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Post by flateric on Apr 1, 2006 12:05:13 GMT -5
Log and linear: A500k pots are for tone and B500k for volume, right? (Off my Epi dot). I always thought log pots were for vol and linear were for tone. ie: Volume (decibel) increase was a log thing. One of the guitar spare parts websites listed A pots as log ones for tone. Have I got it the wrong way round?
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Post by Mini-Strat_Maine on Apr 1, 2006 12:37:51 GMT -5
Now I'll have to look it up to remember all that stuff about why log (logarithmic) taper pots are used, but dB are just that way. (Sound pressure, and all that other scientific stuff.) Usually, 'A' is audio (log), but there was a time when the meaning of A and B were reversed, or maybe it was just certain makers. This FAQ explains how to use an ohmmeter to check the taper of a pot, if you're not sure that what you've got follows the "conventional" marking: guitarelectronics.zoovy.com/category/wiringresources.1basicwiringfaqs/#q2
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Post by JohnH on Apr 1, 2006 16:30:36 GMT -5
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Post by Runewalker on Apr 1, 2006 16:59:19 GMT -5
Over in Pickups there is a wide ranging discussion in "TV Jones... that covers a lot of topics but addresses this Linear vs Log this way:
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Post by woodshedder on Apr 1, 2006 18:27:25 GMT -5
I have two electric guitars in which both came with log pots for tone and linear for volume. I have another one which I wired up myself from scratch a long time ago, and I put a linear pot on the tone, and that pot acts more like a switch than a pot, i.e., there is a dramatic change from bassy to trebley at one point in the sweep of the pot, and away from that point, the pot doesn't do much of anything.
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Post by sumgai on Apr 2, 2006 21:13:04 GMT -5
eric, In essence, what Doug and John have said is the correct way of looking at it - A means logarithmic and B means linear. But Doug is right, that convention is fairly new (in the grand scheme of al things), it wasn't much more than about 20 years ago that the manufacturer's association reversed the original train of thought on how to label these things. That said, nearly everyone here is missing the boat. (Ducks while shotguns are picked up and the hammers c0cked.) A log taper is defined as an increase in resistance from center tap to the counter-clockwise tap that is proportionately greater than the amount of physicial travel. I0W, the small amount of wiper travel exhibits a large amount of resistance change. (This is all in respect to viewing the pot from the front, or the as if you were looking at the knob while operating it.) Now, if you have a volume control that is turned all the way down, and you rotate it say 1/4 of the way around, you will actually increase the resistance between the wiper and the left lug by just about half of the pot's total resistance. The remaining 3/4 of travel will only change over the remaining 1/2 of the total resistance. (These figures are approximate, to be sure.) In a linear pot, it stands to reason that the percentage you rotate the shaft is the same percentage that the resistance changes. So what has all this got to do with the price of corn? Well, how often do you operate with any of your controls turned all the way down? Thought so. That last 3/4 of physical travel is where you are operating when you are actually using your guitar, not the first 1/4. So you can now see that a linear pot will actually have more effect on the parameter (volume or tone) than a log pot. Hence, the differences are quite small, comparatively speaking. To be sure, there are other circuit elements that can affect the overall sound, and some others that will be affected by the pot's taper, even more so than you can hear. But that's all by the wayside, isn't it? What counts is what you get out of the control - is it what you want, or not, that's the only question that needs to be answered. And as at least one of you is going to ask, yes, there is such a thing as a reversed-taper pot. That's what used to be called a "B" taper, but no more. Now, you need to ask for it, or see the physical description declare that fact, you can't take a letter for any kind of clue to how the taper is laid out. (And no, they didn't ask me ahead of time, or I wouldn't have let them change the nomenclature system! It used to be much more useful.) HTH sumgai
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Post by flateric on Apr 3, 2006 10:34:49 GMT -5
Another fascinating insight into the fuzzy world of electronics. Thx for the explanations, guys! So when I'm rewiring my friend's newly purchased Epi Les Paul, hopefully throwing our the cheap scratchy pots and replacing with some better quality ones, although I am ok using either A (Log) or B(linear) type, going for linear with both tone and vol would give me better resolution at the 75% - 100% range? Have i got that right?
How do i know a decent pot from a cheap one? (I'm buying in the UK) Maplins and RS components, for example are way cheaper than Allparts and similar shops, but I don't want to spend out and get no improvement in quality. I don't want to pay £4.50 per pot for something I could get at Maplins for 50 pence either.
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Post by Runewalker on Apr 3, 2006 16:32:10 GMT -5
If you are using conventional pots, I have had positive luck with Alpha, 24mm. Nice viscosity, inexpensive. $.96 in lots of ten at Mouser, which may not help you on the shipping. However, they are light and if you take the slow boat, shipping might not be too bad.
One caution though, if you are installing in a back routed chassis, it is difficult to find switches and parts with long bushings, except at the Guitar parts houses, then they don't have the more exotics in long bushings.
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Post by sumgai on Apr 3, 2006 18:54:41 GMT -5
eric, No, not quite. A linear taper will give you 50% of the total resistance change over just 50% of the physical rotation range. A log taper will need about 75% of the rotation range to give you the same amount of resistance change - a 3:2 difference in resolution. When dealing in fine adjustments for ultimate control over tonal nuance, the log taper will be your better bet. When you desire rapid action more than fine tone control, the linear taper will fill the bill. Two more things: One: A 50 penny pot is worth just that. If you're gonna be your friend's guitar-tech for a long time, be prepared to hear his grousing as you replace that *#&%(@ cheap pot for the umpteenth time. 'Nuff said. Two: We can't empasize enough what RuneWalker just said - you must make sure the threaded bushing on a new pot is longer than usual, long enough to replace the old pots you pull out. In fact, pull one out one of the old pots now, measure the height of the bushing, and write it down. Now you're ready to order parts. HTH sumgai
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Post by flateric on Apr 8, 2006 3:01:53 GMT -5
A £3.50 pot from a guitar parts specialist is probably actually a £0.50 pot from a wholesale electrical trader. Maybe I'm just being cynical, but I resent having to pay over the odds from overpriced parts factors when I can get the same quality component from Maplins or RS components. Trouble is, how can I tell the Guitar Parts retailer isn't just buying cheap crap and marking it up 300%?
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Post by sumgai on Apr 8, 2006 4:10:57 GMT -5
Eric, The problem here is that you are not a retailer, so you won't ever get that wholesaler to give a single piece at a mere £0.50. Part of what you're paying at retail is the store's markup, which goes to cover their having bought the part in the first place, and then sat on it until some poor schmuck finally comes along and buys it. That's called "floor time", and the synomym for it is "money tied up, not able to be used elsewhere". Financial types call that "risk". The retail customer compensates the retailer for that component of doing business, and there's no avoiding it. (Unless you know somebody who constantly finds stuff that "fell off the back of the truck", but that's not copasetic, is it.) When buying a part such as a pot, the vendor will brag about it being one of the name brands. If not, then don't hesitate to either email or call the vendor. If they say they don't know, then they do know that it's not top drawer, and you can make your plans accordingly. If they try to tell you that what they have is 'a direct equivalent, it's just as good', then thank them for their time, and look elsewhere. And if they don't have the time to answer your question, how are they gonna find the time to fill your order? Sorry, I don't make the facts of life, I just report 'em. sumgai
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Post by flateric on Apr 8, 2006 14:54:23 GMT -5
So back to the earlier question, how do I know a decent pot from a rubbish one? When I'm taking out the pots of my squier strat or my Epiphone dot and spending £3.00 a piece on replacing them, how do I know they are going to be any better than the ones so many people criticise? If you look at loads of posts on the epihone forums there is a general consensus that a good quality guitar can be made dfar better by switching out the electrics for better quality components. Anyone have recommendations for good quality replacement components or outlets? I have a nagging suspicion that the pots sold by most of the guitar parts outlets may be in fact no better than the original ones supplied that end up so victimised by their new owners. Any thoughts?
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Post by sumgai on Apr 8, 2006 16:46:47 GMT -5
Eric, Oh, yeah, I've got thoughts aplenty! ;D You do raise a point, how does one know that he's getting something of better quality than what he's already got? Well, perhaps, and this is just a supposition on my part, but you might take out one of your pots now, and see if there's a name on it. (Or can you read it while it's located in place?) No name? Replace it, pure and simple. With what? Chris has already volunteered Alpha, I'll second that. CTS is probably one of the better known top-notch makers, because many high-end guitars have 'em. Ohmite, NTE, and Bourns also come to mind, although I've not seen them in any stock guitars, they are kinda pricey. On top of all this, you keep speaking of £3.00 or £3.50 pots. Have you checked out Digikey, or Mouser, or any of the other American parts houses? I know that if you buy a large handful of goodies (usually a $25 minimum), you get either low shipping rates, or maybe even free shipping. Coupled with $1.50 dollar pots (what's that, about a pound?), that just might be what it takes to ease your mind. Hey, good luck, you deserve it! sumgai
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Post by flateric on Apr 8, 2006 18:48:00 GMT -5
Thx for the good info, much appreciated. First port of call has to be UK sources for decent pots before I go fishing over the Atlantic. A lot of places add such a high premium to postage for such a few little items
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Post by johan on Apr 9, 2006 14:17:11 GMT -5
I'm on the other side of the atlantic as well... so this pot trouble is quite familiar to me.
Went to the music store in town cos i wanted three push pull pots. The dude in the store told me CTS were the best (I know they're "the best") and that they cost 13 EUR (say $15.5) a piece. Considering the nature of the article, I think that's outrageous. Scanned ebay for weeks before ordering transatlantic, acquiring about 15 pots (push pull and normal). They were not Alpha pots and they were handpicked and tested at my request by the seller.
I paid $45 including shipping, as often the tax office in Belgium was on a coffee break, so that's what I call a deal. I grew suspicious of Alpha pots since I found them in my Squiers.
good luck still, J
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Post by sumgai on Apr 9, 2006 17:54:20 GMT -5
johan, Good deal you found on that "sleeping Belgian giant"! ;D Alpha pots are considered high-quality second tier. The jury is still out as to how long the will last, they haven't been used in guitars for decades like CTS, but for the price, I wouldn't argue too much. Eric, what johan says. Even paying the "highway robbery" prices of shipping from America, the parts houses can and will beat your local suppliers every time. And that's before we consider eBay, I hadn't thought of that angle. Tell you guys what. I live here in the good ol' US of A, so why don't you buy the stuff, have it shipped to my joint, and I'll repackage it for shipping on to you. If it's coming from a private party, there shouldn't be any problems with a "gift", should there? I'm referring to customs, duties, VAT, and the like. They may still wanna open it and check for terrorist materials, and I'm fine with that, but do they really want to interfere with gift giving by taxing it to death? I dunno, that part's in your bailiwick, I'm just offering to act as a middleman to try and get you over a hurdle, that's all. Hell, the offer holds true for all out-of-USA members of this forum. Hey, I'm retired, what are they gonna do to me, take away my merit badges? sumgai
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Post by flateric on Apr 11, 2006 10:36:24 GMT -5
I can sense a valuable new business enterprise in formation here! Can you do complete guitars too? It's appalling how polite we are over here, paying the same in GBP as you play in USD, we're just used to Gibsons costing £1000 and upwards, that would make them nearly half price to us when visiting America. The guitar shops are such a huge magnet to me when I'm over. There's virtually parity across all ranges matching $ for £. Now by the time you've paid shipping and VAT and duty it's not worth buying a cheap epiphone or squier strat, but when you look at the high end stuff, someone's making a fortune selling PRS's at £2450 in the UK, thats about $4250 today!
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Post by sumgai on Apr 12, 2006 12:19:38 GMT -5
Eric, Not my intention, as I'm sure I would attract unwanted attention real quick. OTOH, I am more than willing to help out my friends, if you know what I mean. ;D I suppose I could try to pass a guitar off as a gift, but that probably wouldn't fly after the second or third time. Remember, I have only a limited selection of people with whom I can deal (agents of shipping concerns), and they are, down to the last man or woman, not impressed by "good ol' boy" tactics, I can assure you. Parts and pieces, that should be doable for quite awhile, or so I believe at this point in time. The disparity in pricing is more reflective of a "gentlemen's agreement" to soak the buying public than it is to "recoup" some of their investment. The politeness of which you speak would soon evaporate if there were a strong Musician's Union that literally, and publicly, recommended to every member that they buy from overseas (Japan, Australasia, USA, etc.) in order to show the greedy b@st@rds that musicians are no longer gonna take it in the shorts. In fact, wasn't the conversion to the euro supposed to reduce or eliminate such disparities? I note that you are using BPS as your unit of shopping comparison, but here in America, we're being told constantly that the euro is the only valid measure of money in the EU. What's up with that, perhaps old habits do die hard? sumgai
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Post by flateric on Apr 12, 2006 15:33:12 GMT -5
Heh, you know us brits, fiercely independant of anything european! On a serious note, I appreciate the offer, my taking it to the whole guitar level was, as I'm sure you realise, a bit of gentle leg-pulling, but the point regarding cost disparity is a valid one which frustrates so many musicians over here.
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Post by guitardoode on Apr 13, 2006 11:50:23 GMT -5
hehe thats confusing, it would be so much easier with universal currency, mind you there are quite a lot of reasons we dont do that...
What bugs me is why is the brit's so damn expensive, i live down right south of the UK and i needed to replace a Vol Pot in my Ibanez JS once... i went to nevada music and they wanted £8.50 for a "Volume Pot" I even asked them if it was the right one i wanted because it didnt state if it was Log or Lin... they said they dunno if it was log or lin, got home and stuffed it on a meter i found it wasnt either, it was an Anti-log, aka the opposite curve to a standard log!
flateric your right muscians really have a lotta stress down over here, but you were sayin at the begging of your thread, mapins had one? I was looking at them i couldnt find one... I got one from PJ'walker's in southsea in the end. really nice quality smooth and Lin :-)
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Post by flateric on Apr 13, 2006 16:27:13 GMT -5
I've been using 3 outlets for guitar parts: AxesRus Highly Strung Allparts UK When it comes to components they are all pretty pricey for things like pots, switches and caps. Maplins and RS components are way cheaper just I have no idea about quality/reliability. Then I cannot judge the guitar parts retailers stuff either. I reckon there's probably not much extra you get in return for the higher expense of a guitar parts retailer, but I'd be delighted to be proven wrong.
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Post by UnklMickey on Apr 13, 2006 18:24:37 GMT -5
...I reckon there's probably not much extra you get in return for the higher expense of a guitar parts retailer, but I'd be delighted to be proven wrong. Flateric, i'm not gonna "prove you wrong", but there is one slight advantage to buying pots from a guitar supply house. you know right away from the description if it has the right bushing length for a standard guitar, or for a 'paul. it will also have the split-shaft you need for the stock knobs. so, if you are already going to buy other stuff anyway, like bridge saddles or tuners or something, it might be worth it to just pay the extra couple of bucks for a pot or two. you know, like the old saying goes, "keep it stupid, Simple." XD but if you are going to do a lot of building, sure, stock up from an electronics house. the effort of wading through all those part numbers to get the right part, is offset by many dollars in that case. unk
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Post by flateric on Apr 13, 2006 18:32:48 GMT -5
Very true words there on all counts. I can see how you got your forum nickname
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Post by UnklMickey on Apr 13, 2006 19:44:43 GMT -5
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