I may have bitten off more than I could chew here, but I had set out to build a synth multi-fx unit all in one box. Chorus-Flanger-Delay-Reverb. I had a really nice Hammond wood-sided 14" enclosure, and set off to making Veroboards of some of my favorite analogue guitar effects that I loved using on my synthesizers over time.
I did read a bit about line levels as it relates to guitars and synths, but elected to be ok if it’s a little noisy, as my guitar rigs I used with synths always were anyways. I read about how to do the wiring since I’ve only ever done single modules and effects.
So I built 3 9v effects, a chorus, reverb, and delay. I was making an A/DA 18v flanger clone anyways already so I made that the 4th effect to go in the box. Knowing at some point I’d have to put in two power jacks, use a 9v and 18v power supply, unless I figured out some other way.
I’m waiting for some components to arrive and decided I would address this now in the event I can avoid using 2 power supplies with a clever daughterboard or some such solution. I have seen a “power pump” if i recall correctly. It looked like it used audio jacks and a simple circuit to send 17v to the flanger circuit from the 9v wire.
I am wondering if I can apply this to my internal wiring of this multi-fx unit. I had already wired all the LEDs and switches for a previous project, so I’m hoping I can keep the LED wiring all the same, and simply daisychain the 9v wires for my 3 9v effects, and run the flanger through some sort of daughterboard to the 9v.
Thoughts? Are there any obvious things I missed with this? There’s pleeeenty of space in the box for the components to be far apart from each other, and for any additions to be made.
Thanks for any help, y’all are truly the best.
Here’s the flanger I built:
Here are the other three 9v effects I’m putting in the box:
Nice work, and nothing that can’t be fixed! A less efficient approach is to use voltage regulators. Keep in mind that the flanger you’ve built only needs 15V, and that it already uses an onboard voltage regulator (LM7815) that requires (about) 18V to regulate that down to 15V. So you are already halfway there with this approach. I don’t know what power supply you have for the case/project, but you could use an 18V DC wallwart and wire it to the Flanger which will regulate it down to the 15V needed, and, in parallel, wire it to an LM7809 regulator which will feed the rest of the effects. You can find a verified stripboard design for the LM7809 to regulate 12~18V down to 9V in this forum. Make sure to check whether the wallwart is rated for the current required by all the effects combined. [edit: typos]
Thanks so much! And thanks for the big wave of relief you and Shedsynth have provided.
So, this question is more what I feared. I was hoping to run all this off a standard 1-spot 9v center-negative power supply. I made a little ground daughterboard so I wouldn’t have messy ground wiring everywhere. From the reading I did, it seemed like this wasn’t going to be an issue at all, but when you suggested a wallwart I realized I may be understanding even less.
Power supplies have been really daunting to me, and why I haven’t really progressed in my synth building. It isn’t because the process scares me so much, but it is my sheer lack of understanding of what is happening and how to apply certain principles to my builds.
I would almost certainly go for @ShedSynth’s idea, but how do I specifically apply that? I would assume I would be using a step-up converter, wired from the 9v leads, to the step-up converter, (thank you for explaining what that LM7815 is doing there on the flanger, I feel like I understand a little bit more now just from that), and then to the flanger at 18v. I’m assuming I can ground that converter and flanger with everything else and it will still function in the stomp-switch signal flow, because I am using tagboardeffects LED/switch wiring method. If I have all that backwards and should be using the step-down, I see how that could work too, which is precisely why I need your help in the first place.
Pedals often use a charge pump circuit, using an IC like the TC1044SCPA,
to get 18v out of a 9v supply. See any Klon Centaur clone circuit as an example.
Is a charge pump circuit pretty synonymous with the step-up converter mentioned above? I have seen the charge pump idea before for the Centaur (never built one) and it seemed to always use audio jacks, but I guess what I’m curious about is how installing something like that, assuming it’s the same as the step-up converter, would go with the 3 other effects. I guess where I’m lost is the physical application of this charge pump/step-up converter in this particular instance.
I know how to measure current draw with my multimeter when a pedal is plugged in, for troubleshooting purposes. Should I be calculating current draw beforehand unless I’m putting like, 20 modules on one power supply? If so, how does one do that if all you have is a veroboard layout? I don’t doubt it’s glaringly obvious, but google is letting me down right now and I know you all are EE geniuses!
The other three just tap directly into the 9v supply, and the other is the only one that uses the 18v. Technically, the charge pump converts the 9v to -9v, then you combine those to get to 18v.
Here is the example circuit from the pedalpcb klone.
Ah, understood. And is this method preferable to the step-up converter? I’m happy to make a power daughterboard of this circuit, I have everything but the TC1044 in my warchest. But $15 for 10 step-up converters is pretty cool too, considering the hours I have in this build.
I somehow missed your link on the bottom. That SheDX7 is awesome! Also, I’m wondering if you would be willing to help me with the application of the step-up converter, which is what I assume I’d need? I have never built anything remotely close to this, but it looks like you have a heat sink and some other capacitors on there as well. I was thinking it was as simple as connecting the 9v and ground and then out to the 18v for my particular application. I am at a loss a bit.
I think it makes the most sense to me, just due to having the verified layout from @K.ostas, to build the regulator, use an 18v wallwart, and power the other 3 from the 9v regulator. The “suitable DC wall-wart” part has me thrown. I’m assuming you’re referring to current draw.
The last thing is, all my grounds can be connected together still right? Or do the 9v and 18v grounds need to be isolated? It is all currently grounded together.
Approach 1: Start with 9V which will be used for the three effects and step it up to 18V for the Flanger (which will is then regulated down to 15V within the veroboard).
-Approach 2: Do the opposite, start with 18V and give it to the Flanger (which again, regulates it to 15V) and then regulate this 18V down to 9V for the other effects.
Each approach has its pros and cons. They are sort of the opposite of each other as concepts, but in the end both get the job done. I have myself used both charge pumps and regulators according to what I found most convenient for each particular project. For instance, I found the charge pump approach most convenient for getting the -9V needed for those PNP germanium pedals.
On to your questions.
For approach 1 you have plenty of options. You can use a step-up converter module as linked above by Shedsynth, or you can make one using a charge pump (MAX1044 or ICL7660, they are equivalent) just like the stripboard design that you posted. Also, if you are looking for an even more affordable solution, you can configure a 555 timer as a charge pump (see this stripboard design). Some people have reported good results with the 555, others reported problems. Might worth a try (more so with the CMOS version of the 555 perhaps as suggested by this TI note?)
For approach 2 you just need a 7809 voltage regulator, but make sure to attach a heatsink to it. Unlike the 7815, it will dissipate much more heat.
In either approach you can connect all grounds together to a single point.
In either approach, you will need a wallwart, 9V for approach 1, or 18V for approach 2. You can check the current that each pedal needs using this list and choose the wallwart accordingly. You will need a wallwart anyway, most likely you have one already, or you can buy one cheaply. Make sure it is a DC output wallwart. Most likely you will need to modify the connector to make it center negative.
You managed to make the Flanger on stripboard which is 20 times more difficult than the power supply. You can do this!
Thank you so much for your very generous and helpful reply. I look forward to diving in more when I get home. I am grateful especially for the easy link to calculate the total current draw when all four are on, and I did get confused and mistyped, my wallwart is center positive.
I want to avoid the apparent noise of the step-up converter. Not sure if that applies here though.
Regarding approach 2, would something like this work? Or is it simply the 7809 voltage regulator all by itself with a heatsink on it? It seems like logical, bc it is fixed at 9v, but would I simply make a little 3-rail daughterboard with the regulator, heatsink, and follow pinout to take 18v into the regulator, and the out of the regulator is 9v? Seems like I have missed something.
KNACRO LM7809 + LM7909 Dual Voltage Regulator Three-Terminal Regulator Power Supply Module ±9V Dual Voltage Regulator with Rectifier Bridge(LM7809+LM7909 ±9V) https://a.co/d/9Ra2YBe
Thanks again, I’ll be on later to make a final decision on a plan and hopefully after much reading, order some parts!
Second thoughts: forget what I told you about using the 555 timer, it will give you only about 30mA and your flanger needs 150mA! It’s good for distortion pedals, but for a flanger… no.
The regulator that you listed should work but I’d say it’s a bit of an overkill as it also includes a 7909 for the -9V that you don’t need. Also, these SMD capacitors, might be noisier than the regular through hole ones? I don’t know.
The design I shared is from Jack Orman who knows this stuff. Every little bit there is for a reason. The LED for the load, the resistor to protect the LED, the capacitors for filtering, the diodes for protection (the capacitors will still provide some power even after you switch it off, you don’t want that to run backwards and damage the regulator), etc. The whole thing costs maybe 3.50 in components.
Ordering the parts this week to build the 9v regulator per your suggestion! Excited to share the results with you, hopefully soon! Thanks for giving me the pointers and taking the time. I am grateful this didn’t end up being an actual faux pas.
