help me understand a schematic and turn it to reality

[Lost_soul]

your IC5 has pin 1 [an output - NEVER connected to ground] to ground, and no connection on pin 7 [the supply pin].

i fixed it. i finished the layout for the whole thing. i don't know if it's correct tho
it looks like an abomination...




i will try to do and do as ElectricDruid suggested to make it into sections and test it when i finish it and sounds like a good idea!
i will let you know how it goes!
btw are the connections for the switches and pots correct?

Sir Mike is always right. never mind sorry. confidence, bore in, go hard.

Sir Mike always takes the stairs and not the lift as he's always right

[Lost_soul]

You don't have to do it all at once either. In fact, definitely better if you *don't*.

Build one section, get that debugged and working, then move onto the next bit.

This circuit is very "modular", so that's feasible. You could build the input buffer, and the non-inv amp first, make sure you've got signal going through those, getting louder. Then start adding all the stuff in the top row - the octave up stuff. When you get to the end of that, you should have a working octave up signal. *Then* think about the next step!

"Divide and conquer", basically!

that's a great idea. i will do that when i apply the design i made on a real breadboard. make a section then test it and go on. thank you for that advice!

btw i finished the layout for it, it's in the last post!

[Lost_soul]

I say you just need to know which is the Gate..
Then you can name Drain the pin which stands at higher voltage level..

So here in Q1 the pin numbered 3 is gate and 2 is drain and 1 is source?
And for Q2 3 is gate and 2 is drain and 1 is source?

[antonis]

In Common Source & Common Drain configurations, Gate is considered the pin where the signal enters.. 

 

[Lost_soul]

In Common Source & Common Drain configurations, Gate is considered the pin where the signal enters.. 

 

I understand. So it doesn't matter which is drain or source as they are interchangable!
I finally finished it but...(surprise) it didn't work.

The octave down works but it adds a lot of distortion to the signal and it sounds very faint in the background (i can't hear the octave effect)
The switches don't seem to be doing anything.

When i play any note i can't hear the note but all i hear is the notes drenched in distortion noise.

From the layout i made on breadboard, is there something that stands out that is wrong or something? Idk man

The changes i made: used BF245C instead of both 2N5457. Used a BC517 instead of the MPSA13. And i used Tl074 instead of the LM348.
I checked the pinout difference for the trannys btw.

[Lost_soul]

Okay guys, after the build did not work correctly i dissembled some parts to test every section of the schematic alone. I started with the power section and input buffer and the non inverting op amp and it worked, then i made the connections for the octave up section of ic4 and it worked. Then i made the connections to the 3 order salle. Key filter (IC1 2) and the dpdt switch for it and it worked.

Where should i go from there?

[antonis]

First of all, get rid of that input buffer (R2, C1, R3, Q1 & R4) despite its good working status..

IMHO, there are too many needless connections to Vref..

P.S.
The above suggestions come in close to thread's title..

[ElectricDruid]

That sounds like good progress, so well done! 

From the Sallen-Key, just keep going right. You'll need both the half-wave rectifiers and then the flip-flops. You can't really test the rectifiers without a scope, but an audio probe will tell you if they're doing something - they make a fuzzy racket if they're working! The commonest thing to screw-up when building them is getting the diodes the wrong way around, so watch out for that. And they're not the same either! Watch out!
Once you get to the second flip-flop, you can connect its output to one of your mix pots for testing. You should have a square-wave octave-down signal. Some octave pedals work exactly like this and leave it at that. The OC-2 is a bit fancier and then uses that square wave to flip the polarity of alternate cycles of the input signal to make a more dynamic octave-down signal. That's what the final stuff on the bottom row is doing. Once you get the flip-flop octave-down working, you can move onto that final stage.

Good luck! It's a big job, but you knew that when you started, and now you're really getting there with it.

[Lost_soul]

First of all, get rid of that input buffer (R2, C1, R3, Q1 & R4) despite its good working status..

IMHO, there are too many needless connections to Vref..

P.S.
The above suggestions come in close to thread's title..

Okay, i will remove the buffer and see how it sounds

Can you tell me some of those needless connections to Vref?

[Lost_soul]

From the Sallen-Key, just keep going right. You'll need both the half-wave rectifiers and then the flip-flops. You can't really test the rectifiers without a scope, but an audio probe will tell you if they're doing something - they make a fuzzy racket if they're working! The commonest thing to screw-up when building them is getting the diodes the wrong way around, so watch out for that. And they're not the same either! Watch out!
Once you get to the second flip-flop, you can connect its output to one of your mix pots for testing. You should have a square-wave octave-down signal. Some octave pedals work exactly like this and leave it at that. The OC-2 is a bit fancier and then uses that square wave to flip the polarity of alternate cycles of the input signal to make a more dynamic octave-down signal. That's what the final stuff on the bottom row is doing. Once you get the flip-flop octave-down working, you can move onto that final stage.

Thank you so much for the detailed explanation man.
I will do as you said and report back how it went.
I just have one question.
When i finish the connections up until the output of the flip flop, how can i add a mix pot (an octave down pot) for it? Also how can i add one to the octave up?
Do i just do it as the right side in the schematic and connect pin 3 of it to the output if the flip flop instead of the output of IC2?

Good luck! It's a big job, but you knew that when you started, and now you're really getting there with it.

Yes it is really complicated but no regrets as i really wanna make it happen and i learned a lot of stuff from the experience,like how an IC is connected and how to read a schematic and a lot more. but i am yet to learn the FUNCTION of the ICs and other parts in the circuit 
and how the voltage and signel run across the circuit and many many many more.

[Matthew Sanford]

On that, I come from noob, so..

First, as you start reading about ICs and Op-Amps specifically, know typical material out there is doing dual supply, so positive and negative rails, ground (0 volt) is the middle reference. In single supply then you set VCC/2 (i.e., 4.5 volts reference in a 9 volt circuit) which serves as ground does in dual supply, the middle of the voltage road. those references (ground in dual, VCC/2 in single) is what the signal waves around, so keeps it from clipping rails.

From there, read on non-inverting and inverting op amps. I end up on a Basic Electronics Tutorials plenty because Google puts them first for me - on that, read other things too to know what you read is right. Of course there is Carl Jung's Op Amp Applications Handbook, which you should get, but know it's a bit more than you understand so...little articles are good. Beyond that, learn about the different set ups for op amps. All are differential I think, but then you have summing ones, integrator ones, differentiator ones, and more - these are all just op amps, but how they are set up will determine the function and name. Play with stuff like Falstad or Spice to see it in action and test what you think should happen. Actually Falstad has many sample circuits to see different set ups in action.

As you get into different op-amp ICs you'll see they aren't the same, some BJT, some FET input, etc. Some rail to rail, but most not, so be careful. The datasheets are gold here, once you learn to read them and better understand the abbreviations.

For other parts, read on things like high pass or low pass filters to understand somewhat about resistors, capacitors, inductors.

Lastly lean on the good folk here, many a time a much needed slap of sense came to me here. Just don't go start doing Power Slap thinking it will help...

[antonis]

Can you tell me some of those needless connections to Vref?

Any connection other than those biasing op-amps (going to non-inverting inputs)..
(in the cost of some extra DC isolating caps..)

But for the time being, let's try to make the existing circuit working..

[ElectricDruid]

When i finish the connections up until the output of the flip flop, how can i add a mix pot (an octave down pot) for it? Also how can i add one to the octave up?

There are three pots over on the RHS connected up as a mixer already. They take signals from the points in the schematic marked "Direct", "Octave+", and "Octave-". Since you've got the first stage and the octave-up working, you should be able to connect those points to their respective mixer pot already. That only leaves you the "Octave-" pot. I'd connect it up like this for testing (also shown the octave+ connection).



Note I've shown the two points connected with a capacitor.That's probably a good idea since the two ends of the connection have different DC levels. Try 470n. It might rob some bass, but it'll do for a test.

Do i just do it as the right side in the schematic and connect pin 3 of it to the output if the flip flop instead of the output of IC2?

Yep, that's it exactly.

[Lost_soul]

Note I've shown the two points connected with a capacitor.That's probably a good idea since the two ends of the connection have different DC levels. Try 470n. It might rob some bass, but it'll do for a test.

I did make the connections and added the caps as you said, unfortunatley it didn't work. The octave up was still working but it the sound was much lower level and there was a lot of noise whenever i play a note. and when i turn on the octave down via the pot, when i play a note i can't hear it but i hear very loud squarish wave noise that sounds like the amp is gonna explode lol.

I went over and checked the layout i made and compare it to the schematic but i can't find the problem! I also checked the connections on the real breadboard and they were all in place as the layout.
It would be great if you could go over the layout i made and see if i made something wrong. At least we know now it starts from IC3.

Ps: only connection i found that i missed was for one of Q3 Pins to Vcc but that didn't solve amgthing

[Lost_soul]

For other parts, read on things like high pass or low pass filters to understand somewhat about resistors, capacitors, inductors.

Lastly lean on the good folk here, many a time a much needed slap of sense came to me here. Just don't go start doing Power Slap thinking it will help...

thank you for such valuable suggestions. i will definitley look at what you suggested in the free time i have as i like knowledge and electronics are starting to be a hobby for me
you and all the folks here have been really understanding and helping. Thank you all guys

[Matthew Sanford]

For other parts, read on things like high pass or low pass filters to understand somewhat about resistors, capacitors, inductors.

Lastly lean on the good folk here, many a time a much needed slap of sense came to me here. Just don't go start doing Power Slap thinking it will help...

thank you for such valuable suggestions. i will definitley look at what you suggested in the free time i have as i like knowledge and electronics are starting to be a hobby for me
you and all the folks here have been really understanding and helping. Thank you all guys

No worries. I know how it feels to just jump into it! Other thing, not sure your soldering experience, but here I learned that tinning the tip before soldering is to make sure there is solder between tip and lead/pad so it will conduct heat properly to melt solder quickly. I spent so much time poking the spot with the solder and it not melting, not understanding why, but it just makes sense there needs be something solid to transfer the heat rather than small air gaps.

But read, read, read. As you go do small circuits on breadboards to confirm what you read, give you that experience to make the learning more solid. Remember Ohm's Law and Kirchoff's Law are always present, and cover most everything you work on, math wise. Also remember to step away once in a while; I've found myself getting stuck on an idea that is completely wrong, so it's good to back up and reassess. Luckily there are so many great people here that will pull your (ok, my) head outta the muck!

[Lost_soul]

not sure your soldering experience

At the beginning i didn't know much about soldering but now i know the essentials to make a good connection

But read, read, read. As you go do small circuits on breadboards to confirm what you read, give you that experience to make the learning more solid. Remember Ohm's Law and Kirchoff's Law are always present, and cover most everything you work on, math wise

I will definitely try to do that as it's gonna make me learn a lot of stuff about how everything is working.
Right now with this build idk what i am doing wrong. I would really appreciate it if you could compare the layout i made with the schematics to see if i understood something wrong.

[Matthew Sanford]

not sure your soldering experience

At the beginning i didn't know much about soldering but now i know the essentials to make a good connection

But read, read, read. As you go do small circuits on breadboards to confirm what you read, give you that experience to make the learning more solid. Remember Ohm's Law and Kirchoff's Law are always present, and cover most everything you work on, math wise

I will definitely try to do that as it's gonna make me learn a lot of stuff about how everything is working.
Right now with this build idk what i am doing wrong. I would really appreciate it if you could compare the layout i made with the schematics to see if i understood something wrong.

Full honesty, I am far from the smartest of knowledgeable one here. Those that have been helping you? Bunch of super smart nerds! Still, as plenty coming from Vref I'd say hook them all up straight then check the voltage between the 10ks, if it isn't right then maybe use 100k or 1M resistors to take it from that point to where it's needed. Oh! Take a picture of it on your breadboard, maybe two from different angles depending how your wires are, and post them here. That is best way to check it against the schematic, to see what is actually on the board - I know from experience I often find wires jumped over one row from where I swear I had placed them! There are plenty of good eyes here...not mine, but Antonis might put a red circle on the picture and put it right back to you! You say the octave down is squareish, probably from the flip flop that goes to the fet on (is it + in?) to the op amp for that - seems it is to cut Vref in and out, or from 0 resistance to 100k, but maybe something else is going on?

Also, is the LM348 a bjt op amp that can go to ground? The TL072 is a fet op amp that doesn't like getting closer than a couple volts to ground, so might have issues there? I'm grasping at straws there, but it can matter - this I know thanks to these good folk!

But do post those pics! This week's a bit crazy, and you may have an answer before, but I can try to check it out this weekend

[antonis]

[Lost_soul]

battery at 8.37v, no potentiometers connected and the SPDT switch was not connected. removed Q2 pin 1 from the circuit but left R11 and checked for D1 and it was proparlly oriented.

point 1: 4.4v
point 2: 4.4v
point 3: 4.37v
point 4: 4.38v
point 5: 4.36v
point 6: 4.24v
point 7: 4.34v
point 8: 4.42v
point 9: 4.42v
point 10:4.33v
point 11: 4.38v

battery after measurments: 8.21v

just in case you got me wrong from my comment about how it's not working. i didin't mean it was producing a swaure wave octave down signal when i connected IC3 AND 5 but not IC2. i meant that whenever i play a note i can't hear the note itslef but all i hear is a very loud square wave noise like the amp is going to explode. so i think something is wrong with somewhere in IC3 section or IC5 idk.