benmid
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Post by benmid on Feb 25, 2011 15:30:10 GMT -5
Hello! I posted a post recently about an HSS strat that I was treating to the 'Quieting the Beast' modification. At the same time, I was replacing the volume pot for a CTS 500K rather than the CTS 250K currently in use. I was also going to replace the 0.22uf capacitor with a 0.47 orange drop capacitor. I treated the body cavities with copper tape with conductive adhesive. I covered every area of it and came up onto the face of the guitar, ensuring to cover some screw holes. I tested conductivity throughout the cavities with a multimeter and it was perfect everywhere. I then used electrical tape to cover the control cavity. I did this to avoid the components touching the shielding. I left the copper tape coming onto the face of the guitar and only covered the inside of the control cavity so that connectivity with the pickguard would continue. I used a wood screw to secure the tremolo wire to the bottom of the bridge pickup cavity and I used the exact wire described for the jack lead. I reused the other wires and resoldered them in different places. The bridge pickup is an aftermarket Bareknuckle Nailbomb pickup and it was clear that the controls had been altered to the following diagram: www.bareknucklepickups.co.uk/main/downloads/schematics/general/hsh_hss/hss__1_vol__2_tone__5_way_with_auto_coilsplit.pdfI wanted to change the wiring diagram to the one described in the modification. Therfore, I attempted to remove wires from the top of the pots (all CTS 250K with the dimple) and I replaced the volume pot. I also moved all wires described as 'black' in the Bareknuckle wiring diagram to the signal return terminal. The difference was with the black/bare wire from the bridge humbucker. For this, I sent the black wire to the signal return but sent the bare wire to the top of the volume pot. This is the only wire soldered to any of the pots at this point. I replaced the old capacitor directly with the new one and soldered wire to one end to take it to the signal return ring. The wiring diagram is identical at the 5-way switch to the Bareknuckle wiring diagram but the rest is like the 'Quieting the Beast' diagram (apart from the exceptions I have explained). Finally, I noticed that the pickguard on my guitar was aluminium but painted black. I noticed this because under one of the tone pots there were some scratches. They looked metal, so I checked connectivity between the two and it was confirmed. I then checked connectivity between the scratch and the back of the bridge pickup (which is metal). This also had connectivity. I attempted to screw the pickguard straight back onto the body (after insulating the signal return ring). I thought that seeing as it was metal, it should work. This did not remove the noise. It seemed worse actually. In fact, the noise I get is mainly from the humbucker! After this happened, I took the guitar apart again and covered points of the pickguard that would connect with the body with aluminium tape (also with conductive adhesive). I did this because I had no copper tape left. After testing, the noise was still there and not much better. This is where I'm at now! What should I do? Are any of the connections I've described incorrect? I never tested the guitar with strings on, I just plugged it in and listened for noise. It had noise straight away. One other thing I noticed was when I tested the controls. They all worked as expected, except that the humbucker seemed to be picking up signal for every position in the 5-way switch. When I tapped it, it would always respond but not as strongly as when it was its solo position. Thanks for reading this! Any help you can suggest would be great!
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Post by newey on Feb 25, 2011 19:16:27 GMT -5
I am a bit suspicious of this. If the pot shell is not used otherwise for grounding, then this shield is only going to get to ground via the pickguard shielding- which may not be a reliable connection. I'd try running a wire from the Vol pot shell to your grounding point. Not sure that's the problem, but I've got nothing else to suggest!
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benmid
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Post by benmid on Feb 26, 2011 19:00:40 GMT -5
Thanks for helping me out Newey. I'm really stuck here... The reason I did it like that is because of this description: "Some premium and aftermarket pickups have multi-conductor cables with a separate shield that does not carry a signal at all. For unshielded twin wires move the negative side to the signal return ring as shown. Move braided shields that also carry the audio signal to the signal return ring, too. For pickups which have a separate non-signal-carrying shield braid (hint, there must be at least two wires besides the braid), move the negative lead to the signal return ring but leave the non-signal-carrying shield soldered to the pot shell or other shield-ground point." The aftermarket bridge pickup has four wires. A green, red, white, and black one. There is also the bare wire. In total, there are five wires and these are wired exactly as they are in the Bareknuckle diagram. The only differences are with the grounding. I assumed, based on the description above, that the bare wire is 'non-signal-carrying'. Should I attach that wire as you suggested or should I just move the bare wire to the signal return ring which is attached to the 0.33uf capacitor? Thanks again
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Post by newey on Feb 26, 2011 22:00:42 GMT -5
I started writing a long-winded response, but I'll spare you the verbiage. A picture, as they say, is worth a thousand. Read this discussion (if you have not already done so) and look at the second diagram, showing the star-grounding. Pay attention to the blue and red color-coding (which is likewise referenced in the text). Your shielding needs to attach to the blue "operator touchable" part of the circuit. ChrisK's "The Blocking Capacitor"Note that Chris didn't feel that the jumpers between the pots needed to be eliminated, for the reasons he discusses. This is slightly different than the original Guitarnuts procedure, but electrically it's equivalent.
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benmid
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Post by benmid on Feb 26, 2011 23:24:17 GMT -5
Ohh OK thanks for that! This is is a bit clearer now. Although, rather than running a wire from the volume pot to the signal return ring; would it work if I just switched the bare wire (humbucker) from the volume pot to the central tone pot? This is where my terminal is connecting to the shield on the pickguard so would this give it access to ground? Thanks again
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Post by newey on Feb 27, 2011 1:03:53 GMT -5
Ought to, but again, you should check it with a meter just to be sure, since you're in there anyway.
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benmid
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Post by benmid on Feb 27, 2011 12:21:29 GMT -5
Okay I checked connectivity between the pots and the pickguard shield. They were all connecting fine so I left the bare wire on the volume pot for the time being. I also checked connectivity between the signal-return-ring and the pickguard. This did not show connectivity. I take it this is due to the blocking capacitor? I'm not sure if it should be like that but I thought I'd just mention it in case it isn't. I have re-covered the pickguard with copper foil instead of the aluminium stuff I was using because it wasn't particularly good. I also moved the wires on the switch so that they're exactly as described on the Bareknuckle diagram. This resulted in the switching being backwards when I tested it so I'll turn it around when I open it up again. When I tested the guitar after these changes, It was still really noisy on all pickups. It's got to be some sort of wiring problem because it's terrible and it wasn't like it before. The only other possible issue I can think of is with the grounding wire on the 5-way switch as shown on the Bareknuckle diagram but not on the GuitarNuts one. www.bareknucklepickups.co.uk/main/downloads/schematics/general/hsh_hss/hss__1_vol__2_tone__5_way_with_auto_coilsplit.pdfI sent this wire to the signal-return-ring. Do you think that is the right thing to do or I just eliminate it like the guitarnuts diagram? Thanks newey for your help. You're my only hope at the moment!
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Post by JohnH on Feb 27, 2011 14:32:46 GMT -5
Apart from the noise, does the tone sound right? Im wondering if a coil is out of phase. Check each switch setting.
John
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Post by newey on Feb 27, 2011 15:16:31 GMT -5
You have probably already done this, but since you didn't mention it, I'll ask: Did you double-check that the output jack was wired the correct way?
If that's OK, the only other thought I have is that some component may be contacting your shielding, although you said you covered the cavity area shielding with electrical tape.
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benmid
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Post by benmid on Feb 27, 2011 17:58:04 GMT -5
Apart from the noise, does the tone sound right? Im wondering if a coil is out of phase. Check each switch setting. John Before I started the work, the pickup sounded quite metallic (if that makes sense). Although it still sounded quite good. Since doing the work, I haven't actually attached the strings because the noise was so bad. This particularly bad noise has come after doing the work and wasn't present beforehand (as far as I can remember). Yes, I believe the wires are the correct way around. I have the red lead (which I'm assuming is the 'hot' lead) attached to the lower contact and the white lead to the higher contact. I have used the red lead in the hot position and white as ground on the pot as well. Yes, I've covered the cavity that holds the controls (not the pickup cavities) which electrical tape. I think that will stop the controls but it is a very tight fit so things might be getting pushed into other contacts. I'll have another good study of it but otherwise, I'm a bit clueless!
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Post by JohnH on Feb 27, 2011 18:16:46 GMT -5
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Post by JohnH on Feb 27, 2011 19:27:59 GMT -5
Also, if you have a multimeter (well worth the very few $ that they cost), you can do useful checks on your general wiring, by measuring resistance across a lead plugged into the output jack. To do this, if you have the 0.33 isolation cap, youd need to short it out, so the meter can test dc resistance. Set meter to a 20k 200k or 2000k Ohms range as required.
Then, with volume and tone at max, you should read about 2% less tha the pickup resistance in each setting - ie, if set to bridge only, and you have a 10k humbucker, it should read a bit less than 10k. But if it reads very low (unlikely), or very high (quite possible with your symptoms), theres a problem. also if you read half of what you expect, it shows one coil is not working.
You can do that with the two single position 3 and 5 also, and the combos at 2 and 4 should be less.
Now set to 200k, and reduce the volume. The resiatnce should first rise to about 130k (just over 1/4 of the volume pot value), then fall to zero at minimum volume.
In each test, turning the tone pot should make no difference, so if it does do so, it has a problem.
These tests, and the screwdriver pull off tests, and neat non-destructive tests that give a lot of info with no hacking of the guitar, so well worth a try.
John
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benmid
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Post by benmid on Feb 28, 2011 6:33:19 GMT -5
Thanks for those ideas John! I will do them all tonight when I get home. I did try the screwdriver test last night with an analogue multimeter but I think I misunderstood your instructions because I couldn't get it to respond. How do you actually connect the multimeter to the guitar lead? Thanks again
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Post by newey on Feb 28, 2011 6:47:01 GMT -5
If your meter just has the probe ends, and not alligator clips, it can be tricky. You just have to hold the meter to the plug, one lead to tip, the other to the sleeve. It's one of those jobs where it helps if you have 3 hands . . . Better yet, make a dedicated testing cable out of an old guitar cord- cut off one plug, strip the wires back, and solder alligator clips on. Just make sure the plug you keep is good.
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Post by JohnH on Feb 28, 2011 6:49:08 GMT -5
and set to your most sensitive volt setting. Actually, if you can plug into your pc soundcard line or mic input, the pc version is very simple and positive
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benmid
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Post by benmid on Feb 28, 2011 17:43:45 GMT -5
I've done all the tests! The first test I couldn't do with a computer because I don't have a way of plugging the guitar lead in unfortunately. I used an analogue voltmeter which only had 3v or 15v sensitivity to choose from. The changes were so fine but from what I could see, the needle jumped slightly up in every position. These were the results of the second test set at 20k: Humbucker: 15.82 Humbucker and Middle: 3.80 Middle: 7.35 Middle and Neck: 3.55 Neck: 6.59 I did notice some slight changes with the different tone controls rolled off with some of the pickups. These are the changes after rolling off only the neck tone control: Humbucker: NO CHANGE Humbucker & Middle: 3.77 Middle: 7.25 Middle & Neck: NO CHANGE Neck: 6.51 These are the changes after rollling off only the middle tone control: Humbucker: NO CHANGE Humbucker & Middle: 3.76 Middle: 7.21 Middle & Neck: NO CHANGE Neck: 6.47 Changes after rolling off both tone controls: Humbucker: NO CHANGE Humbucker & Middle: 2.45 Middle: 3.55 Middle & Neck: NO CHANGE Neck: 3.55 The final test was done at 200k. The test results were as expected. During this test, changes due to rolling off the tone control were very small but still there. However, this was only in the middle only position and the neck position. In the middle only position, both tone controls would each reduce the value by 0.1. In the neck position, only the middle tone control affected the reading. This was also a reduction of 0.1. Hope that information might be useful! Thanks EDIT: I forgot to try rolling off both tone controls together on the final test and this also had surprising results (as with the second test). With the volume control fully open: Humbucker: NO CHANGE Humbucker and Middle: 03.7 to 02.4 Middle: 07.3 to 03.5 Middle and Neck: NO CHANGE Neck: 06.5 to 03.5 Thanks again
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Post by JohnH on Feb 28, 2011 21:07:13 GMT -5
The fisrt set suggest that inBridge and Middle position, the Bridge Hb is being cut to a single coil to combine with teh middle. It could be as intended, it woul dhave to be the right coil or else hum will add indtaed of cancel. the rest of the combos seem OK, but the tone pot results are suspect, particulatrlt the last set where rolling two tone pots halves the resistance. This unlikley to be as intended, so, you might try fully disconnecting the tone pots and see what that does to readings and to hum. Does this guitar just have a single tone cap, like most Strats? If so, it could explain the tone pot readings if the pots are not being switched out by the 5-way, as they usually are, so that when both are rolled down, it actually connects N to M no matter whatthe 5-way is set to.
EDIT - I just looked tha diagram again, It does seems to be consistent with what I suspected, but unfortunatel that should not affect the hum.
Hum check: ignoring the HB, is the combo of N and M noisy, is it less noisy than N or M alone?
J
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benmid
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Post by benmid on Mar 2, 2011 8:15:08 GMT -5
The fisrt set suggest that inBridge and Middle position, the Bridge Hb is being cut to a single coil to combine with teh middle. It could be as intended, it woul dhave to be the right coil or else hum will add indtaed of cancel. the rest of the combos seem OK, but the tone pot results are suspect, particulatrlt the last set where rolling two tone pots halves the resistance. This unlikley to be as intended, so, you might try fully disconnecting the tone pots and see what that does to readings and to hum. Does this guitar just have a single tone cap, like most Strats? If so, it could explain the tone pot readings if the pots are not being switched out by the 5-way, as they usually are, so that when both are rolled down, it actually connects N to M no matter whatthe 5-way is set to. EDIT - I just looked tha diagram again, It does seems to be consistent with what I suspected, but unfortunatel that should not affect the hum. Hum check: ignoring the HB, is the combo of N and M noisy, is it less noisy than N or M alone? J Yeah the noise is definetely quieter in the N/M and M/HB positions. This guitar does only have one tone capacitor. I replaced it with a new orange drop 0.47 one. I connected it to the middle pot and extended one of the wires on it through to the other tone pot. Is that okay to do or should I use a wire? I haven't yet tested whether the tone pots are causing the problem but I will do as soon as I can. As for the splitting of the humbucker, I think this is part of the design of that wiring. I do have a question about the 5-way switch. Which way around should it be? On most diagrams it is with the thick part facing in towards the pots but on the Bare Knuckle diagram it's facing outwards. I did think this might be the problem so I moved all the wires to be exactly like on the Bare Knuckle diagram but didn't bother to turn the switch around. This obviously means that they're now backwards so I'll have to change them again. Which way do you recommend? Thanks again
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Post by JohnH on Mar 2, 2011 14:19:57 GMT -5
Your wiring of the cap, and of the switch sounds OK. On 5-way switches, you can mount them spun around 180 degrees and they still are fine, and work the same if you then wire them up according to where the lugs are then. Nothing described above seems to point to the source of the hum.
Maybe work on getting that screwdriver test working into the pc? Apart from downloading audacity or something similar, all you need is a 3.5mm jack to plug into your sound card. Then you can be sure of the phase issues.
Check that any back plates pf pickups are grounds, and pot covers, bridge etc.
Other than that, cant think of anything else, since the tests above seem to check out with the diagram. Maybe put a string or two on and check the sounds? J
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benmid
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Post by benmid on Mar 3, 2011 8:17:02 GMT -5
OK thanks for that John. I'll do those things and see what I get. I think I'll make a short video showing the guitar and the connectivity and the shielding I've done. You never know, you might spot something I'm missing completely! I'll plug it in and show the noise as well.
Thanks!
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UlldotteN
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Post by UlldotteN on Mar 21, 2011 16:34:29 GMT -5
I had a similar problem recently with my HSS strat. I had just installed a seymour duncan humbucker in the bridge (after performing QTB), and for some reason the humbucker was noisier than the single coils! O.o Also the noise got worse in all positions when i touched the strings or any exposed metal _except_ the output jack plate. I found that my shielding capacitor was 22nF (=0.022µF) instead of 220nF (=0.22µF). It seems like the capacitor blocked the noise inside the guitar instead of letting it out. Also the bare wire from the SD humbucker was connected to the shielding foil on the pickguard, which is why that pup was so noisy - all the noise that was "trapped" in all the shielding by the cap was connected to the backplate of the pickup :S . I simply bypassed the shielding cap with a small piece of wire between each leg of the cap, hoping that I'll never encounter the amp of doom :/ Now it's all noise free :>
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benmid
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Post by benmid on Oct 8, 2013 13:26:38 GMT -5
Hello!
It's been quite a while since I posted in this topic. I got sick of trying to figure out why the guitar was making noise and I couldn't be bothered to take the strings off and take it apart again. However, I've finally returned the project in the hope that you guys might have an idea! I've done a quick video that shows me plugging the guitar in and switching through the pickups. The noise should be easy to hear (unfortunately)!
You may notice that when I touch the pickguard, it makes a noise. I think this is because the pickguard itself is actually painted metal. I don't know if this is the cause of the noise, but I don't have another one at the moment!
I did plug the guitar into a computer and this proved that the polarity between the pickups was fine. I also tried bypassing the blocking capacitor, but this did nothing to remove the noise. I also know that the guitar cable is not the source of the problem because my Gibson Les Paul is nice and quiet. The same goes for the amplifier. You may also notice in the video that I move a wire around and it makes a crackling noise. This is the wire for the humbucker. I did think that this may have been the cause, but obviously the noise is there on all pickups, so this can't be the cause.
If you'd like pictures of the the wiring, I can take some. Although, I have wrapped them up in electrical tape to avoid any shorting, so they'll require some explanation!
Thanks! Ben
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Post by 4real on Oct 8, 2013 13:48:16 GMT -5
Could it be that you have the ground and hot reversed at the jack or somilar...so the pickguard, strings and such are hot...this is easy to do and a common mistake. Use a multimeter or simply reverse the connections at the jack and see if this addresses the noise...
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benmid
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Post by benmid on Oct 9, 2013 9:18:06 GMT -5
Well I've checked the wiring against the Quieting the Beast schematic and it's exactly the same. The red conductor going to the hot part of the jack socket and the white going to the ground part of the jack socket. The red is then soldered to the end terminal of the volume pot, with a short piece of wire then going from the end terminal to the signal return ring terminal. The white wire is attached to the wiper of the volume pot.
I hope that makes sense!
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Post by Deleted on Oct 9, 2013 9:35:52 GMT -5
The pickguard being metal is fine. As a matter of fact this is part of the shielding job. It has to be conductive and in contact to the cavity shield. I think you should go back to the beginning and start testing each component atomically and also test the system incrementally as you put components into it. So you will have to disconnect everything and start from scratch. Does the humbucker do any noise by itself (by connecting its wires to the amp)? Then test the rest of pups, and also try to compare the various noises to what you are currently hearing.
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Post by 4real on Oct 9, 2013 10:22:32 GMT -5
Well I've checked the wiring against the Quieting the Beast schematic and it's exactly the same. The red conductor going to the hot part of the jack socket and the white going to the ground part of the jack socket. The red is then soldered to the end terminal of the volume pot, with a short piece of wire then going from the end terminal to the signal return ring terminal. The white wire is attached to the wiper of the volume pot. I hope that makes sense! Yes...but have you plugged a lead into the guitar and touched a multimeter to the tipp or goun and touched the strings (which should be grounded) the plate and other things that should be grounded, it is a common thing to do and global and the symptoms do perhaps suggest this...the first test of what might be going wrong before pulling it apart...
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Post by newey on Oct 9, 2013 21:20:14 GMT -5
I haven't gone back and checked the original diagram, but what you describe is backwards, as 4real suggested. The wiper of the volume pot connects to the tip of the output jack, the sleeve of the jack should be connected to the signal return ring connector. The volume pot "end terminal", as you describe it, should also connect to the signal return. EDIT: I went back and looked at John Atchley's original "Quieting the Beast" article. Here's his schematic of the modified wiring. Note that the wiper of the Volume pot connects to the "+" output (i.e., the tip connection of the output jack.)
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benmid
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Post by benmid on Oct 12, 2013 14:26:57 GMT -5
Hi guys. Thanks for that information newey. Unfortunately, I'd just written it down wrong. It actually is done the way that you described! The tip is connected to the wiper of the volume pot and I have tested it with a multimeter and the the grounding seems fine. However, am I right in saying that, by using a multimeter and putting one probe on the tip of the lead, and putting another probe on the strings, they shouldn't be connected?
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Post by Deleted on Oct 13, 2013 9:51:37 GMT -5
Right, strings are - (ground), lead tip is + (hot). With volume at 10, you should get about the resistance of the selected pup.
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