Klone Science

[selfdestroyer]

[blearyeyes]

Splendid and very interesting to see! I must peruse these. Could you shed some light on what transmission means and is that dB voltage peak? Is the the what dBVpk stands for? Haven't seen that one before. Seeing a lot of 1k at higher gain settings...


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[alanp]

Interesting. Not much difference between clones, then. (Wasn't expecting much of a difference.)

It would be interesting to see this done with a Tonebender, Tube Screamer, and Rangemaster, just to see how the frequency response thing differs (not to mention an original Klon )

[JakeFuzz]

Yes I should clarify how the measurements are made.

The frequency response plots are done using a two channel swept sine measurement. In this measurement we measure the voltage put into the pedal using channel one. We simultaneously measure the voltage output using channel two. What we plot is called the transmission because we are dividing the voltage output by the voltage input by the following.

G(dB)=20log(Vout/Vin)

You see now that the output is measured relative to the input so we say it is the voltage "transmitted" through the device under test. This is an especially handy measurement when the input impedance of the device is low or the excitation source is being heavily loaded.

The fft mode is a little different and slightly more complicated. This is a single channel measurement where we measure the output voltage for a snapshot of time. This snapshot is fed through an algorithm called a fast Fourier transform. This transform takes this voltage variation as function of time and converts it into a frequency domain which is what we take as our output. You can analyze the harmonics generated by chopping off the tops and bottoms of our input signal by sending in a sine wave at a single frequency and looking at the magnitudes of the integer multiples of the input frequency that are in the output signal. The different ways we clip our waveform will create different peak ratios between these higher frequencies. Think of it as a distortion "fingerprint". Because this is a single channel measurement, the ratio of the output to input is not known. So in this measurement we just substitute a 1 volt peak to peak (Vpk) where Vin goes in the formula above. I shifted things around though to make it a little easier to read so the actual magnitudes are not real but the peak ratios are and these are what we are looking for in this measurement.

The impedance is measured using the two channel swept sine measurement but we are measuring the voltage across a resistor in series with the input or output. Because we know the resistor has purely real impedance, we can compute the current through it (and the series input impedance). We can then divide the measured output voltage by this current to get our input or output impedance magnitude.

[JakeFuzz]

Guys I am sorry but after writing that I realize that the input impedance shown in the first plot is incorrect. I forgot to account for the current into the analyzer itself. It will be higher than that shown. Will fix it tonight!

[aion]

Very through! Thanks for taking the time to do this.

[GrindCustoms]

Ha Ha! We all win!

Much thanks for your time on this Paul.....

Almost tempted to send you an IDA Tusk with the latest updates.

[sdlogan9]

Did you graph the KTR?


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[Haberdasher]

that is textbook unicorn slaying right there

[mattlee0037]

But they real ones feeeeeeel better

[GrindCustoms]

that is textbook unicorn slaying right there

The whole cattle is dying!

Tusk of the last known «Ice Blue Canadian Unicorn» lulz

[m-Kresol]

Most awesome pic I've seen in weeks!

Paul, thanks for taking the science road on this one. As a fellow scientist I really appreciate it. I tried to apply semi-scientific approaches to applying envirotex as well as developing photoresists to get better results. Proceeding analytically can either be very rewarding or totally frustrating (as I'm sure you know). Good to see it turned out to be rewarding this time.

Just as a slight remark from my end of science: a x-ray diffractometer wouldn't help you in any way. All the parts made from polymers (pcb substrate, etc.) are amorphous and do not yield any signal. The semiconductors would definitely give some reflexes indicating crystalline nature, but I doubt that there is enough of them in the circuits to give you a sample to measure

[JakeFuzz]

Alan, I have a few other data sets for some of my overdrives but no fuzz. I'll try and get some of these together later this week. I can tell they are wildly different. My favorite modified lavache is especially interesting in that it has a flat frequency response and very strong second order harmonics. Cool sound.

Sdlogan I haven't done the ktr or the Klon yet. We are still working that out so stay tuned in the next few weeks for some really interesting stuff!

Keefe I am thinking of a namm far in the future and hearing "yeah he basically wrote the book on unicornocide" haha I love this hobby.

Rej dear god where did you get that ice spear?! Don't see those around these parts. Does that really hang off of stuff? That could kill you! Did you get a chance to try that resistor swap? I am on vacation right now but am going to test this out first thing in Monday. I sold a klone to a guy with a real Klon many years ago and he described that exact discrepancy with the treble response between the two.

Mkresol, yes definitely. CJ and I were just screwing around and poking fun at HAD and his ridiculous video with that crazy Kaiser fellow. I think if I really tried to put a pedal in our xrd the operator would throw a fit! Lol.

[GrindCustoms]

Paul, my appartement is at the second floor, that one was hanging in front of my kitchen window this winter... went on the counter top, took out the windows broke that one from it's base.... but while bringing it back inside i broke the tip... so you can add another 2feet right there... shit was weighting like 80 pounds...lol

[GrindCustoms]

And yes, i've tried it yesterday night. It does improve the over Treble «contour» of the control. Swapped the 8n2 for the original RE 3n9.

I also swapped the Ge diodes for 1N60, thing that i had tried before... but never stick to it. The gain delivery is smoother and less harsh.

Keith @BYOC is very rarely wrong... and he was damn right again this time!