(http://i693.photobucket.com/albums/vv299/pnordeen/20140627_094115_zps94d78764.jpg)
Frequency analysis is coming!
Special thanks to Rej, Kevin and Brian for making this happen. The plan is to have identical components which are swapped between the Aion Refractor, The GC Chimaera and the MB Sunking II. I will also have trimmers for the pot values and will be varying the tone and gain controls as I take frequency response plots. I will have 3 tone positions and 3 gain positions and fixed output volume. I am taking the frequency response, harmonic content (with a 440Hz sine input), input and output impedance at one value. The data will be made available here through some file sharing software. Honestly I don't expect to see a whole lot of variation and worry a little about the additional contact resistance and capacitance introduced by having so many sockets but this should be fun regardless!
I am also going to be testing a load of other overdrives. If I have time on Sunday night I may bring my Skylark and record some comparison tones between the three circuits here in the lab.
This is going to be awesome. I cant wait to see the data collected.
One thought, that bench you have all the hardware on looks way to stable. Can I suggest to use a card table for maximum tonez?
Cody
As logic doesn't work with the cork-sniffers, actual verifiable data has little chance either.
I've had similar arguments with audiophiles. There comes a point where you just leave them to it.
Quote from: selfdestroyer on June 27, 2014, 07:39:26 PM
This is going to be awesome. I cant wait to see the data collected.
One thought, that bench you have all the hardware on looks way to stable. Can I suggest to use a card table for maximum tonez?
Cody
Totally agree. Some goop nearby would be a great toanz enhancer as well.
This looks very interesting. Looking forward to seeing your findings. Love me some test gear!
Quote from: selfdestroyer on June 27, 2014, 07:39:26 PM
Can I suggest to use a card table for maximum tonez?
Well played good sir. ;)
Jacob
Looks like a nice setup.
But I can't help notice that you don't have a Crystal Lattice Detector as part of your test equipment. What's up with that?
The klones look nice and all, but that Agilent scope looks AWESOME.
I'm guessing that isn't your home setup. Those things are pricey.
Yeah I know the audiophile crowd will still be in denial but it will be fun to see what sort of excuses they come up with!
We have some pretty lame foldout tables in the lab I can approximate as a card table ;D
Crystal lattice detector! We actually have one of those, its called an x-ray diffractometer. Maybe ill run my Dumble clones through that guy for the next mythbusting session!
That scope is pretty epic. It is touch screen too! I believe it was around $8000 when we bought it last year. I wish I had it at home but these are all in my lab at work. There is a machine that I rent from another lab upstairs which costs 150K called a network analyzer :o ridiculously expensive.
yeah that looks like one fancy scope
well beyond my $ point lol
Quote from: JakeFuzz on June 27, 2014, 09:28:17 PM
There is a machine that I rent from another lab upstairs which costs 150K called a network analyzer :o ridiculously expensive.
Is it a Rohde and Schwartz?
i'm jelly for that scope and freq analyzer. the scope can also do FFT's too, correct?
The newest PNA upstairs is an Agilent. They have about 6 different ones that all cost 80K+ but that latest one is mucho dinero. It is a 4 port too which I am not too familiar with but will have to play around with to figure out.
Yes the scope has FFT capabilities. It also has two independent function generators and 16 digital probe channels!
Awesome. That is fun stuff.
This promises to be epic and some revelation... watch out TGP... :o
Paul, you realise you'll be killing a whole cattle of unicorns?
Really cool that you jumped into my stupid idea. ;D
Quote from: cooder on June 28, 2014, 05:33:31 AM
This promises to be epic and some revelation... watch out TGP... :o
More epicness to come. ;)
It will never sound as sweet as Henry Kaiser's platinum riffage through the crystal lattice.
Almost done. Just need to populate and finish the Refractor which will be tomorrow. I spent an hour trying to figure out why my harmonic responses on the Chimaera weren't looking normal then I realized I switched two caps :-[ Had to take those plots all over again.
I would like to keep up with this.
I support this...as long as I am #1 (j/k j/k).
Seriously, Paul: this is awesome.
Thanks Brian! I wish spectrum analyzers were cheaper so I could own one personally. They are an excellent tool for designing effects.
All the plots are taken I just need to put them together into easy to understand charts. I also took plots for my Kingslayer in different diode configs, an Apis with LM313's, A Fulldrive II, my Lavache, A Screwdriver clone and an EHX Soulfood. Those may come later as I process them. Very surprising results from just switching around the clipping diode types on the KS!
science is cool!
Have you played around with software based analyzers? I often use Spectra Plus to generate FFT Swept Sine waves to a DUT and then analyze the frequency response with the program. The cost of entry is a lot lower than buying a hardware Spectrum Analyzer.
Ooh that's pretty cool! I have never seen anything like Spectra Plus before ill have to check out the demo software.
A long time ago I was playing around with the idea of building a serious pedal design/test rig with some National Instruments DAQ stuff. I think there must be a way to use their cheap USB DAQ systems and a Labview license to build a multifunction spectrum analysis tool. Those DAQ interfaces only cost around $200 (I think we have lots of them floating around my lab!). Ill look into it.
The DAQ interfaces might be a good way to go. I considered those for a test system a while back and didn't use them, but it's been long enough that I don't remember the reason.
Yeah, let's look into this.
Uh oh. I think I done screwed something up! I went to go put the first frequency plots together tonight and the Refractor and Chimaera are right on top of one another (as expected) but the Sunking has some odd high and lower end behavior. I am thinking I may have messed up some of the switch hard wiring. I am going to repopulate tonight an maybe re-run the Sunking hopefully tomorrow night. What do you guys think? These plots are with the gain at 75% and at three tone settings. On another note is everyone okay with these plot formats?
(http://i693.photobucket.com/albums/vv299/pnordeen/SK_HIGHEND_zpsb217ed77.jpg)
(http://i693.photobucket.com/albums/vv299/pnordeen/37e98edb-43fc-45e5-a820-91912c00c76a_zps33d4baba.jpg)
Don't go in expecting to prove any particular thing. Remember to simply gather the data.
Yes, be sure that everything is connected properly but don't say you screwed up when you've collected the information exactly right.
You're doing a good thing, don't taint it with expectations.
Yes but I also want to report data that is accurate and the discrepancies we see here I think are too large to attribute to transmission line losses or some weird additional capacitance. I don't think it would hurt to go back and repopulate the SK and run it through another time; it does have some additional capacitor switches which I may have hardwired incorrectly which could show what we see. Ill triple check!
That plot format is perfect to me, easy for anyone to get an idea of what is going on too.
Agreed that there might be a little bug with the SKII, looks like your right about one of the switch not hardwired correctly.
If everything turns out ok, the silver box should take off Canuck land this week. Been able to have my friend/customer willing to ship you it even if i don't win my bet. ;)
Don't get me started...I have to think a lot about data presentation in my day job, so I tend to geek out over this stuff!
I think the way you present the plots makes perfect sense. The top version more or less captures the full range of human hearing (the Frequency axis), and the bottom version lets you zero in a bit. I think we all know how important that extra detail will be when attempting to generate a statistically significant statement of the impact of different amounts of unicorn tears. ;)
So far the Sunking's really close to the Refractor except in the low end w/ tone at 25% right?
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.
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.
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.
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!
Great detective work there, good on ya...! 8)
This is awesome.
I'm looking forward to seeing one seriously boring graph when you're all done! :)
The last tear have been dropped!
http://byocelectronics.com/board/viewtopic.php?f=9&t=49894
Quote from: GrindCustoms on July 04, 2014, 06:10:40 AM
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.
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.
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
Quote from: juansolo on July 04, 2014, 04:22:11 PM
Quote from: GrindCustoms on July 04, 2014, 06:10:40 AM
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.
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.
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!
Done!
Picture bomb. Lets start with the the easy one. Input and output impedance.
(http://i693.photobucket.com/albums/vv299/pnordeen/Impedance2_zps7e4821b1.jpg)
Frequency response plots:
Gain control at 75%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain75_FSWEEP_zpsb839e8d4.jpg)
Gain Control at 50%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain50_FSWEEP_zpsfa78c2b8.jpg)
Gain Control at 25%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain25_FSWEEP_zpsf2ce47cd.jpg)
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.
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Tone50_GFSWEEP_zpsedd9b7af.jpg)
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 :o).
Gain control at 75%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain75_HSWEEP_zpsd5b3b6b4.jpg)
Gain control at 50%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain50_HSWEEP_zpsa5f825cf.jpg)
Gain control at 25%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Gain25_HSWEEP_zpsf8dfaacc.jpg)
And again the impact of sweeping the gain on one circuit with the tone control fixed at 50%
(http://i693.photobucket.com/albums/vv299/pnordeen/ALL_Tone50_HGAINSWEEP_zps27d1cc98.jpg)
(http://fitinafatworld.files.wordpress.com/2013/02/130432159012-science-wins.jpg)
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...
Sent from my iPad using Tapatalk
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 :) )
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.
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!
Very through! Thanks for taking the time to do this.
Ha Ha! We all win! ;D
Much thanks for your time on this Paul.....
Almost tempted to send you an IDA Tusk with the latest updates. :P
Did you graph the KTR?
Sent from my iPhone using Tapatalk
that is textbook unicorn slaying right there
But they real ones feeeeeeel better :)
Quote from: Haberdasher on July 06, 2014, 07:20:52 PM
that is textbook unicorn slaying right there
The whole cattle is dying! 8)
Tusk of the last known «Ice Blue Canadian Unicorn» lulz
(https://scontent-a-ord.xx.fbcdn.net/hphotos-xap1/t1.0-9/1013185_10152178920741944_1562430147_n.jpg)
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 ;)
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.
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
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! 8)
Thanks for taking the time to do this.
Now all we need is an original Centaur for analysis, to finally slay the unicorn and put this to bed!
Epic! Well done!
Updated the impedance plot. Looks like input hovers around 2Meg then some inductive reactance comes into play. Output is around 450 over the range.
Here is a collection of the circuit changes made to Klones. Referencing this schematic:
http://1.bp.blogspot.com/-5aEPAyJYOzo/U4ice4jXIvI/AAAAAAAAHiw/7n5jViJkyIQ/s1600/KlonCentaur-Corrected-2009.GIF (http://1.bp.blogspot.com/-5aEPAyJYOzo/U4ice4jXIvI/AAAAAAAAHiw/7n5jViJkyIQ/s1600/KlonCentaur-Corrected-2009.GIF)
The capacitor plots refers to the changing of C14 from 3n9 to 8n2. The resistor plots are a recently discovered potential error in the original schematic mentioned earlier where R21 and R23 are swapped. Sorry for the wacky colors; I didn't want to make three different plots so some things are overlapping but it is pretty easy to understand if you look at it long enough. Very big high end changes with the resistor swap. Gain is fixed at 50% and the treble control is shown at 25, 50 and 75 percent for each circuit.
(http://i693.photobucket.com/albums/vv299/pnordeen/Mods_zps1d87dd06.jpg)
Little cornfused here, is the plot for the resistors cumulative with the Cap change?
And "Stock" is which existing clone circuits?
Thanks!
The resistor change is just the stock circuit shown in the previously linked schematic with the values of C21 and C23 switched.
The cap change is the stock circuit with the value of C14 changed to 8.2nF.
The stock circuit is is the previously linked schematic without any changes.
Awesome thanks!
Sent from my iPad using Tapatalk
That's awesome!
That's interesting! iirc, the 8.2nf swap was described as boosting the bass...
Quote from: jtn191 on July 08, 2014, 09:39:07 PM
That's interesting! iirc, the 8.2nf swap was described as boosting the bass...
We went for it because vs a Gold Centaur, our build sounded to be lacking a little bit of a mid hump. The fact that is exactly what it's added makes me feel a bit better that my ears still work (reasonably) ok ;)
Quote from: juansolo on June 27, 2014, 08:09:51 PM
As logic doesn't work with the cork-sniffers, actual verifiable data has little chance either.
I've had similar arguments with audiophiles. There comes a point where you just leave them to it.
My point, made: http://www.thegearpage.net/board/showthread.php?t=1455624&page=2
haha "graphs were designed to be pretty". no, they were designed to be factual.
Morans. Data is useless. Oscilloscopes don't play guitars
Quote from: mattlee0037 on July 16, 2014, 08:53:10 PM
Morans. Data is useless. Oscilloscopes don't play guitars
I used to use an oscilloscope that could play Asteroids. Does that count?
http://www.freeasteroids.org/
Quote from: jtn191 on July 16, 2014, 06:42:19 PM
haha "graphs were designed to be pretty". no, they were designed to be factual.
That said, you do have to be careful, especially with graphs of statistics, where all kindsa 'orrible visual manipulation can take place.
Greetings fellow Klonologists,
Firstly, this thread is awesome and I'm eager to see what you guys find with the real thing.
Right now I'm researching Klons and looking to get my hands on a KTR to trace and get some high-res gutshots of to add to the body of Klon knowledge. Klownledge? I can't afford what they're going for right now, so I'm looking for someone who'd be willing to let me take a look at theirs. With this being my first post here, I don't expect anyone to be willing to just send me one on faith (but if they are, I'll cover all the shipping expenses and then some). But if any of you guys know someone who has one in the Madison WI area and can hook me up, I could do all the work at their place under supervision and I'd bring along some beers as thanks. Or if anyone would be interested in putting together a group purchase like the freestomboxes guys did, then resell the pedal once it's traced, I'd be up for that. I'm open to ideas.
Quote from: juansolo on July 16, 2014, 05:57:13 PM
Quote from: juansolo on June 27, 2014, 08:09:51 PM
As logic doesn't work with the cork-sniffers, actual verifiable data has little chance either.
I've had similar arguments with audiophiles. There comes a point where you just leave them to it.
My point, made: http://www.thegearpage.net/board/showthread.php?t=1455624&page=2
Anyone else hearing a Stevie Wonder tune in their head when they read that thread?