This is so good! You are absolutely thorough and cleared up so many of the weird little questions. Got my summing amp across the finish line sounding cleaner than ever. Game changers filtering the battery, filtering pre-amplification, and the pulldown resistor. Thank you for walking through the math and using practical numbers :)
I have to say this is the most brilliant explanation and tutorial I have ever seen in these circuits. You are a master at teaching these concepts and have helped me so much in understanding these circuits. Thank you so much!
Yes, you can use the gain calculation to adjust the feedback or the other resistor in the calculation. Staying with the Kilohm range. Remember that it will also shift the cutoff frequency because of the capacitor in the feedback path of the OpAmp. If you get stuck let me know and I’ll run some calculations for you.
Thank you for this video it was very helpful in understanding how distortion effects work. I hope it will get to more people because you've done a great job. I have just one question how is it possible that you get 4.5 V on the input of the op amp? Shouldn't some of the voltage drop across the 2M2 bias resistor and the 1K Rrf? Thank you for your answer.
Excellent observation. Yes, it will drop but insignificantly because the current is so small nanoAmps at the divider (100k) output and picoAmps after the 2M2, so for all intents and purposes it remains 4.5volts. Additionally we're using a TL071 here that has FET inputs, so that also helps negate the effects due to the massive input impedance. If you want to experiment further, nn the folder linked in the description is the Falstad emulation, you could have a play around with the values 2M2 and 1K resistors in the simulator (there's also a video on Flastad if you've not come across it before). Hope that helps.
I also build my own pedals (since 6 years now) and your videos are the best, if not the only proper ones, explanation of the process I came across on youtube...excellent work
Excellent videos, thank you so much for making these. Very clear, logical, well paced. Love the theory, then test on breadboard and oscilloscope. Cleared up a lot of gaps in my learning
I didn't get why the two 2m2 in parallel? Also why output is in parallel? And where would you add a switch. Thanks, I really enjoyed the vid. I did electronics in college years ago. So it's like a refresher. Thanks Tom.
Thanks Tom 👍. Great question, it’s because to an AC signal all voltage sources are grounded so for AC analysis both 2M2 are grounded and therefore in parallel. We also assume the cap between them is a short for the AC maths. A DPDT or a 3PDT (with led) Switch would be added in the usual way, there’s a video, I’ll link it below.
Thank you for making these videos. I’ve been wanting to know how to make small amplifier circuits for years.
Awesome. Watching now
This is so good! You are absolutely thorough and cleared up so many of the weird little questions. Got my summing amp across the finish line sounding cleaner than ever. Game changers filtering the battery, filtering pre-amplification, and the pulldown resistor. Thank you for walking through the math and using practical numbers :)
Excellent stuff on the summing amp, happy to have helped 👍
I have to say this is the most brilliant explanation and tutorial I have ever seen in these circuits. You are a master at teaching these concepts and have helped me so much in understanding these circuits. Thank you so much!
Let say i would like to turn the boost into 20db, how should i do it? Great video, you deserve more subs🙏🏻🙏🏻
Thanks :) You were correct in the other comment about adjusting R1 and R2 👍
This video is great
So if i was to make R1 330k I could decrease the amount of gain.
Yes, that’s right… gain(dB) = 20 x log (1+ (220/330)) which, if my maths is right, would equal around 4.44dB
Immensely helpful, thank you very very much!!
You're very welcome 👍
i would like to make this pedal switchable between 3 and 5 dB.
Yes, you can use the gain calculation to adjust the feedback or the other resistor in the calculation. Staying with the Kilohm range.
Remember that it will also shift the cutoff frequency because of the capacitor in the feedback path of the OpAmp.
If you get stuck let me know and I’ll run some calculations for you.
Thank you for this video it was very helpful in understanding how distortion effects work. I hope it will get to more people because you've done a great job. I have just one question how is it possible that you get 4.5 V on the input of the op amp? Shouldn't some of the voltage drop across the 2M2 bias resistor and the 1K Rrf? Thank you for your answer.
Excellent observation. Yes, it will drop but insignificantly because the current is so small nanoAmps at the divider (100k) output and picoAmps after the 2M2, so for all intents and purposes it remains 4.5volts. Additionally we're using a TL071 here that has FET inputs, so that also helps negate the effects due to the massive input impedance. If you want to experiment further, nn the folder linked in the description is the Falstad emulation, you could have a play around with the values 2M2 and 1K resistors in the simulator (there's also a video on Flastad if you've not come across it before). Hope that helps.
Thank you very much that helped a lot.
I am curious why the extra divider after the power area with the 2M resistors if you already have Rd1 and Rd2 ?
Excellent question. The Cin Capacitor (10n) blocks DC (and low frequencies) so there's effectively no DC voltage division by the 2M2 resistors.
@@MusicTechknowledgyaha! ok thanks!
I also build my own pedals (since 6 years now) and your videos are the best, if not the only proper ones, explanation of the process I came across on youtube...excellent work
Excellent videos, thank you so much for making these. Very clear, logical, well paced. Love the theory, then test on breadboard and oscilloscope. Cleared up a lot of gaps in my learning
Thank you for filling in the missing details. I will have to watch again, ha ha.
I didn't get why the two 2m2 in parallel? Also why output is in parallel? And where would you add a switch. Thanks, I really enjoyed the vid. I did electronics in college years ago. So it's like a refresher. Thanks Tom.
Thanks Tom 👍.
Great question, it’s because to an AC signal all voltage sources are grounded so for AC analysis both 2M2 are grounded and therefore in parallel. We also assume the cap between them is a short for the AC maths.
A DPDT or a 3PDT (with led) Switch would be added in the usual way, there’s a video, I’ll link it below.
ua-cam.com/video/hdu99bkEe6U/v-deo.htmlsi=t5pX8YiufvkDBx79
This one may help with switching too, I don’t use a PCB in this one … ua-cam.com/video/dbROhwy07B4/v-deo.htmlsi=fN9GhBdeF8Sqmt5H
@@MusicTechknowledgy thanks for the reply! Been thinking bout 2m2 in parallel, sort of get it but don't? Der lol.
No still don't get it. Any way you can demonstrate it? Voltage on resistors follow ac the same? No phase shift like caps.
One of the best practical video I've seen - thanks 🙏🏻
Thanks for all your videos! Very informative 👏
Great video! I think using a logarithmic potentiometer would lead to a more "linear" increase in volume, right? i've never experimented with that
You're right, our ears have a logarithmic response to sound levels. So, by using a logarithmic pot, we taper the pot for the way we hear.
This is excellent. Thank you!
Awesome work sir...
usefully
Fantastic video!
Thank you :)