Soft and hard clipping in the same signal path.

[The Gator]

I am sure it has been discussed many places, but I like this community a lot and would like to discuss it here.
I recently built the brown amplification version of the noble circuit known here as the pro-10. This circuit has both soft clipping and hard clipping diodes in the same signal path and on at the same time. They are actually even the same diodes so they clip at the same level. My thoughts are, whatever Clips last is the only thing that is actually doing clipping. I'm sure it is possible to slightly change the sound of clipping with soft and hard clipping together if done a certain way.
The gentleman who designed the noble circuit was most certainly much smarter at Electronics than I. I kind of doubt he would have done this if it didn't do anything at all. I'm assuming slight changes in the signal could be seen on an oscilloscope when combining soft and hard clipping.
I would like like thoughts and opinions from others on this subject.

Thank you!
Gator

 

[DGWVI]

The soft clipping arrangement in the Noble circuit allows some clean bleed (not dissimilar to a Tube Screamer type), so when it hits the hard clippers, it's actually a mix of the overdriven diodes with a smidge of the clean, albeit filtered, signal. So, you get the unmolested attack of your basic clean tone, with the added grit and compression being further squared off by the hard clippers.

The values in the Noble should also allow for some slight opamp clipping with higher gain settings, so it's got all of that going on, too. Together, they all make for a harmonically richer signal

So, while the hard clippers will have the final say over compression levels, they all play their part

 

[ICTRock]

to expand, let's say you've turned on both sets of diodes in a king of tone. Your hard clippers will turn on before you feedback loop clippers because the Vf of the hard clipping antiparallel pair of 1S1588 diodes is about 650mV whereas the feedback loop MA856 (2 in series in antiparallel pairs) is more like 1.6V (all measurements with Fluke 179 meter)

Your logic is flawed in that order doesn't matter as much as forward voltage (Vf). Whatever clipper has the lowest forward voltage threshold will clip first unless there's some weird edge case regarding the knee voltage. If you were to string enough silicon diodes together to match the forward voltage of say a MOSFET clipping arrangement, the silicon may be clipping sooner because the knee is more gradual for the MOSFET

 

[iamjackslackof]

Nothing to add on the question, but I will say I learned a lot from just these 2 posts about clipping and clipping diodes.Thanks for sharing your knowledge.

Also @DGWVI I think you just talked me into building a Nobel pedal, it sounds really cool lol.

 

[DGWVI]

Nothing to add on the question, but I will say I learned a lot from just these 2 posts about clipping and clipping diodes.Thanks for sharing your knowledge.

Also @DGWVI I think you just talked me into building a Nobel pedal, it sounds really cool lol.

I've owned an original, but have yet to populate my own board

I remember liking it, but building straight dirt boxes lately is kinda meh to me

 

[The Gator]

Thank you very much for your responses.
I didn't think it was that simple. I merely wanted to start the conversation to get those with more knowledge than I to assist in the discussion.
I'm glad I did! I figured I was ignorant of some details.
I like learning about the different ways to get different clipping sounds.
Thank you again for participating
Gator

 

[Feral Feline]

A great clipping test-bed is the VFE Distortion³

It has blendable hard and soft clipping, that is

Hard: Two options to blend between
Soft: Two options to blend between


Build one and convert the blend-pots to on-off-on SPDT switches, socket the diodes and you'd be able to compare:

- Two different types of soft-clipping to two different types of hard-clipping. [That's four options right there!]
- Op-amp clipping with soft-clipping (NO hard-clipping, but two soft options)
- Op-amp clipping with hard-clipping (NO soft-clipping, but two hard options)

PCB available at the Angry Legume's site.

 

[HamishR]

Just saw this post. I am always very up-to-date with my reading.

Just thought I'd add that BJF uses a combo of soft and hard clipping quite frequently. Just look at the Honey Bee, or Strawberry Red. Just because one set of diodes might clip before the other doesn't mean that both sets don't have an effect on the sound and feel. I've experimented with a few BJF designs with putting different clipping stages on a switch to hear what each pair contributes. And in the Strawberry Red I like to put the second pair of diodes on a switch, because if I only use the first pair of diodes I get a clearer low end but still have plenty of dirt on tap. Switching in the second set of diodes makes the sound only slightly dirtier, but it really affects how the low strings growl. Bjørn really knows what he is doing.

I suspect that having different types (or even the same type) of clipping occurring in a couple or more places in an overdrive can help the circuit sound/feel more natural. After all, overdrive pedals were designed to mimic the sound of an overdriven amp. A good guitar amplifier will distort at several gain stages if not all when drive hard. Some amps will distort more at the phase inverter, some at the power tubes, and some at the first gain stage. But when really pushed all of the amp should be contributing in some way to the sound of distortion.

 

[jwin615]

PCB available at the Angry Legume's site.

It's early and I literally googled Angry Legume

 

[Robert]

This is an old thread, but this is based on one of my all time favorites:

SoulDrive - PedalPCB.com

Compare to Fulltone PlimSoul

www.pedalpcb.com

Hard clipping, soft clipping, or a combination of the two.

 

[synthesiserror]

This is an old thread, but this is based on one of my all time favorites:

SoulDrive - PedalPCB.com

Compare to Fulltone PlimSoul

www.pedalpcb.com

Hard clipping, soft clipping, or a combination of the two.

I saw this yesterday and was curious... what exactly is the patented part of the original circuit? I did a patent search and found some blurry schematics and about three pages of jargon that sound like he's describing pretty much every dirt pedal out there plus a dual gang potentiometer. I didn't have time to read it that thoroughly, though.

 

[jimilee]

This is an old thread, but this is based on one of my all time favorites:

SoulDrive - PedalPCB.com

Compare to Fulltone PlimSoul

www.pedalpcb.com

Hard clipping, soft clipping, or a combination of the two.

I really like the implementation here. Potentiometers instead of switching. This is a fun drive circuit fwiw.