That is like saying you are going to get electrocuted when you use the insulated multi meter probe to test the plate voltage when you are setting the bias of the amp. Reducing guitar amp buzz and hum. What I did is simple and I want to share it with you all. So then you connect your strong voltage source and that ripple gets kind-of crushed down and the problem significantly reduces. In this example, the guitar is connected to 1: Input 1 (the input name might be different on your computer, depending on which audio interface you use) and we wish to use Guitar Rig 5 In L. Make sure that the corresponding input button (L or R) next to the input level meter is active. There is no response if a bass is plugged in, but the vu meter registers input. If the guitar is unplugged and you turn the amp up, do you still get a hum? Use a 10nF Ceramic cap to tie the "cold" side of the isolated input jack to chassis at RF right at the jack - this has the effect of extending the RF shileding effect of the chassis out along the length of the guitar input cable. ... Connect the amplifier's output to the 1/4-inch input of the direct box with a 1/4-inch cable. If it stops the issue is the input socket wiring. in your area is fairly poor and inconsistent, then this can cause the amp to generate and emit far more noise as it isn’t getting a sufficiently clean supply of power. In fact, it might even be easier to put a clip on one end to attach to ground, and attach the other end to a probe of some sort so you can poke around without risk. Both the standard 1N4005 and the high-quality Hexfred diodes are available from AES. A metal probe might work better than a chopstick. Can You Use an Electric Amp with an Acoustic Guitar? I got the amp off ebay and they said the hum is due to a blown tube. Telecaster Guitar Forum. I've tested all of the DC voltages as per the service manual and they all seem close to spec. Not to disagree, but I've found that new lead-free solder can often give the same look as a cold solder joint but be electrically sound. Forum Index > Electronics: Next oldest topic:: Next newest topic: Author Topic: Copper foil sheet to reduce reverb hum; Tom Campbell . Improve this answer. It gets much louder when it take it off standby. That did not seem to hard to do. If you’re hearing noise, buzz or hum that’s as loud or louder than your guitar, you may have a bad ground inside your guitar. Whenever you are trying to diagnose a suspect tube, keep your other hand on the Power and Standby switches ready to shut them off instantly in the unlikely case you provoke a major short. We know I*R = Voltage and thus imagine currents coupling by mutual inductance or voltage from capacitance being induced on a floating secondary. For a better experience, please enable JavaScript in your browser before proceeding. Most guitar amps have fairly low PI tail Rs and the anode loads, even if correct, are rarely better than 10% tolerance components. Another type of pickup uses a separat… Cables can … This is especially true if plugging in a guitar decreases amp noise. This should hopefully cancel out the hum. Copper foil sheet to reduce reverb hum. Switching different inputs on the input sector knob = hum (but louder on Phono) 4. If the hum is no longer present, then it may be caused by either a ground loop or cable/pedal placed before the input or in an effects loop. In combo amps the cab, speaker or speaker baffle can vibrate, rattle and buzz. I have checked all the voltage and all the resistors and caps have been replaced. I know for sure that my problem is with lose 6V6 socket contacts and specially on the V7 power tube of the amp. See if that helps. Making statements based on opinion; back them up with references or personal experience. Just as was described above. I have a 1484 that intermittently will have a bad hum which occurs in the 1st channel only. Hum-reducing adaptors usually cost around $80 USD, and you can buy them online or from music stores. If you gig a lot or do a lot of studio recording, you should have a good DI box.It’s a good idea for electric guitarists; it’s an even better idea for bass guitarists and acoustic guitarists.. DI (direct injection, direct input—take your pick) boxes are a good idea because they protect your signal from noisy outside interference like that nasty hum you otherwise can’t seem to get rid of. With all knobs on zero and the mute button on...still super loud buzz in the key of B. Haha. It occurs whether the inputs are shorted or not and is made louder when the volume control of channel one is turned up. How to get rid of hum and eliminate other noises from your audio and video systems Don't let buzz, hum, or hiss ruin your AV experience. Does gigging when you're old even make sense? Mine also was particularly bad on presets 2,3 and 4. It does have some attenuation resistors (meaning it can make loud things quieter) for if you are feeding something with higher volume like a speaker output into something that's expecting lower volume like a microphone input. One day it just stopped working, it makes a humming sound as I turn the volume up, but no input sound. It was so bad that I needed to do something. What I sometimes don't get, is why many people keep talking about getting electrocuted when you touch something with high voltage, if what you use to touch is insulated, with plastic, rubber, silicone or whatever they use to cover some screwdrivers and probes. Amplifier humming when no source is attached, Level Up: Mastering statistics with Python, Opt-in alpha test for a new Stacks editor, Visual design changes to the review queues, 2021 Moderator Election Q&A - Questionnaire, Repairing/understanding this guitar amp master stage, Effects of unearthed PSU and shielding on audio 50Hz hum, Source of Audio Noise at Low Volume — BlueTooth Mini Amp board, How to filter hum from transformer for audio rectifier, Can't find source of hum in left channel of bluetooth speaker that I built, Eliminating humming from switched audio jack. Why are the pronunciations of 'bicycle' and 'recycle' so different? https://web.archive.org/web/20161031190255/http://billmaudio.com/wp/?page_id=171. MathJax reference. Without a strong voltage source connected to the input, that ripple could be tens of millivolts and be the problem. With nothing connected, the amp's input jack will be automatically short-circuited to ground; with the guitar connected, but turned down, the input is again shorted, but at the other end of the cable, so the cable is the only variable. Connect your instrument or mic to the amp if no hiss has occurred thus far. The noise is not much different than an amp set to a real dirty channel or with a distortion pedal turned on, yes it is super EASY to set up this app and get too much noise. Any suggestions. Start with the amp switched off for the moment, and follow this step-by-step guide to powering up for the first time… 1. The hum would also almost all go away when I touched the metal around the plug in. It’s generally a good idea to plug your amp directly into a mains socket if you can, and not through something like a multi-socket. How long can a floppy disk spin for before wearing out? But an insulated screwdriver has the risk of shorting two adjacent contacts together. Right angle gearbox, proper name or design, Distorting historical facts for a historical fiction story. If you don't do this, you have no idea whether the noise you are hearing from the amplifier is being generated within the amp itself, or being picked up by the guitar and fed to the amp. This happens with any tube I put in there. Breakup from Bad Cable Solution: Repair or Replace Cable Amp with preamp connected but no sources connected to preamp = hum 3. I didn't think of it your way. How to write a portion of text on the right only? The hum is the same whether there is a cable plugged into the input or not. I have an Epiphone electro acoustic, with an active pickup, I run it through a Marshall AS50D amp, trouble is I get a most annoying hum, Marshall say it is a guitar grounding problem. I also have a vintage (1975) Martin D35, I use a Seymour Duncan ‘Woody’ when I’m gigging, it doesn’t hum ar all. Most wah-wah's are really good at picking up noise from an AC adapter. If you hear noise, try moving around with your guitar. If not, keep going and add a source. The BillM audio site has many good guides, with photos, including one for retensioning sockets, but unfortunately it’s been inaccessible. If messing with the jack changes the hum, suspect this. If you determine that there is still no hum present when the preamp, processor or receiver is connected with no inputs, then selectively begin plugging in your various inputs one at a time. I don't think that model is very old so my guess is its the power tube bias is you have the hum with no input. The amp has a fairly loud hum when powered on that fades to a somewhat loud hum after approximately 3 seconds and stays at that volume level. 2. Messages: 930. WHen I read that no sound came out, I got the mental impression he meant no GUITAR sound, but the hum remained. In fact I just got done working on it and now there is no hum at all. Defective input jack If the input jack is not making good contact to the guitar cord shield, it'll hum. Power hum without anything in the input jack can be caused by the jack. completely. This looks like the board I'm using. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. If there is any more noise than there was before the guitar was connected then the cable is at fault. From what you said there would be hum. The Gear Page is the leading online community and marketplace for guitars, amps, pedals, effects and associated gear. An input jack whose switch tab isn't making contact when no guitar is plugged in can cause loud hum or buzz (see jack picture above). As soon as you kind of touch it/wiggle it back, you get normal sound and play normally. Dual-channel input with reverb and tremolo; Check Price. Some of those hum horribly, some just a little, and some small number have no perceptible hum. Amps/Cabs Tech Corner: Amplifier, Cab & Speakers. The tubes need time to warm up so you can’t play them right away after hitting the power button. The hum is there even with or without a guitar connected and with the input shorted to ground. 2. I recently bought a Harmony h400a tube amp. How do I read bars with only one or two notes? AC Adapter. Now it’s time to make some noise! Single-coil pickups will have more noise than humbucking pickups. this is an over simplification yet true. JavaScript is disabled. Plugging both into same AC outlet = hum 6. You can see how easy I find the root cause using this technique to fix the Fender Pro Junior ampplifier hum noise. 21 1 1 bronze badge. To learn more, see our tips on writing great answers. On math papers and general questions they need to address. 1. I swapped out the KT88s for a different set and the hum increased so I went back to the first set to keep the hum … If no 50Hz but a lot of 100Hz, HT ripple. Are SSL certs auto-revoked if their Not-Valid-After date is reached without renewing? If you gig a lot or do a lot of studio recording, you should have a good DI box.It’s a good idea for electric guitarists; it’s an even better idea for bass guitarists and acoustic guitarists.. DI (direct injection, direct input—take your pick) boxes are a good idea because they protect your signal from noisy outside interference like that nasty hum you otherwise can’t seem to get rid of. It will cause no damage to run the amp briefly with one power tube missing. That ripple will, via amplifier biasing resistors, find its way to the input circuit (the most sensitive part). I've also tried 3 different cables, so I know that's not the problem. If you’re hearing noise, buzz or hum that’s as loud or louder than your guitar, you may have a bad ground inside your guitar. When you want to practise but no-one else wants to listen. If you temorarily bridge R6 with a piece of wire and the hum stops, the hum is coming from the stage before. Using an A/C adapter that converts the amp's plug from three to two prongs is a common method for avoiding ground loop hum, but this is dangerous. I had a look on the internet, but all i could find was about the amp humming if there was something attached. Because of their heat, they need more space so the amps are naturally bigger and heavier. The hum and noise in the amp is minimal, and you can only hear it when you place an ear close to the speakers. They are picking up hum because they have no (significant) input impedance to ground, so they're just picking up any passing induced voltage. Asking for help, clarification, or responding to other answers. Connect the amp into the socket on the adaptor before turning it back on. Hope you get it sorted. Together with Tony Steward's solution, this decreases the noise a lot. rev 2021.2.16.38590, The best answers are voted up and rise to the top, Electrical Engineering Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. They produce sound and as a result, they heat up. The annual Supporting Member Giveaway is on. Thanks! Built into the guitar, under the strings, is a magnetic pickup: a transducer that converts the strings’ vibration into an electrical signal. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Confirmed. I'm trying to quiet a hum from my guitar that stops when I touch the input jack. All we can say is that a good star grounding scheme is guaranteed to be one of that small, non-humming group. To enter Click Here. You may notice a slight background hum, however, as the push-pull becomes unbalanced. Set all the controls on your guitar to full, and select a pickup of your choice. Treeolyfe last edited by Treeolyfe . To view the thread about the giveaway Click Here. The pickup is a bar magnet wrapped with thousands of turns of wire, forming a coil. Use MathJax to format equations. I connected my ipod to the input and can hear the music very faintly as I turn the volume to max. To see all the prizes and full details Click Here. Your amp is also susceptible to Radio Frequency Interference which is worse in areas that are close to radio towers. soundcard gain + guitar gain + DAW input gain(s) + amp sim master gain + amp sim gain throughout the FX chain = it is easy to mess it up. Is it coming from the amp or somewhere else? If it makes no difference, then the hum is coming from the tone/volume control section. Does it hum the same if you plug a guitar in? In combo amps the cab, speaker or speaker baffle can vibrate, rattle and buzz. Do exploration spacecraft enter Mars atmosphere against Mars rotation, or on the same direction? Take notice of any buzz or hum. I've tried all different combinations of cabs and cables with no change. No matter what guitar I use or what speaker cable or speaker cabinet I use, no change to the hum. Overall, an acoustic guitar amp can help you reproduce the lowest of the low frequencies and the highest of the high frequencies. Connect the preamp this time making sure the preamp hasn’t any source connected to it at all (mute doesn’t count). Reply Quote 2. Joined: Jun 5, 2009 Location: Hjørring, DK. When the player plucks the steel strings, they vibrate next to the magnet, producing a similar vibration in the magnet’s magnetic field, which in turn causes a varying current in the coil. I read that jacks are a common issue for no … HELP - Vox AC15C1 Loud Hum Discussion in 'Amp Central Station' started by Scott57, Jan 15, … Input problems can usually be turned down with the volume control. 1). I've got a little problem with an amplifier board. No amount of fidgeting breaks the noise at all. Home Forums > Other Discussion Forums > Amp Input - Normal or Bright > SFSR - Rather loud hum with nothing plugged in Discussion in 'Amp Input - Normal or Bright' started by ledet, Sep 21, 2014. ledet Strat-O-Master. Then I grab that same tube and put it in a known working single ended 6V6 tube socket or another amp and your can touch it or wiggle it all you want and get no popping, crackling or hum of any kind. You could end up taking steps to solve a problem you don't have, as well as completely failing to solve the one you actually do have. you might hear a pin drop onto a table but not when someone is talking to you. Now I am not saying that I gonna do it, but my question is, why would there be any risk of electrocuting your self, with possible left out voltage from the filter caps, if you use an insulated flat fine tip screw driver? I have made several interesting observations. Shouldn't they say ''don't touch something with voltage unless is insulated''. Poor quality pedal boards, FX units or even guitars will feed noise into the amp that will be exponentially amplified. I’m using the Hum X to fix my ground loop problem. Fender Stratocaster Guitar Forum. Why was Hagrid expecting Harry to know of Hogwarts and his magical heritage? Once you've decided what's causing the hum (amp or guitar), then you zero in of the fix. Start with the amp connected to the speakers but with no input cables connected to the preamp. I think I have now finally narrowed down what is going on with my amp. This usually happens when an audio power amp is powered by an ungrounded secondary , which may be for mobile safety reasons. Plug the hum-reducing adaptor into the wall outlet. Since there is no active electronics there is little to no chance of inducing extra noise or hum. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. It is there all the time even with the volume at zero. Share. When they are working right, they switch the input to ground and keep it quiet. Use good-quality diodes. In each of these examples there is a COmmon Mode Hum field being suppressed by the low impedance ratio of the coupling impedance ( yet DC floating) to the low impedance shunting to ground. !So, you play music live, and you use metronome or click-tracks to synchronize your … After each connection, check for hum until you discover the humming culprit. If your guitar has this issue the ground will need to be re-soldered. How to get rid of hum and eliminate other noises from your audio and video systems Don't let buzz, hum, or hiss ruin your AV experience. The resistor slows down the discharge, and reduces voltage discharge. Sounds to me like the inputs are floating. That’s why most tube amps have a standby switch. How they ever passed EMC , CE, FCC is beyond my interest, but that's where the problem lies. Using an A/C adapter that converts the amp's plug from three to two prongs is a common method for avoiding ground loop hum, but this is dangerous. I have an Epiphone electro acoustic, with an active pickup, I run it through a Marshall AS50D amp, trouble is I get a most annoying hum, Marshall say it is a guitar grounding problem. One can interpret early guitar tube amp architectures as examples of "mixed-signal" analog systems ... there we find the presence of up to three types of signals occupying the same platform: (i) signal frequencies from the guitar (ie.