DIY Phase Inverter & Attenuverter

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/ theaudiophool
00:00 Intro
00:26 What is Phase?
02:57 Phase Flipping Circuit
07:53 Phase Flipper Demo
09:01 Attenuverter Circuit
09:53 Attenuverter Demo
12:58 2 Channel Mixer
Today we're looking at how to improve the mixer we built last time with our invertin op amp summing mixer circuit. We had an issue where we needed to flip (invert) the phase of one of our signals, so in this video we're going to look at how the inverting op-amp can give us a binary phase inversion, and how the same circuit can be built to give us a nice attenuverter, which is a cirucit that can attenuate and invert at the same time!
Phase Inverter Simulation: tinyurl.com/y4mgh623
Attenuverter Simulation: tinyurl.com/y2pto33g
Phase Inverter & Attenuverter Schematic: drive.google.com/file/d/1EXlx...
Mixer With Phase Invert: drive.google.com/file/d/1TFlW...

[@ACAustralia50]

magic

[@soubac1]

Man i love your channel, i'll finish electronic engineering this year and i can assure you that i've learned more this last month thanks to your channel than in the whole degree. I love analogic electronics and i love audio and you make it so fun to learn. Thanks a lot!!!❤❤❤

[@TheAudioPhool]

You're too kind :) Thanks for watching!!

[@richardsstark9825]

Beautiful video. Very clear explanation. Feels like you are in the room with me!

[@TheAudioPhool]

Thanks Richard! :)

[@davidrysdam902]

I bought the exact same SPDT toggle switches. You can't find another one somehow! I had to solder pin headers onto them to use them.

[@mixguru9669]

Highly educational content! Keep up!

[@pedrodepacas4335]

Allpass next. 😀

[@erlannderrantem6972]

Cool video! The whole series is really awesome and helpful! Thanks you for your dedication to teach us fellow phools!

[@TheAudioPhool]

You're very welcome and i'm glad you're finding it helpful :)

[@TheNaboen]

brilliant

[@TheAudioPhool]

Thanks for watching :)

[@agemans_stuff]

Great video. And great T-Shirt ;) Thanks, Olli.

[@TheAudioPhool]

Thanks Olli!

[@poynt99]

Greetings! Great channel and info my friend. Do you take requests or challenges? One circuit application that no one talks about is a high impedance inverting buffer. The requirements would be the following: 1) 1M or higher Zin, 2) low noise design, 3) 1k or less Zo, 4) Transistor or op-amp, your choice, 5) Gain of unity (AV=-1), 6) Output must pass full swing of input, without the use of a post amplifier, 7) Standard op-amp R2/R1 inverting amplifier not allowed, as this would not meet the "low noise" requirement above, 8) No restriction on complexity of circuit, 9) 20-20kHz BW. I know of only one circuit configuration that fits these requirements quite well, but it is not well known. I'd like to see what you might come up with, as this is a real challenge.

[@maxwarfield6699]

Great video. I’m a novice at electronics and I’m putting together a modular synth. I’d like to have a module that inverts/reverses the audio signal, without attenuating it. So, I assembled your circuit [the one with the switch], a 555 timer in astable mode and an lm386 op-amp. Something is happening but I’m not quite sure what exactly, as I don’t yet own an oscilloscope. Anyway, with the switch in the non-inverting position - the audio signal from the 555 remains unmodified but when the switch is in the inverting position, the signal sounds like it’s slowly dying out [which kind of sounds like it’s in reverse, I guess] and after a short while, it dies out completely. Now, since I don’t have a scope, I don’t know if I have achieved “signal inversion” or not. In your examples, you say that the signals cancel each other out [blue flatline] in “out of phase” mode. So, what is “out of phase” supposed to sound like? Please let me know - I really want to learn. I’m sorry for the long text and thank you kindly. Cheers!

[@TheAudioPhool]

Doing audio electronics without a scope is very difficult if something goes wrong in your circuit! That doesn't sound right. The signal will only cancel out if you're mixing it back in with the original signal, not sure you're doing that. On it's own the phase inverted signal will sound exactly the same as the original signal.

[@tooboschbosch]

This was very useful, simple, clear and hands-on. What op-amp are you using in your example?

[@TheAudioPhool]

I always use TL074 op-amps. Mostly because they are common, and cheap!

[@plop-4269]

Awsome as always ! Your channel is one of the place where i learn the most thank you Could you (i you want to and have the time to) explain how to constrain a voltage range to an other ? I'm trying to have +/-12v in input and 0v/+5v at the output to be able to use MCU and single board computer with controle voltage.

[@TheAudioPhool]

Thanks for watching! :) It depends a little on the circuit. is your +/-12v AC or DC? Assuming this is all DC, If you want 5v at the output you can simply divide the +12v down to +5v with a simple voltage divider (3.3k & 2.4k for example) and then make sure you reference the 5V output to the 0v reference from your +/-12v supply. If you can attach a circuit of some kind i can be a little more helpful!

[@plop-4269]

Wow thanks that's fast =) It's actualy for both DC and AC as i'd like to use a modular synth's signals as a source and read it with some arduino/raspberry. So circuit "look" like : input jack -> attenuverter -> ??? -> Arduino Where the "???" is constraining the voltage to a range of 0v to 5v i dont quite understand this : " make sure you reference the 5V output to the 0v reference from your +/-12v supply "

[@PermireFabrica]

​@@plop-4269 first you have to decrease the signal amplitude from +-12V to +-2.5V then shift it up by 2.5V to get a signal with a range of 0-5V. Really simple. Take a voltage divider and use a summing amplifier to add the desired Offset. But make sure you build in overvoltage protection in front of your ADC input. A resistor and two schottky diodes will do the job. (Be aware that some Arduino's and Raspberry generally use 3.3V)

[@TheAudioPhool]

@@plop-4269 Sorry mate i misunderstood your question. What i thought you were asking it how to get 5v DC from a +/-12v power supply and i suggested something like this (tinyurl.com/y2hj8u9h ) Now i get what you mean. You want a +/-12v audio source down to within 0-5v so you don't clip the input of your micro? @Permire Fabrica is absolutely right. You need to first shrink your signal down so that it fits into the voltage range you want [+/-12(24v) to +/-2.5(5v)] then shift it into that voltage range [+/-2.5v to 0-5v] That would look something like this tinyurl.com/y49amtyr I have a video on summing amplifiers here if you want to know more about this circuit :) kzbin.info/www/bejne/j3SslKF8qrd-bdk

[@noel101082]

I think i love you a little.

[@PWMaarten]

That disappointment when you realize a component has an alternative pin spacing.

[@TheAudioPhool]

Tell me about it. FML