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Post by unreg on Jul 2, 2020 15:55:17 GMT -5
Hi all.  So the new pot and both knobs have been installed for about a week or so; the sound is excellent; there is still that hum. Hmm... the hum was not present, until I sat down next to my amp to adjust the eq; the new tone pot changed my guitar’s tone, but it has been successfully been adjusted now AND sounds a bit better, to me at least. I am not done fixing the guitar’s hum so I haven’t taken the pic of it yet, sorry frets.  What were the “deeper” points that you all mentioned that I could delve into once the volume pot was replaced? Thank you for reading, Matthew (unreg) |
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Post by unreg on Jul 3, 2020 21:59:59 GMT -5
thetragichero said that in my first thread.
So the hum may be from my amp? The “shorting jack” mentioned kills all sound when the input cable is unplugged?
So my amp may be the hum problem even though when the input cable is unplugged, the amp is perfectly silent?
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Post by newey on Jul 4, 2020 7:22:49 GMT -5
Hmm... the hum was not present, until I sat down next to my amp to adjust the eq; Do you have a second amp that you can try? If the hum goes away when you are not next to your amp, it may just be a "nature of the beast" type of situation. Also try swapping cables, plugging your amp into a different outlet (that is, one that is on a different circuit, which may mean moving to a different room). |
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Post by unreg on Jul 6, 2020 21:50:56 GMT -5
Hmm... the hum was not present, until I sat down next to my amp to adjust the eq; Do you have a second amp that you can try? no. Hmmm, the hum was not present until I sat down by my amp, but ever since then, the hum remains. but, my cable tested great with multimeter... don’t currently have another working cable to try Does that advice try to avoid ground loops? I have my amp plugged into a HumX plugged into an otherwise unused nice power strip plugged into the wall. Thank you newey for your grand help! Your response is much appreciated. |
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Post by newey on Jul 7, 2020 11:06:04 GMT -5
Does that advice try to avoid ground loops? No. Depending on what else may be plugged into the circuit you are using for the amp, another circuit may be quieter. For example, CRT monitors or fluorescent lamps are notorious for creating noise in a circuit. Even if you don't have anything else plugged into that circuit, some circuits are just inherently noisier than others. All of my suggestions are directed towards eliminating the variable factors that may be causing the hum. In other words, let's make sure it is actually the guitar wiring that is the culprit before we go off on the proverbial wild goose chase. I don't know what a "hum X" is, but again, trying to eliminate variables here, try it without the power strip and without the Hum X. |
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Post by unreg on Jul 7, 2020 11:32:55 GMT -5
Does that advice try to avoid ground loops? No. Depending on what else may be plugged into the circuit you are using for the amp, another circuit may be quieter. For example, CRT monitors or fluorescent lamps are notorious for creating noise in a circuit. Even if you don't have anything else plugged into that circuit, some circuits are just inherently noisier than others. All of my suggestions are directed towards eliminating the variable factors that may be causing the hum. In other words, let's make sure it is actually the guitar wiring that is the culprit before we go off on the proverbial wild goose chase. Thank you newey, I’ll try that today. humX @ Amazon(don’t remember where I got it from, but that site should be informative ) The power strip allows me to use the humX; from much reading that power strip was purchased. And after using both, the hum is reduced. |
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Post by newey on Jul 7, 2020 16:38:45 GMT -5
humX @ Amazon(don’t remember where I got it from, but that site should be informative ) The power strip allows me to use the humX; from much reading that power strip was purchased. And after using both, the hum is reduced. I am not familiar with your household AC current. Do you have 3-phase AC main current (i.e., using a three-pronged plug). And what type of amp are you using? Tube or solid state? And, how old? |
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Post by unreg on Jul 8, 2020 15:38:03 GMT -5
I am not familiar with your household AC current. Do you have 3-phase AC main current (i.e., using a three-pronged plug). And what type of amp are you using? Tube or solid state? And, how old? 3-phase AC main current (using a three-pronged plug), Solid State Fender “Frontman 25R” amp, it was bought around 1999... but, hasn’t been used extensively. I plugged the amp into plugs around the house and sometimes the hum was more silent... the HumX wasn’t being used. edit 29 minutes later: my guitar was plugged into the amp b4 testing the amp at each outlet it’s evident to me that 25 watt solid state isn’t good, but that’s all I could afford when purchased AND it has worked for me |
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Post by newey on Jul 8, 2020 20:40:29 GMT -5
I have a Frontman 25R also purchased in about 1999 or so. It was not overly noisy in my experience, although I haven't used it in a while. If the level of hum varied with trying it plugged into different circuits, were there any where the level of hum was at a non-obnoxious, tolerable level? Or was it always bad enough to be an issue, even though it may have varied somewhat?
We may have to delve deeper into how your guitar is wired and whether the hum might be ameliorated there. But I wanted to be sure to pick off the low-hanging fruit first- eliminating the cable, amp, electric mains issues, etc.
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Post by unreg on Jul 9, 2020 10:35:54 GMT -5
I have a Frontman 25R also purchased in about 1999 or so. Yes, one outlet/spot was a pretty quiet hum; that outlet was on the other side of the house. The varied-level of hum I experienced wouldn’t be an issue when recorded with my four track recorder’s DBX NR on - at least, I think so, I remember a somewhat-ugly hum that disappeared during past recordings; it’s just annoying to listen too and I wish it would stop. Really helpful! Thank you so much!  |
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Post by unreg on Aug 11, 2020 4:37:53 GMT -5
Finally, here is my guitar's diagram. It's accurate to today. Anything about the wiring scream, "HUMMMMMMMM"? edit: ooooh, I forgot to mention that the use of the green wire is an alternate setup suggested by my DiMarzio instructions when the pickups are out of phase using their normal wiring. My HBs didn't make any sound, so the alternate setup was followed by me and now I can still hear both pickups.
final edit: Revised diagram. Old incorrect diagram is below for whatever reason. final edit epilogue: My old diagram will spoil you just like food spoils (bad) bc it is incorrect... my two diagrams displayed were annoying to me so now the lesser one is a spoiler.
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Post by newey on Aug 11, 2020 6:47:49 GMT -5
Your diagram looks fine, but I don't understand why there are two resistors across your tone pot. Maybe this was discussed previously, I didn't re-read the whole thread, but since you have 2 HBs and are using 500K pots, not sure why you'd put those on there. As for your .047 tone cap, the green caps are typically polypropylene, not ceramic, but they aren't shaped like a box. They're typically called "chiclets" because they have that shape. (although I'm not sure if younger folks even know what a "chiclet" is or was anymore  ) |
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Post by unreg on Aug 11, 2020 10:41:31 GMT -5
Your diagram looks fine, but I don't understand why there are two resistors across your tone pot. Maybe this was discussed previously, I didn't re-read the whole thread, but since you have 2 HBs and are using 500K pots, not sure why you'd put those on there. The resistors are there bc I wanted to change my guitar’s tone a long time ago, someone somewhere suggested doing that, and it solved my “too much treble problem”. I’ve never mentioned the resistors before. No, I don’t know what a “chiclet” is. The “box” is a thin rectangular prism... but, “box” was a much shorter phrase. Thank you newey for looking at my diagram! Since it looks correct, I’m actually sad that you didn’t find a problem. edit: It’s been a long time since the two resistors were added... I, actually, don’t remember exactly why those resistors were added; they did solve an ugly tone problem; such a blessing! |
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Post by newey on Aug 11, 2020 11:44:19 GMT -5
 These are also sometimes called "plastic film capacitors" or just "film capacitors", as a plastic film is used as the dielectric material within. I'm assuming yours are similar to the picture. I use these type of caps in all my guitar builds, they are cheap and work well, and are of better quality than the ceramic caps, IMO |
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Post by unreg on Aug 11, 2020 15:07:50 GMT -5
These are also sometimes called "plastic film capacitors" or just "film capacitors", as a plastic film is used as the dielectric material within. I'm assuming yours are similar to the picture. I use these type of caps in all my guitar builds, they are cheap and work well, and are of better quality than the ceramic caps, IMO Thank you newey for the photos and explanation! That looks about right, but I believe mine has 90 degree angles... I’ll recheck later today. |
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Post by unreg on Aug 12, 2020 18:11:34 GMT -5
These are also sometimes called "plastic film capacitors" or just "film capacitors", as a plastic film is used as the dielectric material within. I'm assuming yours are similar to the picture. I use these type of caps in all my guitar builds, they are cheap and work well, and are of better quality than the ceramic caps, IMO Thank you newey for the photos and explanation! That looks about right, but I believe mine has 90 degree angles... I’ll recheck later today. Ah, newey, you are so right! It is a plastic film capacitor (or chiclet)! I had been looking at its side bc I soldered it sideways, so I missed its pointed top. I’m going to recheck the output jack’s wiring bc, after looking at stewmac’s guitar setup output jack page, it seemed to me that they wanted the ground and hot lines reversed (or switched) from my diagram. But, I copied YogiB’s diagram’s output jack. Maybe I soldered those wires wrong; would that cause hum? Or does that cause no sound at all? My guitar definitely produces sound. |
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Post by Yogi B on Aug 12, 2020 19:37:37 GMT -5
But, I copied YogiB’s diagram’s output jack Whoops. That's my bad. This is why I shouldn't place the output jack sideways, there's probably a 80% chance I'll get it wrong -- that's pretty bad considering, it'd be 50/50 if I were just randomly guessing. I know why I get it wrong: my brain goes "down = ground", plus it's more aesthetically pleasing that way. In general if you see one of my diagrams with a sideways jack then don't trust it.I've updated the diagram from the thread your diagram specifies ( in this post, within the spoiler) on the image host, though I'm not sure that's the right one (they do share some common features, HH & three way switch, it is an odd starting point), or whether it's just another that I've botched. The image may or may not have already updated at everyone else's end, Cloudinary seems to have changed its old asset invalidation rules to trigger almost immediately even on versioned urls, but I've yet to look if this is now the documented behaviour. |
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Post by unreg on Aug 13, 2020 3:12:26 GMT -5
But, I copied YogiB’s diagram’s output jack Whoops. That's my bad. This is why I shouldn't place the output jack sideways, there's probably a 80% chance I'll get it wrong -- that's pretty bad considering, it'd be 50/50 if I were just randomly guessing. I know why I get it wrong: my brain goes "down = ground", plus it's more aesthetically pleasing that way. In general if you see one of my diagrams with a sideways jack then don't trust it.It’s ok YogiB. I’m actually glad to know that I wasn’t having problems reading stewmac’s instructions. They’re what I looked at before soldering my output jack... so I guess I’ll change my diagram too. Though, YogiB, my diagram isn’t being used like yours. Oooh, yes your update loaded for me (like 10 minutes ago). The vertical change was funny to see after reading your reply. Haha. pointless note: I had it the correct, I guess, way, but then I noticed your diagram’s output jack was wired different. |
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Post by unreg on Feb 28, 2022 4:49:39 GMT -5
These are also sometimes called "plastic film capacitors" or just "film capacitors", as a plastic film is used as the dielectric material within. I'm assuming yours are similar to the picture. I use these type of caps in all my guitar builds, they are cheap and work well, and are of better quality than the ceramic caps, IMO I need to buy another green plastic film capacitor bc I don’t want to remove the one I have from my current tone pot. This new plastic film capacitor will be soldered to my new long shaft 250K CTS Tone pot. I can’t find a store, so I’m hoping newey will share his store with me. Hmmm… I don’t even know the measurement of my current plastic film capacitor, but it’s green and looks similar to newey’s film capacitor photo. Maybe .47uF? EDIT: on my green chiclet capacitor’s side, it says: 473J 2ASIC |
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Post by newey on Feb 28, 2022 6:17:22 GMT -5
Learning to read the code on capacitors is fairly straightforward. The "2A" indicates the voltage rating, you don't need to worry about that. The "473" indicates the capacitance, in picofarads. The first 2 digits give the base value, in this case, it's "47". The 3rd digit indicates the number of zeros to add at th end, so a "3" means 47000 picofarads, which is equal to 0.047µf There are some exceptions to the coding rules, however. You can read all about those a'web. The "J" code indicates the tolerance, in this case it's 5%. I usually order most components, caps, pots, switches, etc, from mouser.com |
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Post by unreg on Feb 28, 2022 19:21:28 GMT -5
Thank you newey! 👍😀 Your instruction is excellent and much appreciated! |
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Post by unreg on Mar 8, 2022 11:40:22 GMT -5
The "2A" indicates the voltage rating, you don't need to worry about that. Thank you newey; after reading this: Only to your wallet. For passive guitar controls, a 10 VDC cap would be fine. I will definitely NOT worry about a 2A voltage rating when buying my cap (in April). 😀 |
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Post by unreg on Apr 1, 2022 16:58:42 GMT -5
newey, I’m wondering about DC plastic film capacitors. www.mouser.com/ProductDetail/Panasonic/ECQ-E2473JF9?qs=9ouE0kzBZ2o1CJ8ic29%2FnA%3D%3DThat’s the one I’m planning to purchase… it’s 43¢ and it’s the same as my current one except that it’s 250VDC. Caps are supposed to be limited to AC? While, I’m guessing that I wouldn’t have to measure “inside” this cap, is an AC cap beneficial to guitar circuits? ChrisK said we only need a 10VDC cap, so I’m just curiously wondering. (The 100VDC Panasonic caps are not in stock. I know that 250V is overkill.) EDIT: Since my house uses AC… actually, does a DC cap not fit in a guitar circuit bc… I mean, the guitar doesn’t receive current from a wall… that current in a guitar starts at string vibrations; it leaves the guitar and enters my amp… perhaps, a DC cap doesn’t work in a guitar bc a guitar’s pickups only produce AC? (I’m fumbling; please guide this purchase with your logic.)
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Post by unreg on Apr 1, 2022 20:44:14 GMT -5
Found this: Your pickup generates an AC signal. "Hot" and "ground" are more accurately used to describe DC circuits. In reality, the hot and ground from your pickups are alternating at the frequency of the vibrating string(s). We use the terms "hot" and "ground" just becasue we have to have a way to designate one end of the AC circuit from the other. (ChrisK used to call them "hot" and "not hot" to emphasis that there is no absolute ground, as there is in a DC circuit). Ok, thank you newey! So, I need an AC capacitor to go in my AC guitar circuit. Good to know! 👍 EDIT: note, I believe I read reTrEaD saying that active pickups output DC voltage. Then, with active pickups, I’d need a DC cap. 👍 |
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Post by unreg on Apr 1, 2022 21:08:27 GMT -5
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Post by reTrEaD on Apr 2, 2022 4:17:14 GMT -5
I believe I read reTrEaD saying that active pickups output DC voltage. No. I would never say something so preposterous. Do not associate my name with falsehoods. "I believe I read" does not give you license to recklessly recite a mangled misinterpretation of what I have written, and attribute it to me. Invest more time and effort into carefully reading and thoroughly comprehending, before any future posts. |
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Post by Yogi B on Apr 2, 2022 8:12:37 GMT -5
Can caps work with both AC and DC? It depends how exactly we might choose to interpret what "work with" means — but, in short, I'm going to say yes. Hopefully you know that the (magnitude of the) impedance of a capacitor is inversely proportional to frequency (the impedance is larger at low frequencies, and smaller at higher frequencies). This is (in part) why a tone control works the way it does. As the tone cap is in parallel with the pickup: for progressively higher frequencies the cap looks progressively more like a short circuit; whereas for progressively lower frequencies the cap looks progressively like an open circuit. That covers how caps behave in AC circuits, but what about DC? Since a direct current does not vary with time, it can be thought of as an alternating current that takes an infinitely long time to alternate — in other words it has a frequency of zero. Combining that with the above, you should realise that, for DC, an (ideal) capacitor is essentially an infinite impedance, an open circuit. With that being the case, you my be wondering: what possible use could a capacitor have in a DC circuit? One example would be power filtering. Most circuits require DC, and yet mains electricity is AC — as such each device needs to convert the AC supply into DC. There are various techniques to achieve this but undoubtedly all of them include capacitors to reduce ripple (distortions which mean the converted output is not pure DC). Another application is in circuits that mix AC & DC, for example: I believe I read reTrEaD saying that active pickups output DC voltage. No. An active pickup (preamp) that could supply (a significant amount of) DC at its output is either faulty or poorly designed. Preamps, pedals, and similar use DC power sources (either batteries or, as previously mentioned, mains AC converted to pseudo-DC) in order to amplify an AC signal. We want to allow the AC signal to easily pass into and out of the preamp. However, we also want to isolate the DC, in order to stop it from affecting / being affected by other external circuits. This is done by passing the input and output through coupling capacitors. (Caps can also be used like this between sections of a single circuit that need differing DC voltages.) |
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Post by ashcatlt on Apr 2, 2022 10:12:15 GMT -5
There is no such thing as AC or DC cap. It’s just a capacitor. An AC signal with peak-to-peak voltage of 63V gives an RMS voltage a little over 40V, which is probably what that spec is trying to say.
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Post by Yogi B on Apr 2, 2022 18:11:18 GMT -5
An AC signal with peak-to-peak voltage of 63V gives an RMS voltage a little over 40V, which is probably what that spec is trying to say. My gut was telling that something wasn't quite right with this, but I couldn't put my finger on it. A 63 V pp sine wave actually equates to approx. 22 V rms, whereas it is an amplitude of 63 V that is 44 V rms. Since we're dealing with an unpolarised cap (and thus the DC rating applies in either direction), we should rightly be talking about a 63 V amplitude rather than peak-to-peak.
That being said, it is probably also worth pointing out that this near eqivalence of DC rating and amplitude-converted AC rating in this specific instance should NOT be used to infer that this is applies equally to all capacitiors, especially at higher voltages. If, for example, we look at the datasheet for the other cap (the Panasonic), we'll find another model from the same series rated at 1000 V DC and 125 V AC (specifically if used on the primary side of a power supply). It also mentions another value ( which can be found here) permissible if used on the secondary side — in this case 400 V rms. With the 125 V rating I assume they're concerned about having to survive voltage transients (spikes), but still the other (400 V rms) figure is still significantly lower than the 707 V rms of a 1 kV amplitude sine wave. My assumption here is that alternately recharging the capacitor to its full DC rated voltage one-hundred (or 120) times a second, as would be happening under the specified AC conditions, would have a detrimental effect on the dielectric. Whereas, remaining (mostly) fully charged, as would occur with DC (while in use) is much less problematic. |
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Post by unreg on Apr 10, 2022 21:43:49 GMT -5
Can caps work with both AC and DC? It depends how exactly we might choose to interpret what "work with" means — but, in short, I'm going to say yes. Hopefully you know that the (magnitude of the) impedance of a capacitor is inversely proportional to frequency (the impedance is larger at low frequencies, and smaller at higher frequencies). This is (in part) why a tone control works the way it does. As the tone cap is in parallel with the pickup: for progressively higher frequencies the cap looks progressively more like a short circuit; whereas for progressively lower frequencies the cap looks progressively like an open circuit. That covers how caps behave in AC circuits, but what about DC? Since a direct current does not vary with time, it can be thought of as an alternating current that takes an infinitely long time to alternate — in other words it has a frequency of zero. Combining that with the above, you should realise that, for DC, an (ideal) capacitor is essentially an infinite impedance, an open circuit. With that being the case, you my be wondering: what possible use could a capacitor have in a DC circuit? One example would be power filtering. Most circuits require DC, and yet mains electricity is AC — as such each device needs to convert the AC supply into DC. There are various techniques to achieve this but undoubtedly all of them include capacitors to reduce ripple (distortions which mean the converted output is not pure DC). Another application is in circuits that mix AC & DC, for example: An active pickup (preamp) that could supply (a significant amount of) DC at its output is either faulty or poorly designed. Preamps, pedals, and similar use DC power sources (either batteries or, as previously mentioned, mains AC converted to pseudo-DC) in order to amplify an AC signal. We want to allow the AC signal to easily pass into and out of the preamp. However, we also want to isolate the DC, in order to stop it from affecting / being affected by other external circuits. This is done by passing the input and output through coupling capacitors. (Caps can also be used like this between sections of a single circuit that need differing DC voltages.) The meter applies a DC voltage, which can’t flow through the capacitor. Hi Yogi B and ashcatlt. Since caps are neither AC or DC, as ashcatlt said above, why is my capacitor not able to have a DC voltage flow through it? Just trying to understand; I’m personally confused; I totally believe you Yogi B and ashcatlt. Does DC not flow through my cap bc it’s not (acting as) a coupling capacitor? |
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