Gorn Overdrive: Li'l help

[Fancy Lime]

Hi there,

since I am cut off from my work bench for the foreseeable future, I'm left with designing on paper. Doing some research into Zeners recently, I realized why back-to-back low-voltage Zeners as clippers sound as great as they do. Very dynamic and natural. If I were in the business of selling these things, I would probably call it "tube like" and for once that would be more than just an empty phrase. But seriously, such a Zener arrangement is a great way of getting sound reminiscent of FET clipping out of an opamp circuit.

Here is a little demonstration circuit:



The "woody/tinny" switch is a Z-switch. In the middle position, both legs should be connected to ground, in position 1 and 3, one or the other should be. The output volume may be a bit low as shown, unless this thing is driven with hot pickups or a booster upfront. This thing is going to be quite responsive to whatever input it is fed. One may opt to leave out D2 for symmetrical clipping or Change one or both of D1 and D3 to 3V3 Zeners to get more volume. If the circuit is not fed straight from the guitar, R1 can be lowered to a few hundred kiloohms. C5 and C6 may need adjusting by ear but the given values should be a good start.

As I said, no breadboarding or soldering for me any time soon, so here is the deal: If someone breadboards or builds this and uploads a half decent or better sound sample here, I am going to write a detailed description why it does what it does. That sound like a deal?

Cheers,
Andy

p.s. Stupid corona virus may as well be used to inspire some international cooperation instead of just interrupting it all over the place.

[Fancy Lime]

No takers, huh?

Well, maybe the sort of people who build nice overdrives for a pleasant guitar tone are a less adventurous bunch than I thought. Maybe millions of Tube Screamer, OCD, and Klon clones get build for reasons other than their sound. Would it help if I told you that Jimi played the Gorn Overdrive on his top secret solo album that the gov'ment does not want you to know about because they made him record it after staging his death in order to communicate with aliens from planet Swagulon-5 whose language consists of epic blues licks? I swear!

Andy

[Kipper4]

I'll clear the breaker and give it a whirl tomorrow . Pretty sure I've got a Zener kit somewhere.
I like a nice dynamic drive.

[iainpunk]

hey, im sorry,

your project seems very interesting, especially with the jimi record, but im not in to building "nice" pedals, im the kind of guy who builds pedals that will try to steal your girlfriend.

ill look for some zeners in my pile tomorrow and breadboard it up. and if i have zeners, ill give you a report on the sound.

iain

[idy]

Interesting diodes. So the Zeners are 2.7v in one direction and .6 in the other? More or less?
So just the two in series and reversed would be about 3.3v in each direction?
the extra BAT 42 is about .4v. So in one direction you get it in series with a zener, 3.1v, and in the other, the two zeners as before, 3.3?

Is that enough asymetry to be interesting? I have usually found a more extreme difference more interesting.... Am I missing something?

[Fancy Lime]

hey, im sorry,

your project seems very interesting, especially with the jimi record, but im not in to building "nice" pedals, im the kind of guy who builds pedals that will try to steal your girlfriend.

ill look for some zeners in my pile tomorrow and breadboard it up. and if i have zeners, ill give you a report on the sound.

iain

Oh boy, have I got the design for you! The last thing I actually managed to breadboard was a high gain fuzzstortion. The underlying motivation was that I have always found the Big Muff too polite, the Rat to be lacking in chest hair and the HM-2 to have too narrow a range of usable sounds. I have the schematic on paper and hope to digitize it one of these days. I originally planned to release it when I had the time to design a PCB for it but considering the current situation, I might as well release the schematic now. Stay tuned.

Interesting diodes. So the Zeners are 2.7v in one direction and .6 in the other? More or less?
So just the two in series and reversed would be about 3.3v in each direction?
the extra BAT 42 is about .4v. So in one direction you get it in series with a zener, 3.1v, and in the other, the two zeners as before, 3.3?

Is that enough asymetry to be interesting? I have usually found a more extreme difference more interesting.... Am I missing something?

Yes. Yes you are missing something, that something being current. The actual clipping thresholds in this arrangement come out to something more like this:
BAT42: 150mV
1N4148: 400mV (as a proxy for the Zener forward, for which I could not find the relevant data)
2V7 Zener revers: 1000mV
So the asymmetry is more like 1150mV vs 1400mV. But this all changes strongly and differently for all the involved diodes with changing amplitude of the input signal, which is the main point of this whole thing. The values above are for a 0.1V input signal. With higher input signal, the thresholds go up and the clipping becomes more symmetrical. If you like, you can swap D3 for a 3V3 and/or D1 for a 2V4 (if you can get hold of one) to make it more asymmetrical across the whole range.
But like I said, detailed explanations to follow in exchange for some sound samples. Preferably with guitar and bass 

Cheers,
Andy

p.s. The tone pot can of course be a normal audio taper A10k wired in reverse, in which case custom dictates to call it "filter".

[iainpunk]

hey, im sorry,

your project seems very interesting, especially with the jimi record, but im not in to building "nice" pedals, im the kind of guy who builds pedals that will try to steal your girlfriend.

ill look for some zeners in my pile tomorrow and breadboard it up. and if i have zeners, ill give you a report on the sound.

iain

Oh boy, have I got the design for you! The last thing I actually managed to breadboard was a high gain fuzzstortion. The underlying motivation was that I have always found the Big Muff too polite, the Rat to be lacking in chest hair and the HM-2 to have too narrow a range of usable sounds. I have the schematic on paper and hope to digitize it one of these days. I originally planned to release it when I had the time to design a PCB for it but considering the current situation, I might as well release the schematic now. Stay tuned.

i don't have any zeners under 7 volts, so im not going to be able to breadboard that overdrive of yours, but i am very very interested in a fuzzstortion. i am going to build a grind booster circuit which turns any overdriven amp in to a gain monster, with two flavours, with the same reasoning in mind as your fuzzstortion has, hahaha

[Mark Hammer]

"Gorn".  I see what you did there.  A l'il bit of Graham Chapman.

[Fancy Lime]

hey, im sorry,

your project seems very interesting, especially with the jimi record, but im not in to building "nice" pedals, im the kind of guy who builds pedals that will try to steal your girlfriend.

ill look for some zeners in my pile tomorrow and breadboard it up. and if i have zeners, ill give you a report on the sound.

iain

Oh boy, have I got the design for you! The last thing I actually managed to breadboard was a high gain fuzzstortion. The underlying motivation was that I have always found the Big Muff too polite, the Rat to be lacking in chest hair and the HM-2 to have too narrow a range of usable sounds. I have the schematic on paper and hope to digitize it one of these days. I originally planned to release it when I had the time to design a PCB for it but considering the current situation, I might as well release the schematic now. Stay tuned.

i don't have any zeners under 7 volts, so im not going to be able to breadboard that overdrive of yours, but i am very very interested in a fuzzstortion. i am going to build a grind booster circuit which turns any overdriven amp in to a gain monster, with two flavours, with the same reasoning in mind as your fuzzstortion has, hahaha

Oh, have you not heard? It was my understanding that everyone had heard:
https://www.diystompboxes.com/smfforum/index.php?topic=124063.0

"Gorn".  I see what you did there.  A l'il bit of Graham Chapman.

I just like the word. It gives me confidence. Gorn ... gorn. It's got a sort of woody quality about it. Gorn. Gorn. Much better than `newspaper' or `litterbin'. 

Started to fear it may have been too subtle or too obscure for anyone to notice. Glad someone got a smile out of it...

Andy

[duck_arse]

it also has a tinny switch, nur?

[Mark Hammer]

There are some of us who probably know the Python "liturgy" better than we know the words to our respective national anthems; likely because there was a period when it was being repeated, socially, far more often than the national anthem.

A tinny switch?  Ewwww!

[Fancy Lime]

There are some of us who probably know the Python "liturgy" better than we know the words to our respective national anthems; likely because there was a period when it was being repeated, socially, far more often than the national anthem.

A tinny switch?  Ewwww!

As far as I'm concerned, this may well be a better world if we replaced all national anthems with Monty Python sketches.

[iainpunk]

There are some of us who probably know the Python "liturgy" better than we know the words to our respective national anthems; likely because there was a period when it was being repeated, socially, far more often than the national anthem.

A tinny switch?  Ewwww!

As far as I'm concerned, this may well be a better world if we replaced all national anthems with Monty Python sketches.

but i really really like the Dutch anthem, its a sarcastic/mocking song about the spanish king being an idiot (the song came about in the Dutch-Spanish 80 years war, where we defeated the spanish and kicked out catholicism)

[Fancy Lime]

Granted, some are funny. Sweden for example does not officially have a national anthem. There is a song that they use as such at sporting events and so on but it has no official status. The Finnish anthem has the melody of a German drinking song and the lyrics were originally a Swedish rendition of a Hungarian patriotic folk song. Now, the German national anthem... let's not talk about the German national anthem. Let's just say you can usually tell which stanza people sing in their heads when the melody plays at football games by the stupidity of their facial expression.

Andy

[iainpunk]

i just remembered that the province i live in also has its own anthem, the province is Gelderland and the anthem is called "Het Gelderlands Volkslied" which means the Glederlands Anthem, but there is a local germanic folk metal band who have also done the anthem

[Kipper4]

Haha too funny.

Sadly our village has it's own anthem too.

A reflection of the fact we live on what was an island, surrounded by marsh bogs, back in the day.
Cut off from most places and the main access to the village was two troll bridges over the river.
The Billinghay ruffs where a gang of local tax and security lynch mob who would count your livestock in and out of the village.
Aribtrarily taxing and beating up those from outside the village who sought to date local ladies.
This was still effective after the 1950's.
Strange place. locals have been self isolating since 1100 AD.
Have a great day and dont forget to socially distance. Stay safe.
Rich

[rockola]

There are some of us who probably know the Python "liturgy" better than we know the words to our respective national anthems

Once upon a time, in a faraway country (Batchelor, NT, Australia) I entered a talent show and introduced myself with "Ladies and Gentlemen, the national anthem of Finland", then proceeded to sing The Finland Song. When the audience figured out there was more than one verse, empty beer cans started flying, and I think some footwear too. Luckily I was able to duck under a table and finish the song from there.

In the unlikely event that there is someone out there who doesn't know The Finland Song, here it is.

We now return you to our regular scheduled programming...

[Mark Hammer]

Long ago and far away, Saturday Night Live overseer Lorne Michaels was half of a comedy team with partner Hart Pomerantz, and they had a brief-lived CBC television show named The Lorne and Hart Terrific Hour.  One of my favorite bits of theirs concerned the newly-declared-independent Baffin Island (just to be clear, something that never actually happened).  The representative from the new republic sang their new national anthem which consisted of the words "Baffin Island", repeated, and sung ceremoniously slow, to the tune of God Save the Queen.

"Ba-ffi-in Is-la-a-and, Ba-ffin Is-la-a-and, Baffn Island...etc."

[highwater]

It is my humble opinion that Freedonia and Strongbadia have the best national anthems... with an honourable mention going to California.

[duck_arse]

There are some of us who probably know the Python "liturgy" better than we know the words to our respective national anthems

Once upon a time, in a faraway country (Batchelor, NT, Australia) I entered a talent show and introduced myself with "Ladies and Gentlemen, the national anthem of Finland", then proceeded to sing The Finland Song. When the audience figured out there was more than one verse, empty beer cans started flying, and I think some footwear too. Luckily I was able to duck under a table and finish the song from there.

thongs? nice one bruce.

I was working my way up to the finland anthem. I have a cap my sister brought back from a jaunt to Finland, and it has the lyrics of the Python [Monty] version printed real small around the edge of the peak.


I think that overdrive is real gorn by now.