Dealing with amplifier power on/off pop sounds

[@Elnufo]

Back in the mid 80s, i had a little class ab amp with 2x35 watts from poland, called ALTUS V60. The power up/ down pop this thing produced was out of this world, it made the voicecoil of my 8" speakers hit the poleplate more than once. And it killed several tweeters as well. "funny" little amp that was.

[@TurboLoveTrain]

Neat explanation. I just know If I turn on everything in a specific order I get no popping--and if I don't I get popping.

[@northox]

Thanks John. Glad to see you’re still at it.

[@bobisyouruncle1]

I experimented with a Pi filter in my power supply and came to the conclusion that a 2mH inductor between the 10000uF reservoir bank and a 8000uF bank almost completely eliminates the power on pop as well as the mains hum. Yes, that's a lot of capacitors, but it's worth it and the sound is more dynamic as well. I did also add a back emf diode across the inductor bank. The power supply plays a very important role in dynamics and noise filtering.

[@MichaelBeeny]

I would never dream of using any amplifier without a delayed start and possibly more important a DC monitor. Changing a relay after 5 years is a small price to pay rather than replacing the bass drivers on a pair of speakers. 30-60 volts across any speaker is never good.

[@iulianbaicu6900]

Its possible to eliminate the power on pop using a speaker coupling delay circuit with a relay? I saw this in speaker protection circuit when the amplifier powers up puts itself in the protect mode for 1-2 seconds.

[@JohnAudioTech]

Yes, that would help provided the output is not capacitively coupled to the speakers.

[@samppazzz]

I have a small bass thumb when power on, and barely noticable when power off. My amp is somewhat simple circuit type and less part means not so much possible fault expectitions and good troubleshoot knowledge if and when there is something malfunction somewhere in the amp. Just resently i changed output mosfet, becouse old lost linearity and other parameters to work as intended. New mosfet in and bias adjustment for driverboard potentiometer and amp is back in operation.

[@gamiwv]

Does any "slow initial charging" (of the P.S. smoothing capacitors) resistor reduce the "pop-on" ? But to be honest I prefer a manual "rotary" knob switch OFF - STANDBY - ON. It takes me 5sec and - to my taste - it is more "cosy"

[@JohnAudioTech]

It may depend on the design of the amp. Different stages may "bias up" at different voltages. It may help or worsen the effect.

[@gamiwv]

@@JohnAudioTechYes. Indeed

[@Elecifun]

Can some of these clicks, pops be produced by the power rails not energising components at the same speed ?

[@JohnAudioTech]

I would say that it is due to different stages of the amplifier's bias currents starting/stopping at different times. Also charging/discharging rates of capacitors used in the circuit among other things.

[@darrenmurphy6251]

nice to see this often ignored topic , came across a known issue with quad amps where they break into oscillation (405 i think) within the audio spectrum at switch off, a high midrange squeal, i was never impressed with the whole current dumping complexity already then that on top! and no mute circuitry is a bit obsesssive on something consumer grade, ditched that and made my own amps since my own amps just have a 2 second turn on mute and any switch off noise is something that needs fixing. now asus motherboard windows boot up pop is something i need a solution for , a driver update caused it!

[@bobisyouruncle1]

It's sad to find that many of the elite audio brands are after all not that great, as you mentioned with the quad.

[@darrenmurphy6251]

@@bobisyouruncle1 yes never meet your hero's, I used to love Aston Martin till my job means I work on them, held together with duct tape and stacks of washers under panels to get the height right, and led headlights (the sidelight bar) where if one led fails the whole lot go out, and anteque sat nav lifted straight out of volvo that's the db9

[@bobisyouruncle1]

My home-brew pre-main amplifier pops upon power up only, so i added a toggle switch between amp and speakers, which i switch on a few seconds after i switch on the power supply. My amp uses a single supply, so the delay i give it, gives the output caps to charge. The pop you hear, with a single supply amplifier is the dc rushing through the output capacitors until they are charged up & is not good for the speakers. My power supply is external from the pre-main amplifier.

[@TurboLoveTrain]

My problem was a little different buy my solution was almost exactly the same--I have to power everything on in a specific order. In this case I have a secondary amp for my surrounds that I have to power up before the main amp else it does the popping.

[@austayo]

I wonder if you could change out the output bd139, bd140, 2sa1943 and 2sc5200 with the 2sd1895 and 2sb1560.

[@Tarodenaro]

You can use solid state relay and trusty UTC1237 (uPC1237) or other similar "speaker protector" but then again it still added complexity, maybe it's safest to just couple it with "old school" audio trafo and be done with it.

[@QoraxAudio]

Dirty contacts inside switches can be a reason too, if it's a switch in line with the power or signal. Cleaning them and adding a decoupling capacitor helps.

[@andymouse]

Yeah my CAS4040 used to do that and it didn't bother me either and sounded great....cheers

[@philipscharles1333]

Sir very nice videos I have learned lots from your videos sir I have a request please make a video about how to select transformer voltage for audio. Amlifier boards.thank you so much for making good video a.

[@billspencer8540]

My amps turn on totally silent with over speced solid state "relais" on the output. Works great and does not suffer from contact degration.

[@Synthematix]

Would a timer relay connected to the speaker outputs cure this?

[@JohnAudioTech]

Yes, that is how it is often done.

[@Anthony-cc8bx]

hi, i have a car deck that makes the system pop. It's only this deck but not the others. what can it be? Thanks

[@basserex4991]

Hello! sorry for my bad eng language. Can you help me? i watched your video: Correcting hum, buzz or distortion in audio amplifier projects. But i dont understand lines on this diagram. my issues: blowing spekaers, amp have voltage on body, rca voltage loss, bass is weak itp. I see this speaker - on diagram, but this + line above amp what is this? disconect the - wire or + from speaker and put to this line? Please help, Thanks!

[@garygranato9164]

good subject, thank you

[@codebeat4192]

Is a soft start or slow start PSU not an option?

[@Shyamkumar-di5fu]

Excellent! Can you make a video about apex audio amplifier circuits... Like apex ax14,etc

[@josephsaucedo8691]

I bought a Dayton audio $400+ 1000w amp from parts express brand new and it has a really hard thump on and off ridiculous for the price the thump really bad it a class ab i hate even using it because of it. The amps new none to do this. you think for the price it wouldn't do that. It sounds like the speakers going to blow up . I thought mybe a speaker pertection board might stop it i lightly was going to ask you then this video came up probably because iv been look for a way to solve it. Part express should be ashamed of them selves for sell a amplifier that literally sounds like the speakers going to blow on turn on for the price point. Thank for the video much appreciated sorry just a little up set.😅

[@JohnAudioTech]

It would be interesting to capture the transient on a scope if possible. If it is more than a couple volts, I'd be concerned, otherwise probably just a harmless annoyance.

[@josephsaucedo8691]

@JohnAudioTech thanks I'll look in to that. I had messaged parts express about it and if it will damage my sub and they Said it best to just always leave the amp on wich I thought that ridiculous I can live with a small thump but its not small and the speaker moves quite violently. For 800$ for amp a sub I will never order from parts express again thanks for your time and reply it's much appreciated thanks again John 💯🙏👍✌️

[@archieapril5284]

was that the 1000w plate amp or the rack mounted version?

[@josephsaucedo8691]

@@archieapril5284 plate mount

[@archieapril5284]

@@josephsaucedo8691 I have had no issues with my plate mount, which is going on 10 years. i almost went with another plate mount, but decided to go the rack mount version. the popping/thump is out control with this one.

[@amitghosh6966]

Nice video

[@wooferhound7571]

Is that aluminum foil on the fuses ?

[@JohnAudioTech]

Yes it is!

[@listerine-pr5lt]

I do agree with you that the output relays are liability to audio amps.

[@robertdubard7959]

Just, never turn the amp off?

[@suvamdas5470]

This amplifier pcb PDF file upload file please

[@copernicofelinis]

As a non native speaker I have to confess I am disturbed by how you pronouce "transient" at the beginning of this video. Is this some regional or local inflection?

[@TurboLoveTrain]

"Tran z ance" Must be a regional thing or some people just like alternate pronunciations. The USA has all sorts of language bubbles where certain words are pronounced very differently or even an entirely different word is used. I live in the west and every time I hear an easterner pronounce masonry "Ma son Airy" I cringe... there is no second "A" silly east coasters!

[@bobisyouruncle1]

John is a good person. There's no need to criticize him over pronounciations. If that's your objective, then you should join a grammar critic forum instead!

[@copernicofelinis]

@@bobisyouruncle1 what on earth are you talking about??? I was not criticizing. As a non native speaker I was trying to understand if this is a regional inflection, that's all. If you could hear me speak English you'll know I cannot afford to criticize the pronunciation of anyone, native speaker or not. Why do people feel so triggered about questions?

[@RPike-bq3xm]

@@copernicofelinis That's funny. After hearing John pronounce “Transient” I thought I was saying it wrong. I can’t really think I’ve even said it out loud. I work with lovable knuckle heads. No reason to use such a word.

[@andymouse]

@@copernicofelinis Lol ! I understood exactly where you are coming from ...you are just curious that's all!! and this IS an engineering channel so curiosity is normal :) (UK)