tukak0210
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Post by tukak0210 on Oct 21, 2009 11:26:16 GMT -5
i have a problem regarding neck volume controls: i have this Dame Les Paul ( a korean musical instrument, maybe not a familiar brand), when i roll down the NECK volume to 0 with the BRIDGE volume on full volume, the sound is not cutted off, there is still a sound coming off on the amplifier when i strum my guitar as if i just rolled down the volume to 1-2. Also, i cannot do volume swells on that volume pot because instead of getting that "smooth" increase in volume, there is a "sudden" increase, just like from 0 to 2, or from 2 to 0. I use orange caps .015uF on the NECK, .022uF on the BRIDGE, 500k pots on both. I installed a volume kit 1000k resistor and 1000pF capacitor. I already tried to remove to consider that it might causing the problem, unfortunately, there is no problem on the kits. I dont know what is the impedance of the pups.  the volume pots are: 25K (embeded on the POT case) btw, i'm not having a problem on the bridge volume pot. i can do smooth volume swells. It's the neck POT only. There is no hum that i've encountered. It was properly shielded including the aluminum foil on the cover. i am thinking that there might be a problem on the components of the circuit. wirings are properly grounded and soldered. Someone help me to diagnose the problem.. thanks  |
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Post by newey on Oct 21, 2009 12:37:37 GMT -5
tukak- Hello and Welcome! I have several questions, and not much in the way of answers. First, you stated that: Then you stated that: Are they 500K pots or 25K pots? Or, do you mean that the tone pots are 500K while the volume pots are 25K? And, are you sure that the "25K" isn't really 250K? Unless you are using active pickups, 25K pots would be a very odd choice. It is possible that the neck volume pot is faulty, meaning that it's not turning off completely. If these are audio taper pots (i.e., log taper), that could be the reason. Switching to a linear taper pot for the volume might help that problem. Also, the way in which the volume and tone pots are wired can affect interaction between the 2 pots. You should read JohnH's exposition on modern vs. '50s wiring: guitarnuts2.proboards.com/index.cgi?board=wiring&action=display&thread=1885 |
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Post by ijustwannastrat on Oct 21, 2009 15:11:34 GMT -5
Just throwing my two cents in, one of my two volume guitars does this also, and the reason that was given to me was because the volume pots were hooked up backwards in order to "make the middle position (both pickups) blend better using the volume controls". I don't know if there is any validity in this, but you might want to open up your guitar and check it out.
Edit: Thought I'd add, I have to have the amp volume CRANKED, and even then, it's a very soft, clean-ish whisper.
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Post by ashcatlt on Oct 22, 2009 23:48:40 GMT -5
In which switch positions do you experience this behavior?
Are these pots wired "backwards" - with the pickup to the wiper?
Pending these (or any) answers, I'm wondering if it's not simply a poor ground connection on the neck pot.
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tukak0210
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Post by tukak0210 on Oct 23, 2009 6:27:03 GMT -5
i really much appreciated the effort of helping me. and i'm sorry 'bout the previous details regarding the POTS, please disregard those details on pots. after I reviewed the wiring, i noticed that on the bridge tone pot, there is an embeded letters & numbers: Alpha A25K, the neck tone pot is covered by soldered leads, im assuming that the neck and bridge tone pots uses the same type( Alpha A25K). on the volume pots, those are also covered with soldered leads but on the bridge tone pot there is a letter which was not covered by the lead: Alpha B...(numbers were covered). And also, i forgot to tell that the bridge pup's volume is weak that i have to adjust it about 5mm from the string and the neck pup too low just to make the volume equal. and by the way, i am using 150k resistor only, not 1000k ;D for the volume kit. anyway, in order to solve this dilemma ;D, i'll change the entire pots and rewire it, but still, explanations from you guys will be considered, please keep it coming.  thanks a lot! |
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tukak0210
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Post by tukak0210 on Oct 23, 2009 6:30:55 GMT -5
In which switch positions do you experience this behavior? on the neck position.. |
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tukak0210
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Post by tukak0210 on Oct 23, 2009 7:04:32 GMT -5
ohh wait a minute.. capacitors were attached on the TONE pots with the label A25K, and the VOLUME POTS have the letter "B" labeled on it, which maybe a B500K POT? isn't it? so if that's the case, the pots are not in their proper places? and maybe they made the "volume pot" a "tone pot" vice versa?  is it possible that the problem regarding the NECK volume, and the weak bridge PUP volume caused by that wiring schematic? |
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Post by newey on Oct 24, 2009 9:21:57 GMT -5
tukak-
We don't know what "that" wiring schematic is since you haven't posted it.
We're sorry to be asking so many questions, but it's difficult to visualize what you have in there in the absence of a schematic or of some well-focused pictures of your wiring.
But have faith, we'll get to the bottom of this with sufficient information.
I'm going to list several questions, most of which have already been asked- and I'll tell you why the answers are important.
First, you should understand that there are no "volume pots" or "tone pots"- "pots is pots", so to speak, the difference is in how they are wired.
Without going into a long exposition, a volume pot is a pot which is wired on all three terminals. Input (from the pickups or switches, depending) goes to one terminal, output comes off another terminal, and the third is grounded.
A tone pot is wired as a 2-wire setup (known as a "rheostat"), with the third terminal unused. Usually, the input goes to the "wiper" (the center terminal), and the second terminal goes through a capacitor to ground.
Now for the questions:
1) Are your pickups active? You'd know this if there's a 9V battery in the picture somewhere. This is important to know for several reasons, but mostly because the pot values used are very different with active pickups.
2) Does the wiring from your pickups go to the tone controls first, or to the volume controls first? See the link to "modern vs. '50s wiring above for why this is important to know.
3) Does the wire from the pickups go to the center terminal of the volume pot or to one of the side terminals? As mentioned above, guitars with individual volume controls are usually wired "reversed", meaning that the pickup is wired to the center, or wiper, of the volume pot. This is done so that turning one vol down does not turn both pickups off when the switch is in the center position.
4) Is your guitar currently all wired up, or are there things that are disconnected at present? The type of diagnostic testing you may be asked to do depends on the answer to this.
5) Do you own or have access to a digital multimeter? This is necessary to do the aforementioned diagnostic testing.
EDIT:
I'd hold off on the soldering for now until we can isolate the problem, otherwise you may find yourself doing a lot of unnecessary work.
On Alpha pots, the "A" designates an audio (log) taper pot, while "B' means a linear pot. While there's a bit of variation in pot values used, most 2 humbucker guitars use 500K pots for both volume and tone. 25K makes little sense unless, as noted above, you have one or more active pickups- but then, all the pots would normally be 25K (or 50K) pots. A combination of a 500K pot with a 25K pot would make the guitar sound very dark.
EDIT 2: Oh, and one more question: Is the wiring in the guitar the way it came from the factory, or was it rewired by persons unknown before it came into your hands?
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tukak0210
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Post by tukak0210 on Oct 24, 2009 10:50:26 GMT -5
Are your pickups active? You'd know this if there's a 9V battery in the picture somewhere. This is important to know for several reasons, but mostly because the pot values used are very different with active pickups. i have passive pups only 2) Does the wiring from your pickups go to the tone controls first, or to the volume controls first? See the link to "modern vs. '50s wiring above for why this is important to know. the hot wires (red wires from pups) goes to the volume control first. 3) Does the wire from the pickups go to the center terminal of the volume pot or to one of the side terminals? As mentioned above, guitars with individual volume controls are usually wired "reversed", meaning that the pickup is wired to the center, or wiper, of the volume pot. This is done so that turning one vol down does not turn both pickups off when the switch is in the center position. the wire goes to the center terminal. And yes sir, in center position of the toggle switch, you can turn the volume of the desired pup. 4) Is your guitar currently all wired up, or are there things that are disconnected at present? The type of diagnostic testing you may be asked to do depends on the answer to this. it's all wired up. 5) Do you own or have access to a digital multimeter? This is necessary to do the aforementioned diagnostic testing. unfortunately, i don't have one.. Oh, and one more question: Is the wiring in the guitar the way it came from the factory, or was it rewired by persons unknown before it came into your hands? I bought this just few months ago and it is a brand new. BTW sir, the stock caps when i bought it were .022uF on the bridge and a 104 caps on the neck (.0010uF - i used to think that this cap value is uncommon) |
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Post by newey on Oct 24, 2009 14:17:34 GMT -5
tukak-
OK, we now know more. You have the original wiring. It it wired like a '50's Les Paul, with the volume controls first in line. The volume controls are "reverse wired".
You have a .o22µf cap on the bridge, which is a commonly-used value, and which was the original value the guitar came with. The .015µf on the neck you installed, the original value was .001µf.
Your volume pots appear to be 500K linear taper pots, while your tone pots are perhaps 25K audio taper pots, although the lettering is obscured by solder.
I am assuming you have 2 HB pickups, as is the usual LP practice, although some LP-types use P-90 style pickups. If these are in fact P-90s, my answers might be different.
You now have a choice to make. You can either obtain a multimeter so that we can check that all the components are working appropriately. Or, you can start blindly rewiring and replacing components, hoping that you improve things.
First off, the volume problem you are experiencing may be the normal consequence of the '50's style wiring. I'll let someone with more experience with LPs speak to that question, since I don't own any LP types.
Second, Gibson LPs (and many others) use 500K pots on all 4 pots and use .047µf caps for both tone controls. The .001 cap which was stock, as well as the .015, on the neck sound like they'd be too little. If the tone pots are indeed 25K, that's odd to say the least. Neither of these things should be affecting your volume control, except for the question of interaction in the '50s wiring, which as I noted, I'm no expert on.
A faulty pot remains a possibility, but there's no way to know for sure without a meter.
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Post by JohnH on Oct 24, 2009 21:12:50 GMT -5
Definately go get a digital multimeter. $10 will get you a perfectly fine yellow plastic one, that will read resistance. Having read whats above, its still not clear (to me) how your guitar is wired up. Photos would help. 25k pots in a passive guitar are pretty much unheard of, but anything is possible. Finally, I reckon a cap with 104 written on it is 100,000 pf (10 plus 4 zeros), so 100nF = 0.1uF, a large but not impossible value for a tone cap (Sumgai - is that correct?).
cheers
John
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Post by sumgai on Oct 25, 2009 1:12:53 GMT -5
John, you're correct in all regards, although a 0.1µf cap is overly large for any guitar or pickup type. I think that a guitar using this value would sound very dark, and not just mellow. I follow newey's analysis, and if tukak is correct, then the tone controls are after the volume pots, and as you're usually the first to point out, that's not correct. Even the earliest Les Pauls had them correct - tone before volume, as well as all later editions. That's a bad sign right there. One more thing - English doesn't appear to be tukak's native language. He (?) may have to spend considerably more than a measly $10 for a meter. But it's still cheaper than almost any viable guitar part, and will pay itself back time after time, there's never any doubt about that!  tukak, Let's get one thing out of the way right now: Hi, and  to the NutzHouse! That said, I think that if earlier posters had known this was a new guitar, they'd've said the same thing as me - take it back, it's under warranty, and it's not wired correctly. If all the replacement guitars sound the same, then they're all bad. At that point, you have to decide if you like the feel of the guitar well enough to keep it. We can always change the electronics inside of the guitar, but when we do that to a new one, we void the warranty. That's worthy of some thought on your part. Where are you from, may we ask?  HTH sumgai |
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tukak0210
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Post by tukak0210 on Oct 25, 2009 1:17:36 GMT -5
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Post by JohnH on Oct 25, 2009 3:31:51 GMT -5
Tukak - thanks for posting those, it really helps. I think you were right to post them just as links without the IMG tags, because I was able to download them all at full size and squint at them!
One thing is clear - that is one weird-butt wiring scheme! but its obviously been thought out, by someone. But what were they smoking?
The 25k tone pots should leave you with a very dull sound, you could try disconnecting one end of each (wherever is easiest, maybe the hot wire that goes from tone to volume, or one end of a tone cap.
All the wires seem to be screened, but there seems to be no wire joining all the grounds of the pickups and pots. So that would rely on the grounds all being joined up at the toggle switch. If you can, have a good look inside the toggle switch cavity and see if all the outer braids are joined there - another photo or two would help.
Another thing you can check, without a meter, is tapping the pickup poles with a screwdriver, to see which ones make a click and so are the active ones. You could test that odd condition where the volume was not being cut off as you expected, to see which pickup is active.
cheers
John
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tukak0210
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Post by tukak0210 on Oct 25, 2009 4:30:09 GMT -5
img2.imageshack.us/img2/3986/wiringscheme009.jpgthere are only 3 colors of wire: yellow, red, gray So i was wrong again 'bout the red and black wires on the previous pics ;D I apologize for that confusion. Upon doing some research, Audio Log Tapers (A) are typically used as volume controls since it is designed to change the resistance on a curve which is perceived by the ear as "smooth increase in volume", while Linear Tapers (B) as tone controls, but not always. You could use either of the two, but for the best result, you should stick to the recommended POT for passive pickups. In my case, the typical wiring scheme for my passive humbucks, is to use a 500k linear taper pots for the tone control, and a 500k audio taper for the volume (Am I right?), and use .022uF caps. If that's so, mine is kinda' bizarre. That is why I think there is lacking on the sound of my guitar. I'm not satisfied with it. 
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Post by JohnH on Oct 25, 2009 4:54:03 GMT -5
On that toggle picture, can you confirm if the outer braids of all three wires, grey, yellow and red are all joined?
What I reckon is:
pickup wires: neck black, bridge red
output to jack, red
volume to toggle switch - yellow from bridge volume, grey from neck volume
It seems the volume pots are 'reversed' ie independent, which would explain why one pot does not cut off both, with output taken from outer lugs instead of inner
Tone caps, the bridge has 0.022uF, and one of the treble retainer caps is 1000pF - all good values
Its not yet clear why the pups are acting differently - but if one or more of the braids was not joined at the toggle switch it might explain it.
John
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tukak0210
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Post by tukak0210 on Oct 25, 2009 23:49:13 GMT -5
On that toggle picture, can you confirm if the outer braids of all three wires, grey, yellow and red are all joined? Yeah they are all joined together. I was thinking that I just change the 25k audio taper pot to 500k and change it as a volume control, and the linear taper pot as tone control, or adopt the usual wiring scheme for LP's. I saw an article which states that "gibson uses all linear taper pots regardless of the function - if it is a volume, or tone control. It might fix the problem.. Hopefully  It seems that the problem is not on the PUP's instead, on how the POTs were wired, or the value of the pots and the type. |
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Post by JohnH on Oct 26, 2009 1:07:29 GMT -5
A lot of recent Gibsons use 300k linear volume pots and 500k log tone pots. The vintage ones use both 500k log pots, which i think is better, combined with the treble retainer circuits.
If you want to make a quick test, I would disconnect both tone pots (those 25k pots are just wrong), and swap the volume pot connections to the normal arrangement so that the pickups are connected to the outer lugs and the toggle switch to the center lugs. That should give you back proper volume swells, and a better tone. Then if that works, you can get new tone pots, or maybe all new pots.
J
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tukak0210
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Post by tukak0210 on Oct 26, 2009 5:45:08 GMT -5
I'm considering the modern style wiring. What would be the best pot to use as volume control? Audio taper or the linear? I'll just move the 2 linear pot (which is currently a volume control), then get another 2 pots for the volume. For now, what's important is to get it playing. And also, gotta have that multimeter! ;D Could you please give me a diagram for it, or maybe a link. There's a bunch of diagrams on the web, kinda bit confusing Thanks a lot for the help guys! |
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Post by JohnH on Oct 26, 2009 6:10:36 GMT -5
I like audio taper, 500 k for volumes and tones, with the treble retention circuit that you have, which has the effect of making the effective taper between audio and linear. This is a good diagram for normal modern wiring: Lp wiring - Serymour Duncan see the inset for single conductor pickups. all your wires are shielded, and that is a good thing, just connect the outer braids to a nearby grounded pot when you follow the diagram John |
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Post by tukak0210 on Oct 26, 2009 10:38:01 GMT -5
After i have finished it, I'll show you the photos again to confirm the proper placement of the wires and PUP's. Thanks again! |
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Post by tukak0210 on Nov 12, 2009 11:13:05 GMT -5
At last, I already replaced the bridge pots with 500k audio taper pots. Now my bridge pickup is now screaming (yey! ) I found out that the pots before were: A25k on tone control, B25k on volume (which i thought a B500k ;D). Still i got one more problem left. The volume control which is not cutted off when the other volume control is fully turned on. As I stated before, I'm only having such problem on the neck volume control, well now, I'm having that on both. Does the wiring diagram of my guitar affects the transfer of the signal to the ground(pot cover)? That's what i think.. |
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the volume pots are: 25K (embeded on the POT case) 
thanks a lot!
