping diodes as selected by the mode switch. Fork mode gives you asymmetrical clipping. The smaller capacitor (C5) means that only mids and highs get clipped, making for a pokey, open, and dynamic response. Spoon mode gives you full-frequency symmetrical clipping. This is spongier and more saturated.
The clipped signal is then fed into the tone stack. Contour is a simple input capacitor blend which can gracefully roll off low end. Filter is a low pass filter which creates a resonant peak right before the cut off frequency. This keeps things sounding lively even with heavy treble cut. The other half of the mode switch sets the resonant peak of the Filter control: a higher more prominent peak in Fork mode, and a lower, softer peak in Spoon mode.
While I think this circuit sounds good into a clean amp, my favorite use is approach many people take with a Tube Screamer: to cook the input of another dirt box or dirty amp and tighten things up.
Here's a demo:
If you'd like PCB, send me a DM!
This is not a Tube Screamer. If anything it's more in the lineage of the Distortion +.
The Filter and Contour controls are lifted almost directly from my Clever Hans circuit. The mode switch does a few different things at once. Fork mode has a little extra poke. Spoon mode has an extra dollop of gain.
The signal first hits a non-inverting opamp stage. The Gain control is set up so that, as it is turned up, the upper-mid content is emphasized. This helps retain clarity. Bass is progressively rolled off, up to about 723Hz at the highest Gain setting. The 100pF capacitor in parallel with the 1M resistor set a low pass filter with a corner frequency of 1.6kHz. The non-inverting arrangement means nothing ever gets attenuated, the mids just get amplified more than everything else. Lower gain settings sound transparent. As again is increased, the mids saturate first, keeping everything tight and articulate.
The gain stage then feeds one of two sets of hard clipping diodes as selected by the mode switch. Fork mode gives you asymmetrical clipping. The smaller capacitor (C5) means that only mids and highs get clipped, making for a pokey, open, and dynamic response. Spoon mode gives you full-frequency symmetrical clipping. This is spongier and more saturated.
The clipped signal is then fed into the tone stack. Contour is a simple input capacitor blend which can gracefully roll off low end. Filter is a low pass filter which creates a resonant peak right before the cut off frequency. This keeps things sounding lively even with heavy treble cut. The other half of the mode switch sets the resonant peak of the Filter control: a higher more prominent peak in Fork mode, and a lower, softer peak in Spoon mode.
While I think this circuit sounds good into a clean amp, my favorite use is approach many people take with a Tube Screamer: to cook the input of another dirt box or dirty amp and tighten things up.
Here's a demo:
If you'd like PCB, send me a DM!
Attachments
Last edited:
