Clipping Diode Shootout

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In the time it takes to post "I'd like to see" you could measure it yourself and post something
But then this forum wouldn't have 1000 keyboard "experts" for every 1 person that actually does something 🤣

Adjust the pot for Vf = 4v to 0v in 0.5v steps. At each step measure Vf and Vr
 

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I guess I would be one of those "(computer) keyboard experts". I never had much interest in making distortion on purpose. The last time I intentionally clipped audio I used a less than $0.01 common diode (1n4148) that we were already using 1M per month.

I just offered the possibility of looking at semiconductor junctions.

Last century I paid attention to diode junction characteristics inside log conversion circuits inside dynamics processing side chains.

JR
 
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A cheap V-I curve trace can be made with a signal generator and scope with x-y capability. Put a current sensing resistor in series with the diode and probe at the two nodes. There are offset errors because of the shared grounding. Depending on your equipment (current probe, differential probe, scope math) you could correct this.

 
Loads of circuits around for DIY 'octopus' boxes that will draw component curves on your scope. Fit an A/B switch and you can compare components quickly.
 
as luck would have it, somebody just walked in the shop with a couple of screamers,

one is a TS9 , 1983, with the Maxon battery cover, no CE sticker, and the green goop on the leads,

yanked out one of the blue stripe diodes and it plots exactly like the 1S1588 that i bought and plotted, not even 1% percent difference,

ts9.jpg

tsa.jpg
 
I worked on a number of different TS starting around 95.
A real 808 did sound different however, you would not notice it in a mix or on stage.
As best as I could tell this was caused by the tantalum caps used IIRC they were blue and I did not notice a manufacturer mark.
ICs don't make much difference except for noise.
Things that matter are the EQ points
IMO there is a lot on nonsense on the web about the TSs.
 
I was simulating the frequency response of different pedals, bluesbreaker, KOT, rat, etc... and they all have a different kind of EQ before the clipping section.
I'm thinking of using a EQ pedal on either side of a flat clipping section, with a rotary knob for different diodes.
I have a couple tubescreamers and they can be a little too honky I think.
 
Cool idea on the eq!

I would like to see a freq pilot of the Cornish buffer. It sounds real good even in the pedal off situation.

I used a 0.1 uf film tone cap on the tube screamers in place of the .22 tants. One of the screamers had a shorted tant (tone circuit). It took down the JRC 4558. Put in a TI 4558 and heard no difference. I did hear a slight difference on the 90 screamer, it had the 5550 opamp or whatever the used. I swapped in a socket and another 4558 and it seemed more like the 80 screamer. Variations in the pots can make A/B testing hard in any position but wide open.
 
Cool idea on the eq!

I would like to see a freq pilot of the Cornish buffer. It sounds real good in the padal off situation.

I used a 0.1 uf film tone cap on the tube screamers in place of the .22 tants. One of the screamers had a shorted tant (tone circuit). It took down the JRC 4558. Put in a TI 4558 and heard no difference. I did hear a slight difference on the 90 screamer, it had the 5550 opamp or whatever the used. I swapped in a socket and another 4558 and it seemed more like the 80 screamer. Variations in the pots can make A/B testing hard in any position but w
dmp said:
The Cornish st-2?
Click to expand...
Yes, or any of those Aion fx Cornish knockoffs, I think there are about 4 of them, only difference seems to be 10k/20k on the output side,

The Aion guy says "the meticulously engineered Cornish buffer" but there are only about 5 parts so I want to see just where he is coming from , if you search "Aion FX Cornish" you should get all of the projects, my simulator skills are pretty weak, mostly from lack of use.


Edit: I think I quoted myself, wtf? Phones are weird.
 
The Cornish buffer is a bootstrapped EF.
I like adjusting the bootstrap cap value smaller sometimes with bootstrapped input circuits.
You can find bootstapped circuits in books

Another adjustment for the TS I have done is add a .1uf cap and a switch for .1uf or 1.1uf after the input EF to the gain stage to move the HPF up.
I did this for someone I know that played with Bernie Worrell.
The person I adjusted the TS for, used a Fender twin on stage.
Bernie Worrell played so loud that the twin was having issues with open back cab speakers being driven hard that they needed to reduce the lows going to the Fender twin.
Another cool circuit is the one you can find in some G&Ls that have a bass cut control on the guitar.
Sometimes you can have too much bass level.

EDIT a link I found
https://tonefiend.com/guitar/two-band-ptb-tone-control-useful-easy-cheap-awesome/
 
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Gus said:
The Cornish buffer is a bootstrapped EF.
I like adjusting the bootstrap cap value smaller sometimes with bootstrapped input circuits.
You can find bootstapped circuits in books

Another adjustment for the TS I have done is add a .1uf cap and a switch for .1uf or 1.1uf after the input EF to the gain stage to move the HPF up.
I did this for someone I know that played with Bernie Worrell.
The person I adjusted the TS for, used a Fender twin on stage.
Bernie Worrell played so loud that the twin was having issues with open back cab speakers being driven hard that they needed to reduce the lows going to the Fender twin.
Another cool circuit is the one you can find in some G&Ls that have a bass cut control on the guitar.
Sometimes you can have too much bass level.
Click to expand...
My G&L Legacy has the bass cut circuit- I've actually converted my LP to global ton controls with a bass cut as well. Lets you get some killer tones out of the neck pups without getting muddy - esp for big chord voicings.
 
Thanks Gus! Never seen that before.

Stuck some Ge diodes in the king of tone pedal last night and it kicks the donkey's butt. The hard clipping circuit was too harsh with the stock diodes.
 

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