My SSTC with Mads' Audio Interrupter and Guitar, and first-time PCB etching

[nabzim]

Mads' told me to post this here, after I had shown him my video:

Well I finally had some time to make a post about it! (I also had since then, a crap-ton of views on the video)
So I tried building steve ward's sstc a while ago, and it took me a long time to get it to work; i had never realized that I needed to ground all the unused inputs on the 74hc14, and that caused the feedback loop to never work and I only got the output of the 555 to be switching the bridge, so never more than a half-inch of spark. But After i fixed that I have gotten a max of 13-14 inch sparks with extra top-load and fat pulse-widths.
I had really wanted some form of musical-manipulation over my tesla coil, so I decided to try Mads' design, afterall, it did seem from his videos to work pretty damn well And then I thought, I may as well go all-out and try to learn PCB-etching at the same time!
Here I have an album with pictures and videos of building and experimentation: https://goo.gl/photos/y9NqKmgMKqsAPUsx5
Its ordered chronologically, and there are pics of my first GDT attempts (before I figured out that wasn't the problem) before I actually bought one. I tried to scavenge for some parts and ended up buying most components, but the best recycled-part are the MOSFETS which came out of a big flat-screen TV that had been used by some folks as a shooting target around the outskirts of Calico ghost town. Luckily, there were quite a few mosfets that didn't have bullet-holes through them! And they have higher voltage and current ratings than irfp260's!

Anyways I also have here an album that shows some of my steps to making the audio-interrupter, my first PCB: https://goo.gl/photos/2BLhveGQihzkcd4f6
You can see I used a method that I made-up, that I call the "glue it to a stick" method. I thought of this as an answer to getting it done quickly and evenly, after seeing several different methods on youtube, and I didnt want to just let it sit for a long time, or have a setup that blows air bubbles through the solution, or wear gloves to rub it against a sponge by hand, so basically I can have a constantly mixing solution as well as not getting my hands all acidy and still being able to rub it on a sponge. I guess it would only work for single-sided PCB this way though...
So, I knew the audio input was able to be just regular audio, not some special-magical MIDI, so what not better to try, than my guitar as the input. Turns out it does work great!
Thanks Mads!
Just wanted to share with everyone on the forum, and let me know what you think or if you have questions

[CCX191]

Woah that's pretty neat, thanks for sharing it here! I probably should try PCB-etching when I get some free time.

I saw that you've mentioned that the unused pins of the 74hc14 has to be grounded(negative terminal)??

I've been struggling to get my SSTC to run for about a month already

[nabzim]

Woah that's pretty neat, thanks for sharing it here! I probably should try PCB-etching when I get some free time.

I saw that you've mentioned that the unused pins of the 74hc14 has to be grounded(negative terminal)??

I've been struggling to get my SSTC to run for about a month already

Yes, all of the unused inputs, not the outputs, on the inverting logic-gate IC, I grounded to the negative of the logic power-supply, and then it started working for me.
I had tried so many things to remove possible sources of the problem from the circuit, until I read, in tiny-print at the bottom of the page in a Texas Instruments datasheet, that the pins need to be grounded for proper functioning.
Does your coil have any sort of small-spark being output, when you try to test it?

[CCX191]

Yes indeed! I have been getting extremely small sparks just like a van de graaff, about 1.5cm max  It does not occur naturally but it needs like a metal pole or a fluorescent lamp close to it to draw such small sparks. Perhaps I should look up on the datasheet. By unused pins you meant pin 5,6,8,9,10,11,12 and 13?

[nabzim]

Yes indeed! I have been getting extremely small sparks just like a van de graaff, about 1.5cm max  It does not occur naturally but it needs like a metal pole or a fluorescent lamp close to it to draw such small sparks. Perhaps I should look up on the datasheet. By unused pins you meant pin 5,6,8,9,10,11,12 and 13?

not all of the pins, just the inputs. so like in the schematic symbol, your signal is entering one side (input) and then your signal is exiting the other side (output). pins 1 and 2 make up a single "inverter-gate" on the "hex-inverter" IC (just means six inverting logic-gates). Pin 1 is an input and pin 2 is the output of that single inverting-logic-gate, then 3+ 4 is the next gate after that, and so on, etc.
So, just ground all the Inputs and not the Outputs for each gate. Definitely give the datasheet a look.

as for the little sparks you speak of, what sort of sound do they make? does it make a 555-timer sound? (like a square-wave sound)

...van de graaff sparks can be big too, if you really want them to be

[Mads Barnkob]

Hey Nabzim, welcome to the forum

You really ended up with a good performing coil despite much bird nest soldering, but that just shows that beauty is not always equal to great performance.

In electronics, it is common knowledge that no unused inputs on TTL/CMOS ICs should be left floating, simply because the unknown state can drive it into high frequency oscillations from nearby noise, it can short out the power rails of the IC for short periods and disturb the whole ICs operation and so on, for a longer explanation see here: http://www.piclist.com/techref/logic/xtrapins.htm

If it is not already mentioned on my website, I will add a note or trouble shooting chapter where it is mentioned.

CCX191, if you want to etch PCBs yourself, did you see my simple guide for great results? https://highvoltageforum.net/index.php?topic=59.0

[nabzim]

Hey Nabzim, welcome to the forum

You really ended up with a good performing coil despite much bird nest soldering, but that just shows that beauty is not always equal to great performance.

In electronics, it is common knowledge that no unused inputs on TTL/CMOS ICs should be left floating, simply because the unknown state can drive it into high frequency oscillations from nearby noise, it can short out the power rails of the IC for short periods and disturb the whole ICs operation and so on, for a longer explanation see here: http://www.piclist.com/techref/logic/xtrapins.htm

If it is not already mentioned on my website, I will add a note or trouble shooting chapter where it is mentioned.

CCX191, if you want to etch PCBs yourself, did you see my simple guide for great results? https://highvoltageforum.net/index.php?topic=59.0

Thanks! Yeah it never occurred to me because I have no formal education of electronics ( I'm going to be taking the physics class on electromagnetism this fall, but I am majoring in Chemistry). But hey, y'know, its just one of the many little things you learn about building electronics, like decoupling-caps and filter caps or other trivial-but-important components in circuits.

[CCX191]

Yes indeed! I have been getting extremely small sparks just like a van de graaff, about 1.5cm max  It does not occur naturally but it needs like a metal pole or a fluorescent lamp close to it to draw such small sparks. Perhaps I should look up on the datasheet. By unused pins you meant pin 5,6,8,9,10,11,12 and 13?

not all of the pins, just the inputs. so like in the schematic symbol, your signal is entering one side (input) and then your signal is exiting the other side (output). pins 1 and 2 make up a single "inverter-gate" on the "hex-inverter" IC (just means six inverting logic-gates). Pin 1 is an input and pin 2 is the output of that single inverting-logic-gate, then 3+ 4 is the next gate after that, and so on, etc.
So, just ground all the Inputs and not the Outputs for each gate. Definitely give the datasheet a look.

as for the little sparks you speak of, what sort of sound do they make? does it make a 555-timer sound? (like a square-wave sound)

...van de graaff sparks can be big too, if you really want them to be

Ah. I see ... Just had the look at the data sheet I guess I understand it now. Thanks!

The sparks just turn on and off as to the 555 timer so I guess it's okay.

The sparks reminded me of the van de graaff generator I've built. So I guess it's like a referencing point sort of.

[futurist]

but I am majoring in Chemistry

Welcome colleague 

[nabzim]

but I am majoring in Chemistry

Welcome colleague 

Thanks! What kind of chemistry do you work in?

[futurist]

Organic 

[nabzim]

Organic 

Whoah thats awesome! I'm actually, an SI-leader for organic chemistry at my school...
(SI stands for supplemental instruction )