Analysis of the Klon circuit

[ulysses]

hey all

has anyone gone through and done a circuit analysis of all the frequencies cut and bypassed and passed around on this circuit?

i had a look at it again this evening after not looking at it for years.

looks like a complete mess to me. lol. there is no linear flow to the design and the fact that the knob controls two separate ideas gain /blend makes me think this was just breadboarded until a pleasant sound was found.

for me the most unique thing about the klon was the sand-cast case i thought it sounded like most shitty tl072 overdrives. lol.

anyway, id be interested to see if someone sat down and did the math on the circuit to see how it all comes together

cheers

[Mark Hammer]

Sigh....one more time.....

In 2007 Bill Finnegan contacted me because there was something he was thinking of trying with the Klon, in response to client requests, and he felt he could trust me.  He sent me two populated ungooped boards, one of which had every single component socketed, and a schematic, all of which was returned.  One of his stipulations was that anything I would suggest to achieve the experimental objective had to make use of the existing layout.  So this necessarily involved tinkering with component values, and comparing the socketed board to the unsocketed one.  I built myself a chassis with stompswitches to be able to do A/B comparisons between the socketed and unsocketed boards.  In the end, I wasn't up to the task, and we parted ways; amicably on my part, and I hope amicably on his as well.

Part of what many people don't understand about the Klon is that it is NOT an overdrive pedal in the usual sense.  That is, it is not designed provide an overdrive sound that would be pleasing if listened to through a clean amp.  Rather, it is designed to precondition the signal to provide desirable amplifier overdrive.  Bill did not design it in any sort of theory-driven way.  Rather, he worked with a consulting engineer, asking him "Could you get it to provide a little more/less X or Y?", and the consultant changed it, brick by brick until Bill got the audible result he wanted.  Bill is not an engineer, but he has GREAT ears.  And the result was a design that was/is a complete house of cards, design-wise, but sounds amazing through the right amp.  That's a big part of why I couldn't deliver on what Bill was thinking of.  If you changed something over here it would have implications over there.  And I was in no position to play a big amp loudly, then push it a little harder.

I can't speak to now, but it was standard practice throughout the 90's and into the 2000's for Bill to engage prospective customers in a long discussion about their rig and style.  If he felt the pedal was not going to serve their needs, or dovetail with their rig, he would deter them from purchase.  That sort of conscientiousness is rare.  Unfortunately, those discussions ate into his build time, and production wouldn't/couldn't keep up with demand.  As legend and E-bay grew and folks figured they could get big bucks for their Klons, more and more people who were unwilling to wait for Bill started buying theirs from other owners.  Where Bill would provide the 30-minute guidance chat, owners contacted via E-bay would not.  This is part of why so many like yourself mistakenly think it is an overdrive pedal.  I'm certainly not blaming or shaming you.  Rather, there is a missing step that would have normally cleared that up.

P.S.: Bill trusted me, so I am not going to divulge anything about the design, other than what I've revealed here.

[Frank_NH]

Based on my experience with a klon(e), I concur 100% with what Mark says above.  I use mine as a preamp for other pedals in my chain, and in that it excels.  My settings are gain at 9 o'clock, tone at 3 o'clock and volume at noon.  It REALLY makes a tube screamer shine, so much so that someone should make a double pedal with a klon(e) followed by a tube screamer.   In addition, you can turn up the gain and then go directly into a tube amp on the edge of break up.  I would not use it as an overdrive into a clean amp.

[bartimaeus]

Thank you for that, Mark! I've been browsing pedal forums for years, but never heard some of those details of the Klon's history. It seems lkike you've posted that before, but I appreciate the repeat.

[ulysses]

 

[ulysses]

hey mark,

thanks for that reply i really appreciate your account of the history here. sounds like he had the boards made up, but was then unhappy with the sound and so asked you to tinker with it to get a better sound using the PCB's that he had made up.

i certainly do not want to get into a rhetoric debate about whether something is or is not an overdrive pedal. however i disagree that the circuit would not sound overdriven into a solid state amp. saying its not an overdrive pedal seems like a very wittgenstein thing to say -- "this is not a chair, it's a stool with a back"

in any case, there IS something going on here with frequencies cut and then passed about in what appears to be a very illogical circuit. for me the interest is in the fact that people DO like the sound -- is it just MOJO -- is it the custom designed sand-cast case? (which IMO is awesome aesthetically) -- is it the fact that he value added to the pedal by getting to know each owner? or is there something in the frequency shaping and passing around spaghetti mess, and wondered if someone had done the math on the curves.

edit: as a point of interest, the neve 1073 is said to be one of the best sounding EQ's -- but then you look at the circuit you see where it is in fact simple and well thought out, the real magic lies in the curves chosen by rupert. these musical curves are what i consider to be the magic -- and so i ask the question about the klon -- is there something we could learn from the math?

peace

[Mark Hammer]

Let me be clear.  Bill did NOT contact me because there was any sort of "weakness" in the existing circuit.  Indeed, my reply to him was that I felt like I was being asked to re-edit "Gone With the Wind" and "sex it up a bit".  Some customers asked if it could do a little more X, and he wanted to know if it could; plain and simple.

And yes, it does produce some clipping, but the primary purpose is to push an already edge-of-breakup amp into more desirable clipping/overdrive, and NOT to produce a desirable overdrive tone on its own.  The Treble control is primarily for taming the high end in anticipation of pushing the amp into overdrive.

[robthequiet]

Well, there is a schematic floating around *cough* but how can anyone tell how accurate it is?

Anyway, Ulysses, is there a version you're looking at that could be linked to somewhere in this thread?

From what I've seen the circuit seems to rely on positive feedback with some filtering. Running at a higher V+ certainly gives it more headrooom, according to legend, but I've always wondered why it's so special that it couldn't be replicated with a simpler 4-stage amp and filter device. I suspect that the dual drive pot may compensate for high-gain roll-off as you turn down?

[ulysses]

hey mark -- sorry if i offended you -- that was not my intention

regarding the schems -- im not sure what the rules are these days on this forum -- but if you google image search you can pretty much find anything these days

peace

[Mark Hammer]

Absolutely no offense taken.     I just didn't want to start any weird rumours.

[reddesert]

There are analyses of the Klon circuit out there on the web.  For example,
http://www.coda-effects.com/p/klon-centaur-circuit-analysis.html
http://www.madbeanpedals.com/forum/index.php?topic=16207.30 with measured clone frequency response plots,
http://rezzonics.blogspot.com/2016/09/klon-centaur-3v3-clone-ltspice-analysis.html LTSpice model with frequency response plots.

Not a Klon fanatic, but I don't think the facts that the Klon uses multiple signal paths or a dual control for gain/blend suggest that it is illogical or poorly designed.

[Outlaws]

I still have never figured out how to use a compressor on my pedal board. It isn't for lack of trying.  I just cannot make it work or sound good. Doesn't mean they are bad.  At this point I just assume they don't work with my style and move on.

[Mark Hammer]

how to use a compressor:

1) They will boost everything they receive during quiet segments, so be sure not to stick them after anything that generates hiss.  First in line is often best, but is not an absolute requirement.

2) People generally need less compression than they think they do, just the same way they often need less distortion than they think they do.

3) There is a frequent misunderstanding that compression is somehow for solos, like other kinds of effect pedals.  Compression is often better for rhythm playing because it allows you to flail away and not inadvertently drown out the singer/s.  Anywhere that you want to keep a relatively steady level is a good spot for compression.

4) Compression will, just as the name indicates, alter your dynamics.  Anything that is relying on playing dynamics to do what it does will be affected by compression.  So, any overdrive preceded by compression will behave more consistently, but it won't respond to your picking dynamics as much.  Similarly, pedals that also use a sidechain, such as autowahs, noise gates, or anything envelope-controlled, will be less responsive to picking dynamics.

5) Optimum gain-recovery time (often labelled "Attack" on many commercial compressors) can lend itself to different needs.  Slower gain-recovery is better for longer apparent sustain on single-note solos or slide work.  Shorter/faster gain-recovery is better for choppier staccato rhythm work where a compressor will begin to function a bit more like a peak-limiter.

[EBK]

5) Optimum gain-recovery time (often labelled "Attack" on many commercial compressors) can lend itself to different needs.  Slower gain-recovery is better for longer apparent sustain on single-note solos or slide work.  Shorter/faster gain-recovery is better for choppier staccato rhythm work where a compressor will begin to function a bit more like a peak-limiter.

I think you are lumping together Attack and Release....
The sustain-for-days feature is a function mainly of Release time.
The peak-limiting feature is a function of Attack time.

Otherwise, I agree with everything as you've summarized it. 

A compressor before an autowah can provide a convenient way to limit sweep range if you are looking to make the wah easier to control or sound more subtle (adding to point number 4).

[Mark Hammer]

Nope.

If a studio-type compressor does have separate Attack and Release controls, you're probably right.  But the vast majority of stompbox compressors that include an Attack control, however, tend to use pretty much the same rectifying circuit as the Dynacomp, and their "Attack" pot is simply a variable resistance that dictates how quickly the max gain is restored - i.e., gain recovery.

The reason that such controls are labelled "Attack" is because a slow gain-recovery tends to obscure the pick attack in a flurry of notes, as the rectifier works its way back up to max gain after the first picked transient has knocked it down.  Fast gain recovery makes the pick attack of subsequent notes more audible.  But the control does diddley-squat to the attack or rise time of the envelope controlling gain.

I suppose we should be thankful for small mercies like DOD not intruding and further confusing things with the sort of literary legending they used on so many pedals.  Heaven forbid gain-recovery would have been legended as "Resurrection", "Wakeup", or "Return"; "Attack" was bad enough. 

[EBK]

Now that I've reread what you wrote earlier, I think I understand what you are saying.  I misread the "often labeled 'Attack'" as if you were saying this is technically known as attack.  My apologies.

[Mark Hammer]

It's not you who needs to apologize.  It's those manufacturers who legended the pedals in the way they did to produce that confusion.

They're often the same manufacturers who created the widespread confusion between "gain" and "distortion", that regularly results in forum questions here and elsewhere from folks who say they want more "gain" in their tone.

[Outlaws]

I think the crux of my comment was lost.

[Mark Hammer]

Was the crux not knowing how, or was it knowing how but simply not finding a "home" for it?

[Outlaws]

Was the crux not knowing how, or was it knowing how but simply not finding a "home" for it?

I know how to use compression, I just cannot make it work in my rig.  But it doesn't mean those pedals don't have a perfectly fine home in everyone else's rig.