Breadboarding a Phase 45

[audiobalm]

Hey folks

I thought I'd share my breadboarding project of a phase 45. It doesn't work yet and I'd be interested in your thoughts but it's the most ambitious breadboarding I've done yet.

Built off the attached schematic and bought as a kit from Bitsbox.co.uk I followed every point in the schematic and hooked it up without much of a plan. As you can see I used space and jumper wires liberally!

So far I've got a pretty gnarly distortion going. With a clean sound on top which is very strange. The trimmer either increases or removes the distortion but so far no phasing.

I know it's probably impossible to see what's going on. But be interested in how you think I should approach working on this. It could very well be that the breadboard is crap and I need a better one 🧐

[garcho]

I followed every point in the schematic and hooked it up without much of a plan

I always draw a plan for breadboarding circuits more complicated than a basic block. It's probably the rats' nest and difficulty making any sense of it, not the breadboard.

[duck_arse]

voltages. measure them, post results.

[deadastronaut]

When i bread up more complex circuits, i have the schematic image in a graphics prog on pc and i follow the schematic and draw a coloured line over every part in the schematic as i place them on the breadboard....then you cant get lost, or miss a node, connection......otherwise its too easy to miss something just going by eye.....

[audiobalm]

voltages. measure them, post results.

Thanks! Here's some measurements

Power supply - 9V - 9.83

Q1
Gate - 4.74
Source -5.17
Drain - 5.25

Q2
Gate -4.69
Source -5.00
Drain -5.00

IC1
Pin 1 - 4.93
Pin 2 - 5.04
Pin 3 - 4.97
Pin 4 - 9.30
Pin 5 - 3.32
Pin 6 - 4.96
Pin 7 - 4.82
Pin 8 - 0.60

IC2
Pin 1 - 1.26 (gains when I probe 2)
Pin 2 - 4.72 (drains when I probe it)
Pin 3 - 3.40
Pin 4 - 9.00
Pin 5 - 4.65
Pin 6 - 4.82
Pin 7 - 5.00
Pin 8 -0.22

[audiobalm]

When i bread up more complex circuits, i have the schematic image in a graphics prog on pc and i follow the schematic and draw a coloured line over every part in the schematic as i place them on the breadboard....then you cant get lost, or miss a node, connection......otherwise its too easy to miss something just going by eye.....

Yeah that's how I did it but with a paper copy of the schematic and a highlighter. Did it in stages took three days and think I made all the connections correctly.

Might just tear down and rebuild again for the practice and for the troubleshooting. See if I can't make it more efficient

[garcho]

See if I can't make it more efficient

That goes a long way to alleviate breadboarding woes. Once you start drawing out a plan or breadboard diagram or whatever (I make a breadboard diagram like a perf or vero board layout), you'll find you might end up with something of a more concrete strategy to testing out circuits, tweaking, and developing the one you want to build. It can help all the way until you've boxed it up and are testing it out and *possibly* troubleshooting it Especially if you take voltages and write them down, and don't forget to write them down once it you have it where it sounds good! It can also end up being a big part of your actual perf/vero/bus/proto/etched board's layout. It also gives you something to write notes on (date everything!) about tweaks and substitutions and what-have-you and file it away when you're done. That will prove very valuable later on, I promise.

[ElectricDruid]

The IC on the right of your photo has the power rails reversed. Unless the chip is in upside-down, in which case you have other problems to contend with.

Your voltages seem to suggest that *both* chips have power reversed, but I don't see that on the breadboard, so something is *very* wrong.

For a start, make sure you always place ICs with the notch pointing left and power them up accordingly. Like all rules, you can break this one, but doing so before you're absolutely sure of what you're doing is asking for trouble. Stick to a standard.

[audiobalm]

The IC on the right of your photo has the power rails reversed. Unless the chip is in upside-down, in which case you have other problems to contend with.

Your voltages seem to suggest that *both* chips have power reversed, but I don't see that on the breadboard, so something is *very* wrong.

For a start, make sure you always place ICs with the notch pointing left and power them up accordingly. Like all rules, you can break this one, but doing so before you're absolutely sure of what you're doing is asking for trouble. Stick to a standard.

Thanks for your advice. The IC on the Right is reversed but it should still line up to the schematic correctly. I've got power rails on the top and bottom of the board and have grounded 4 and 8 where they need. It just made more sense for the layout (somehow) to have this one reversed so that the dot faced to the right otherwise there would have been too much overlapping of components. But having said all that the wiring should be accurate despite it being reversed

[duck_arse]

doesn't matter which way you plug them in, but you do need to pin-number them correkt every time.

your 0V on the pin 4's doesn't show 0V. this might indicate a problem.

[GibsonGM]

I'd consider building the LFO on breadboard, make sure it works...then put it on a PCB (even perfboard; leave room for the rest)...line out the LFO to the now-breadboarded filter sections and see how that goes. Break it into sections.   I personally feel you're approaching terminal component count for someone fairly new   Yes, VERY ambitious, ha ha.

I did this with my perfboard Easyvibe way back when.  Bonus: my LFO is on a tiny daughter board 2" away from anything and well-filtered, so it's quiet as heck.  Just a thought.

[audiobalm]

I'd consider building the LFO on breadboard, make sure it works...then put it on a PCB (even perfboard; leave room for the rest)...line out the LFO to the now-breadboarded filter sections and see how that goes. Break it into sections.   I personally feel you're approaching terminal component count for someone fairly new   Yes, VERY ambitious, ha ha.

I did this with my perfboard Easyvibe way back when.  Bonus: my LFO is on a tiny daughter board 2" away from anything and well-filtered, so it's quiet as heck.  Just a thought.

That's a really great idea. I have a small board nearby that I can build the LFO on separately and like you said "wire it in" the trouble is because it's one half of the TL072 it can't be separated as such but I'll see what's possible

How do I test to make sure that is working?

I've decided to start again, with a different idea in mind. Here's the first stage. I've laid down the ICs JFETS first and created a direct path from start to finish and will  everything around that. Let's see how we get on

[GibsonGM]

If you can lay your hands on 2 TL071s, you can use 1 for the LFO, and the other for one of the opamps in the rest of the circuit.   "Cheaper" op amps can work for the LFO, too...4558 and so on.

To test it, I assume you can attach an LED to the output (w/resistor), or just use your DMM to see the voltage go up & down...actually, an analog meter would show that well (needle movement).    There is some reading you can do:  https://www.diystompboxes.com/smfforum/index.php?topic=82069.0
Others have done it....they probably mention how to test it 'right', too! 

[antonis]

actually, an analog meter would show that well (needle movement).

Only for a very Low FO..
(from 24 Hz and above, "afterimage" (motion after-effect) makes needle to appear motionless..)

[audiobalm]

Ok folks, so the last breadboard build didn't work either. I definitely got into a rats nest of connections and decided to scrap and start again.

I've decided rather than using 2 TL072, to 4 TL071 just to space things out a bit. I felt I kept running out of room to manoeuvre.

In the attached picture I have a couple questions:

1. (Orange) are the pinout numbers correct for the TL071 in all 4 uses?
2. (Blue) is this the LFO and can I set it up somewhere completely different on the board and simply patch it in via the 3M9 resistor?
3. (Red) I'm finding this rail of attachments difficult to recreate on a breadboard. Is there a secret to recreating something like this, a bar that so many things attach to on a breadboard? Would be useful to have something like this like the positive or negative supply that run in this direction, horizontal instead of vertical
4. (Green) with this capacitor, can I just plug this in to the power rails right next to the power supply and be done with it? Meaning + to + of capacitor and - to - of capacitor.

Thanks for the advice!!
I'll breadboard this damn thing yet!

David

[deadastronaut]

just in case, are your breadboard rails ''split'' in the middle. ?

e.g do you have continuity from one end to the other??? on both + / - rails.

some breadboards are split. some aren't...

[Kevin Mitchell]

Man, I feel your pain. I've successfully breadboarded the latest Microsynth to correct the schematic floating around. Took 4 boards.

The rails for your breadboards don't seem to split. The blue and red lines would show that.

Add a ~6.8K resistor and LED from the LFO single (+ side of the 10uF cap). Better than trusting voltage swings on a meter IMO. Though an oscilloscope would be best.

LFO output to 6.8K to LED anode, LED cathode to GND.

[garcho]

Generally, regarding spacing things out, you want compact as long as nothing is bent out of shape. The more wiring, the more chances for mistakes and breadboard gremlins.

are the pinout numbers correct for the TL071 in all 4 uses?

Yes. It's always best to double check with datasheets, but you can reliably assume single op amp DIP packages have that pinout. The same goes for the dual op amp DIP package (different than the single op amp package, but similar to each other). Still an assumption, but a good one.

is this the LFO and can I set it up somewhere completely different on the board and simply patch it in via the 3M9 resistor?

As long as it shares a ground, yes. Generally, it's a good idea to keep everything on the same power supply, especially if you plan on boxing it up that way. There is a strategy to layout in terms of how grounds (0V reference points) find their way back to the power supply. It's important, but worry about it later.

I'm finding this rail of attachments difficult to recreate on a breadboard. Is there a secret to recreating something like this, a bar that so many things attach to on a breadboard? Would be useful to have something like this like the positive or negative supply that run in this direction, horizontal instead of vertical

I'm a little confused by this question. The long red and blue lines are for +V and -V, or 0V. Sorry if that's obvious to you but there's a lot of true beginners here. Do you have the +9V on the hot rail of the breadboard? If you do, just have the +9V go to a regular small bus (one of the many short rails) and use that 10k resistor to go to the hot rail instead, since that's what all that stuff is connected to.

with this capacitor, can I just plug this in to the power rails right next to the power supply and be done with it? Meaning + to + of capacitor and - to - of capacitor.

Yes, that's the right way to do it.

I'll breadboard this damn thing yet!

You're damn right, you will!

[audiobalm]

I'm finding this rail of attachments difficult to recreate on a breadboard. Is there a secret to recreating something like this, a bar that so many things attach to on a breadboard? Would be useful to have something like this like the positive or negative supply that run in this direction, horizontal instead of vertical

I'm a little confused by this question. The long red and blue lines are for +V and -V, or 0V. Sorry if that's obvious to you but there's a lot of true beginners here. Do you have the +9V on the hot rail of the breadboard? If you do, just have the +9V go to a regular small bus (one of the many short rails) and use that 10k resistor to go to the hot rail instead, since that's what all that stuff is connected to.

Hahah thanks for the great organised response and encouragement.

I suppose what I'm asking by the red box question is as follows. Yes I do know that red is +V and black is -V.. but I don't think that means I can necessarily connect all those components on the +V rail simply to positive and be done with it can I? That would be amazing however I think (though I'm not sure) that the zener diode at the end of the chain creates a Vref that is different, and the current voltage for all these components. Electrosmash shows Vref to be 5.1V for the phase 90, not sure if it's the same here.

What I might do is since all the power rails are split I might use another one specifically for that Vref voltage and connect them all if what I've written above is true

[garcho]

but I don't think that means I can necessarily connect all those components on the +V rail simply to positive and be done with it can I?

Why would you think that? Of course you can, and must, if you want this to work. If components are connected by a line on a schematic, then they're physically connected by a wire or trace (or "rail").