darwin999
Well-known member
Has anyone tried silicon carbide (SiC) diodes as clippers in their circuits?
If so, can they comment on how they sound compared to other options?
SiC diodes have a quoted forward voltage of ~1.35V, putting them between Si diodes (Vf ~ 0.7V) and Red LEDs (Vf ~ 1.7V) and comparable to infrared diodes (Vf ~ 1.2V). So that seemingly makes them another candidate on the clipper spectrum. (Note industry quoted Vf's are typically measured at much higher currents than we stompbox users typically explore.)
Here's the forward bias characteristics from one randomly picked SiC diode, with 2A forward current capacity.
Rohm SCS302AH (SiC 2A 650V) - left is linear plot, right is semi-log plot which better displays the characteristics for the current values that most stompboxes explore (e.g., roughly 0.1-10mA).
Here's 1N4148 Si diode curves for comparison. Left plot is an NXP 1N4148, right is for a Diodes Inc 1N4148. 1N4148's are usually rated ~0.2A & ~75V.
(I show different 1N4148 diodes simply because I didn't find one spec sheet with both linear and log I-V plots.)
At low currents (~1-10mA), the SCS302AH SiC diode has a steeper derivative ∂[log(I)]/∂V when it turns on near ~0.85V than the 1N4148 does when it turns on near ~0.4V. This observation suggests a more compressed behavior when entering distortion. Of course, the SCS302AH is just one of many SiC diodes, so I will explore others.
Anyway, I'm starting to build a PedalPCB Pandora's Box (Bixonic Expandora), and wanted to add a higher voltage clipper per what @Zanshin did (https://forum.pedalpcb.com/threads/...cist-aion-distortron-bor-and-expandora.21387/). But I didn't want to jump all the way from Vf~0.7V (1N4148) to Vf~1.7V (red LED), so I'm thinking of trying a pair of SiC diodes to see what happens...
Added comment: I was thinking of using an IR LED, however all the ones I looked at had very low reverse voltage tolerance - e.g., max reverse voltage was between 2 and 5V. That's just not good enough.
If so, can they comment on how they sound compared to other options?
SiC diodes have a quoted forward voltage of ~1.35V, putting them between Si diodes (Vf ~ 0.7V) and Red LEDs (Vf ~ 1.7V) and comparable to infrared diodes (Vf ~ 1.2V). So that seemingly makes them another candidate on the clipper spectrum. (Note industry quoted Vf's are typically measured at much higher currents than we stompbox users typically explore.)
Here's the forward bias characteristics from one randomly picked SiC diode, with 2A forward current capacity.
Rohm SCS302AH (SiC 2A 650V) - left is linear plot, right is semi-log plot which better displays the characteristics for the current values that most stompboxes explore (e.g., roughly 0.1-10mA).
Here's 1N4148 Si diode curves for comparison. Left plot is an NXP 1N4148, right is for a Diodes Inc 1N4148. 1N4148's are usually rated ~0.2A & ~75V.
(I show different 1N4148 diodes simply because I didn't find one spec sheet with both linear and log I-V plots.)
At low currents (~1-10mA), the SCS302AH SiC diode has a steeper derivative ∂[log(I)]/∂V when it turns on near ~0.85V than the 1N4148 does when it turns on near ~0.4V. This observation suggests a more compressed behavior when entering distortion. Of course, the SCS302AH is just one of many SiC diodes, so I will explore others.
Anyway, I'm starting to build a PedalPCB Pandora's Box (Bixonic Expandora), and wanted to add a higher voltage clipper per what @Zanshin did (https://forum.pedalpcb.com/threads/...cist-aion-distortron-bor-and-expandora.21387/). But I didn't want to jump all the way from Vf~0.7V (1N4148) to Vf~1.7V (red LED), so I'm thinking of trying a pair of SiC diodes to see what happens...
Added comment: I was thinking of using an IR LED, however all the ones I looked at had very low reverse voltage tolerance - e.g., max reverse voltage was between 2 and 5V. That's just not good enough.
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