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I was out for a 10km yesterday, and it occurred to me. I have a 180 phased output from the ecc99 from the cathode follower. It won't be directly anti-phase from the long tail pair due to the decoupling cap but it will provide a maximum current solution. vs the output. It would be relatively easy...

Managed to get onto this early this morning, reverse the cap and do a run with -7.5V comp bias. Sometimes the reality doesn't match the model. This is one of those times - diode noise. In the output (yellow) you can see noise on the output. This when traced back is switching noise from the...

So first - this shows the input from the hot pickup, Key point is the max 5.52Vpp (746mVrms) and mean 2.31Vpp (344mVrms) which is measured across the plug whilst plugged into the amp. Compare this to: https://sound-au.com/articles/guitar-voltage.htm Next step is to look at that and adjust the...

So I've had a little break, distracted by the arrival of a new fuzz pedal.. but this afternoon I think I've managed to get the tuning of the ltspice back to looking good. So I know the changes I need to make (again) bus this should really do a better job. This is will work with 5Vpk 10Vpp input...

I was considering a couple of 'additions' with an input buffer and driver with switchable bypass for each, and some power supply options. The idea being I can slowly collate a number of options without having to build yet another pedal.

I'd be tempted to make a multi pedal with a number of fuzz circuits in it - 2x pnp and 3x npn then have a 5 way rotary selector switch on the front. The support components can be SMT leaving THT for the transistors themselves and allowing more to be packed in to target a small pedal board foot...

I may have had an oops moment due to an unexpected tax refund.. Given the CV7003 are £54 each at the moment (not including eBay fake/busted roulette) and basically unobtainable military version of the OC44 and that's about the last pedal I can find not for stupid money.. I'm still interested...

Better on the harmonics too - the second harmonic being dominant on a 1KHz 1Vpp signal. The output (bar the noise created by the 9V cheap pedal PSU wall wart is now as it should be: The result when it gets overloaded does go into class A distortion. I've not got to work through the...

I did the change and there's still some blocking. This time from the ecc99 grid capacitance. Both the spice model and the real circuit demonstrated it (adding the probe helped by adding what is a high Meg path to ground). Instead I went back to the schematic and walked through modelling the...

Getting down to the bottom of the distortion- this is my fault in assuming. I love my scope.. after tracing through the signal path grid to anode/cathode etc... I've found the source: * purple is the input straight from the sig gen at 4Vpp * yellow is the output from the TC to the amp - note...

Just did some updates on the voltages to match the model you've seen. Just uploading the sig gen/scope demo I'm going to have breakfast and then plug in the guitar and amp to see how it sounds. Update, there's a few bits that need doing after playing: * currently I have a 1M put in the...

Rehoused.. and running. Currently I have the sig gen using into it with the scope - this doesn't have any adjustments yet. It's just come off the lightbulb limiter. Video uploading.... This is the XY plot - it hints at the current curve (see the persistence of vision) but it shows the full...

I know.. odd ey! It's probably something like the maximum AC signal Vpp/Ipp given the testing (from memory) was low voltage plus the sig gen is limited in it's current delivery capacity, even in 50R mode. My point here is not all testing is perfect, at the same time A/B testing on a stereo amp...

I've stuck caps on an sig gen and scope, then bode plotted the human range and I didn't find any difference between Panasonic and Wima. Yet the sound difference between them as a cap between a solid state amp pre and power sections was marked. As too vs the old electrolytic that had been fried...

Agreed, in the main audio tends to be film in polyester/polyprop, electrolytic, and then the high frequency tends to be ceramics (microphonic) etc the main target for those is making the wave guides not reflect and bypassing the switching frequencies. Tantalums have fallen out of fashion but the...

Source: https://www.aictech-inc.com/en/valuable-articles/capacitor_foundation04.html The source of this image is very interesting, littered with mathematical witchcraft but it's understandable. Another source would be Panasonic: https://industrial.panasonic.com/ww/ds/ss/technical/lc3 ESR/tan...

When you're designing/selecting the cap there's a tan loss angle (basically ESR) that changes over frequency applied. Typically film caps are fine at higher frequencies but once down in the 100Hz and below, we start seeing some key differences as the ESR on those smaller film caps start...

The more switches and pots are exposed, the more dirt and grime gets in. It's good to play but once the pedal is in use it's likely they're not going to change. I'd prefer a removable metal covers for the toggle switches and pots.

Minimising switching noise. Current flows in loops, and that (being high frequency and with higher harmonics) follows the impedance rather than resistance that DC does. This can mean flow through the components rather than the actual PCB ground planes! Anyone interested may be interested in...

Usually a bit of new solder and wipe on heatup and it’s good to go. Weller tip activator works wonders when the iron has too much oxidation or impurities to clean normally. This is basically an agressive fllux solder. Stick the hot soldering iron in it, take it out and leave it bubbling untill...