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Post by asmith on Nov 13, 2010 20:07:49 GMT -5
Hello all. Glad to be here. I'll keep this concise. Please bear in mind I'm learning and understanding more as I go along. My electronics education was six years ago and very shallow. I have a standard Stratocaster, 500K pots. I've already shielded my guitar. GoalVolume for Neck and Middle pickups. Volume for Bridge pickup. Master tone control. "Bridge in series" ('BIS') switch, much like the Strat Lover's Strat. "Volume bypass" switch, bypassing both volume controls. As an added complication, when the BIS switch is flipped, I'd like the Bridge volume to become a master volume. Here's my latest draft schematic, a reworking of GuitarNut's own. Old schematicSW2 is the "Volume bypass" switch. SW3 is the BIS switch. Problems I immediately seeI'm concerned that when I flip the BIS switch, and I'm in position four on SW1 (the five-way selector), the middle pickup's signal will travel through SW1, through SW3, round the bypass wire to the connection with the 'Bridge volume' part of the circuit, up back through SW1, into the 'Bridge in series' part of the circuit, through SW3 again and back to the middle pickup, effectively short circuiting. Is this a legitimate worry? Have I made any more mistakes here? If I have, please explain the science of how my mistakes have happened, as believe it or not, that's far more helpful to me than a direct solution. Thanks in advance for your help. Much obliged.
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Post by newey on Nov 13, 2010 22:42:47 GMT -5
asmith-
Hello and Welcome to G-Nutz2!
I don't have an answer yet to your question about position 4, I'm still tracing all that out.
I do think SW2 has some issues. Your stated goal for this switch was to have it bypass the volume controls, but I see at least one control in the circuit with the switch flipped either way. Also, I don't think the upper leg of R2 can be connected to the wiper of R1.
In order to do 2 volumes with a master tone, the tone pot needs to be a dual-element pot. JohnH did a 2-volume Strat scheme with that approach, I'll have to dig it out of the Schematics section.
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Post by newey on Nov 13, 2010 22:52:24 GMT -5
Here's the design I was thinking of, courtesy of JohnH and Runewalker: Strat with 2 volume controlsThe "Plus" version seems pretty close to what you have in mind.
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Post by ashcatlt on Nov 14, 2010 13:20:47 GMT -5
Is there a standard for numbering this 5-way switch? I always get confused. Anyway, I think you're right. When in Series mode, with the 5-way at what would be B+M, the M is shorted a couple different ways. I don't know that this is such a big deal. You're gonna end up with a redundancy here either way. Does it matter whether you've got the Bridge alone twice or the B*M?
The "volume bypass switch" leaves does bypass the volume control action of the N and M volume, but leaves its full resistance parallel yo the output, loading the pickups a bit. In this case it doesn't matter what position the 5-way is in.
Worse is the fact that the bridge volume becomes a variable resistor to ground. That's a Tone control which maybe doesn't get quite so dark toward the bottom, but turns the guitar off when cranked all the way down.
I think the master tone here works fine.
I do see another potential issue which has not yet been mentioned: In Series mode, all non-selected pickups are hanging from hot. Yes, their hanging by their "ground" ends, but I think it could still be a noise issue.
BTW - where's the phase switch?
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Post by asmith on Nov 14, 2010 17:21:36 GMT -5
Thanks for your quick replies.
First, I must have been very tired when I wrote "phase switch." Obviously there is no phase switch.
Newey, cheers for your digging out, that's really helpful.
Ashcatlt, I see what you mean about the bridge volume becoming a variable resistor to ground. Thanks for the heads-up. Redundancy in certain selections isn't a problem for the goal of this setup, I just naturally associate "short-circuit" with the words "very bad things." Things like "frying electronics." I like a fry-up as much as the next man, but I don't want to spark my guitar out.
Unfortunately, I don't understand half of what else has been said. "Hanging from hot" means nothing to me, nor whether they're "hanging by their ground ends." I see what you mean about "leaving it's full resistance parallel to the output," but I only understand some rudimentary science behind it, and I've very little idea what you mean by "loading the pickups."
See, it's a shameful admittance, but I'm drawing this circuit up like a water system. In my mind, I'm seeing it easier to imagine the circuit as "power comes from pickup, bridge acts as a sluice gate, resistor lets only so much through, water travels to output, etc." OBVIOUSLY this isn't the way electricity works, but it's certainly the way my mind comprehends it.
I've googled basic electronics, but my knowledge still falls short. If someone has a spare five minutes, would they be kind enough to post some kind of explanation, or at least an introduction, to where and why I'm going wrong. I'd be most appreciative.
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Post by Yew on Nov 15, 2010 16:47:57 GMT -5
The water system isnt a bad way to imagine parallel and series resistors.
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Post by ashcatlt on Nov 15, 2010 18:20:40 GMT -5
Okay, let's see if I can clear up some of the questions you've raised. It'll probably lead to more questions, but that's okay. It's what we call learning, and that's always a good thing. Lucky for you I'm not an EE, so I wont be getting too far into the technical specifics. There are some EEs around, who might step in to correct or expand on what I have to say. So let's start at the very beginning. Ohm's law. If you've read much of anything about electronics theory, you've likely come across it, but we'll restate. Voltage (V or E) = Current (I) x Resistance (R) If we assume that Voltage remains constant (pretty safe for this discussion) we can rearrange to say: Current = Voltage / Resistance From this we can see that for a given Voltage, a greater Resistance will demand less Current. A lower Resistance will draw more Current, and that's basically the source of your (quite reasonable) fear of short circuits. As R approaches 0, I approaches infinity. The source will supply as much Current as it can, and if that exceeds the current carrying capacity of some component along the way we will see sparks and smell smoke. Luckily out passive pickups are incapable of sourcing enough current to harm themselves or anything else in the circuit, so we can short them with impunity.* When we talk about the load on a circuit, we're referring to that current demand. A large resistance at the "receiving" end will draw a smaller current and be a smaller load. A smaller resistance therefor will be a larger load. If you've been poking around a bit, you may have come across the formula for calculating the value of parallel Resistances. Its laid out quite nicely here, if you need it. The gist, though is that for any two or more resistances in parallel, the total resistance seen by the circuit will always be less than any of the individual resistances and therefor a greater load. What's this got to do with your Volume control? Well, without any controls, just the pickups and the amplifier, the load is determined by the resistance between "hot" and "ground" at the amp. Typically this value will be between ~500K and 1M Ω, let's go with 500K for now. Now, when we add the resistance of that pot from hot to ground, I think you can see that it is parallel to the amp input. If that pot happens to be a 500K pot, the total resistance seen by the pickup will be halved, and the current load doubled. But what does that mean? Well, honestly this is where it gets a bit over my head, so I'm going to gloss over some of it. Let's just say that on top of these resistances, we also have quite a bit of inductance in the pickup coil and significant capacitance across the cable. This all creates a low pass filter which doesn't do a very good job of letting high frequency signals (treble) through. A lower resistance - or higher load - means even less treble gets through. This is partly how a tone control works, and why I said that Bridge Volume would act like a tone control when "bypassed". It's also the reason we usually use bigger value pots for humbuckers - they're already darker (thanks to greater inductance) and we don't want to lose much more. Like I said, kind of glazed it over, but smaller pots or more pots means less treble. Then there's the "hanging from hot" thing. It's as simple as seeing that one end of the pickup is connected to the jack tip (the "hot output") while its other end is not connected anywhere. What's the big deal? Well, the pickup is a big long coil of wire, and acts as an antenna. It collects all the Radio Frequency/Electromagnetic noise flying through the air and pumps this straight through the amplifier. This post has already gone on quite long enough so I'm not going to go into relatively poor explanation of the why, but leaving a pickup connected to "ground" (the jack sleeve) is usually not a big noise problem. It's standard procedure in the vast majority of guitar wiring. Hanging from hot is to be avoided, though. Shielding might help, and humbuckers will still tend to buck hum, but we still generally prefer to avoid this situation. If we look at your scheme in its Series mode, we see that both M and N pups have their "bottom ends" (which would normally be connected to ground) connected to the "top" of the B pup. In the B only position this is connected directly to jack tip, and both M and N are thus hanging from hot - albeit "upside down". In B*M mode, the N pup is hanging kind of halfway between hot and ground. This will probably also be a noise issue. Something similar happens in B*N position. I hope some of this helps. If you've got more questions, or if anybody's got anything to add, don't hesitate to speak up. *ChrisK used to point out that while we won't actually hear anything out of a shorted coil, it still tries to generate current, and that energy has to come from somewhere. "Conservation of Energy is.". We talked about that most recently here. Based on that discussion and (more importantly) practical experience I'm convinced that this effect is negligible and not any real concern.
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Post by asmith on Nov 16, 2010 10:36:52 GMT -5
Brilliant! That is such a help. Thank you so, so much.
When it came to the volume control, I'd been seeing it as a variable 'gate,' letting some signal trundle off to the output and the amp and sending some to return back to the pickups depending on the setting, instead of seeing them for what they are, variators between making the volume resistance series and parallel.
Thanks for clearing up everything else as well. I shall have a good rethink.
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Post by asmith on Nov 17, 2010 11:40:33 GMT -5
Well, newey's Strat plus was pretty close, but I didn't want an out-of-phase switch, so I changed it to a "solo switch" for the bridge pickup. Old schematicI'm aware about the weird things that will happen when I used the series switch with this as well, but I'm excited to try it. I think this is all kosher. Yes?
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Post by JohnH on Nov 17, 2010 14:31:06 GMT -5
my old diagram!
Your mod is OK, but why not use the solo switch to put the bridge hot directly to the output instead of through the 5-way? ie, the upper half of the solo switch, which currently is between the B volume and 5-way, is moved, so that its pole is to the output, one lug to the 5-way pole and the other to the other half of the solo switch (as now)
This will mean that you can be using a neck rythym sound, and go straight to bridge solo without moving the 5-way, so only the solo switch to flick.
In series+solo mode, the neck/middle is still in the circuit, but i think thats a good thing, it gives you another option for a louder solo. Some of the best sounds from these series wirings IMO, is with full bridge and a bit of neck in series, which this sytem would give you. You can also then turn the tone control down, which in solo+series mode, will affect the neck/middle only, adding extra bass to the biting bridge treble which will come through strongly
cheers
John
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Post by asmith on Nov 17, 2010 15:13:12 GMT -5
Yes, John! Yes! Old schematicI'm very excited to get this all soldered together. Thanks for your help, everybody. Really appreciate it. I'll be sticking round here for certain.
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Post by asmith on Nov 17, 2010 20:10:32 GMT -5
Hold on, what if I simply added the tone resistor/capacitor outsider the selector? Surely that'd work as a master tone system? Old schematic. Turns out it doesn't work as well as a master tone system.I realise this won't give me the individual tone control on the neck and middle when the bridge is in series, but it saves me having to buy a double pot. EDIT: You should probably ignore this post.
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Post by newey on Nov 17, 2010 21:54:19 GMT -5
Asmith- JohnH's discussion of this scheme, in the link above, answers the question of why to use a dual-gang pot- the tone control needs to be on the pickup side of the vol control (as in LP wiring) to avoid interaction with the 2 volume controls- at least that's what I understood John to mean. Earlier, Ash asked an unrelated question about numbering the positions on a 5-way switch, and whether there was any convention on how to do so. The short answer is that there doesn't seem to be any uniformity. Certainly, there isn't any on this Board! Fender, in its diagrams, consistently calls the bridge position "1" and the neck "5": support.fender.com/diagrams/stratocaster/0131002B/SD0131002BPg4.pdfSince Leo introduced this switch to the world of guitars in the first place, I think we should try to stick with that numbering. But I'll admit to doing it the other way myself on occasion. Somehow, the opposite way from Fender seems more "natural", designating the neck as "1". Maybe because we read from left to right, and so look at the switch , as mounted in the guitar, as being 1 to 5, left-to-right. With Fender's way, it's more like a NASA countdown, with the bridge as "blast off". (mini-rant over)
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Post by ashcatlt on Nov 17, 2010 22:06:03 GMT -5
Usually we try to maintain the continuity of the thread by not deleting parts which have been discussed at any length. I noticed that you've replaced most of the pics of the "Old Schematics" with links. I think that's an acceptable way of handling it, but I notice that the very original schematic did not get this treatment. It may seem a little embarrassing leaving a "bad" schematic up there, but it kind of leaves folks wondering what the heck I was babbling about. Also I feel I'd ought to warn you that after you've got it all wired up you're going to have to give us some pics and sound samples!
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Post by JohnH on Nov 17, 2010 23:30:27 GMT -5
I liked the dual-gang tone pot better, for its consistency of tone as you reduce volume, as I wrote previously, but what you have shown is not too bad. Youll still be able to get the solo/series max-bridge - neck-with-tone turned-down sound that Im talkin' about. With one tone and 2 volumes, when not in solo mode, its not worse than a Gibson Explorer which sort-of works that way.
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Post by asmith on Nov 18, 2010 7:26:16 GMT -5
Second shameful admittance of the thread is that I fiddled about with the "design4.gif" schematic in paint and then hit "save" without thinking. Then uploaded it to my ftp space so's I could use it, then realised I'd written over that as well. I had no real intention of dropping the schematic. I think I've still got a close approximation of the (heavily flawed) circuit design. The "old schematic removed" text has been modified to a link. I'll probably not jump blindly into my own personal Eureka moments in the near future, especially when it comes to tone controls. John, I'll re-read your thread. Thanks again for your help. Newey, understood. About the positions - insert your own karma sutra joke here - I won't take it as far as pinning a numbered diagram above my bed and reciting it to myself every night, but I'll make the conscious effort required. Thank you everybody for your help. Looking forward to pics and recording. For the purposes of better thread organisation, here's the finalised circuit diagram.
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Post by JohnH on Nov 18, 2010 14:43:49 GMT -5
All good! but please dont stop having eureka moments.
The design you have settled on is likely to be a killer. Id also like to post your graphic on the 2Vol Strat schematic thread for future reference, maybe with some pics when you have it built
John
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Post by asmith on Nov 18, 2010 15:40:54 GMT -5
By all means please do. Pssst. Fellas. Just need a yes or no on this if it's not too much trouble. If I changed the tone circuits to "Greasebucket Tone Circuits", and used connector rings so 1) I don't have to solder three different things to one lug numerous times and 2) my brain can re-understand the circuit at a glance it if I needed to mod it some time in the future, It'd look like this, right?
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Post by wolf on Nov 20, 2010 4:03:21 GMT -5
That greasebucket circuit is kind of popular so I drew my own. The values are based on what I've seen at other websites. If nothing else, I think this shows the circuit more clearly.
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Post by newey on Nov 20, 2010 9:26:43 GMT -5
Wolf-
Much clearer, but I think you should show the input, to the right-hand lug, so we know where this "plugs in".
asmith-
Your implementation of the greasebucket look OK, but I'm not so sure that using "connector rings" is wise. (I assume that you are planning to solder to a ring connector, just as is done in the star grounding scheme set forth on the original Guitarnuts site.)
That's OK to do for a single grounding point, where you might have 5 or 6 things to wire together. But, it's not always so easy to get a good solder joint to those connectors. And, bear in mind that the more solder joins you add to a design, the more places it can fail. Each ring you add . . . adds more solder joints.
You will be substantially increasing the under-pickguard "spaghetti" by doing so, and each connector ring will need to be taped up to avoid inadvertent contact, so I fail to see how it's going to be any easier to "wrap your brain around".
And while soldering 3 things together to one lug can be a bit tricky, it's doable (and is done all the time). Any modifications down the road will require desoldering anyway, whether from a lug or a ring.
So, to my mind, no real benefit to using ring connectors at every junction, and a big downside in added complexity and potential for problems.
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Post by JohnH on Nov 20, 2010 14:26:49 GMT -5
I wouldn't get too excited about that greasebucket gizmo. Its easy and cheap to try, but I would not expect too much from it. At max tone it will make no difference, (the 0.1 cap is bypassed and the 4.7k resistor is negligible). At medium tone settings maybe a tiny differencemeasurable in a lab. At low settings, the two caps combine to effectively act like a slightly lower value cap, and the resistor acts to stop the tone control going to zero. That part might be worthwhile. Sometimes there is a nice sound to be found with the tone control almost at zero, just before all treble is lost, but it is difficult to set being so close to the end of the turn. This could make it easier to find.
On your diagrams - I agree with newey. Also, the schematic diagrams that you have been posting are not really the place to figure ot how you arrange the wires physically. Its better to think that through with a more pictorial wiring diagram - see the scheamtics post for the 2Vol Strat for example.
cheers
John
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Post by asmith on Nov 20, 2010 21:26:11 GMT -5
Righto chaps. I've managed to lay my hands on a small Breadboard. I've drawn out a diagram for myself of where all the capacitors and resistors will go, and the wires to the pickups, switches, pots, output and ground. To me, it's a lot simpler than the spaghetti junction of wires to here there and everywhere. I much prefer the idea that the switches and pickups all run - with few exceptions - into one circuitboard to do all the dirty component work, than have to jump about everywhere. Most wiring diagrams of something so complex just look to me like someone had plastic for breakfast and it didn't agree with them. Maybe so many years in the future, I'll be able to read it like one would read a foreign language. But not in my early twenties, when rash decisions with a get-out clause provide me with life's great pleasures fast and often much more than spending half an hour scratching my head about something, knowing that if I flip-flop, it takes two hours to solve. A little PVA or some wax drops here and there should secure the wires firmly in place, but only semi-permanently, if anything ever wants changing in the future. I may well get two years down the line and figure I want a different circuit, or indeed as John says, I may decide that the Greasebucket is no more useful than a bucket of grease and remove it a few months from now, after careful consideration and not-so-careful playing. Instead of tons of soldering, the breadboard makes that entire process a lot simpler. Thanks very much for your help again folks. The guitar parts websites are already mincing their hands at the prospect of a potentiometer binge. By the way, for the tone - instead of just using a dual gang, I'm going to use a concentric pot. Individual tone controls for Neck + Middle and the Bridge, on one knob, is better than a master tone - although the master tone was my first idea, more versatility is always welcome. I planned to change all my control knobs to blackened Tele-style ones a while back anyway - they're a lot easier to work with on the fly than my current stock Strat ones. Steve Vai agrees.
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Post by wolf on Nov 20, 2010 22:25:52 GMT -5
Okay, newey, I made the changes and added a volume control:
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Post by newey on Nov 20, 2010 23:13:37 GMT -5
Well, breadboarding it is a whole different story than ring connectors. I'll sign off on breadboarding it.
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Post by asmith on Nov 25, 2010 15:20:13 GMT -5
Due to size restrictions in the cavity and my complete refusal to do some routing on the body, I'm using stripboard instead of a breadboard. Flippity flop again. I'm less decisive than... I can't make my mind up.
I apologise for bringing up my shortcoming in the knowledge here again. But here it is.
I was just about to buy the pots, and then somebody looked at the guitar as it is now (standard Strat) and said, "these are 250k pots." I was sure they were 500k. Turns out they're not.
This isn't a problem on the push-push switches - the volume controls - as the two resistances are both available; I can purchase 250k switch pots for the volumes instead, and Bob's your uncle. But I don't seem to be able to find a dual-gang 250k. A concentric 500k/500k pot is the immediate option.
I've done some preliminary research and Googled and the like, and the difference seems to be that should I use a dual 500k/500k pot, my tone control would be 'brighter' at full whack. I don't mind this at all, as I'm usually playing at full on the tone. Indeed, I like the idea of playing at a mid-level, with the option to blast the treble up if I wanted. (If I'm playing through the bridge and middle pickups, a split humbucker if you will, with a high treble setting, I'd probably start channeling Edward Van Halen. Bitchin'.)
Is my reasoning correct? Can I use 500k pots for the tone, playing them at a mid-level setting for the Strat tone that I'm used to?
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Post by newey on Nov 25, 2010 15:58:01 GMT -5
It has often been said around here that a 500K (log) tone pot will sound like a 250K if you set it at about "8". You can go ahead and use 500K no problem.
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Post by asmith on Nov 25, 2010 19:29:37 GMT -5
Brilliant! Thanks. The only questions now are, which resistors to use in the treble bleed circuits, being that I'm using 250k pots instead of 500k ones, and which resistors to use in the tone circuits, being that I'm using 500k ones instead of 250k ones?
Or are they changed at all?
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Post by JohnH on Nov 27, 2010 17:28:46 GMT -5
Brilliant! Thanks. The only questions now are, which resistors to use in the treble bleed circuits, being that I'm using 250k pots instead of 500k ones, and which resistors to use in the tone circuits, being that I'm using 500k ones instead of 250k ones? Or are they changed at all? OK, this is an interesting question for me, since I have now submitted my PhD thesis to the University of GNuts, on treble bleed circuits. To work out an optimum treble bleed, I could take account of your specific circumstances, so some questions: what do you know about your pickups? are they fairly normal single coils? do you know what type? What length of cord do you prefer? or do you equally use different cord lengths? other than full volume, what is the volume setting that you most use and on what guitar? or might you use the full range? cheers J
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Post by asmith on Nov 29, 2010 8:35:02 GMT -5
Well, the guitar is a second-hand Squier Silver Series Stratocaster. A nightmare for this fella. The headstock says "Made in Japan," but the series number begins with a K, indicating a Korean-made model. I've narrowed the production year down to about 1989. The pickups haven't been changed since the guitar was purchased, so I'd assume that they're standard Squier ones. Indeed, Squier doesn't give much more information on their website than the description '3 Single-Coil Pickups.' Nothing is written on the pickups at all, so I can't indicate any specific model. To cut this long answer short, I'd hazard at stating they're 'fairly normal single coils.' I have used all sorts of cord lengths but the longest and most frequent I use is about four metres. I expect my gig-hit-count to rise soon though, so I'll be investing in a wireless system before too long. I use full volume most of the time, cutting down to anywhere between 1 and 4 for 'cleaner' overdriven playing on the fly, similar to what Ed Van Halen does live for 'Hot for Teacher.' I used to touch down to 8 or 9 when playing rhythm and riffs with a band, nipping up to full for lead parts and back down to 8 or 9 afterwards, but I expect I'll probably use the series switch more for that after I wire this all up. Read into that what you may... I'd say I use reasonably limited areas of my volume control, but I'm the subjective player. A more objective mind might say I'm using a lot of the range. I'm sorry my answers are much vaguer than optimally so, that's really as much information as I can give you and it's as clear and concise as can be made. If you've got any more questions please don't hesitate to ask and I'll scarper off to have a second look at the instrument. Thanks for your help.
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Post by JohnH on Nov 29, 2010 14:42:27 GMT -5
Thanks, those are good answers. The reason I asked is that with single coils, for some reason, its not as easy to find the best theoretical values.
So in summary, (let me know if wrong), you have 250k volume pots, 500k tone pots, cords up to 4m, and standard sort of single coils. The target range on the volume control will be the low end 1-4. It will still work well outside that range though, but these values will be the basis.
Ill have a play around and make some suggestions.
cheers
John
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