18V Klon (No Charge Pump) Variant?

[Fingolfen]

Has anyone ever tried to design the charge pump out of the Klon? I know that in at least one stage the Klon is using a combo +18V and -9V to get a 27V swing...

... which may mean I should be asking if anyone has done a 27V Klon, but most people have easy access to 18V in their standard power supplies...

 

[coltonius]

This was given to me by CJ Wattage on TGP. It’s a version he and someone else tweaked:

 

[Fingolfen]

Looks like this guy has an 18V version, I haven't found a schematic / board for what he did - I've asked in the comments though...

 

[pnggolf22]

I think Effects Layout Skeleklone is what you’re asking for.

 

[szukalski]

The dylan159 Clown Centaur does a reasonable approximation of a Klon without a charge pump. It doesn't have the insane volume levels of the original, but for the overdriven tone, it does the thing.

I believe @jimilee may have a board..

 

[Harry Klippton]

Clown Centaur

Oh good someone else already thought of this

 

[Guardians of the analog]

The skeleklone from effects layouts says this in the build doc:

 

[jimilee]

The dylan159 Clown Centaur does a reasonable approximation of a Klon without a charge pump. It doesn't have the insane volume levels of the original, but for the overdriven tone, it does the thing.

I believe @jimilee may have a board..

Yessir

 

[jubal81]

Rose of Tralee

 

[jubal81]

The Rezzonics blog engineered a Klone that runs on 3.3V, and did the same conversion on a few other pedals.

 

[jimilee]

Sounds cool with LEDs

 

[Fingolfen]

I went ahead and picked up a couple of the EL Skele Klones, though jimilee's design and jubal81's designs look cool too... May need to try and get ahold of them...

 

[jesuscrisp]

The Klon uses 27V only on the last 2 IC stages, mind you!

The input buffer and gain stage run at 9V, and if I had to guess (but also speaking from experience with charge-pumped circuits) I'd say it is so that the gain stage can saturate as you turn up the gain and you don't only get empty-sounding diode clipping, especially as that the germanium diodes would saturate quite early. Considering the story how the Klon was designed, I'd bet if Bill Finnegan wanted the gain stage to have more than 9V, he would have made it so and there's also good reasons to run the later stages at higher voltage, as in those you want CLEAN amplification and tone shaping despite the huge volume boost the circuit is capable of.

Other than splitting up the buffer and gain stage so you could run the buffer also at higher voltage (e.g. single-op amp for gain, JFET for input buffer), I see no real benefit in messing with the Klon charge pump power supply.

Nevertheless, it's easy to rework a Klon to single supply, just ditch the protection zener diode, charge pump with all diodes and extra electrolytic caps, jumper the 9V and 18V rail on any Klone PCB and connect -9V to ground. As far as I'm concerned that will do the trick. (see attachment on how to massacre your horse).

 

[jubal81]

In most cases, I see a charge pump in a 9V pedal as adding more issues than it solves.

When designing for low noise, one of the best things you can do is avoid boosting the amplitude of the signal more than is necessary. "Extra" gain only hurts the signal-to-noise ratio.

Creating distortion is the only reason a pedal would be designed to make the amplitude of your guitar audio signal exceed 9 volts. This is the noisiest way to distort a signal and the chief source of decay fizz, artifacts and other nastiness. If you want more headroom, it makes a lot more sense to create less gain than to boost the supply voltage.

This explains my design decisions in the Rose of Tralee build. I used modern audio opamps with signal protection features that were not so available in the 90s and an option for limiting diodes in the feedback loop of the distortion opamp stage.

IMHO, using a charge pump for this circuit is a case of outdated design, about like adding a 'choke' on a modern, fuel-injected car.

 

[jimilee]

I feel like the parts count outweighs the benefits when adding the charge pump to this particular unit. I have a clown centurion board, I ran at 9v and 18v. Just more headroom, nothing more.

 

[owlexifry]

In most cases, I see a charge pump in a 9V pedal as adding more issues than it solves.

I feel like the parts count outweighs the benefits when adding the charge pump to this particular unit.

+1 agree.

 

[jesuscrisp]

In terms of charge pump and parts count... If you design an IC-based circuit that you want to have 18V you can do a +9V/-9V supply which, yes, adds an IC and 2 caps but also saves you the Vref voltage divider and filter as Vref is now ground. So 18V for the grand total of 1 IC and cap more, 2 resistors less, wouldn't say that's a deal breaker. Plus you don't have to worry what goes to Vref and what goes to ground anymore.

 

[owlexifry]

In terms of charge pump and parts count... If you design an IC-based circuit that you want to have 18V you can do a +9V/-9V supply which, yes, adds an IC and 2 caps but also saves you the Vref voltage divider and filter as Vref is now ground. So 18V for the grand total of 1 IC and cap more, 2 resistors less, wouldn't say that's a deal breaker. Plus you don't have to worry what goes to Vref and what goes to ground anymore.

true. maybe for a low gain circuit.
but idk if i’d be comfortable with that. not sure the power filtering would be adequate to get rid of the BS noise that chargepumps bring, even with the ‘right one’.
i’d want additional protection diodes and filter caps, similarly to what maxon did with the OD820 on their +/-9v supply

 

[jesuscrisp]

I used modern audio opamps with signal protection features that were not so available in the 90s

May I ask at this point what op amp models and signal protection features you're referring to? I'm genuinely curious.

 

[szukalski]

Sounds cool with LEDs

I just did this. It’s almost minor but makes the difference. I also swapped the volume for a B10K and the gain for C-taper and it’s much more usable.