120hz Hum Tube Amp












120hz Monitor found in: Acer KG271P 27" 165Hz FHD FreeSync ZeroFrame TN Gaming Monitor, ASUS ROG Strix XG438Q 43" 120Hz 4K UHD FreeSync 2 HDR Philips Momentum 558M1RY 55" 120Hz 4K HDR1000 Gaming Monitor with Soundbar. The sound is a bit more tube like, and truly organic. Another update: Actually the noise isn't a 60Hz hum; it sounds like the 120Hz "angry insect" hum that is often associated with ground loops. The Rocktron Buzz Kill AC HUM Exterminator Audio Isolation Transofrmer is designed to kill 60Hz/120Hz ground hum (BUZZ) by cutting the ground loop that can exist between audio products such as guitar rack systems, pro audio products, mixers, etc. The power supply hum spurs were -92dB at 60Hz, -80dB at 120Hz Higher frequency hum spurs are below -100dB with those above 360Hz below -110dB. I know they look clunky!. The horizontal scale is 2ms, the waveform is 200mV peak to peak. 2mvAC one channel and 38. Thanks for everyone's reply. The power tube grounds are "high current" grounds and should be kept apart from the preamp grounds. monolith amp, Connect your Monolith as shown in Figure 1 or Figure 2. I found that a choke helped reduce noise and hum. Tube complement: four EL34, four 12AT7. In this case, the HUM would be heard as 120 Hz (the rectified. Mono-block. The power supply rectification and regulation is done as it would be in the 1940s with a tube full wave rectifier, gas ionization voltage regulators tubes, and LC filters. For example, if you have a 100-watt tube amp, it will automatically produce more noise than a 15-watt tube amp. In my layout I used a single 33 uF cap instead of two 16 uF caps. I'm pretty sure its' 120hz hum because I tore apart the incoming wall supply piece by piece, several times with no change. 6% of 350 V, pretty decent especially for a push-pull amplifier. It makes total sense that it would still be a 120hz hum, as the input signal was getting mixed up in the PS circuit by sharing the ground. THD at 4 Watts into 8 ohm is 0. As an aside to illustrate the point, you can plug a 12AU7 or a 12AX7 in the same socket, and you amp works regardless. I have a constant hum in the guitar sound, almost like a 120hz hum in a tube amp, and I can't seem to get rid of it. Tube guitar amps run on DC voltage. To determine which of these you have, listen to the two examples. 17%, THD spectrum is 2nd -72. In vacuum tube equipment, one potential source of hum is current leakage between the heaters and cathodes of the tubes. There is a hum parameter as part of most of the power amps, it might need turning down. The level of hum is usually directly related to the guitar's proximity to any large mains transformers in the room. 3rd harmonic 180Hz doesn't usually show up as a prominent component unless you have a compare the amount of hum in each case with the same settings on the amp. ) I know it's just the heaters, since I can pull out the relay which switches on the HV and I still hear it, and it sounds to be coming from the tubes. The power supply smoothing filters in this amp are RC filters. Their sound and purity are classic, but, to purchase a tube amp in modern times seem impossible due to their exorbitantly high price. Moved the PC, the noise disappeared. C1 and C2 affect the sound quality generally as well as the bass response. Later Fenders (Blackface) would use the. Noise / Hum -79 db U / -58 db [email protected]: Response. Most importantly The circuit has residual 120Hz hum. Quick Search. To minimise hum in a p-p amp, especially one with a shared bias arrangement, its power tubes should draw closely similar plate currents at idle. 60hz hum could be tubes ending their life and AC from filaments flods across cathode ends. The rest of us will be hearing at least a bit of buzzing and maybe a bit of 50/60Hz hum as well. I also replaced the rectifier tube. I am getting a lot of hum and hiss from my system. This includes (but is not limited to) discharging the electrolytic capacitors if you are troubleshooting the circuit within the amp chassis. 3 mS, that would be '120 Hz' hum, which would be more normal from a full-wave power supply. Later solid state amps up to #549 are also compatible. The amplifier inverts signal polarity. Sep 29, 2020 · An electrical buzzing sound can also be referred to as a mains hum. audioengineering). A couple of them have a little hum, ether 60 cycle or 120 cycle. So I took it out of the rack and measured 120Hz at 40mV p-p on the left channel and about 44mV p-p on the right. This is in the US, where the mains are 60 Hz. It makes the mic sound tinny and adds a hum. Push down firmly until the tube is seated on the tube socket. Biasing Single-Ended Amplifier Output Tubes: A Basic Explanation and Demonstration. , and then this week, an extreme loud buzz/hum. The electricity in our house is AC, so outlet voltage swings up and down 60 times a second. 60hz & 120hz TUBE AMP HUM - DIAGNOSE THAT! Graham Leach. Hum by unproper shielding from the pre-amp and/or the end amp. Speaker cab is connected(nothing else). It may be due to mains hum or if at 120hz a ground loop issue. It was mentioned elsewhere in this thread to just run the preamp tube filaments on DC, and run the power tubes on AC. I know several people who prefer to have the "tube sound". To get rid of the hum you can tighten the screws on the PCB to restore good contact, cut the green wire, or both. I will put a pic of it up. Connect up to 5 sources with RCA cables to the inputs of Saga+. I assume this is introduced into audio the same way as above (maybe not ground loops). Extremely powerful 5kW vaneaxial fan. 2 6V6’s on the output, 2 6SQ7 triodes (preamp and tremolo) and a 12AX7 for the (long tail*)PI. A quick tap on the reverb tank showed me that the verb was there but the huge hum was gone - so the First day tube amp class. Here's a link to amazon for more. It's either the AC ripple in the DC supply, the power transformer too close to the output x-former (not much I can do there), inadequate. Quick Search. It is now dead quiet, where the left channel still has the hum. This can be used to achieve a “tighter” tone and to reduce low-end “flub”. Tube amp hummmmmm. It is there all the time even with the volume at zero. Triode Electronics TF103-48. Reducing guitar amp buzz and hum. HP Pavilion 27q Monitor. 99 in kit form ($129. Tube Amp Hum. How to do this, that and the other. ly/2sf7RAm Music: ✖ ES. THD at 4 Watts into 8 ohm is 0. It pretty much is a Fender tone stack between 12A*7 stages. If you reach the end of your DC Balance adjustment before nulling out the 120 Hz hum, your output tubes are more than likely mis-matched. Start date Sep 2, 2020. I had an amp that developed a serious AC hum and it turned out to be a loosened nut for the ground attached to the power transformer. Boost in the 2 to 20 k range. 5dB, THD for individual signal is 0. It's the common mode rejection nature of the circuit. If you have the skills to fabricate a chassis by drilling and/or punching then suggest building from scratch using the tube amp circuits widely available. 60 or 120hz hum? If I advise you on a tube amp repair, please be aware that they store lethal voltages even when off - don't go touching anything unless you're sure it has been discharged. The 5VDC can also damage the PR 30 element. It provides a low frequency cutoff near 300 Hz helping to reduce first stage hum. Audio amplifiers, and tube amplifiers in particular, contain high voltages. Tube complement: four EL34, four 12AT7. ) I know it's just the heaters, since I can pull out the relay which switches on the HV and I still hear it, and it sounds to be coming from the tubes. …HDR VA Display - Panel: VA LCD - Backlight. While a 60 hz hum indicates ingress into the audio circuits from a 60 Hz line frequency source. As I have seen in quite a number of other amplifiers measured, there is quite a bit of 120Hz power-supply hum modulation around the suppressed fundamental 1-kHz test frequency. RESULT 1: 120 HZ hum is coming from the filaments, not ground, in, or B+. Found 200 records in Search of Amp/Preamp Asylum. One behavior is like this: All preamp tubes removed except the PI tube. so i have no idea whats wrong, i just turned it on and the buzzing was so louddd!!! if the volume is at the lowest and still producing sound, it is bu. I'm using the Hum X to fix my ground loop problem. Some light humming from a tube amp with your ears at the speaker is not unusual. Bad caps result in 120Hz hum, bad rectifier is 60 Hz. sounds "duh" but when you turn off the HT supply and let the power smoothing caps power the amp. At start up, maximum voltage is across the lamp and so the filaments are fully on. Yet another idea for an independent test signal is to probe a 60 Hz signal within the amplifier's power supply and see if similar distortion presents. It is a solid state Q-tube 70 guitar amp probably from the 1980's. I moved these amps to other rooms with the same result. ), but all my attempts to bust this hum have been unsuccessful. 6dB and 7th at -86. The DMD 465 contains a precision differential instrumentation amplifier with voltage output. It is only noticeable at bed room levels. Edit: Update! The hum I experienced was from a nearby PC. In this video, I discuss two types of hum found in tube amplifiers, how to easily differentiate between the causes, and how to effectively remedy the situati. It does not increase when the volume control is turned up, and it is 60 Hz hum, not 120 Hz supply ripple. That's not quite as low as it could be with a DC supply, but about 10dB quieter than an AC heated amp. I've also tried unplugging all the devices in my room, unplugging all devices from nearby outlets, and turned off the lights and still the hum is happening. I'd like to hear about other software players that are successful able to smoothly play back 120Hz videos on a 120Hz monitor. Original PCB's are intact and are as they should be. The design of the amp started when Bill suggested that he wanted to build one of the YAHA (Yet Another Hybrid Amplifier) amps , but using a different design. Result: With a high impedance microphone connected, 120 Hz ripple was neither visible on the scope (<1 percent modulation), nor heard on the air. This class-D amplifier is rated at 2x 80 Watts into 4 Ohms and features multiple connection options. But the Heil PR 30 is a dynamic mic element, and that 5VDC will change the sound quality of the PR-30 for the worse. A lower 60hz hum can be an indicator of poor shielding, but a 120hz hum is usually an indicator of bad filter capacitors. The amplifier has a power isolation circuit and bandwidth limiting to reduce oscillations and "motorboating". So amp ground is at -15V potential relative to mains ground? That seems like a big problem to me but I can't wrap my head around how it would affect things just now. I compare my old 60 Hz screen with my 120 Hz screen, filming everything with my 120 FPS camera. The original owner had taken it to three different repair shops, and been told it wasn`t. Many notes and explanations about completely re-engineering a pair of 1960 Dynaco MkIV tube amps. Trust us when we say you will know it is the higher-pitched sound. If you have an amp which uses power tubes which are not listed above, you will need to consult a spec manual (the RCA RC-30 Receiving Tube Manual is one of the best) for the basing, and adjust these instructions accordingly. This transformer is about half the size of the others tested. It turns on now and plays music, but immediately after powering on, even without music playing, it emits through the speakers a horribly loud, constant buzzing/humming sound. 60hz & 120hz TUBE AMP HUM - DIAGNOSE THAT! 7 anni fa. I was noticing the comment about hum. It works just fine, however, it is a bit noisy with nothing connected The noise is generated within the amp itself. 60hz & 120hz TUBE AMP HUM - DIAGNOSE THAT! One of a pair of monoblock amplifiers manufactured in Canton province by Antique Sound Lab in the early 2000's. Life is too short for bad food. The hum starts only after the amp has warmed up a bit. Been working on a friends "Sligo" clone of a Deluxe reverb. Many notes and explanations about completely re-engineering a pair of 1960 Dynaco MkIV tube amps. Turning the master volume up makes the noise louder. 53%, almost only 3rd harmonics. When grounding filter caps,the power tube plate and screen caps should be grounded near the PT,along with the PT CT,the power tube cathodes. Occasionally it can be from tubes or currect. Suitable for use on 120V 60Hz grounded Having issue with my tube amps,I own two different makes and both had a slight hum,issue wasnt the amps. The hum has frequency 120 Hz (2 * AC). The wiring was fine and a need to go DC was almost apparent. One behavior is like this: All preamp tubes removed except the PI tube. Which means the cartridge ground pins are at -15V. But the main recommendation is to thoroughly check out the entire amp's cicuit by comparing it with the schematic. If we presume that the residual hum is 100 mV, a hum voltage on the order of 4. This is usually a leaky cap in the power supply. Found 200 records in Search of Amp/Preamp Asylum. A dying tube can cause 50 or 60Hz hum from heater-cathode leakage but can also cause 100 or 120Hz hum so swapping out every tube should be done before going any further. Power Transformer 120V/60Hz – P/N 205. But it’s not all doom and gloom though, as below we take you through the causes of unwanted amp hum and ways to battle against it! Type of Amp: Different amps can have different noise issues. This new amp I have in mind will contain both tube and transistor components along with a integrated computer system to run amp modeling software but that is a whole different threadlol Cheers, Billy BTW My 120 hz hum statement was a mistake. So not a huge difference really. A couple of them have a little hum, ether 60 cycle or 120 cycle. The 5VDC can also damage the PR 30 element. 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. fects the 120 Hz to 10 Hz range or the 240 to 20 Hz range depending on the EQ switch’s setting. Diameter about 240mm, 120mm Fan for size comparision. With up to 200 watts RMS of output into a 4 ohm (100 watts into 8 ohms), this class A/B amp produces low distortion with excellent control. All hum in the US is 60Hz and sometimes 120Hz depending on the lighting. Using a tube tester may or may not tell you if you need a replacement. com 102 tube amp. The hum level does not change if I increase master volume. A 30 watt mono amp uses the same amount of output tube power as a 15/15 stereo amp. It would not turn on, so I had it repaired at a stereo repair shop. Peavey 5150 2x12 combo # Five 12AX7 preamp tubes # Two 6L6GC power tubes. , and then this week, an extreme loud buzz/hum. I'm getting 60 cycle hum + harmonics from a MILA tube preamp I just finished. I cut the fat bare wire between the contol and a chassis ground lug and ran a gator lead to a ground lug alongside the 12AX7 volume-control preamp/squelch tube V402. 05khz dual waves the separation of waves is 43. which ever one of the first 4 most closely resembles #6 would be a good. 60Hz is raw mains hum, while 120Hz is a failed filter capacitor in the amp's power supply -- the frequency gets doubled by the rectifier in the amp and then the cap that would normally smooth out the power ripply, if it's failed, leaves that hum in. It makes the mic sound tinny and adds a hum. amplifier hum troubleshooting, Jan 22, 2014 · Just posting a DIY so maybe someone else will stumble across it and save a few bucks on a possible repair. Thread starter GDHAMTON7. No, you shouldn't. Plug it in, turn it on, and select Tube Output if you want to use tubes. The amplifiers’ power rating, wattage, can also impact the noise floor level. Is the noise the sane level on both speakers? How many tubes are we dealing with in preamp/amp?. In this case, the filament divider resistors are tied to the -50V bias (see schematic). This is usually a leaky cap in the power supply. The DMD 465WB is similar, but has a frequency response to 2 kHz. You'll need a 1-ohm resistor for each power tube in the amp. 15, in value, shunted across the first choke. The hum was not a single frequency, such as the common 60-hz or 120-hz hum that you would expect in a typical amp. Post 6 is that the output directly from the siggen? or the output from the amp. Which means the cartridge ground pins are at -15V. I'll contact the repair shop. Some are dead quiet, some are not. The amplifier has a power isolation circuit and bandwidth limiting to reduce oscillations and "motorboating". The Dynaco (or Dynakit) Stereo 70 (also known as the ST-70) vacuum tube amplifier was one of the most popular tube amps of its time. There's also nothing quite like the hum you get out of one of these rigs. Had the scope on the wrong setting. These changes do seem to introduce hum to some AC/DC tube circuits. But MANY tube amps are going to hum with low-impedance Grados. C1 and C2 affect the sound quality generally as well as the bass response. Biasing Single-Ended Amplifier Output Tubes: A Basic Explanation and Demonstration. Remember these are $18 transformers. It is not interferance from anything, just the nature of tube amps. Possibly a lot. So you get years and years of enjoyment. There are two basic types: 120Hz buzz, typically caused by ground loops, and 60Hz hum, typically a result of poor shielding, cable problems, or close proximity to strong magnetic fields. By this I mean a capacitor usually between. Gregorian Chants at 432Hz | Very Soothing Healing Music with Orchestral Arrangement For Hi and welcome to Beard on Gear, I would like to demonstrate the Pyle Audio PHE400 Hum Eliminator. Here's a link to amazon for more In this video, I discuss two types of hum found in tube amplifiers, how to easily differentiate between the causes, and how to. To minimise hum in a p-p amp, especially one with a shared bias arrangement, its power tubes should draw closely similar plate currents at idle. Hum is a constant low-frequency buzz, usually at about 60 Hz or 120 Hz, which results from voltage differences between true "ground" (what you'd Failing this there might be a dried out overheated electro capacitor in the amp circuit causing the hum. No other controls on the amp have any effect on the volume of the hum. The channel's phase-splitter tube is always removed during this test. Check the period of the 'hum' you're getting to see if it's really almost 17 mS; if it's only 8. I tried using one of those 2. At 4 Watts, 2khz+2. The 5VDC can also damage the PR 30 element. The hum was not a single frequency, such as the common 60-hz or 120-hz hum that you would expect in a typical amp. An ac line coupling too close to an audio circuit. Presence: an active 6 dB per octave, shelving upper-mid to high frequency control. 2 6V6’s on the output, 2 6SQ7 triodes (preamp and tremolo) and a 12AX7 for the (long tail*)PI. Re: [Shocking Update] 120Hz Hum without Tubes inserted. It is there all the time even with the volume at zero. The 6SN7GT tube was originally released on the eve of World War II and saw extensive use during the war years, primarily in radar installations, as its high power dissipation and construction made it. The Goal: A 30 watt all tube stereo guitar amp with good stereo effect projection all in one box. I suppose all tube amps do. At a distance of a couple of feet, no more 120-Hz hum. DHT đốt AC tại 100-120HZ tôi làm mọi cách vẫn ù 4mv SE 211 và 813 đốt AC tại 100-120 Hz soi bằng occilo nhiễu 0V Để giảm ù do đốt AC bóng DHT tôi làm các giải pháp sau: + Cao áp cực sạch + phần cấp công suất, đốt tim cho các bóng khác đều có ổn áp. As Justin pointed out, the 60Hz hum will have harmonics at every multiple of 60Hz (120Hz, 180Hz, etc), so a simple EQing won't remove all of the hum. The sound is a bit more tube like, and truly organic. Hum from the B+ would be 120 Hz in nature. You have some sort of hum coming in from the early stages, and it is out of phase with whatever hum is after the volume control. The amplifiers’ power rating, wattage, can also impact the noise floor level. Baby took a long nap, so I had time to run and properly cut the trace with my dremel and install the ground lift resistor on the right channel. 60hz & 120hz TUBE AMP HUM - DIAGNOSE THAT! 2036 anos atrás. With the 112-A tubes the hum is audible during quiet passages. After deciding on the basic circuit, the SRPP version, I read a bunch of webpages about various amps and. It makes the mic sound tinny and adds a hum. There’s hiss/white noise, which can come from the tube themselves, or even from faulty components. We first need to divide our search into two categories; mechanical If the hum/buzz goes away when you remove the inputs to the power amp, your next step will be to reconnect the amp and move further down the chain. If it's a 120Hz hum, there's a power supply problem - filter caps or an open diode (but most of the time diodes short instead of going open, but it's still possible for one to go open). CS - Summer Vibes - soundcloud. The noise floor is not as quiet as with the other PASS F and J clone amplifiers I have built myself, but the only self noise from the amp is a quiet 120hz hum noted with my ear to my 98db sensitive speakers, and it is not at all noticeable with music playing. A buzzing sound could be created from debris in the drain pipe. Which means the cartridge ground pins are at -15V. After restoring a nice old 1938 Sparton Model 1568 console radio, I was so impressed with the I liked the looks of this amp with the nice wood frame and black panel. Do not attempt to repair an amplifier without following the appropriate safety protocols. This solution would make the amp more expensive, including user inconvenience. It is a first-order shelving filter (high-pass) at 120 Hz, at the input of the Amp block. If I put the last audio tube back and then pull the one before it, the HUM IS GONE. 60Hz Electric Noise. A 120hz hum indicates (usually) that filter caps are going bad. Bought a nice used solid state bass amp on craigslist lasted a month or so, went through practices and gigs. This question is more complicated and abstract, but it is not too difficult to understand after some careful thought. I suggest an active crossover at 85 Hz or so and a good sub, see here: – You must invert the phase of one of the. Before I go on, yes, I like playing a big amp even at bed room levels. 6dB and 7th at -86. I also replaced the rectifier tube. DOWNLOAD LINK : (mp3) 60hz & 120hz TUBE AMP HUM - DIAGNOSE THAT! Reducing guitar amp buzz and hum. – The amp channels need to be closely matched in gain and freq response, not always the case with old tube amps. Then there’s 60 Hz hum, which is most likely to come from the heater supplies. Please login or. if you run a 120hz tone through the amp you can't really hear the oscillation but if you switch it by 1hz up or down you can distinctly hear the hum oscillating against. The problem turned out to be that the interstage transformer was inductively coupling hum from the power transformer. My question is: Does that mean twice as. A dying tube can cause 50 or 60Hz hum from heater-cathode leakage but can also cause 100 or 120Hz hum so swapping out every tube should be done before going any further. The tube amp kit comes with a nice steel enclosure and the power output is about 25 watts. Ground hum and 60hz hum are not the same. 2mvAC one channel and 38. The power supply hum spurs were -92dB at 60Hz, -80dB at 120Hz Higher frequency hum spurs are below -100dB with those above 360Hz below -110dB. Do not connect them directly to the chassis ground. Boost around 50Hz to 120Hz and Sweep the EQ to hit the offending frequency. I have been troubleshooting my 6100 to get rid of 120Hz hum (heard at the speaker). Power Amp Section: Tube complement: 4 x EL84, 1 x 12AX7 • Output power: 50W RMS into 8 or 16 ohms • Frequency response: +0, -2dB, 50 Hz to 15 kHz @ 40W RMS into 16 ohms • Hum & Noise: no greater than 80dB below rated power. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours. 3mV of hum would be OK with me. No, you shouldn't. It registers 60hz and 120hz on my tuner. From here, checking with the manufacturer and dealing with an exchange. But the Heil PR 30 is a dynamic mic element, and that 5VDC will change the sound quality of the PR-30 for the worse. This brought the ripple down to 2. Hum and bacon sounds are two completely different things in terms of how they sound and how they are made in a amp! Hum issues can be 60 hz which is below the low E string, or 120 hz which is above the pitch of the low string, so what do you have more of noise wise, hum, or bacon?. After restoring a nice old 1938 Sparton Model 1568 console radio, I was so impressed with the I liked the looks of this amp with the nice wood frame and black panel. So I recently had a scare with my amp where the fuse blew for seemingly no reason that I posted here and I replaced that fuse with a new one, but now I've noticed my amp has developed a hum around 120hz that oscillates a bit. Hum enters the signal path from the heater (filament) wiring, poorly filtered B+, improper ground wiring or ground loops, right out of the air as radio frequency interference coming into unshieled signal lines, via direct magnetic coupling frm PT to OT, or from ancient amp wiring connecting tube filaments directly to the AC mains (no tranny). Hum sometimes couples into audio circuits so you've got to find out where it enters the system if that happens too. These are award winning Hurricane amps, but. Been working on a friends "Sligo" clone of a Deluxe reverb. Since I've been having problems with 120 Hz hum I tried adding another 47 uF (80 uF total) cap here. It's either the AC ripple in the DC supply, the power transformer too close to the output x-former (not much I can do there), inadequate. Trust us when we say you will know it is the higher-pitched sound. If you have the skills to fabricate a chassis by drilling and/or punching then suggest building from scratch using the tube amp circuits widely available. The phase inverter/output transformer secondary ground point may need to be connected to this first star for lowest hum, but usually to the second star, if a multi-star system is used. I compare my old 60 Hz screen with my 120 Hz screen, filming everything with my 120 FPS camera. In vacuum tube equipment, one potential source of hum is current leakage between the heaters and cathodes of the tubes. Before I go on, yes, I like playing a big amp even at bed room levels. As Justin pointed out, the 60Hz hum will have harmonics at every multiple of 60Hz (120Hz, 180Hz, etc), so a simple EQing won't remove all of the hum. Picture of mint condition pair of Dynaco MkIV mono amps. The Rocktron Buzz Kill AC HUM Exterminator Audio Isolation Transofrmer is designed to kill 60Hz/120Hz ground hum (BUZZ) by cutting the ground loop that can exist between audio products such as guitar rack systems, pro audio products, mixers, etc. Regards, Maveric Manic - 'Knowledge is Power and Wisdom is knowing how to use it'. I tried moving. 120Hz is the 2nd harmonic of the mains. The DAC 2 has been superseded by the DAC 3. The first export models in this range are being built at this moment and should be seen here in the UK within the next six to eight weeks. I am not 100% sure what it is, but after watching some YT videos and discussion with other guys, I think that it is the 60hz or 120Hz sound of transfomer. The electricity in our house is AC, so outlet voltage swings up and down 60 times a second. Modulation hum. The hum increases/decreases with the adjustment of only the master controls. 82) Posted by trietngo on 2005-01-04, 12:36:30 (4. It just started while I was playing. If it's 120 Hz hum, it's probably something to do with the DC power supplies in the amp, starting from the power transformer hi-voltage secondary center-tap ground (if used), and moving on to every filter cap and its ground, and also (sometimes I tend to forget this, and it's especially important in the 2205/2210) any other DC voltage derived. net has successfully created full screen video game play recordings You must be using a 120hz monitor to play these video files at a full 120 frames per second. Most importantly The circuit has residual 120Hz hum. Retailing for $99. The hum is the same with the 1/2" and 1/4" head blocks, so the problem is not in the heads or the It could still be a problem in the power supply that only shows up in the high gain structure of the playback amp. Extremely powerful 5kW vaneaxial fan. In vacuum tube equipment, one potential source of hum is current leakage between the heaters and cathodes of the tubes. Baby took a long nap, so I had time to run and properly cut the trace with my dremel and install the ground lift resistor on the right channel. For a few reasons: SS rectifiers are more efficient, the filtration is a little lacking, and fullwave rectification shifts the PS wave peaks from 60Hz to 120Hz. com THAI EXHIBITION ASSOCIATION. Does the 120Hz iPad Pro Make a Difference? All my iOS 11 Videos!: bit. 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 at a lower level. I know they look clunky!. hifi tube preamp schematic, The circuit above shows a 4-transistor utility amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. It is not interferance from anything, just the nature of tube amps. It is now dead quiet, where the left channel still has the hum. Humbucking And Noiseless Pickups. I can't get any signal coming from the input section either. Test Your Player At 120fps On 120Hz. There’s hiss/white noise, which can come from the tube themselves, or even from faulty components. , and then this week, an extreme loud buzz/hum. No other controls on the amp have any effect on the volume of the hum. A 120 Hz humming noise will be caused by ground loops. I've rebuilt the power supply, swamped all the tubes etc. is the hum 60 or 120 hertz? Is the power supply a full wave rectifier type? I was told it's 60 hz hum with some high end static. A dying tube can cause 50 or 60Hz hum from heater-cathode leakage but can also cause 100 or 120Hz hum so swapping out every tube should be done before going any further. The best approach is to buy a new set of tubes, and install. Under the hood, it runs on a 7nm Snapdragon 870 5G SoC which comes with LiquidCool Technology 1. Mike/W8BAC: I can understand fairly easy how 60Hz hum can be injected into AM audio. 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 at a lower level. Check the period of the 'hum' you're getting to see if it's really almost 17 mS; if it's only 8. is it 50 HZ or a 100 HZ hum you are hearing your PSU may be failing in your amp, say if the PSU condensers are dried out they will give you 100 HZ hum, bad RCA connectors earth loops not using 1 AC outlet for your AC supply. The modkits web site points to a faulty/less than ideal pre-amp tube as the cause of filament current amplification. Gregorian Chants at 432Hz | Very Soothing Healing Music with Orchestral Arrangement For Hi and welcome to Beard on Gear, I would like to demonstrate the Pyle Audio PHE400 Hum Eliminator. Connect the output of Saga+ to your amp or amps using RCA cables. I suspect you have two hums going on. The final tube gets its plate voltage from the reservoir capacitor which creates a bit of hum so I addad a filter with 2 H and 16 µF to get rid of it. This eliminates the negative feedback loop, permitting a more precise DC Balance adjustment. I'm not sure what the deal is I just never noticed it before. hifi tube preamp schematic, The circuit above shows a 4-transistor utility amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. It was mentioned elsewhere in this thread to just run the preamp tube filaments on DC, and run the power tubes on AC. Presence: an active 6 dB per octave, shelving upper-mid to high frequency control. This is probably the most common hum in an amp. I'm using the Hum X to fix my ground loop problem. The hum remained on the same level. Push down firmly until the tube is seated on the tube socket. I tried moving. An ac line coupling too close to an audio circuit. It can be caused by: A bad tube so swap out the tubes for known, good tubes. I always try to use elevated heater supplies (see schematic), even for push-pull amps. If the hum changes levels as you do this, then the source of the hum is something that affects the stages of the amp before the volume control. After deciding on the basic circuit, the SRPP version, I read a bunch of webpages about various amps and. Do not attempt to repair an amplifier without following the appropriate safety protocols. It would not turn on, so I had it repaired at a stereo repair shop. If the humming problem is still there, then the problem lies with the receiver or the power amp. Picture of two 45 Watt Dynaco MkIV tubed monobloc amps with 2 x 6CG7 for input/driver stages and 2 x KT88 output tubes. by rfbro on Tue Dec 29, 2015 8:26 pm. isolated input and output jacks with a single-point grounding bus bar, etc. The amp is a very primitive design: class A, 4 tube operation consisting of 5U4 rectifier, push-pull 6L6's, and 6J5 preamp tube. Connect your sources. Solid state amplifiers do not require valves to work, but rely upon a combination of transistors to deliver their sound. I am selling this incredibly sounding tube amp, second owner, comes with original box REASON why I am selling it is that, I hear very little hum/buzz or something like that with my Empyreans. I've also tried unplugging all the devices in my room, unplugging all devices from nearby outlets, and turned off the lights and still the hum is happening. , and then this week, an extreme loud buzz/hum. This means the 4-125s and the 6C4 tube and the power supplies are NOT causing the hum. Here's a link to amazon for more. This question is more complicated and abstract, but it is not too difficult to understand after some careful thought. For you tube amp lovers with more bench time than me (I'm more of a hobbyist): I was recently gifted one of those cool Gretsch amps with the two 6 X 9 oval speakers (and a tweeter!). It's either the AC ripple in the DC supply, the power transformer too close to the output x-former (not much I can do there), inadequate. monolith amp, Connect your Monolith as shown in Figure 1 or Figure 2. Patient presented with loud 120 Hz hum, bum tubes, a volume control that didn't do anything. As Justin pointed out, the 60Hz hum will have harmonics at every multiple of 60Hz (120Hz, 180Hz, etc), so a simple EQing won't remove all of the hum. Fault 1 Amplifier powered up but 50hz mains hum present on both channels. THD at 4 Watts into 8 ohm is 0. If there are any tube experts out there with any ideas, please let me know. The first export models in this range are being built at this moment and should be seen here in the UK within the next six to eight weeks. Which means the cartridge ground pins are at -15V. at 0 volume you hear it the most, but at 1/2 volume I am no expert but it just sounds like you are getting feed back from the electrical workings of the This is all connected to my amp-a Zapco 360. The noise floor is not as quiet as with the other PASS F and J clone amplifiers I have built myself, but the only self noise from the amp is a quiet 120hz hum noted with my ear to my 98db sensitive speakers, and it is not at all noticeable with music playing. Single Coil Pickups: Unfortunately these pickups commonly produce a hum due to the way they are designed. The hum increases/decreases with the adjustment of only the master controls. I am getting a lot of hum and hiss from my system. I have tried multiple pickups through it with the same noise sound coming through, I've tried humbuckers, piezos, single coils double tapped, etc. 5 mm jack input, and a subwoofer output. net has successfully created full screen video game play recordings You must be using a 120hz monitor to play these video files at a full 120 frames per second. Hum enters the signal path from the heater (filament) wiring, poorly filtered B+, improper ground wiring or ground loops, right out of the air as radio frequency interference coming into unshieled signal lines, via direct magnetic coupling frm PT to OT, or from ancient amp wiring connecting tube filaments directly to the AC mains (no tranny). So I took it out of the rack and measured 120Hz at 40mV p-p on the left channel and about 44mV p-p on the right. I tried using one of those 2. 6dB and 7th at -86. The signal is clean and there is no noticeable hum on the RF but man it makes a pretty loud noise when I key with about a 1000 watts of output in RTTY. After 12 oclock, its pretty loud. ), but all my attempts to bust this hum have been unsuccessful. I have a constant hum in the guitar sound, almost like a 120hz hum in a tube amp, and I can't seem to get rid of it. After deciding on the basic circuit, the SRPP version, I read a bunch of webpages about various amps and. You may have to register before you can post: click the register link above to proceed. 3 mS, that would be '120 Hz' hum, which would be more normal from a full-wave power supply. Tube complement: four EL34, four 12AT7. Some are dead quiet, some are not. I have used different amps in the same setup and no hum. Do not attempt to repair an amplifier without following the appropriate safety protocols. But MANY tube amps are going to hum with low-impedance Grados. I'll check all my ground connections and see if I can find You also said that the hum is 100Hz, that is what you get from a bridge rectifier! on 50Hz mains. After 12 oclock, its pretty loud. PP tube designs kind of cancel or mitigate 2nd order harmonics, where as decrease over all THD too and runs linear. It has been my experience, from over 50 years of tube electronics, design and repair, that the 120 Hz hum is due to not having the choke tuned. The electricity in our house is AC, so outlet voltage swings up and down 60 times a second. It was mentioned elsewhere in this thread to just run the preamp tube filaments on DC, and run the power tubes on AC. Tube amp hummmmmm. Plug the hum-reducing adaptor into the wall outlet. An input jack that doesn't ground out when nothing is plugged in. That is unacceptable, and Allnic has overcome the issue through its automatic pure vacuum tube voltage regulation circuitry. My big tube amps are part of my manhood. At a distance of a couple of feet, no more 120-Hz hum. The DMD 465WB is similar, but has a frequency response to 2 kHz. But MANY tube amps are going to hum with low-impedance Grados. I am getting a lot of hum and hiss from my system. Suitable for use on 120V 60Hz grounded Having issue with my tube amps,I own two different makes and both had a slight hum,issue wasnt the amps. The obvious flavor of the higher-pitched hum usually ranges from 100 to 120 HZ. Alex, being mostly interested in tube amps, was not initially interested but as Bill and Mark began to suggest requirements for the amp and some options for the input tube, it was obvious. audioengineering). The Dynaco (or Dynakit) Stereo 70 (also known as the ST-70) vacuum tube amplifier was one of the most popular tube amps of its time. hifi tube preamp schematic, The circuit above shows a 4-transistor utility amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. ) and most harmonics nearly perfectly cancel out. amplifier hum troubleshooting, Jan 22, 2014 · Just posting a DIY so maybe someone else will stumble across it and save a few bucks on a possible repair. There is noticeable increase in noise, which you can hear at the speaker in the form of hum. When I short all 3 input pins, the harmonics disappear, though a lesser hum at 120 Hz remains. Welcome To the Hoffman Amplifiers Forum March 24, 2021, 09:19:46 am: Welcome, Guest. I am selling this incredibly sounding tube amp, second owner, comes with original box REASON why I am selling it is that, I hear very little hum/buzz or something like that with my Empyreans. All other controls have no effect on the hum. 1), Bangna, Bangkok, 10260, Thailand Tel : +66 2744 5370 to 1 Fax : +66 2744 5385 Email : [email protected] The video shows the effects and the solutions. 60Hz is raw mains hum, while 120Hz is a failed filter capacitor in the amp's power supply -- the frequency gets doubled by the rectifier in the amp and then the cap that would normally smooth out the power ripply, if it's failed, leaves that hum in. S/N ratio: 95dB at 120Hz. Ground loops and lack of filtering in a supply but 120Hz hum is less clear. If 120hz, then probably either an open filter capacitor or a faulty solder connection connecting a filter capacitor in the power supply. Now turn both the high level and low level gains to the minimum position, and the frequency control to 120Hz. The capacitance multipliers provide 37dB of attenuation at 120Hz, increasing to over 60dB of attenuation from 2kHz to beyond 100MHz. just came across a Knight KP-40 32 watt amp that was assembled as a kit 120hz hum ( in US , 100 in europe) means bad electrolytic caps. Connect the amp into the socket on the adaptor before turning it back on. hifi tube preamp schematic, The circuit above shows a 4-transistor utility amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. But the pre tube should be ruled out by the masterpot. With inputs grounded and amp set to full gain, but no Mapleshade Grounded Brass Tube Halos. Another update: Actually the noise isn't a 60Hz hum; it sounds like the 120Hz "angry insect" hum that is often associated with ground loops. I've rebuilt the power supply, swamped all the tubes etc. Power line noise is broadband. 100 or 120Hz buzz can be caused by a bad tube so swap in a new set of tubes. The PCB holds a pair of cathode followers, each loaded by a triode current source, and a respective power supply. I don't know if it's relevant but in a tube amp, power supply hum will be 2x line current frequency (100/120Hz) whereas ground hum will be 50/60Hz. 5 mV will appear at the output of the amplifier. I know several people who prefer to have the "tube sound". I have replaced all the tubes with new ones and tried the amp at different locations. An input jack that doesn't ground out when nothing is plugged in. Since I've been having problems with 120 Hz hum I tried adding another 47 uF (80 uF total) cap here. 53%, almost only 3rd harmonics. Ensure tubes are well-seated. It makes the mic sound tinny and adds a hum. I've been told the rectifier diodes might be the source of the problem, but without a schematic the cost is through The amp was restored to the original values on the board(it's pcb) and 2 traces were reconnected. 3mVAC the other on a no volume amp. The B+ used for the plates contains a high amplitude 120Hz 'ripple' signal due to poor filtering by the first filter cap. It makes the mic sound tinny and adds a hum. Hum by unproper shielding from the pre-amp and/or the end amp. The modkits web site points to a faulty/less than ideal pre-amp tube as the cause of filament current amplification. Most importantly The circuit has residual 120Hz hum. Please tell me, what is the problem with a tube amp, when you have 120 Hz hum that gets louder, when you turn the gain/volume pot. not a slight background noise). 120hz hum is always related to the B+,the 60hz,when rectified becomes 120hz. There are several types of noise that can come form a tube amp. I have looked for loose wiring (I recently unboxes it after my move across country) or anything visible--nada. Regards, Maveric Manic - 'Knowledge is Power and Wisdom is knowing how to use it'. Another update: Actually the noise isn't a 60Hz hum; it sounds like the 120Hz "angry insect" hum that is often associated with ground loops. To determine which of these you have, listen to the two examples. This hum is usually at the second harmonic of the power line frequency (100 Hz or 120 Hz), since the heavy ground currents are from AC to DC power supplies that rectify the mains waveform. Actually, what really matters is the overall sensitivity of the amp. This is usually a leaky cap in the power supply. which ever one of the first 4 most closely resembles #6 would be a good. Before I go on, yes, I like playing a big amp even at bed room levels. – The amp channels need to be closely matched in gain and freq response, not always the case with old tube amps. Bought a nice used solid state bass amp on craigslist lasted a month or so, went through practices and gigs. Using a tube tester may or may not tell you if you need a replacement. I don’t know the cause, so I’ll withhold blaming it on the MT-34. amplifier hum troubleshooting, Jan 22, 2014 · Just posting a DIY so maybe someone else will stumble across it and save a few bucks on a possible repair. Interestingly enough, power cables and audio cables do not like to play nice together, which results in a hum when they are too close without proper shielding or isolation. A tube testing power supply consists of pulsating voltage (mains AC full-wave rectification without filtering), negative BIAS Step (step wave) and filament power supply:. The most noticeable issue with the amplifier was a very loud hum coming through the speakers even with the volume turned to zero. The signal is clean and there is no noticeable hum on the RF but man it makes a pretty loud noise when I key with about a 1000 watts of output in RTTY. 120hz and qhd. This problem of hum induced Eddy currents can be solved by having the amp and power supply on separate chassis. Thanks again. If the hum changes levels as you do this, then the source of the hum is something that affects the stages of the amp before the volume control. Just tube noise! I still use the Mapleshade Brass Tube Halos because they help with microphonics and hum induced by my hand getting close to the tubes when I adjust the volume. Re: [Shocking Update] 120Hz Hum without Tubes inserted. 2hsn xf-455c ym-34 ym-35 ym-36 ym-37 ym-38: antenna tuner, 10-160 m, 1. 7dB non-average weighted. So amp ground is at -15V potential relative to mains ground? That seems like a big problem to me but I can't wrap my head around how it would affect things just now. In part Moondog makes it easier to investigate this simply because its PS Because hum seems a property of tubes, not circuit, we could try reduce the hum by tube selection. Regards, Maveric Manic - 'Knowledge is Power and Wisdom is knowing how to use it'. Smooth Action A super-fast 120Hz effective refresh rate combined with enhanced backlight scanning deliver an outstanding Clear Action of 240 for perfectly sharp images. It's a 1080p, 120Hz-capable projector with low input lag, a listed light output of 3,800 lumens, and even a few bonus goodies like HDR10 support and 4K input compatibility (scaled down to 1080p. Tube guitar amps run on DC voltage. To figure the attenuation: Use an RC filter calculator to determine the cutoff frequency. In this video, I discuss two types of hum found in tube amplifiers, how to easily differentiate between the causes, and how to effectively remedy the situati. I'd like to hear about other software players that are successful able to smoothly play back 120Hz videos on a 120Hz monitor. This hum is usually at the second harmonic of the power line frequency (100 Hz or 120 Hz), since the heavy ground currents are from AC to DC power supplies that rectify the mains waveform. Typically, alternating current that is found in most power lines has a frequency of 60hz. 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. com an Aikido Cathode Follower 2 (ACF-2) All-in-One 9-Pin PCB, designed by John Broskie, the editor of Tube Cad Journal (tubecad. I know they look clunky!. As I have seen in quite a number of other amplifiers measured, there is quite a bit of 120Hz power-supply hum modulation around the suppressed fundamental 1-kHz test frequency. Then attach your subwoofer to the power supply using the power cable supplied, at this point have the power switch in the off position. It turned out that the loud 60Hz hum was a result of using a footswitch whose cable wasn't shielded (not the original FS). If it's 120 Hz hum, it's probably something to do with the DC power supplies in the amp, starting from the power transformer hi-voltage secondary center-tap ground (if used), and moving on to every filter cap and its ground, and also (sometimes I tend to forget this, and it's especially important in the 2205/2210) any other DC voltage derived. So in the quest for a hum-free amp, I've modified the circuit somewhat. Message-ID: 2079500859. Bought a nice used solid state bass amp on craigslist lasted a month or so, went through practices and gigs. I recently got a used Exposure Super XV integrated amp. This approach keeps the mains and its associated hum and noise out of the box. Turn the phase control to. I'm also going to test the noise and see if it's 60 or 120 Hz hum. I don't know if it's relevant but in a tube amp, power supply hum will be 2x line current frequency (100/120Hz) whereas ground hum will be 50/60Hz. Icom and Yaesu insert 5VDC on the mic line to power the electret mic elements in their hand and desk mics. One of a pair of monoblock amplifiers manufactured in Canton province by Antique Sound Lab in the early 2000's. Replaced nearly all electrolyitic caps on all boards. I have a constant hum in the guitar sound, almost like a 120hz hum in a tube amp, and I can't seem to get rid of it. Smoother motion and less input lag. audioengineering). 60 and 120 Hz hum. Engineers chose the smallest value filter that would just get rid of the 60/120Hz hum. Hum and bacon sounds are two completely different things in terms of how they sound and how they are made in a amp! Hum issues can be 60 hz which is below the low E string, or 120 hz which is above the pitch of the low string, so what do you have more of noise wise, hum, or bacon?. Under the hood, it runs on a 7nm Snapdragon 870 5G SoC which comes with LiquidCool Technology 1. I have the (I believe Integrated Amp since I have to use my pre-amps tapeout loop for connection to the amp) powered through a power line conditioner (tried. Outputs: 1 pair solid-metal gold-plated four-way speaker terminals per channel. The modkits web site points to a faulty/less than ideal pre-amp tube as the cause of filament current amplification. Bought a nice used solid state bass amp on craigslist lasted a month or so, went through practices and gigs. Not much background noise, but a little. Baby took a long nap, so I had time to run and properly cut the trace with my dremel and install the ground lift resistor on the right channel. , tested every ground in the amp as best I can (no schematic anywhere on this unit). It registers 60hz and 120hz on my tuner. Some are dead quiet, some are not. This means the 4-125s and the 6C4 tube and the power supplies are NOT causing the hum. THey only create a hum when there's power going through them (it's caused by the alternating current, and in the US, that's typically 60Hz (but sometimes you get a harmonic at 120Hz). I don't like small amps. The channel's phase-splitter tube is always removed during this test. Anyone know a qualified tube amp tech in CT? Discussion in 'Amps and Cabs [BG]' started by 40Hz, Mar 28, 2021 at 11 there was very little 120 hz hum at all. An input jack that doesn't ground out when nothing is plugged in. Power Amp Section: Tube complement: 4 x EL84, 1 x 12AX7 • Output power: 50W RMS into 8 or 16 ohms • Frequency response: +0, -2dB, 50 Hz to 15 kHz @ 40W RMS into 16 ohms • Hum & Noise: no greater than 80dB below rated power. I always try to use elevated heater supplies (see schematic), even for push-pull amps. Noise / Hum -79 db U / -58 db [email protected]: Response. That is unacceptable, and Allnic has overcome the issue through its automatic pure vacuum tube voltage regulation circuitry. In part Moondog makes it easier to investigate this simply because its PS Because hum seems a property of tubes, not circuit, we could try reduce the hum by tube selection. I've built tube amps from scratch previously, so I'm no stranger to the established techniques for eliminating ground loops (i. Reducing guitar amp buzz and hum. important is noise in the low frequency range of 60 and 120 Hz. Turn it all the way down and solve that hum first. 6dB and 7th at -86. Had the scope on the wrong setting. The amplifier has a power isolation circuit and bandwidth limiting to reduce oscillations and "motorboating". I was noticing the comment about hum. You have some sort of hum coming in from the early stages, and it is out of phase with whatever hum is after the volume control. It makes total sense that it would still be a 120hz hum, as the input signal was getting mixed up in the PS circuit by sharing the ground. It is now dead quiet, where the left channel still has the hum. The Manley Massive Passive Stereo Tube EQ is a two-channel, four-band equalizer, with additional high pass and low pass filters. Outputs: 1 pair solid-metal gold-plated four-way speaker terminals per channel. I'm pretty sure its' 120hz hum because I tore apart the incoming wall supply piece by piece, several times with no change. Is there a quick way to tell if the amplifier is making the noise, or is it a problem with my system? The fastest way to tell if the amplifier is the cause of the noise, is to disconnect the input cables from the amplifier. Hum enters the signal path from the heater (filament) wiring, poorly filtered B+, improper ground wiring or ground loops, right out of the air as radio frequency interference coming into unshieled signal lines, via direct magnetic coupling frm PT to OT, or from ancient amp wiring connecting tube filaments directly to the AC mains (no tranny). The output tube cathode grounds should be run to this first star point. I tried different tubes--nada. , and then this week, an extreme loud buzz/hum. A lot of amps, both tube and solid state, will experience failure in electrolytic caps, particularly ones made during the "Capacitor This is a video showing the sound of a 60 hz transformer. Hum by unproper shielding from the pre-amp and/or the end amp. But the Heil PR 30 is a dynamic mic element, and that 5VDC will change the sound quality of the PR-30 for the worse. My question is: Does that mean twice as.