Recent content by thunderaxe

it looks like the 555 is switching the ground for the LED, so it shouldn't affect anything negatively to just switch the current source from Vdd to the LFO, right?

inspired by this thread, i've been designing a board that contains: -in & out jacks -DC jack -relay switching -LED -power conditioning -input buffer -option between buffered or true bypass -VREF -- which, since i'll have a spare op amp from the input buffer, may as well be buffered. TL072s are...

the rail-to-rail only comes into play when there are no clipping diodes in the negative feedback loop, right?

is that the TLC2272 by chance? also is there anything more to biasing a TL072 properly for clipping than giving it a half-voltage VREF? or does it have an internal offset?

i'm just curious because it seemed like one of the goals of your redesign was to do it with the minimum required number of op amps. do you prefer the op amp clipping sound of the CA3130 over that of a TL072? i'd also be curious just in general which op amps you consider to have the most...

looking at this again, i'm curious why the output buffer/buffered output volume is necessary, in either the original or your redesign. wouldn't the impedance coming off the output of the treble filter op amp be almost zero already? so would there be any disadvantage to just sticking an output...

i'm having a hard time understanding how the 10k dynamics pot can get the voltage down to 5-6 volts. if i'm seeing it correctly, it forms a variable voltage divider with the existing VREF static voltage divider. but even turned to max resistance, it would be 10k on top and 20k on the bottom...

did you consider replacing the 3x series 4148s with LEDs? the keeley rotten apple (pedalPCB sour grape) did that, being an adaptation of the op amp big muff (pedalpcb dream fuzz). the LEDs would have about the same Vf but maybe a different curve and tone.

TEACH US YOUR WAYS

the marshall bluesbreaker/guv'nor circuits have a very clever way of controlling the gain of two cascading gain sections via a single-gang pot but it requires the second stage to be inverting with its gain controlled by a variable input resistor, and i think it would be way too much to convert...

with the values the way they are now, it would require a dual-gang pot. i was talking about what it would take to make them the same value so you don't need a special pot. i feel like the drive section could use more gain, so i would maybe up that to 10K. and then in order to get the first gain...

unfortunately for me i know even less about cars than i did about guitar pedals when i first asked this question. fortunately, i have learned a lot more about guitar pedals in the year and a half since. so here's what i understand about the circuit and you can let me know if i get anything...

a pot sweeps lug 2 (the wiper) from lug 1 (far left, CCW) to lug 3 (far right, CW).

do the MOSFETs produce noticeably more harmonics than the other clipping options? also, with the gain pot also being in the feedback loop, C13 interacts with it and really only comes into play in the highest gain settings, correct?

maybe it's just all the diode switching that's throwing me off, but what is the purpose of C13?