DIY Phaser Circuit With Voltage Control

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This week we're going to be expanding on the simple phase inverting circuits we made last time, this time adding a bit of voltage control to make a Phaser! This circuit shifts the phase of a selected range of frequencies, so that when you mix the phase shifted frequencies back in with the oringial, you get a really thick sound. It's a pretty simple circuit using Op-Amps, a few resistors & capacitors, along with a JFET based voltage controlled resistor (VCR).
Phase inversion circuit simulation: tinyurl.com/y8h2xfza
Schematic: drive.google.com/file/d/14Ab-...
Patron video: / 63352854
00:00 Intro
00:35 What is Phase?
02:00 Phase Flipping Circuit
03:30 Phaser Circuit
04:44 Circuit Demo
06:16 How Do Sines Add?
08:04 Phase Shifting Network
12:44 Simple Phaser Demo
14:38 Circuit Improvements
16:45 Improved Phaser Demo
17:20 More Circuit Features
20:37 Plugin phaser
23:47 Outro

[@felliperockz7857]

One of those KZbin gold videos for electronics

[@LimJim]

I know this is an older video but i just want to say thank you so much for your in depth explanation and example schematics. This video was the inspiration for my senior design project where me and a partner built a really cool modular synth style guitar pedal with a 3-notch phaser and all of the notches broken out with 3.5mm jacks. We also made a whole stage of digital effects using a Daisy Seed and because of your channel, my partner and I graduated last weekend with BS's in electrical engineering at the university of florida. Much love!!!

[@LabSkaterPussies]

No way! I was literally just researching making an analog phaser. Your videos are awesome.

[@TheAudioPhool]

Haha, spooky!! Thanks for watching!

[@damantis79]

Same here! I'm working on a modified Compact Phasing 'A' design with additional controls & (hopefuly) shrunk down a bit. It's partly breadboarded right now, working on the LFO design at the moment. What is your basis of design? # of stages?

[@damantis79]

I'm not sure what everyone else's inspiration was, but I first started to take a look at this a couple years ago when I first found the J. Haible PCB/schematic & then got really motivated once I watched the Hainbach CP-A video last year.

[@LabSkaterPussies]

@@damantis79 do you have a link to the schematic?

[@cwrigh13]

More videos please!!!

[@TheAudioPhool]

There's plenty on the way! :)

[@fano72]

When I see a bread board, I like 😁

[@diabolicalartificer]

A lot to digest in this video but I'm slowly starting to understand. Thanks very much for taking the time to make these video's, I really appreciate it; subscribed......DA.

[@bayareapianist]

Great stuff. I was thinking about how to change a signal's phase from 0 to 180 degrees without changing the output average voltage. I wanted to use a square wave and change the width of it from 0V to Vcc. Even better, i could control it by an external voltage and a resisitor instead of the pot. ❤

[@peterlin409]

I wish you were my college professor! extraordinary video. very easy to understand! Thank you so much.

[@zapp442]

This is some good stuff. Just started experimenting with guitar pedals and preamps a few weeks ago. It’s cool you use Ableton as well!

[@error8418]

Excellent explanation! Now I finally understand what the number of stages is supposed to be.

[@TheAudioPhool]

Thanks for watching!! :)

[@DJDiskmachine]

Phaser design got u another subscriber. Great stuff! ✌️😇

[@CJGausvik]

Awesome video! I always thought you needed some kind of bucket brigade chips or crazy FETs that can not be found by mere mortals... Nice to know they can be done "homebrew"!

[@TheAudioPhool]

Really glad i could help! Definitely will do a full videos on JFETs & Voltage control as there's lots of stuff you can do with them :)

[@larrymorley8968]

​@@TheAudioPhool I work with electronics in the context of sound - and everything else, or so it seems. And, it's feeling a lot lately like new or recent EE grads can't - or won't - try anything that's not FPGA based; uses a microcomputer or ASIC custom tailored for whatever they're tring to build out. I use OpAmps for signal processing because they're generally cheap: lots of LM358s and LM1324s; TL082s and what not. I love the sound of a multi-stage diode ladder. I don't care much for 555 based sequencers because I've yet to hear one that doesn't click and pop incessantly. A good decade counter, particularly one that'll reset at 5. VCRs built from a single JFET and not much more, now that's impressive. I've gotten some sweet results out of an NPN and a PNP 'long tailed pair" when the BJTs are complimentary and biased properly, too. Nice video; really like that you took the time to set up some simulations with Falstad's simulator; pix are worth a thousand words. Hope to see more from you and maybe exchange some iideas; maybe chat some. Thanks.

[@rafaelribeiro3972]

Thank you for the excellent videos! Greetings from Brazil :)

[@TheAudioPhool]

Thanks for watching :)

[@zapp442]

That ringing feedback could be a nice effect.

[@MrChopin2323]

very very nice

[@pol.kraine7890]

Gonna try to implement this for a Chroma signal to see if I could add color to a composite signal

[@CaHeoMapMap]

Awesome

[@jrapplefan2231]

Good job. If I well understand, we are close to built a circuit that are an active canceling noise ? It could be a great topic for your next project.

[@ofootyeabicc201]

Would I use a JFET if I want to add in CV control over the wet/dry on ye old PT2399?

[@happyjellyfish2008]

What if you not only put the amplitude of the waves out of phase of each other, but also had the frequencies of the waves not match so they overlap at less predictable moments? What would that sound like? What would you call this effect?

[@scottk3292]

Do you do anything with bucket brigades? I have a flanger that appears to have fried, and I'm curious how much goes into getting that effect. (And I have a cool trick for getting beautiful phase cancellation effects at low recycle rates, sounds beautiful on guitar)

[@tziirkq]

Holy crap, you just explained how to fix a problem I've been having and thought was unfixable at a DIY level. I've been wanting to align the phase of my pedals in a live setting, you're a legend. Do you happen to take requests for simple subjects?

[@TheAudioPhool]

Glad I could help! :) I'm open to requests I just can't say when I'll be able to fill them!!

[@tziirkq]

@@TheAudioPhool Hopefully it's not overly complicated, but I've been curious on how to make a smoothed random LFO. The S&H style isn't applicable in most cases, but a smoothed random would be amazing. While I think about it, maybe a video on random voltage on a button press would be cool. I really can't express how big this phaser circuit is for me. I make bass heavy guitar music, with four pedals output into a mixer.

[@TheAudioPhool]

@@tziirkq Both great ideas! It's on my list! :)

[@electronicsandmusic2077]

I’m going to put this on my Hammond clone I’m building from scratch

[@davidrysdam902]

That first pot-controlled phase shifter confused the hell out of me for hours. In the first schematic, you have the input at the top of the pot, ground at the bottom and the non-inverting input on the wiper. You specifically draw it that way and call it out like that in the video. Then you "add a single component" and re-draw the schematic. In the new one, there's no wiper connection. But in fact, both the input (through the cap) and the non-inverting input are connected to the wiper. Or so I deduce, by trying every which way and finding one that works.

[@M_TELEDO1212]

Great video! I'm just curious how you are inputting the audio signal through your circuit? Probably this is quite basic but no video I've seen of creating these sort of effects circuits show how this is done. And then how would you connect with the output signal? I don't see you using a jack socket anywhere.

[@ivolol]

I think it'd be easier to visualize these if you also showed a computer-drawn schematic for these circuits, which you can highlight parts to focus on, etc, when they get more complicated.

[@nelsone9520]

Thanks! Very well explained. Would this circuit work in a eurorack system? Greetings from Buenos Aires

[@TheAudioPhool]

yes!

[@davidrysdam902]

I did the experiment at 12:30. With the LPF, it seems to match. At low freq I get no phase shift, at 3dB I get 45deg and at high freq I get 90deg. With the HPF, I don't get this. At low freq I have 90deg as you do, but at 3dB I have 45deg and at high freq I have 0. This makes sense to me from a symmetry POV--the HPF is just the inverse of the LPF and presumably has no phase shift in the pass band. According to your graph, I should see the output 180 out of phase with the input in the pass band of a HPF. But it's also possible I'm screwing this up. When I make it the network as you show (i.e. both cap and resistor connected to V+ and measuring between them), correctly see not much attenuation but I also see no phase shift.

[@LabSkaterPussies]

Where did you get those jfets? I can't find 2n5460s anywhere. Same thing with the MXR Phase 90 which used the 2n5952. Also don't they need to be very closely matched?

[@HeimdallAfBifrost]

Falstad?

[@phyphedelic3214]

Wow, I was literally about to ask you if this was possible, since my research only found circuits which effected the fq. when implementing a phase shift.

[@TheAudioPhool]

With Op-Amps, anything is possible!!

[@phyphedelic3214]

@@TheAudioPhool is it possible build a triangle wave where both the rising and falling edges can be adjusted (I.e. from sawtooth to reverse sawtooth)?

[@TheAudioPhool]

@@phyphedelic3214 tinyurl.com/y9fxk3x7 Just threw this together! As chance would have it a version of this circuit is going to be in my next video so a detailed explanation will come there, although i don't know if i'll add the saw adjust, it's essentially a triangle wave generator with the ability to turn it into a saw :) If you need mroe help, join my patreon where i take suggestions and help my patrons design circuits, and you'll also get early access to new videos! Thanks so much for watching :)

[@phyphedelic3214]

@@TheAudioPhool that is waaay easier than the method I’ve been failing @. I’ve been trying to do it following this method ( kzbin.info/www/bejne/n5PRq2iLn7Znq5I ) to no evail for ever. Guess you can do anything wit an op-amp😲. Thanks for the knowledge! I’ve gonna need some of your patreon support for another issue I’m having involving linear-exponential conversion. Being that it’s my first fully-functional VCO, I’m sure there will be many more questions to follow. Looking forward to working with you.

[@TheAudioPhool]

@@phyphedelic3214 Glad i could help :) Next few videos will be on VCO's, voltage control & CV so stay tuned!

[@LabSkaterPussies]

Do you think I could replace the jfets in the voltage control part with like a BC548 PNP transistor? I have a bunch of those on hand

[@TheAudioPhool]

Unfortunately not :(

[@TheAudioPhool]

You could try a P-channel MOSFET if you have some of those kicking about. The channel resistance will probably be much lower but it should still do some modulation

[@LabSkaterPussies]

@@TheAudioPhool ok I will probably buy the components in the schematic then since I dont have any mosfets at all. Looking forward to if you do a video on voltage control cus I have no idea how to implement that kind of stuff on my own

[@TheAudioPhool]

@@LabSkaterPussies Videos on voltage control are incoming :) Got a few videos on oscillators coming up next where we will go over a few different types of voltage control

[@woosix7735]

uh, hey the jfet you say in the schematic is the 2N5460 which seems to be discontinued. what can I use that they still make today, will any p-chanel jfet work?

[@TheAudioPhool]

Yes any P-channel JFET will work. That's just what had on hand!

[@woosix7735]

Cool!

[@MyProjectBoxChannel]

It's basically the opposite of a whaa effect. The notch is just invited 🤔

[@SouthShoreSonics]

Is your schematic dual supply or single supply?

[@TheAudioPhool]

Dual supply

[@smellymala3103]

Some bastard guitarist stole my 75 phase 100 and if I find out who it was I will do the 10 years