Members sirhcathome Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by TheGZeus,OnFire Actually a FEW pedals are switched at the output. DSD-2, for example. Right but if you are going balanced you have to assume that you are going balanced from the guitar otherwise how would such an amp work for a guitar that is plugged straight in? Link to comment Share on other sites More sharing options...
Members zachary vex Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by dot-dot-dot You're absolutely right. What I was thinking (and I might be wrong) is this; take the hot and cold outputs of the coil as normal, but have another connection halfway through the windings, and connect that to ground. Then the two halves of coil will be picking up the same noise, but erm, no. Sorry, my idea doesn't work. Doh. The noise and signal will both be in-phase. Don't mind me. you have the right idea. to make the guitar system balanced using standard pickups, you'd need to take both ends of the coil and make them + and - signals within a shield, but simply connect the shield to the ground plane or any metal protective parts like the backs of the pots and metal protection sheets and the strings. the tone control and volume controls would have to be rewired to only have their connections at their lugs, not at the backs (shields) which would be grounded. the output would be TRS with balanced signal passing through the tip and ring, but from there, you'd be in serious trouble because all of the rest of the guitar system woudl be unbalanced, screwing up your plans! Link to comment Share on other sites More sharing options...
Members dot-dot-dot Posted January 2, 2006 Members Share Posted January 2, 2006 I was wondering if you could just unbalance at the amp's input, but I think it's just too complex. The real noise issue for guitars seems to be with single coil pickups. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted January 2, 2006 Members Share Posted January 2, 2006 i was wandering about how exactly the signal from a mic is balanced/unbalanced, the mic will put out a passive signal like a guitar pickup would (assuming a passive mic, not phantom powered) so i would guess there would be some way to do it with guitar too my thinking is you would need some way of interfacing it with normal gear, so a small pack in the guitar to balance it, then another box to unbalance it before the amp (connected to the amp with a normal patch lead) David Link to comment Share on other sites More sharing options...
Members TheGZeus,OnFire Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by Narcosynthesis my thinking is you would need some way of interfacing it with normal gear, so a small pack in the guitar to balance it, then another box to unbalance it before the amp (connected to the amp with a normal patch lead) David That's....pointless. Unbalancing removes anything you've gained.inless there's some transformer involved, and then you're introducing another chance for noise and moving it really close to your amp's power transformer.Op-amps can do it, too but then you've just buffered the signal, and you can do a better job of noise rejection by doing that farther from the amp. Balancing a guitar is a losing battle. I've looked into it. It's poinltess. The onle reason i'm putting that transformer in that bass is to avoid haulinga direct box to all gigs. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by TheGZeus,OnFire That's....pointless.Unbalancing removes anything you've gained.inless there's some transformer involved, and then you're introducing another chance for noise and moving it really close to your amp's power transformer.Op-amps can do it, too but then you've just buffered the signal, and you can do a better job of noise rejection by doing that farther from the amp.Balancing a guitar is a losing battle. I've looked into it.It's poinltess.The onle reason i'm putting that transformer in that bass is to avoid haulinga direct box to all gigs. i will admit to knowing virtually nothing about the topic, only that was something i had thought of after looking at balanced/unbalanced signals in mic cables and so on, so i still dont know what componentry or whatnot is involved my figuring was that balancing the cable over the long run cuts down on virtually all the noise, with only a short patch cable at the end being susceptable so picking up less noise if someone could direct me to somewhere explaining a bit more on balanced cabels and all that i would be most grateful, something i have been menaing to look at for ages i would guess there are enough reasons why it hasnt been done before, otherwise we would be using it now... David Link to comment Share on other sites More sharing options...
Members spentron Posted January 2, 2006 Members Share Posted January 2, 2006 There's only two cases where balanced are really important. One is traditional recording mic use. In this case one could be recording a quiet acoustic instrument at a distance. The rock case of close miking cranked amps and screaming singers results in levels 10000 times as high. Low impedance is still important though due to the immense cable runs often involved. The other case for balanced lines are anywhere a ground loop is involved because different boxes require seperate grounds. For example, between a grounded rack effect and your grounded guitar amp. I've learned you're better off with wall-wart supplied effects if you can. In the case of guitars, you're connecting to an electromagnetic pickup and no humbucking pickup is perfect. So that's your big limiting factor. Noise almost always can be clearly identified as being related to the pickup or hiss and microphonics due to the immense gain of distortion. Almost everyone prefers the sound of pickups in an almost unloaded condition -- your 1 megaohm or higher load impedance. Whereas mics are tuned for almost a "maximum power transfer" case of relatively equal source and load impedance, guitar relies on extremely unmatched impedances. The source impedance of a guitar pickup is far lower than 1M, and is the only thing that stops that 1M load impedance from being a huge noise generator. Tranformers are always a weak link in an audio signal train, and would be only worse interjected into the unusual signal coupling between a guitar pickup and its preamp. Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by dot-dot-dot pjp - I usually just use an op-amp follower, or have a look here - I've not tried it myself, but it's a well regarded design:http://www.till.com/articles/GuitarPreamp/index.html thanks for the link, mate!will check it shortly.peace Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by andreas Absolutely - the type of contact doesn't matter, as long as it can carry the three connections needed. So TRS 1/4" plugs will work just as fine as XLR's. However, a balanced guitar -> amp cable wouldn't remove hum from single-coil pickups, would it? After all, that hum is already there before the signal becomes balanced. AFAIK, balancing only cancels noise that is generated or picked up between the two balancing points (i.e. in the cable). Er... I think. /Andreas Andreas, i think it WOULD work...the idea of the balanced system is kind of like a humbucker, from what i understand... by having the audio signal in and out of phase on the two hot conductors, when you recombine them at the other end it will cancel the hum induced into the signal. {censored}, Dot is right, it would HAVE to work... the only real issue would be the transformer and associated power supply you'd need in the guitar....i'm assuming this kinda system IS active, right? not my forte.... but i think Dot may have nailed it... god, i'd LOVE to play my strat with out that annoying hum (although i DO like how it breaks thru in the background during octavia and fuzzed whammy bar freakouts...) imagine a strat or a tele in front of your computer monitor without the baggage... man, it could make ya tumescent..... Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by zachary vex lifting the ground on a guitar cable going directly to the guitar will cause immense hum and loss of signal. it's not going to work except in a situation where there is already a shared ground connection between the guitar and the amp and you are trying to avoid a ground loop.in studios, it works well, because everything is grounded together. in a guitar system it is very difficult to implement. Zach,i'm not talking lifting the GROUND on one end...hot and ground are connected on both sides....ya lift the SHIELD on one end, bro...ya need standard 2 conductor plus shiled cable to do it, and it definitely helps lower the noise floor noticeably...not noticeably live necessarily, (background noise masks most of it live) but definitely an improvement when recording brother. seriously, try it!! Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by dot-dot-dot You're absolutely right. What I was thinking (and I might be wrong) is this; take the hot and cold outputs of the coil as normal, but have another connection halfway through the windings, and connect that to ground. Then the two halves of coil will be picking up the same noise, but erm, no. Sorry, my idea doesn't work. Doh. The noise and signal will both be in-phase. Don't mind me. no dot, i think you may be RIGHT! see my other post...a BALANCED line would definitely nuke 60 cycle hum...that's why they use it, right? if ya take two signals that are noisy, and out of phase, you can use them to kill the noise, right? isn't that the whole idea behind using balanced connections in the first place? Link to comment Share on other sites More sharing options...
Members TheGZeus,OnFire Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by pinkjimiphoton Andreas, i think it WOULD work...the idea of the balanced system is kind of like a humbucker, from what i understand... by having the audio signal in and out of phase on the two hot conductors, when you recombine them at the other end it will cancel the hum induced into the signal. {censored}, Dot is right, it would HAVE to work... the only real issue would be the transformer and associated power supply you'd need in the guitar....i'm assuming this kinda system IS active, right? not my forte.... but i think Dot may have nailed it... god, i'd LOVE to play my strat with out that annoying hum (although i DO like how it breaks thru in the background during octavia and fuzzed whammy bar freakouts...) imagine a strat or a tele in front of your computer monitor without the baggage... man, it could make ya tumescent..... That's not how it works. It's signal hot, signal cold, and a seperate ground. It's not a phase reversal. A guitar signal is centered on ground, and can't be balanced without a transformer or active circuitry. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by pinkjimiphoton god, i'd LOVE to play my strat with out that annoying hum (although i DO like how it breaks thru in the background during octavia and fuzzed whammy bar freakouts...) imagine a strat or a tele in front of your computer monitor without the baggage... man, it could make ya tumescent..... have you looked at shielding inside the guitar? a well shielded instrment should be able to get rid of a vast chunk of the noise you get from singlecoils, which you can do yourself easily enough, there was a really good tutorial on it online somewhere, but i cant emember where it was (one of the bigger sites) David Link to comment Share on other sites More sharing options...
Members andreas Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by pinkjimiphoton Andreas,i think it WOULD work... [snip]Nope, sorry. It will remove any noise that has crept into the cable (noise that wasn't there when the signal became balanced), but that's it. It will not remove any part of the original signal (which, in this case, includes single-coil hum). Plug your guitar into a DI box and hook it up to a mixer (using the balanced XLR out and an equally balanced XLR in on the mixer) and try it - your single coils will still hum just the same. /Andreas Link to comment Share on other sites More sharing options...
Members 5F1G Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by pinkjimiphoton Dot, can you reccomend a really simple to build buffer?i looked at anderton's, the one that runs off a 9 volt batterybut could never get the power supply right.would be nice to insert a signal buffer at a few points in my rig!!! I can be done, jimi. Years ago I built Anderton's buffer into an Ibanez Strat clone I had at the time. Since I didn't use the trem assembly, I stashed the 9 volt behind the back trem panel and ran supply leads to the control cavity where I placed the circuit. Worked great. Of course it might be harder/impossible to do this with an LP, or other guitar.I also read an article on the net a while back about this engineering-type guy who actually built a buffer into his guitar cable. I'll see if I can dig it up, but it seemed like a hassle to build. Link to comment Share on other sites More sharing options...
Members dot-dot-dot Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by TheGZeus,OnFire That's....pointless.Unbalancing removes anything you've gained.inless there's some transformer involved, and then you're introducing another chance for noise and moving it really close to your amp's power transformer. Shield the transformer - trivially easy. And you gain noise immunity for the entire cable run. Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by andreas Nope, sorry. It will remove any noise that has crept into the cable (noise that wasn't there when the signal became balanced), but that's it. It will not remove any part of the original signal (which, in this case, includes single-coil hum). Plug your guitar into a DI box and hook it up to a mixer (using the balanced XLR out and an equally balanced XLR in on the mixer) and try it - your single coils will still hum just the same. /Andreas gotcha!!! oh well, back to ye aulde drawing bong!!! Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by Narcosynthesis have you looked at shielding inside the guitar?a well shielded instrment should be able to get rid of a vast chunk of the noise you get from singlecoils, which you can do yourself easily enough, there was a really good tutorial on it online somewhere, but i cant emember where it was (one of the bigger sites)David yah,i used to shield all my guitars back in the day, these days i'm too lazy to take 'em apart, redo all the gk2 crap and stuff...my old bassplayer hooked me up some killer shielding tape from the phone company where he works...one of these days....i've been thinking about going to the fender noiseless pickups, but haven't for the same reason.just don't have the time right now to even think about it unfortunately, but a good call.but even the shielded guitars are kinda buzzy around the monitor at certain angles...i guess i could try and use EMG's, but i never got used to their feel...i can handle their sound, but the way they interact with fingers/amp has always seemed kinda clinical to me. Link to comment Share on other sites More sharing options...
Members pinkjimiphoton Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by dot-dot-dot Shield the transformer - trivially easy.And you gain noise immunity for the entire cable run. i'm telling you bro......hey, what about the firewire equipped guitars gibson was supposed to introduce a few years back?i know NOTHING of such tech....but i assume they must be sending a digital signal with those, right?i mean, if they can use firewire equipped guitars, maybe that's the way to go...but i can't see the guitar sounding the same if it's a digital signal. noise immunity for the entire cable run would freekin' RULE, if ya ask me.....i have alotta cable between me, my pedalboards and amps...when i was running my gt3 still, i used that "4 cable method" with a homemade snake..(i'm talking 80 feet of cable between pedalboard and rack, and another 20 feet going to the guitar)..proper shielding helped alot, but it could STILL be noisy in some rooms....being able to play with COMPLETE SILENCE BETWEEN NOTES would make me...welll..ugh...probably PAST tumescent. Link to comment Share on other sites More sharing options...
Members Brian Marshall Posted January 2, 2006 Members Share Posted January 2, 2006 considering that 99% of the noise you get with a guitar is from the guitar pickups using ballanced cable wont do anything to negate that. for me, i hate guitars with active electronics in them... long cable runs... without active electronics in the guitar you will still have signal loss due to the high impedance of the pickups. In order to take full advantage of the ballanced cable, you would have to retrofit all your stopmp boxes.... OH yeah want trube bypass. youll probably need a 5pDt or some rediculous switch that would need to be custom made. Link to comment Share on other sites More sharing options...
Members dot-dot-dot Posted January 2, 2006 Members Share Posted January 2, 2006 Originally posted by TheGZeus,OnFire A guitar signal is centered on ground, and can't be balanced without a transformer or active circuitry. Rubbish. A guitar pickup just creates a potential difference; it's only centred on ground because traditionally the cold lead is connected to ground. Instead you could take one output lead as hot, the other as cold and use ground to connect to the shielding. It's the connection of the cold output to ground that unbalances the output of a guitar. Link to comment Share on other sites More sharing options...
Members TheGZeus,OnFire Posted January 3, 2006 Members Share Posted January 3, 2006 Originally posted by dot-dot-dot Rubbish. A guitar pickup just creates a potential difference; it's only centred on ground because traditionally the cold lead is connected to ground. Instead you could take one output lead as hot, the other as cold and use ground to connect to the shielding.It's the connection of the cold output to ground that unbalances the output of a guitar. The ground would just shunt some hiss and a little hum to ground. Single coils are 2 conductor 90% of the time, and ALL pickups have to be grounded. Furthermore, take a mic that's not over 20' of cable from the board. Now lift the ground(of course, this isn't a phantom powered mic, in which case balancing makes TONS of sense) and I doubt you'll hear a difference. Balancing sends shielding noise rejection to ground, and the ground has nothing to do with the signal. This IS a losing battle.Balancing mics under 20' is more dangerous than beneficial(live).Cut the ground, and you'll never get shocked. Link to comment Share on other sites More sharing options...
Members psalt_phallow Posted January 3, 2006 Members Share Posted January 3, 2006 I figured the best reason not to do this was to keep the sound guys from having yet another reason to say: "Why can't you just run direct into the board?" And then after attempting not to hurl yet again explaining about how the amp is a part of the instrument and its sound while induring the sour face and blank stare of the sound guy. Or does this only happen to me almost weekly? Link to comment Share on other sites More sharing options...
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