Klone Science

[JakeFuzz]

From about 300Hz to 5kHz they are all pretty much the same (that is the Chimeara and the Refractor are right on top of one another). The differences below and above that range are quite large. The transmission (terrible name) is shown in a logarithmic scale.

[raulduke]

Interesting frequency plots.

It could be interesting to see fourier analysis of waveforms with varying values on the drive/gain control. That would show if there is any different harmonic content between the pedals when distorting/clipping.

[JakeFuzz]

Yep that is all coming. So I have 18 sets of data for each circuit; 3 tone settings and 3 gain settings. I have swept sine frequency analysis at each setting and FFT harmonic plots with a 1kHz sine wave input. I also have two additional plots for each one showing the input and output impedance as a function of frequency.

[JakeFuzz]

Hehe so I figured it out. I am using polarized 1uf bypass caps in the post clipping gain stages and I reversed the polarity of one of them! Everything looks normal now. I will process the rest of the data this weekend and have it ready to go!

[cooder]

Great detective work there, good on ya...!

[aion]

This is awesome.

I'm looking forward to seeing one seriously boring graph when you're all done! :)

[GrindCustoms]

The last tear have been dropped!

http://byocelectronics.com/board/viewtopic.php?f=9&t=49894

[juansolo]

The last tear have been dropped!

http://byocelectronics.com/board/viewtopic.php?f=9&t=49894

Very interesting. I must now make one with this change to compare and contrast.

[JakeFuzz]

Yes very interesting. Thanks for linking Rej. While I have the SK back in the test enclosure I'll swap those resistors and take some frequency sweeps for comparison.

[GrindCustoms]

Paul, when you'll have the KTR in hand... could you trace that part of that of the circuit, to see if it corresponds with what Keith came up with?

Gotta say! That i'm now fawking excited about all this! hahahaha

The last tear have been dropped!

http://byocelectronics.com/board/viewtopic.php?f=9&t=49894

Very interesting. I must now make one with this change to compare and contrast.

I have 2 Tusk right in front of me, will make the swap on one and do an A/B.

[stecykmi]

the only suggestion i have for the graphs is to use logarithmic scale for frequency, it makes more sense for audio analysis. in particular, it'll space out the low end more and make it easier to see what's going on.

[JakeFuzz]

Sure Rej Let me ask the owner to make sure that's cool. I would be very interested to see what the values turn out to be. The ktr is smd right?

Misha, excellent suggestion. The plots look much better on a log scale. I also added color so its a little easier to see. Finishing up the last harmonic plots tomorrow!

[JakeFuzz]

Done!

Picture bomb. Lets start with the the easy one. Input and output impedance.

[JakeFuzz]

Frequency response plots:

Gain control at 75%


Gain Control at 50%


Gain Control at 25%


And because it isn't super obvious from the above plots here is a sweep showing one of the circuits with the tone fixed at 50% and sweeping the gain control.

[JakeFuzz]

And last but not least these are FFT harmonic spectra of each circuit with a 1kHz 100mV amplitude input. These are taken with the tone control fixed at 50%. I have data for the other tone control values but they look the same. These are zeroed to a -107dBVpk noise floor (so thats not ~90dB of gain  ).

Gain control at 75%


Gain control at 50%


Gain control at 25%


And again the impact of sweeping the gain on one circuit with the tone control fixed at 50%