Hello,
Am new to it all and have building on perfboard. I always run into trouble when it comes to connecting all the grounds. What I've been doing is taking a piece of solid copper wire across the whole width of the bottom of the perfboard and soldering each lead that needs to be grounded to it, including the negative battery wire(if it's grounded as well), and also connecting a wire to it that goes to the sleeve of the output. But it ends up being a mess really and I run into issues and sometimes barely have enough room for everything to fit there. I read about the "star" grounding and assumed that was just twisting everything together and solering it?not sure but the grounding has been the one thing that makes my perfs look like a mess at the bottom. Just curious of the methods others use.
Thanks,
Brian
Quote from: janus on February 22, 2006, 02:40:51 PM
I read about the "star" grounding and assumed that was just twisting everything together and solering it?
That would give you star grounding, yes. With star grounding, you're eliminating the possibility of ground loops by having all ground connections come to a single point. I believe "tree" grounding also counts as star grounding, as long as there are no ground loops. That is, you can have intermediate branch points, before you come to the center of the "star."
I usually run some tinned bare wire around the perimiter of three sides of the board adn tack it down every third hole or so.. I can then ground things as close to thier physical location on the board as possible. ( ie Input jack on one side, ouput jack on the other, gain pot, volume pot etc..)
Scott
at first, i ran all grounds to the board. you see that style at generalguitargadgets.com and a lot of folks use it happily. i now take a different approach that has worked perfectly so far. i treat the ground lug on the output jack as the ultimate ground for the circuit and take a "tree" approach. my goal is to keep wires short and few in number, while avoiding ground loops.
i usually use the metal switchcraft jacks without insulating washers. so the aluminum enclosure is grounded through the ground for the output. and the input jack ground is grounded through the enclosure. this removes two wires from a generalguitargadgets-type layout. some people prefer to run wires from the ground lugs of the jacks to the board. you must do this if you are using plastic jacks. with uninsulated metal jacks, such wires technically create ground loops but these loops seem to be irrelevant.
if a switch needs a ground, i run that to the output ground lug if it's closer than the circuit board (which it usually is). i also run the power ground wire directly to the output jack ground lug and i connect the ground net of the pcb or perfboard to that same lug. so i have (at least) three wires going to the output ground lug. this will cut down on the number of wires that you are connecting to the pcb and help tidy things up a bit.
i connect pot grounds to the circuit board ground net. that's typical. the pots are usually close to the board. nice layouts make this particularly neat. for example, see a tonepad.com layout. you do not need to twist all the wires together. i place them side-by-side in a row of holes on the perfboard and solder them together there. the layout of the circuit determines where the ground net/rail will go on the perfboard for grounding the components. around the edges is common, even for etched pcbs. putting it there at the beginning seems like a fine idea. i build sequentially from input to output and design my layout before i start building, so my ground net gets built up just like all the other nets on the circuit board.
when i first started making pedals, this whole grounding thing confused me. so i thought i'd share and i hope this helps. search the forum and you will find plenty of discussion of this topic.
Everything goes to the ground line on the board and from the sleeve tab on the nylon jacks I use, I run a wire (or as I've seen, a capacitor) to a solder lug riveted to the metal enclosure.
"tree" grounding will free you of ground loops..... but what it won't do, is guard against the problem of noise pickup from high current transients. If you have say a 555 timer putting gurrent pulses into a tree that is partly shared with a sensitive amplifier, then the amp input will see the pulse as an input & there it is!!
I don't do perf, but if I did, I'd run fat insulated solid wires from various ground points, to the ground at the power supply. Normally, for our stuff, it doesn't matter..... until it does :icon_mad:
Quote from: Paul Perry (Frostwave) on February 22, 2006, 09:17:43 PM
"tree" grounding will free you of ground loops..... but what it won't do, is guard against the problem of noise pickup from high current transients. If you have say a 555 timer putting gurrent pulses into a tree that is partly shared with a sensitive amplifier, then the amp input will see the pulse as an input & there it is!!
I don't do perf, but if I did, I'd run fat insulated solid wires from various ground points, to the ground at the power supply. Normally, for our stuff, it doesn't matter..... until it does :icon_mad:
hey paul, thanks for joining in. :icon_biggrin:
the ground in a every stompbox that i have seen goes through the output cable. any star ground system must use that ground as the center of the star, right? so why would you go to the ground of a battery, or an transformer-isolated power supply? :icon_confused:
Guys, I did the offboard wiring from Tonepad TS clone project. why is the Tonepad Millenium off board wiring the STAR GROUND is the input jack sleeve or shield not the output jack shield? Is there a diffirence co'z my project TS clone is noiser than the original I bought? I'm using the input jack as the star ground but not grounded on the stainless enclosure neither the output jack, is this the cause of the noise? Also when I touch the enclosure or the jack the noise is little bit reduce like my LED also become little dim that you may not notice but only if you observed. By the way I built the project so that I could fine a cure to the noise of the original TS9 I bought but the clone one is more noisy. I think this grounding might be the cause. Thanks to all guys. Anyone?
I can't comment on the TS clone, but I use the input jack for the ground connection if I use only one of the jacks grounds.
I began to do that when I saw that Boss was doing that... If it's good for them, it's good enough for me. Another reason is that the input jack is also used for the battery connection, so I find it better to connect the board ground to that jack ground also.
Like this
(http://www.gtechblues.com/images/Boss.jpg)
But the contact between the jacks and the metal enclosure must be good for it to work correctly.
Gilles
Quote from: rogeryu_ph on November 05, 2006, 09:24:00 PM
Guys, I did the offboard wiring from Tonepad TS clone project. why is the Tonepad Millenium off board wiring the STAR GROUND is the input jack sleeve or shield not the output jack shield? Is there a diffirence co'z my project TS clone is noiser than the original I bought? I'm using the input jack as the star ground but not grounded on the stainless enclosure neither the output jack, is this the cause of the noise? Also when I touch the enclosure or the jack the noise is little bit reduce like my LED also become little dim that you may not notice but only if you observed. By the way I built the project so that I could fine a cure to the noise of the original TS9 I bought but the clone one is more noisy. I think this grounding might be the cause. Thanks to all guys. Anyone?
the route to ground for a stompbox is through the output jack. as Gilles notes, you can use the
input jack as long as both input and output jacks are not insulated from a conductive (metal) enclosure.
there are very few projects that require insulation of a jack, and certainly the tubescreamer is not
one of them.
improper grounding can be a source of noise. and if you touch the enclosure and it changes the
hum that also suggests improper grounding. so it sounds to me like you are on the right track! :icon_biggrin:
--gm
I use "Tree grounding" from input jack, with a nice serrated washer around the input jack collar.
This should ensure that the connection to the "box" is permanent.
My vero builds normally have one continuous ground strip, which connects to the input/pots/power jack
etc - unless pwr is switched by the input jack ring.
Seems to work great for me like this EVEN in a plastic box !
MM.
Quote from: MartyMart on November 06, 2006, 03:34:28 AM
I use "Tree grounding" from input jack, with a nice serrated washer around the input jack collar.
This should ensure that the connection to the "box" is permanent.
My vero builds normally have one continuous ground strip, which connects to the input/pots/power jack
etc - unless pwr is switched by the input jack ring.
Seems to work great for me like this EVEN in a plastic box !
MM.
so marty, how is your output jack ground hooked up? by wire to the input jack? or via the
board's ground rail? either way, your ultimate ground for the box is still the output jack, right?
i did not mean to give the impression that you cannot use the input jack ground with a plastic
enclosure. :icon_wink: it's good to clarify.
you can always use the input jack lug to collect grounds, as long as that also connects to the
output jack ground. or you can just go straight to the output jack. i prefer the latter because
it seems more in the spirit of tree or star grounding.
all the same, in my reading of this forum ground loops are rarely an issue in stompboxes.
forumites describe setups with loops in them all the time. for example, lots of folks seem to use
an aluminum enclosure, uninsulated jacks, and wire running from both jacks to the ground rail
on the circuit board without apparent problems. still, it's good practice to avoid ground loops.
i feel like a bit of a broken record about this. :icon_redface: the whole grounding issue was confusing to me
when i started this hobby and the issue keeps coming up for others. so it seems helpful, if
tedious, :icon_confused: to keep repeating this mantra: the output jack is the ultimate ground
for the stompbox circuit.
all the best, gm :icon_biggrin:
I prefer to not use the input jacks as a ground point, as the input section is most sensitive to hums/noise. It has to carry a good clean signal to the first stage. Good input=nice output ;D
Quote from: gaussmarkov on November 06, 2006, 11:56:18 AM
so marty, how is your output jack ground hooked up? by wire to the input jack? or via the
board's ground rail? either way, your ultimate ground for the box is still the output jack, right?
Input jack ground is direct wire to output jack ground.
Input jack ground also to board ground.
All other pots etc use the same board ground.
In/Out jacks have serrated washers to box ( if metal )
Never had a single "hum" problem, even in plastic box's
MM.
Quote from: gaussmarkov on February 22, 2006, 04:08:26 PM
at first, i ran all grounds to the board. you see that style at generalguitargadgets.com and a lot of folks use it happily. i now take a different approach that has worked perfectly so far. i treat the ground lug on the output jack as the ultimate ground for the circuit and take a "tree" approach. my goal is to keep wires short and few in number, while avoiding ground loops.
i usually use the metal switchcraft jacks without insulating washers. so the aluminum enclosure is grounded through the ground for the output. and the input jack ground is grounded through the enclosure. this removes two wires from a generalguitargadgets-type layout. some people prefer to run wires from the ground lugs of the jacks to the board. you must do this if you are using plastic jacks. with uninsulated metal jacks, such wires technically create ground loops but these loops seem to be irrelevant.
if a switch needs a ground, i run that to the output ground lug if it's closer than the circuit board (which it usually is). i also run the power ground wire directly to the output jack ground lug and i connect the ground net of the pcb or perfboard to that same lug. so i have (at least) three wires going to the output ground lug. this will cut down on the number of wires that you are connecting to the pcb and help tidy things up a bit.
i connect pot grounds to the circuit board ground net. that's typical. the pots are usually close to the board. nice layouts make this particularly neat. for example, see a tonepad.com layout. you do not need to twist all the wires together. i place them side-by-side in a row of holes on the perfboard and solder them together there. the layout of the circuit determines where the ground net/rail will go on the perfboard for grounding the components. around the edges is common, even for etched pcbs. putting it there at the beginning seems like a fine idea. i build sequentially from input to output and design my layout before i start building, so my ground net gets built up just like all the other nets on the circuit board.
when i first started making pedals, this whole grounding thing confused me. so i thought i'd share and i hope this helps. search the forum and you will find plenty of discussion of this topic.
This is exactly what I do as well ;)
Janus,
Nothing wrong with the way you do yours. That's the way I've done it for countless circuits. The only difference is I use the resistor/component leads instead of a wire tacked on at the end.
I also just use the component leads, then ground to output. The exception being if I'm just testing a circuit, then I tie the output ground to the input. I don't ground the input jack directly to the board. Never had a loop problem yet...
Time for a question from the misinformed fool:
What is a ground loop? Is this where various parts of a circuit go to ground, but not all the different grounds are connected to one another?
Thanks!
If you were to draw a ground loop on a schematic it would look like input-board-output-input. It completes a circle, not necessary for grounding. Better to have the ground all going in one direction... like a drain... Ground loops have a way of picking up 60 cycle hum. If you ever saw a ground lift switch on a power amp that's what it's for- to cut the circle that a hum is riding, not eliminate the ground entirely. It's assuming you are also grounded thru chassis, or possibly input. Generally ground loops aren't much of a problem on dc powered circuits, but you still don't need or want one.
I just used star grounding to the input jack (per Tonepad's wiring layouts) for my first complete project, a Fetzer Drive. No noise issues, but man, it was no fun trying to get all of those ground wires twisted together and securely attached to the jack. :icon_frown:
Is there a secret of the masters that I need to learn?
Ok, I made a couple little drawings to help explain here...
1. The ground loop. Here we have everything connected to the pcb. Note that the input and output jacks are connected thru the chassis(the aluminum enclosure itself), and also thru the pcb.
(http://i86.photobucket.com/albums/k99/jprak1/loop.jpg)
2. No ground loop. Here the input jack is grounded thru the chassis alone, eliminating the ground loop.
(http://i86.photobucket.com/albums/k99/jprak1/noloop.jpg)
If you start working on AC circuits this becomes much more important.
Thanks Gaussmarkov to your reply.
Meanderthal, as per your description of the ground loop and no ground loop what then the star grounding used in the Tonepad project call? Is it ground loop? If your not familiar to the Tonepad project, the project uses the input jack as the star ground.. This technically I don't know if it is a ground loop or no ground loop. I only use wire tapped from input jack connect to output jack and both jack were isolated from the chassis. Is this ok?. Also, can we use output jack as the star grounding? Co'z some say can. Thanks in advance.
Yes, isolated jacks are ok, and no, star grounding is not going to create a ground loop, rather it's going way out of the way to avoid one! Keep in mind, though, that if your jacks are isolated you should connect ground to chassis at some point so you have shielding, which is much more important than worrying about a ground loop in a stomp box! In fact, if you have isolated jacks, you shouldn't have a ground loop anyway at all unless you have a wacky layout or something...
Thanks, Meanderthal. My jack are isolated co'z i'm using temporary plastic box as the casing, now as you said I should connect the ground at (chassis) or some point so I could have shielding, but mine is plastic box so where should I connect the ground? Thanks again....
Hmmm... in that case you'd have to line the enclosure(lid and all) with aluminum or copper foil. The idea is to surround the circuit with ground, blocking RF interference. You can't solder to aluminum though, so you'd have to attach ground to it with a screw or something.
But, if you build it and it dosen't pick up weird buzzes, hums, or radio signals, don't worry about it, especially since the plastic enclosure is temporary. Some circuits seem to be pretty quiet without shielding for whatever reason, and others are like radio recievers, especially high gain distortions. However, if the circuit actually calls for star grounding it must be pretty sensitive, so ya better shield it!
Meanderthal, Thanks.. So far in the plastic box no weird frequencies or hum... But time when I got a die cast casing should I ground the input or output jack with the case? Again thanks
If they're metal jacks they will be grounded to the enclosure just by being attached to it.
Thanks you so much Meanderthal.... :icon_biggrin:
The funny thing is, I have a bunch of those Dano plastic enclosure pedals and none of them pick up stray RF, not even the Fab Metal. Maybe the tiny SMD components don't have enough surface area or something... But for that matter the only noise that bugs me about Arion effects is hiss...
i run a peice of copper wire along the bottom of the board,
then connect that to the input jacks ground, then run any off board grounds to the jacks as well (input or output depanding on which is closer)