Guitar amp transformer hum May 23, 2016 · Its a 60Hz hum that doesn't respond to volume control and is still audible when the instruments are not plugged in, but in the case of my guitar amp it can be drowned out by raising the gain and distortion levels and just creating a different hum than the one the amp makes which is still incredibly annoying. Let’s back up a Dec 2, 2010 · Guitar Amps; Maintenance, Troubleshooting & Repair; New Month We are at $30 this month in Donations. Feb 22, 2022 · If the volume of the hum changes as you rotate the guitar or as you approach a piece of equipment, that’s a big clue. To put it simple, the transformer inside the Hum X "balances" the guitar's circuit just like a balanced May 29, 2015 · Hi everyone new member first posting. which is far more noticeable when playing into a distorted amp. I DISCONNECTED THE PRE-AMP which means nothing from any instruments is Oct 21, 2007 · So the outcome came down to either replacing an otherwise perfectly good transformer (which I didn't have), or mounting it external to the amplifier. I pulled the amp section out of the amp and everything looks clean. Solution: Test your tubes by swapping them with known good ones. The difference in-between watts and VA (volt amperes) is watts is actual power used vs actual power used plus the magnetizing current in Jul 24, 2017 · Hi all, I have some HUM problems (60Hz) with a mesa boogie guitar amp. I have an old Peavey Pacer 100 SS Series amp that a friend just gave me and it has a problem. Because of sim stupidity, I have modeled with DC. Jan 19, 2023 · Repairing a Buzzing or Vibrating Transfomer CasingI have a couple of very simular videos, this was just another one that I thought I would try some This resi Feb 3, 2015 · The buzz does not change depending where the guitar is positioned or oriented relative to the amp, nor is it affected by single coils vs humbuckers. It's the transformers that differentiate one amp brand or sound from another. Dec 10, 2020 · This amp came to me in reasonably good condition. Everything’s powered on and ready to go, but there’s just one problem: the buzz. By Rob Robinette. Didn't work, Sep 24, 2024 · The Electromagnetic Induction Principle is the fundamental concept behind transformer operation. Let’s go over each of these in detail. Using the amp at unnecessarily high volumes is also ill-advised if you want to avoid distortion and premature tube damage. On some hifi amps the designer would actually drill only one mounting hole on the output transformer so he could rotate it a bit from exactly 90 degrees. Top. Jun 4, 2007 · Hi everyone. The transformer can transmit your guitar signal without a ground connection, Isolation transformers, like the Ebtech Hum Feb 15, 2019 · Moral of the story: Carry spare tubes, and pick up an isolation transformer to keep on hand in case unexpected noises arise. To check, I left the amp on for a half hour, to see if the power-amp gets unusually hot. Listening to what (if anything) comes out of the speakers can help you isolate the problem to Aug 12, 2020 · @bdgregory the hum is not audible from the speaker drivers. The guitar is floating so noise gets equally induced to both ground and signal. Since it's apparently a known issue with these amps for the power transformer to be the culprit, and since the transformer is physically humming, I'm leaning towards that, or possibly the output tubes or rectifier. Dec 21, 2012 · I had a similar problem a few years back involving a SE guitar amp. So maybe the RCA's I'm using are noisey but I'm not sure. That was about 2 years ago. The owner did a great job constructing this machine. Cable Nov 4, 2022 · Do not do this. This is not a power transfer. So I replaced the power supply 2000uF/35V caps with new 2200uF/35V caps. May 7, 2012 · No, they don't. Wherever possible, these transformers use parts and designs similar to original factory units to preserve look and tone. It dopes however hum quite a bit. You can hear it when you place your ear close or next to the chassis. This creates the dreaded 50/60 Cycle Hum that we’ve all heard of before. It's enough to vibrate the rack it's in and set off other hums and resonances. Use one isolated power transformer for the amp-input chain, and another for the FX Loop chain. What is giving me nervosa is an amount of Jan 15, 2018 · But this didn't work as significant humming noise was heard when connected to pedal and to amp. Echo Flo suggested connecting the amp to a power strip, then plugging that into one of the 120 V outlets on the pack. Post Cancel The ART Dual Transformer/Isolator Hum Eliminator uses a pair of high-performance transformers to totally separate input and output signal grounds, thereby isolating the 2 systems and reducing hum and ground-loop noise. SE designs are much more susceptible to this than PP. Jan 14, 2021 · With the Hum X, the transformer inside disconnects the guitar's ground from the amp's ground. So, l can't see the OT I replaced having any effect? I pulled each tube, hum doesn't leave. It has a single 12AX7 in the preamp (along with a bunch of op amps) and a Mosfet power section. I p Apr 5, 2008 · Hi there, I spent the last days trying to build a guitar amp. Live relevant things: Suite 12, MacBook M1 Max, RME UFX II (kext drivers), Push 1. And by "audible" I mean "with your ear in front of the faceplate. I do get the usual 60 cycle type hum with single coils, but that comes on top of the buzz I am trying to diagnose. Solution: Transformer hum is usually normal, but if it’s excessively loud, consult a technician for evaluation. Now I have a hum when the amp is turned on. Guitar amplifiers are integral to a guitarist’s setup, enhancing sound quality and providing the power needed to project music to an audience. Just today (03/23/14) it started to hum again. Single-coil pickups (most commonly found in Strat-style guitars) tend to generate noise due to their design, Single coil pickups. Typically, a choke would replace a resistor that sits between the output transformer and output valve screen grid nodes in the HV rail. They are usually large and step the voltages up to 200~600V. This is what it looks like on an oscilloscope, at 20mV/division. The amp has a fair amount of buzz/hum which makes it pretty unusable in a recording situation. If your amp has only one transformer (the output transformer) the answer is YES, you need one. The fender is running on a transformer cos its a US model running 110v, so the converter takes 240v from the wall and means i did not have to modify the amp to use australian voltage. This one had a strange whistle, kind of like feedback, however the tone and amplitude could be maintained by the level control. Now when I turn it on you hear hum that lasts about 5 seconds then fades to a soft hum( you have to be 2ft or so close to the speaker) that . C. Nov 27, 2023 · Most likely the Imac power supply. Ground Loop Hum. Moreover, if I pull P24 signal header from the power amp section (see the attached schematics) the hum disappears. Luckily, there are a few things Nov 4, 2022 · My favorite solution is a passive isolation transformer such as the Lehle P-Split II. If your amp has two Sep 26, 2022 · For some years my Cabre AF-25 power amp has been humming through the speakers so annoyingly that listening at low volumes is really unsustainable. Comment. Mar 17, 2020 · What Is A Hum Eliminator? The humming sound on your audio setup can get into the nerves, and it must be eliminated before the performance. Allot of that has to do with how Sep 24, 2023 · Troubleshooting guitar amp hum and buzz can be a frustrating process, but with a systematic approach, you can identify and address the source of the noise. The main transformer began to hum, so I removed all the tar and replaced it with a heat conductive epoxy that I placed under a vacuum to remove all the air. Many large amplifiers have a really annoying mechanical hum (emitted from the toroidal transformer itself). // Kindly sponsored by my favorite PCB manufacturer PCBWay! h Only at Sweetwater! Bulk Pricing and Easy Payments for your ART CleanBOX II 2-channel Hum Eliminator! Hum and Ground Loop Remover. It's noticeable buzz when the amp gets to heat and doesn't change when the volume pots are adjusted, it's just there. 50 or 60Hz hum usually comes from the power transformer or its wiring, the fixed bias circuit, the tube heater wires or from external RFI caused by fluorescent lights, Apr 17, 2015 · The valves used in guitar amps are indirectly heated (except for some rectifier valves discussed shortly), meaning the heater is a completely separate and not electrically connected to any other part of the valve. But it requires a dedicated device designed to remove most audio noise issues. What yoiu want is a Power Transformer, not an Output Transformer and yes multi-tap power transformers are quite common and a few may even drop in place but that will take some research. (alternating current), a 50 or 60 4 days ago · Hoffman Amplifiers Tube Amp Forum, Transformer orientation/location considerations. We recommend temporarily removing any pedals or effects from your rig so that only the guitar is Oct 4, 2024 · Tube Amp Hum: Tube amps naturally create some level of noise due to the vacuum tubes, but a significant hum might indicate an issue with the tubes, transformer, or grounding. The most common causes of buzz and hum actually come Aug 22, 2004 · If you can, and IF THE AMP DOES NOT USE TUBES, you could do the following: measure the incoming voltage at the transformer's primary, and then measure the voltages on Sep 25, 2023 · Transformer Hum: Cause: Transformers inside your amplifier can produce a low-frequency hum. The output transducer of the reverb tank is a single coil, it will pick up hum, just like a single coil in a guitar does. To the question about changing cables; the hum was consistent whether the cable was plugged into the guitar and even if you unplug the cable between the guitar and Helix from the Helix, it was a Apr 5, 2021 · Then you've got hum from the guitar getting to the amp. Apr 26, 2008 · Small amps, output transformer hum 04-26-2008, 03:53 PM. Sep 18, 2014 · Plug your guitar into one of your other amps which is placed some distance away. Start with the basics, such as checking cables and your guitar, Jul 28, 2022 · In this guide, we will show you how to diagnose and remove unwanted noise (buzz or hum) from tube amplifiers. So i thought, maybe the power-amp is drawing to much current and is loading the power supply. No rattle, no fizz, nothing when turning knobs, just a slight hum. Sep 28, 2008 · The hum is quite loud irrespective of volume knob position (volume knob does not affect the volume of the hum). While we know the noise is coming from your amplifier, it is important to identify that the source of your noise is actually coming from the amplifier. Amp Buzz When Guitar Is Jun 30, 2019 · > hum decreases to nothing as I turn the volume down. Please consider making a Jan 10, 2025 · I have this Ampro New Educational projector that I am in the process of converting into a guitar amp. I was wondering if replacing the Apr 9, 2020 · The hum comes as soon as I turn on the power with amp in standby mode (no signal to OT), just a/c and filaments. Hum in kit amps? Always comes back to grounding techniques. I can feel a fair amount of physical vibration from all points of the transformer, including the mounting frame, when I touch it with a stick when it's powered up. FWIW, on guitar combo amps, the amp chassis is fastened upside down to the underside of the top of the cabinet. 😂Most amp h May 24, 2017 · Types of Pickups in your Guitar: The types of pickups in your guitar can also affect the amount of hum coming out of your amplifier. I pulled it out and turned it on and it had quite a bit of hum(60Hz). This time, a MojoTone Fender Deluxe Reverb. This is caused by Mar 11, 2024 · Lil' Tiger Hammond AO-43 Organ to Guitar Amp Conversion (C) 2009-2023, G. If nothing is broken in the signal chain, or super-cheap, most of your audible 60 cycle hum comes from you guitar pickups. Apr 9, 2017 · Allot of it has to do with the type, size and voltages of the transformer too. You may have a similar situation. If your reverb pan has been removed and replaced in a different orientation that can cause hum. As with most of my other projects so far, that involves installing an isolation transformer so I don't get fried. Jan 15, 2009 · 3) With regards to the output transformer, can I touch it when the amp is powered up? Also. At this point I'd almost call it 'done', except for one last annoying thing, that being that when I turn the amp 'off', there is a momentary (and rather loud) hum that comes out of the speaker. If you're using a ground-lift adapter on one amp that is connected to the other grounded amp through cable, when you touch both guitar plugs at the same time, you will get a jolt of electricity through your body. By understanding this principle, we can design and construct transformers that efficiently transmit electrical energy from one circuit to another. The first item in your signal chain to investigate during the event of guitar amp buzz is the guitar The humming noise can be caused by a faulty connection in the cable connecting the guitar to the amp. It's old. Of course, it also helps to roll off the volume pot when not playing. Looking at your case; did you try to short the reverb return input at the amp when disconnecting the reverb. It is entirely up to the circuit designer to decide whether a choke would be beneficial or not versus the additional cost involved. After a while the hum becomes less until it is almost totally gone. Which will require 100k impedance of transformer on the guitar side. As you found out, the ideal solution is to use longer Jul 1, 2014 · When I do this, the noise floor from the amp (small amount of hiss, guitar noise, etc) drops as expected but the hum level is still the same. We need to transfer maximum voltage. Forrest Cook Build #2 of the Lil' Tiger amp with 6FQ7, the reverb tank is above the amp. Here's a simulation of this effect, which should be familiar to any guitar-amp builder. Hammond's Fender Blues Junior series guitar amp replacement transformers are designed for 15 watt Fender Blue Jr amplifiers. On another note, old tube amps often have leaky transformers so I wouldnt be surprised if you get some AFCI tripping in some cases. Jan 12, 2012 · Sounds kinda like 60 cycle hum to me, could be a ground loop, and/or poorly shielded parts of the amp, could be a bad tube, lots of things can accept hum from the outside. I've gotten hum from many tube amp transformers before. The transformer just carry whatever signal that the guitar output provides. Apr 12, 2019 · The filter choke helps smooth ripple or hum in the power supply and is most often found between the main filter cap, which feeds the output transformer/power tubes, and the screen supply filter cap. 8. These unwanted noises can disrupt your playing and diminish the May 8, 2017 · When you seek a solution be sure not to make the mistake emboldened in the quote. If he says yes, have the amp serviced or possibly replace it. However, one of the most frustrating experiences for musicians is Jul 30, 2010 · This is my first tube amp, but I'm aware that tube amp does have some hum. On my single coil guitars, I try to keep the guitar away from power transformers and sometimes must change my position to keep the hum at acceptable levels. May 19, 2005 · I am working on one of my old amps, a Gibson GPA50(50 watt PA amp). NO popping or rattling type of sound - starts to be audible at master=3 volume=3 - hum is significant at master=6volume=3, or master=3volume=6] There are dedicated hum eliminators that really just have inputs and outputs, and a isolating transformer in between. Dec 31, 2024 · 2-channel Hum Eliminator with XLR, 1/4", Bass Guitar Combo Amps Bass Guitar Amp Heads Bass Guitar Amp Cabinets Bass Guitar Amp Accessories View All Bass Guitar Amps DTI 2-channel Hum Eliminator. Not sure if that is sufficient time to note if the transformer is heating up. To convert amps to watts or VA, multiply the amps x 120 volts. It has to do with their Y capacitor in the power supply, which when they were utilized in some guitar amps, they got the name 'deathcap' because the industry at the time (60s) didn't know how to make that saftey cap correctly. Here's my technique for troubleshooting a tube guitar amplifier. If you have guitar related questions, start with the "search" field at the top of the page. Annoying buzzing, humming, whistling, whistling, etc. Such devices include the ART DTI. Jul 8, 2018 · Here is a generic method for repairing a vintage power transformer that has excessive noise caused by loose iron core lamination's. Leave the transformer on for ten minutes, or until it gets hot, Aug 22, 2004 · I need related help on transformer hum I have a McIntosh mc7106 amp. However, the problem is there is a strong 60-cycle hum now. Just about every electric guitarist or bassist has experienced “the hum. This puzzles me because the fact Nov 26, 2024 · While trying to record a guitar part using the Hiwatt Hi-Gain 100 amp, James discovers a new and highly unwanted type of sonic interference. You can change VA directly to watts if rated such. In my experience, and I’ve owned and sorted out many a tube amp, if I hear any 60 hz buzzing, Dec 18, 2023 · Jason Tong of Headfirst Amplification spoke up on one of the problems he noticed with Marshall’s 2203X guitar amplifier head. IMHO this is wiser than just getting a step-down unit since those mean another Apr 22, 2020 · Have a couple questions hoping I can get more clarity on. Hum Eliminator also converts back and forth between balanced and unbalanced connections and prevents the cable to act as an antenna for noise. 2 ohm Jensen) and the output transformer is long gone and was replaced with a classy Mercury Magnetics May 9, 2020 · The right way to put it is: amp causing reverb hum. Your reverb recovery transducer is like a little guitar pickup. Oct 14, 2009 · Turn up the guitar’s volume and treble controls so that the guitar signal overrides hum and noise picked up by the guitar cable and guitar amp. Is the hum directional? So many power transformers radiate hum for miles. Jul 30, 2024 · Unwanted feedback from your amp can be caused by bad wiring, radio interference, or loose connections between your equipment. All of them seem to be needing replaced as they make the clinking sound when tapped. Widowmaker Amps. Luckily, there are a few things you can try to help reduce or completely eliminate the constant hum. The buzzing will happen even if nothing is connected to your amplifier. Now substitute another amp for the DR and do the test again. I tried replacing the reverb driver tube, cleaning all the contact points from the RCA cables to the chassis and the connection points on the reverb tank. It has a low level hum that sounds like 120 hz AC leakage. Jan 26, 2019 · I had a question from a viewer about how much hum comes out of the power section of an amplifier. (818) 998-7791 Jun 8, 2011 · Every time I run 2 guitar amps in stereo I have had ground hum. The amp is idling and the load is an 8 Ohm power Apr 6, 2021 · Before you start modifying your AC30, get to know it well, because development engineers have done it much better before you. Nov 1, 2013 · You need to know how many watts, VA or amps the guitar amp draws to calculate VA size of the isolation transformer. Aug 31, 2018 · The moment it is turned on, the speaker jumps and looks like it’s being pulled into the amp, and a loud hum is present. Feb 1, 2019 · Hi all, I have a small guitar amp which, even if nothing is plugged in and all preamp tubes are pulled out, has a low level 100Hz hum which bothers me. I'm dealing with a hum from my 3120 amp. It sounds great, except for one thing that occurs when gain is too high. I tried to troubleshoot it by taking all of my pedals out of the equation and just plugging it into Jul 27, 2021 · If the amp is humming with no guitar plugged in, then either something is wrong with the amp or with the circuit. It is a solid state Q-tube 70 guitar amp probably from the 1980's. Bye bye mechanical hum. The power ground of a guitar amplifier, connected to a signal processor which has a second guitar amplifier on the other channel, and then the second guitar amp's power ground. There are three transformers. When I turn the amp on (without a guitar being plugged in), there is a loud hum. Cute amp and it sounds fine for what I do and it will most likely work for some of my gigs. Sep 24, 2023 · Guitar amplifiers are essential tools for any guitarist, but they can sometimes be a source of frustration when unwanted hums and buzzes creep into your sound. However, joining amps is often fraught with buzzing and noise etc. Currently, I have a Vox AC30 CH Head with Vox 2x12 Cab, Marshall JCM900 50W Combo, Fender Mustang 2 combo and a Hartke HD25 bass combo. Oct 2, 2021 · I’ve had issues with amps before where a speaker goes bad from the power being cut off while the volume is up. I have a 45 based single ended amp and the transformer has a bit of mechanical buzz but that doesn’t bother me too much. For audio speakers and amplifiers, this commonly happens when two or more electronic devices with grounded power cables are connected on May 31, 2018 · Recent repair at D-lab. Now here is the big question: If the transformer is bolted tight on the chassis, and it buzzes in several different buildings across town and even when plugged into a Aug 27, 2021 · A safer and more effective solution is an isolation transformer at the input of your guitar amp. Normally, when you get a lot of hum in an amp, it's caused by bad filter capacitors. I’m not sure where monoprice sources their transformer, but that’s probably the culprit. Re: How to clean up Guitar hum. Dec 19, 2016 · I went to guitar center with a band in search of their sound just a couple of days ago to play some amps. So 10k:10k transformer will not be the correct choice. A working amplifier can produce some “normal” low-level noise, especially at high gain or high volume. ” It seems ubiquitous, like no matter what you do, how you stand, what you play, the way you hold your mouth, it’s there. You can hear it within 2 feet. Aug 21, 2012 · Standing up close to an amp with big transformers is a great way to make you guitar hum due to the big transformers in it. What happens is that when I turn one of the preamp volume pots high enough strange ringing occurs. The location of the 6FQ7 is preferred over the 6SN7 location since the latter is close to the power transformer and can pick up hum. Oct 17, 2021 · I bought a used amp that uses 4 x 6L6. This reduced the hum, but it is still way too distracting. After getting his hands on one of these amps, which was manufactured in 2023, Jason took to Jul 9, 2023 · 1. The OPT was picking up hum electromagnetically through the Power Transformer. I think one of the reasons I don't care about video is because most of TV's common when I was a child (CRT's) gave me - and still do - bad headaches from transformer Dec 11, 2010 · My amp just started making an odd humming noise coming from the transformer near the power tubes when i turn it on ,and it seems like every once in a while it will loose all crunch and clarity and become really muddy,sometimes loses some volume , also even when the amp has no guitar plugged into it it will make a wierd low voiced "pop pop" sound coming from Jun 26, 2023 · We’ve all been there: your carefully concocted rig is finally ready to evoke the meticulously honed tones you’ve been designing. -g Last edited by mooreamps; 04-30-2008, 05:25 AM. And some PTs (such as that used in the Kalamazoos) don't have filament winding center taps. The P-Split II makes it possible to route an Mar 22, 2006 · Ok, let's say you have a power transformer in a tube integrated amplifier and it hums / buzzes. Aug 30, 2022 · If your guitar amp is buzzing, the root of the problem could be due to poor guitar grounding, improper shielding, dirty power, damaged cables or amp malfunction. Aug 22, 2020 · Hey folks For as long as I can remember, I've suffered from noisy guitar amps. Apr 25, 2008 · My nephew brought me his ailing ASI solid state guitar amp to take a look at. In the store everything was fine, but when I came home I realized there was a persistent low humming noise, irrespective of channel and volume. Sep 25, 2023 · 7. Dec 16, 2018 · I'm often asked about tube rectification in guitar amplifiers. Jan 8, 2018 · Hi all, I've been working on this for a few weeks but have run into this little problem low level hum. The hum level does not change if I increase master volume. Jun 15, 2009 · Hi guys, I have an Ashdown Klystron 1200 amp head and when I turn it on there is a pretty prominent hum, like from a transformer (might actually be from the transformer). Ask the guitarist to move around, or rotate, to find a spot in the room where hum disappears. With PedalSnake, when isolating power, use two separate MF1-H Single P-Line Pigtails, 60Hz ground loop current can flow between the amps in the ground wire of the audio guitar cords. One of the band's guitarists was thinking Marshall so, having played through Marshall amps Nov 8, 2022 · Investigating and fixing what's causing the 100Hz hum in my Marshall practice guitar amplifier. Jun 13, 2023 · Usually, that hum is from the supply line. 4) The hum occurs when all pots are set to zero. The volume controls have no effect on the hum at all. [] Hi all! So in the last few days I wrote a post about a Jet City head I was about to purchase except for a weird noise it made when switched on (even in standby) around the transformer. It might not help now but if the speakers are the problem that little trick can help make your amp last a lot longer. unless they just happen to be good together. This is a mechanical event, coming from within the chassis. If that’s the case make sure to turn your amp and guitar volume down before turning off the amp. This helps, but isn't always enough. What is the cheapest way I can 100% get rid of it safely? I am itching to record a 5150 and a JCM800 at the same time for ryth tracks. ). Tube Issues: Cause: Faulty or worn-out tubes can introduce noise. This is a forum where guitarists, from novice to experienced, can explore the world of guitar through a variety of media and discussion. If it's just the amp (try plugging in a short pedal-board patch cable not a long guitar cord) Or, it could be a bad output transformer, as the noise really increased when you turned up the volume. 2. When it comes to designing and constructing transformers, two crucial aspects First, mains-rectified amps were generally small output, 1-5 watts. I’m running the amp with a DAC and a CD transport is it ok to Jul 12, 2000 · This causes the amplifier to blow fuses or the transformer to overheat, and may cause electrical shocks if the short is from the primary winding. Mar 9, 2015 · In most instances, it will only come from the equipment with large toroidal transformers, like large power amplifiers. The church I was at uses Kempers exclusively. 3 days ago · Understanding the problem of tube heaters and hum is the first step toward ensuring your wiring job will be good enough to give happy results (no hum). Jan 1, 2012 · So, I'm getting 60Hz magnetic induced hum from the amp's power transformer. Aug 27, 2020 · For good amps, transformers are shielded and the physical layout of parts have considered EMI. ” To that end, the first test you should perform is whether you can hear anything coming from the speakers. Most other modern electronic devices don't have such transformers anymore; other strong sources include electric motors and CRT monitors/TVs, but I reckon that's unlikely in your case. We chose the latter option. Ground Loops, which are also referred to as Mains Hum and Power Line Hum occur when there are multiple Ground Paths on the same circuit. Reason: grammer _____ Gary Moore Moore Amplifiication mooreamps@hotmail. Find a position with the least hum. Victor Not all guitar amplifiers will have a choke because not all amplifiers need one. Is So, it's either shielding the output transformer, or it's coming in from the front end from the guitar. Also, one side of the wiring is grounded (this is a bad idea, right? Could you comment on that, grounding Jul 22, 2007 · A good amp tech should be able to fix it so it doesn't hum. I'm considering building a faraday cage, to kill the last traces of hum. Mar 10, 2020 · There is a chance they’re not great and therefore not phase cancelling the hum from the transformer. I did change all the electrolytic's three F&T's and two Sprague's are new. First, keep in mind that a tube rectifier is not an audio amplifying 5 days ago · Ghost notes are notes that are "riding on top" of the guitar note, not generally harmonically related to the note being played. IMHO, the power within amps range from minor inherent hum (from cheap or broken amps) to inaudible by the human ear. Here's what Morley says about the Hum Eliminator: The Hum Eliminator uses our custom in-house made isolation transformers to break loop antennas that cause ground hum and buzz. The 60-cycle (or in your case 50-cycle) hum is a characteristic of AC voltage. I tried moving the transformer and its wires around with it unmounted from the chassis and the chassis out of the amp, but neither its position nor orientation seems to affect the hum. Filter caps have no effect on grounding hum, and shielding signal leads does nothing about power supply ripple, for example. The hum changes volume as I turn direction and increases greatly as I approach the amp (using just guitar and cable). As I turn the volume up, I get a very loud 60hz hum, but then it suddenly falls off to a reasonable level as the volume reaches maximum. " Then again, perhaps I'm more sensitive to HF noise than most. Dec 6, 2020 · After 9 months of trying to resolve the hum in this awesome Vox V125 amp, I discovered it was as simple (and free) as this 'one weird trick'. Try a different guitar cable to isolate if you have a bad cable. The heater is 6,3VAC and conection between heaters are (saddly) PCB traces and flying wiring without twisted wires. I compared the performance by powering the pedal with a linear power supply which consists of a single transformer and eight LM7809 regulators at parallel outputs. How do I know this? I shut off all other household electronics/lights, and tried various room locations. (This is, of course, after you have eliminated the possibility of trivial problems. Aug 29, 2021 · I've been asked about tube amp hum/buzz and how to get rid of it. I believe that some (very few) transformers can produce hum no matter what for some crazy reason. Turn on the DR and move the guitar around the DR noting how the hum picked up by the guitar and amplified by the other amp is affected by the guitar pickup's proximity to the DR. S, I live in Australia. Also passive DI boxes also include "transformers", and thus can also isolate ground hums. That is why the impedance of guitar preamps vary from 220 k to a few meg. If the hum goes away when you unplug the speaker (caution this is not a healthy practice for your OT), it's definitely hum. Feb 2, 2019 · Hey all, Last night, when I went to play through my amp I noticed a persistent hum on both standby and when the amp is on that was never there before. My worst source of hum was my AC ground. When its relationship is aligned with a source of hum like the power transformer in your amp it will hum. At gigs this probably isn't loud enough to be a problem, at home it's a bit of a pain though. Manufacturers usually didn't skimp on the larger amps. I absolutely love this amp and it's possibilities, but I have to get rid of the hum! Apr 9, 2022 · I'm trying to connect a tube guitar amplifier to the Delta 1300 W battery pack by Echo Flo. Potentiometers, sockets, and switches Nov 17, 2020 · After having installed them, I realized that this amp had quite a bit of 50/100Hz hum. Jan 21, 2021 · Hi Chris, I recently took my Marshall JCM800 into my local tech because it was making an awful hum and he said that it needs a cap job, what does this mean? – Russell, Aberdeen. Speaker was replaced with an 8 ohm (I installed an early 70's 3. Not torroidial. If your problem is a ground loop issue and that is the most common cause of hum, you can try lifting the ground which you have, you can try improving the ground through various mechanical means, but the method that is typically the most successful is to use high quality isolation transformers in the May 8, 2013 · My tube amp, a Marshall jtm30, gives no sound. Nada. The funny thing is that on the other channel (which is identical, because it is a stereo amp with switchable guitar add-on, so you have two totally Apr 17, 2015 · The valves used in guitar amps are indirectly heated (except for some rectifier valves discussed shortly), meaning the heater is a completely separate and not electrically connected to any other part of the valve. Feb 9, 2008 · Then make sure that the same applies to the guitar, and that it is well wired with spidered grounds without loops. Mar 28, 2021 · So I finally finished building my guitar amp. However, when I turn down the treble control on the pre-amp, the hum progressively disappears until you turn the control completely down, when there is (almost) no hum. I noticed my sansamp had Apr 3, 2021 · However the hum is bad enough that I don't think lifting the heaters 10 volts or adding a humdinger is going to cut it. Sep 3, 2017 · However a very low level hum remains which is transferred onto the chassis. Again, the level of the hum is below what I think most people who use tube amps would consider an acceptable level. It seams to originate from the power-amp, since its less loud at the transformer. This happen weather or not the speakers or bass is Apr 26, 2020 · Welcome to r/guitar, a community devoted to the exchange of guitar related information. It’s not offensive, but it’s noticeable, and right when you think it’ll never, ever stop, you touch your strings or the jack, and it does. The ghost notes are usually caused by inadequate power supply filtering, which allows a 120Hz component to modulate the guitar signal. The chasis was loose in the enclosure and I was trying to tighten it with the screws and I believe the transformer touched the metal grill no my amp has a humming noise. Since signal is referenced to ground, the noise is cancelled out. Types of noises from a guitar amp Normal noises of a tube or solid state amplifier. The passive isolation transformer makes it possible to keep your amps grounded while isolating one from the other. The power tubes glows, the preamp tubes does not! I have replaced the preamp tubes but nothing. Jan 2, 2025 · I've got an otherwise lovely Murray Amplifiers power amp that physically hums like a *insert humming thing of choice*. Flip the polarity switch on the guitar amp to the lowest-hum position. Apr 6, 2014 · And that's exactly it. Like a fly you can’t swat away, it’s difficult to focus on anything but that annoying humming coming from your guitar. However, with th Aug 28, 2021 · Hum is coming from the main power transformer. Culprit #1: Your Guitar Is Causing Buzz. This probably comes by-design on this amp, 100W isn't exactly meant to be used as a bedroom amp. Starting with the high gain stage to test for stability, I get lots of hum and also oscillation, which can be controlled with the gain knob. Transformer Design and Construction. Nov 8, 2017 · I’m sorry I wasn’t clear in this case. It could be a dodgy cable, faulty connection to the jack or just an inferior cable. Welcome To the Hoffman Amplifiers Forum This minimizes any hum coupling between them. For some reason, the Vox is perfect. The basic thing is to know how to distinguish the different types of noise. Even when the guitar was not plugged in and it was just the amp connected to the cabinet, the hum was still present. I normally kill the power (put it into idling/standby mode) quickly as I fear the hum will destroy the speakers. Tube amplifiers, alternatively referred to as valve amplifiers, employ vacuum tubes (or electron tubes) for the amplification of audio signals. Apr 22, 2020 · If your amp makes no sound, it is first important to define what you mean by “no sound. The pack is not grounded, so I get a hum. When I turn the master volume down the hum disappears. Oct 21, 2024 · Check out our guide about the different options of virtual amp. But generally; hum can enter in three ways: Directly, inductively or capacitively coupled. SS amps run on low voltages. Jun 30, 2023 · Widowmaker Guitar Amplifiers. If the circuit runs on 24V or less there isn't going to be much EMF generated from the wires feeding the power supply. Mar 11, 2021 · If your amps have two inputs like Fenders, you can simply plug a guitar cord from input 2 of your main amp and then into input 1 of your second amp. trevox Posts: 659 Joined: Wed Mar 23, 2011 12:58 am. You can easily hear it when the volume is all the way down. The i Jul 11, 2023 · Tube Guitar Amp Troubleshooting. These are large round components (about 1"x3") usually found near the power transformer. Transformer Hum: Cause: Transformers inside your amplifier can produce a low-frequency hum. Nov 24, 2019 · Hi everyone, Some six months ago I bought a Mesa Boogie TC-50 head (great amp!). But I am now a bedroom guitarist, and I've decided to try and address that. Through searches across the internet I've found a few potential issues with the safety of running the amp through a 240-110v step down transformer. The ART DTI's audio transformers have an extremely flat and wide frequency response and can handle high signal levels while maintaining an isolated balanced Jul 30, 2024 · It can be really annoying when you plug into an amplifier and it starts humming. There was no pop or smoke nothing at all. For many players, it's a subject that could stand a little deeper scrutiny from an engineering and design perspective. Nov 8, 2016 · Hi so I've just bought a 60's tube guitar amp from the U. Some can be repaired, but it’s better to buy good quality cables to prevent this problem. Not out of the speakers; just the transformer itself. This can be a bit disconcerting when it is mixed in with the guitar tone. Hum again is the result. The fuses look alright and Nov 12, 2015 · Last night at a rehearsal, the guitar amp wouldn't stop humming until the guitarist stood up off of her metal folding chair. Jan 26, 2024 · All that is now 'done', alone with a few adjustments to a few caps in the signal path just to open the amp up a bit more and give it a bit more gain. Reply reply Nov 17, 2024 · 34. Many 1940's and 50's radios powered their tube circuits directly from mains (wall receptacle) voltage without a power transformer and their chassis was connected directly to Jul 27, 2019 · EDIT: sam_adams just posted a diagram of the classic ground loop. If you were to bring that buzzing equipment to another home, the symptom may disappear (a telltale sign of DC offset). No problems before this one. Sep 12, 2023 · You should also avoid overdriving your guitar amplifier as it can easily damage the tubes. I've got a Deluxe Reverb '65 reissue, and had a heap of hum that came through whenever I turned up the reverb. Feb 18, 2011 · Re: running two amps and eliminating hum im running them both on the same powerboard, but i have tried separate wall sockets too. Chris Fantana: Much like the tyres and brakes on your car, there are components inside your amplifier that’ll wear out with everyday use. (1) The heater supply is usually A. If the hum only happens when you plug your guitar in - that's a whole different kettle of worms. Oct 12, 2023 · Fix: Tube Amp Hum With Increases Volume – 1) Understanding Tube Amps – a) Introduction to Tube Amplifiers: Before we delve into the intricacies of tube amp hum, let’s begin by providing a concise overview of tube amplifiers. It seems that after a few minutes of being powered up the hum decreases to an almost tolerable level, but certainly not quiet. The hum has these characteristics: - NOT related to the reverb amount - worse after pressing the fat switch - the hum is constant. This completely eliminated the hum. Not all amps have all types of hum. Aug 9, 2019 · There are many different ways that you can get hum in an amplifier, and its hard to troubleshoot without the amp at hand. Lately I also noticed that the right side of chassis got very hot Mar 23, 2006 · Many amps try to reduce hum by grounding the center tap (CT) of the power transformer's (PT's) heater (filament) winding. A Must-Read: How Do I Stop My Guitar Picks From Dropping? It is the hum eliminator, essentially an isolation transformer that prevents the Dec 11, 2010 · The new transformer has really opened up the sound of this little amp, and I like it very much. I had to move the OPT to the opposite side of the chassis to fix it. As soon as I realized what happened I pulled the plug. If you unplug the apollo, and the hum goes away, that is your problem. Note, that most active DI boxes have no transformer, and won't stop ground hum. I would return any AVR or amp that had audible hum. If it occurs as soon as you power up the amp before Apr 9, 2017 · Amplifier Transformers can generate hum in other circuits if they are in close proximity, like having a stomp box sitting on top of a tube amp. If it makes a loud hum, gets noticeably hot to the touch, or emits a burning odor, it is defective. I find that this will fix most grounding problems between the stage and house PA in a safe manner. Reactions: Guitar_Paul, tedanderson, SWDweller and 3 others. To better assist it really helps if you have high quality pics of the amp, so we can look around for potential sources of the problem. My guitar rig has at least a few iso transformers in key places, and even with long cable runs and Jan 9, 2018 · Such transformers are found in most guitar amps, so magnetic hum is often worst when you're close to the amp. It's not real loud, not 60 cycle hum, more like a power transformer on a telephone pole that's humming, like buzz. which occurs in worn-out amplifiers and even in AC30, is mainly caused by the aging of the tubes and +HV elco. Jul 3, 2023 · Guitar amp hum with nothing plugged in can be a challenging issue to troubleshoot, but by addressing grounding issues, inspecting internal components, eliminating environmental interference, checking transformer health, and investigating potential circuitry problems, you can identify and resolve the source of the hum. Failing this effecting a cure, you might want to ask another guitarist whether he gets an unusual amount of hum when he plugs into your amp. May 30, 2017 · There are a zillion sources of hum, each one different from the next, and each with its own solution. @brownsfan how do I detect tube issues like you describe- microphonics, etc? @stereo5 I always enjoy the humming of my wife, but it seems her tone is at a much higher frequency. Adjust each amp tone and volume to suit. Unwanted feedback from your amp can be caused by bad wiring, radio interference, or loose connections between your equipment. com. Here's the video showing how much you should see-~-~~-~~~- Transformers are the most important and most expensive components of guitar amp's parts list. Sep 26, 2014 · I just bought the Epiphone Century Amp, the 75th Anniversary edition that just came out. I have a original Fender 1953 Deluxe amp it uses the infamous 6SC7 tubes (preamp). Reply reply There probably isn't anything that you can do except get an isolation transformer which is a little different than a surge protector. Lots of amp parts companies offer some replacement transformers for these small watt budget amps though. The traditional way to reduce hum is to use a transformer with a centre tap, and connect it to ground. Jul 12, 2007 · I'm getting some hum that I had assumed was 60-cycle hum coming from a mismatch in the output tubes (as it was present when I accidentally cut the power to all my pre-amp tubes). My chain was Guitar-> Helix instrument in->Helix 1/4†out ->Kemper input. I utilized DEFT to dampen Got big amplifier. After an exhaustive investigation, I found that this phenomenon is called "transformer hum", but I don't know if this is normal and most importantly if it implies any sort of danger to the electronics and Mar 21, 2020 · Hey guys, just posting this as a bit of a resources for others that might run into this issue. At first the channels should have three and four tube stages, a cathode follower before the tone stacks and one stage for makeup gain for the power amplifier. Result: Linear power supply gave very less humming noise than the cheap SMPS. ktcix sggevnt nlrkooc yzoydys eytwwl qhq swbq rlcuc lcqu amrlw