- This topic has 2 replies, 2 voices, and was last updated 2 years, 11 months ago by Anonymous.
January 23, 2019 at 6:12 pm #3956AnonymousInactive
I’m new here and while I know which end of a soldering Iron is dangerous (hint: it’s the held by the operator), I’m pretty much self taught and have many holes in my knowledge base, some known and some not.
I was perusing through the shop and found the page for “3PDT Wiring Boards-Perfect for Combo Builds”. In the list of features, it’s stated, “Eliminates Need for Star Grounding”. I’ve built a couple of small general purpose, low power valve amplifiers and Star Grounding was an essential technique in creating an amp that did not have an unignorable amount of static/hiss in the output signal. I recall something about there being enough resistance (the circuits involved were all DC, being after the filter caps and before the inverter stage) in the individual ground paths that this resistance needed to be taken into account. The amount cumulatively was interfering with the impedance loading at the input stage of the amp. The preceding was explained to me and it was suggested that I utilize a Star Ground for the reference ground on the chassis. I did and the amp performed swimmingly well.
That’s my understanding of what a Star Ground is and why it’s beneficial, at least in the context where the device in question is manipulating potentials in the hundreds of volts.
So why would such a grounding technique not be used in a pedal or when there are many pedals running simultaneously on a board? Is it not necessary? Is it deleterious to the integrity of the signal?
Oh, I’m also a guitarist and bassist going on close to 40 years now and have experienced just about every musical gigging misadventure that could involve electricity….especially the what felt like the 350 volts jumping from my microphone to my upper lip and then emerging out of my right hand into the strings on my Stratocaster is my least favorite. I have a special place in my soul for anything related to proper and effective grounding whatever the issue may be. 😆January 23, 2019 at 9:37 pm #3958BarryKeymaster
Hello and welcome,
Pedal building and amps are two different things as you indicated. I understand your question. IMHO, in something as small as a pedal, star grounding or loops don’t matter much. Also consider many builders new to the hobby and need a simple method (like pads) to complete their projects. With that:
We use the circuit board ground plane which contains a good deal of copper as a grounding point as opposed to a jack which could come loose, a problem very common to pedal building and one to avoid among other scenarios I might think of. Likewise our method uses both jacks avoiding a potential stage disaster since there is a backup.
Other benefits are that we can easily wire 2, 3, 5 or 10 circuits inside a single enclosure and I can testify traveling to Colorado seeing the one below. No rats nest, grounding issues or noise to be found.
All of that said since you have your way of doing things we do not discourage it but what we do is offer more than one way of wiring all of our boards together which will suit multiple build styles as opposed to just one way and looking back over the past 10 years of GPCB “not star grounding” in the traditional sense has never been an issue.
The unique T&S wiring scheme that is available on all of our boards was created by Tonmann when we started GuitarPCB and he is a vetted veteran of everything electronics as well as having a lot of practical experience working for some big names back in the 70’s. He also repairs and designs amplifiers.
I hope that helps explain our position on wiring.January 26, 2019 at 6:59 pm #3987AnonymousInactive
Thank you for the thoughtful, informative reply. Thank you also for the links. I’m here to learn and start filling in those holes I mentioned in my previous post. I actually built those amps (no PCB-all point to point wiring) before I ever attempted a pedal, which seems backwards compared to most of the DIY amp and/or pedal builders with whom I’ve dialogued. I do have my ways of doing things that are a result of trial and error in amp building; these methods may be inferior when it comes to pedal builds. So I’m open to learning different ways to accomplish a solid, dependable pedal build.
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