Bare Bone Klone (no charge pump)

Lucifer · Post by **Lucifer** » 21 May 2012, 13:37

Your suggestion (earthtonesaudio) prompted a few memory cells to stir.

Somewhere in the back of my cupboard, I had a test bed layout for the Klon which I'd made a good while ago and then forgot about as other projects stole my time. On this test bed, each op-amp stage is brought out separately (using TL071s - but in sockets to allow experimentation) - stage 1 is top left; 2 is top right; 3 bottom left, and 4 bottom right.

All the other components are soldered onto pins, to allow changing of values or component (eg cap) types - and to allow easy access for scope probes, etc.

The board is shown in the attached picture, and near the bottom right can be seen a toggle switch. To the left, it supplies stages three and four with a regular 9v supply, and to the right it supplies them with +18v and -9v (approximately). These are derived from the additional charge pump board to the right of the main board.

At low gains, there is no real change in sound, but taking either the gain or the treble control (or both) above half way causes the simplified version to go into hard clipping, while the full version keeps its soft clipping. The attached picture from my digital scope shows the input (yellow trace - approximately 100mV peak), and the output of the full version (pink trace, soft clipped) and simplified version (green trace, hard clipped).

Playing my guitar through the circuit I was able to hear the differences quite clearly - the hard clipping made the circuit sound harsh, whereas the soft clipping of the full version is what we love about the Klon.

earthtonesaudio · Post by **earthtonesaudio** » 21 May 2012, 16:23

Could you clarify what version of the schematic is represented by the scope shots? Is it Mictester's tweaked version or the original?

Lucifer · Post by **Lucifer** » 21 May 2012, 18:15

This configuration is from the original schematic, as the idea was to test the theory that the charge pump made no difference.

I didn't want to introduce other variables that might confuse the issue.

I hope the findings are helpful to the dedicated users of this site.

Lucifer

swt · Post by **swt** » 22 May 2012, 14:55

the output of the full version (pink trace, soft clipped) and simplified version (green trace, hard clipped). [/quote]
isn't the green one the softer? pink looks squarish and green rounder on the tops...

earthtonesaudio · Post by **earthtonesaudio** » 22 May 2012, 16:50

I think that was either a typo or colorblindness.

Since you used the original (with its higher gain) it makes sense that it clips when starved of voltage.

Lucifer · Post by **Lucifer** » 23 May 2012, 13:33

Yes to the 'typo' .

Didn't have the picture in front of me at the time so I was working from memory - and the memory isn't that good any more (I'm 102 and still rocking).

mattlee0037 · Post by **mattlee0037** » 22 Sep 2013, 14:09

Hey, I was building the simplified klon schematic, but when put together it passes no signal bypassed or in effect mode, so I'm thinking maybe there's something wrong with my wiring or buffer? I wired it up according to this https://s1280.photobucket.com/user/mattl ... 5.png.html

And some voltages that I got are
TL074
1 4.76
2 4.76
3 1.35
4 9.54
5 4.58
6 4.76
7 4.52
8 4.81
9 4.77
10 4.71
11 0
12 4.71
13 4.76
14 4.72

1N34A's Both about 0.1 seemed to be going down slowly.

Just wondering if you could offer any insight. If you need pictures I could provide those as well, Thanks

Regards,

Matt

Lucifer · Post by **Lucifer** » 22 Sep 2013, 16:35

If it's not passing a signal in bypassed mode, then it suggests a simple error in your input/output wiring (so your circuit build might well be OK).

Get the bypass signal working first - and with any luck, the pedal will spring to life.

If you post some gut shots, we might be able to pinpoint the problem.

mattlee0037 · Post by **mattlee0037** » 22 Sep 2013, 18:31

Ok I will post some pics later today, I figured it was my wiring because the buffer seems simple, I just wasn't sure where I went wrong with it.

mattlee0037 · Post by **mattlee0037** » 22 Sep 2013, 22:24

Here are my pics. It can be hard to see what everything is connected to due to the wiring, but if anyone has questions just ask and I can clarify. Right middle lug (5) of the DPDT switch goes to output sleeve (that one's under the board)

Lucifer · Post by **Lucifer** » 22 Sep 2013, 22:41

Hi Matt,

It seems pretty foggy where you are

Seriously, the pics are hard to follow - and the fact that you've used the same coloured wire for everything makes it impossible to see what goes where. I know it costs more to have wires of every colour, but you'll appreciate it when you can say "that orange wire goes from here . . . to here - so that's correct".

Having said that, something that does appear out of the mist is that your jacks each seem to have only one wire going to them. One lug on each jack seems to be totally devoid of connecting wire or solder.

If you are relying on the metal box to provide the extra connection, it's not a good idea. Paint, oxidation, or a loose nut can all cause intermittent faults or even failure. But if the jacks are fully wired, then paint, oxidation and loose nuts won't stop your circuit from working.

But let's assume for now that the metal of the box is grounding both your jacks, as you would wish. I can't be certain from the foggy pictures whether you've got your wires to the hot side of the jacks or to the earthy side. But I suspect that at least one of the jacks has its wire to the earthy side - which means that you are either shorting the input or output of your circuit.

So, as a first move, check out those jacks, then add the missing wires.

If there's still no joy, then check that your circuit is getting power, the right way round. A red wire to the positive side would have helped here.

If the jacks are OK, and the power's getting to the board, then it's time to do some signal tracing through the circuit until you find where the signal stops.

Good luck - and keep us posted.

mattlee0037 · Post by **mattlee0037** » 22 Sep 2013, 22:56

Thanks, sorry aboout the pics, all I have is a crappy phone camera! Do'h I thought I had the input tip going to buffer input (not grounded by wire, just enclosure) and buffer/circuit output to output tip with board, power, and switch grounding going to sleeve, but I'm an idiot and wired the tips to rings

let me see if switching that to the tips helps a little bit.....

(I'll also ground the input jack)

mattlee0037 · Post by **mattlee0037** » 22 Sep 2013, 23:22

Apparently I'm my own worst enemy! Works great now (well as great as something can work through a headphone amp I suppose) Thanks for the help Lucifer, probably wouldn't have looked as close otherwise!

mattlee0037 · Post by **mattlee0037** » 23 Sep 2013, 01:34

One last thing: when engaged with gain at 0 and volume all the way it just reaches unity. Is this normal of the simplified circuit, also can it be run at 18V?

Lucifer · Post by **Lucifer** » 23 Sep 2013, 11:55

Hi Matt,

Glad you got it going.

The bare bones Klon has much lower output than the full version with the charge pump (which gives unity output about 12 noon on the volume control with the gain pot at zero) - so what you're getting might be about right, though I might have expected a bit more but not a lot.

In the full version, the 18v (approx) from the charge pump only powers the final chip (which also gets negative 9v from the charge pump circuit, giving a 27v supply on that chip). I'm not sure if you can run the whole circuit off an 18v supply, but the TL074 should be able to take that in its stride.

Only one way to find out, if you're brave enough.

Keep us posted if you do try it.

mattlee0037 · Post by **mattlee0037** » 23 Sep 2013, 17:29

Interesting.... so could I theoretically take a 9v line from power to board like normal, but take another line off the DC jack to a voltage doubler feeding into the opamp? Also interested in running the whole circuit off of 18v.... if I tested it and fried the circuit would I just have to replace electrolytics, diodes, and op amp? I sockets the diodes/opamps so that wouldn't be a problem.

Lucifer · Post by **Lucifer** » 23 Sep 2013, 21:56

The op-amps and diodes should be fine with an 18v supply.

Your electrolytic caps are probably rated at 10v or 16v, so you would need to upgrade them to 25v to be on the safe side.

mattlee0037 · Post by **mattlee0037** » 24 Sep 2013, 02:26

Oh sweet, well my caps are all rated at least 25v so I'll try to make a voltage doubler soon and report back.

mictester · Post by **mictester** » 24 Sep 2013, 06:20

earthtonesaudio wrote:I can't take credit for the schematic for the single-rail Klon, that is Mictester's work. If that's the version you built the component changes could account for the sound. While the filtering time constants are basically the same (close enough to fall within part tolerances and unlikely to be audibly different), the gain is reduced. On the original, there is enough gain to clip the mixer op-amp. If clipping occurs in one but not the other, that is very likely to be audible.

I revisited the Veroboard lash-up I made a couple of years ago. The Low-voltage version works fine at all settings with single-coil pickups (I used a stock Telecaster), but I was able to get hard clipping at some settings when I used a Les Paul - it ran out of headroom when the gain was cranked.

Finally - the "magic" of the Klon has been thoroughly demystified - it's not a particularly great design, and was obviously arrived at by just tweaking values until it sounded right - there wasn't a lot of theory involved. I've said it before, and I'll say it again - it really isn't worth bothering with. There are plenty of better circuits out there!

Lucifer · Post by **Lucifer** » 24 Sep 2013, 10:09

mictester wrote: . . the "magic" of the Klon has been thoroughly demystified - it's not a particularly great design, and was obviously arrived at by just tweaking values until it sounded right - there wasn't a lot of theory involved. I've said it before, and I'll say it again - it really isn't worth bothering with. There are plenty of better circuits out there!

Hi MicTester,

I (and many others) respect greatly your opinions and experience, so are there any specific 'better circuits' that you would recommend to all of those guys (including me) with Klon fixations ?

I've heard good things about the Timmy, but haven't tried one yet, and I really like the ROG Peppermill. Do you have a favourite OD ?

I know this is a very subjective thing but , like I said, your views and expertise are highly respected around here.

Cheers,

Lucifer