Finding A Bad Tube In A Tube Amplifier

[@rjs2104]

Used this tapping method on my 93 fender blues deville. After hearing a loss in amp output and a weak dirty channel, i found a bad 12ax7 closest to the power tubes. Saw this vid and figured id try it before i get beat over the head by a tech.. and honestly with the volume up, a extreme light tap will do, its very audible. Total cost $14 Thanks for the video

[@mw9558]

getting your dirty hands on a tube won't damage them in any way... This is a myth Still a good video mate!

[@Danielburke-go8dc]

Yep. It’s not a halogen lightbulb, it’s a vacuum tube.

[@ryantoomey611]

Another funny thing was he tried to listen for microphonics on the rectifier tube!

[@furyiiiplate]

Why take the chance? I just tested my headlights with a drumstick.

[@tonys4396]

@@Danielburke-go8dc I was a Type C color darkroom technician all my life. (until film went to digital) The bulb in the enlarger was halogen. We never touched the bulb. The reason was, that the oil of your hands would change the color (Kelvin Temperature) of that bulb. That was why. It never shortened the life of a halogen bulb to touch one. That myth all started with not touching darkroom halogen bulbs and spread to everything.

[@jameseetseggs5798]

Been a BMW technician for 8 years and touching the globe is an absolute no no. The amount of globes I've had to re-replace because the apprentice got his fingers on them.. not saying its applicable to vacuum tubes but when it comes to cars.. its not about the colour its about residues remaining on the glass can't dissipate heat as well as it should when 100% clean and it causes internal temps to raise beyond spec. You can literally see the finger prints burnt into the and the filament damaged on the other side of the glass directly at the point of contamination.. I suppose automotive applications have a much longer on time/ heat aswell so maby not relevant to vac tube amps.

[@davidjonsson1649]

My amp has 12 tubes. I tried this and it worked. The one bad tube made a loud noise through the speaker when I tapped it. Thanks Renato.

[@danedgar1539]

Awesome video thankyou so much! Just did it tonight on my marshall and was actually relieved to find one bad preamp tube. Reassuring that i wasnt going crazy!

[@renatopasqualini5989]

Glad it helped!

[@StonyRC]

Good demo of some bad tubes. Thanks for posting your video.

[@renatopasqualini5989]

Thanks!

[@humbuck59]

Man you helped me chase down a problem on my Orange Rockerverb that had been bugging me literally for years... thanks so much!

[@renatopasqualini5989]

You're welcome!

[@mississippiredneck123]

I remember back in the 50s and 60s in some convenience stores there would be tube testers

[@furyiiiplate]

They are very expensive man cave items now.

[@fullcirclejams]

with every knob turned up i would say those tubes are pretty quite ! and dont worry about touching them with your bare hands it has no effect on them, it's true ! cool old amp man !!

[@renatopasqualini5989]

+fullcirclejams. Thanks man! Yea I love this amp!

[@huejass1325]

Thanks for that! I don’t know why some/most treat it like a halogen bulb! 🤷🏼‍♂️

[@ashscott6068]

Yeah. It's the first few stages of the amp. I'd expect them to be slightly microphonic at that volume. Especially the tube that has the very first stage in it.

[@zzubuzz]

Christopher Walken as recording Producer Bruce Dickenson walks in your studio.."honestly, it was sounding good, but I could have used more chopstick"..."Renato, explore the cabinet space".

[@TheVinylGuru]

Damn so many components in this! Amazing.

[@stephenclark9598]

Credibility lost when I heard oils from hands can cause tubes to fail 😂😂😂

[@FrankZen]

Damn! I thought to myself "wow! Never knew that!" 😆😆

[@williamsimmons4678]

Hhhhha

[@RyanMcQuen]

There's some truth to it actually.

[@allrequiredfields]

No, for real. The second I heard that, I said out loud "You cannot possibly be serious".

[@Vichedges]

@@RyanMcQuen no there’s not.

[@danniemoore97]

finally a dude that puts gloves on before he touches the tubes thats the reason why i don"t trust amp techs thumbs up.

[@renatopasqualini5989]

Thank you!

[@midnightskate]

I'll give you a thumbs up after I put my gloves on

[@JohnBindon]

Dannie Moore That's the 1st thing that I thought !!!! Kudos to both of you !

[@mb125hh]

Why though?

[@amaurythewarrior]

as other comments say - it's a myth

[@ashscott6068]

If you're changing preamp tubes again after one year, something is not right with that amp. If it sounds harsh, maybe you have a 12AX7 in a socket that you should really have a 12AT7/AU7 in. It's a common mistake. They look the same, fit the same socket, and the amp still works. But a 12AX7 has a lot more gain. The driver tube and reverb driver, are often a 12AT7 or 12AU7. But I'd get the amp looked at, rather than keep destroying tubes, if there's a problem. Maybe you have plate and grid resistors that are way off value and your B+ is too high. It's also possible you bought trash tubes or got gypped. If you work in a place that sells tubes, you probably play guitar. When your own tubes need replacing, it's all too easy to swap them out with good ones from work. just pop your bad tubes in the box and put the box back on the shelf. I'm sure it happens. If tubes are going bad in one year, something ain't right.

[@giulioluzzardi7632]

Thats right, I have only needed to change valves once in 17 years on a combo used every day.I think they are using low quality bases and not checking the circuit cis you can get that problem in a brand new amp.

[@Shadowman-1960]

He shortens the tubes' lifespan by all that unnecessary tapping.

[@RomanChugz]

Hi! Just bought a used Mini Rec off of Guitar Center and noticed that Channel 2 Vintage at 10w is dead silent while Channel 2 Modern is extremely loud an bright (as in 3x louder than other channels). Could you help me diagnose the faulty tube? Thank you.

[@giulioluzzardi7632]

..just putting out there. I have found most of the new fender amps develope that microphonic ring. Sometimes just replacing the noisey ones alone does it but I have found that the valve bases are sometimes not fitted properly with enough solder.

[@Andres_VB]

Hello. Thanks for the video. I recently bought a second hand bugera333xl (not the infinium version) and i found out two of the pream tubes are microphonic. Here in my country replacement tubes are either hard to find and expensive. I need to know how dangerous is operating the amp with microphonic tubes? Shoud i wait until i can replace them before using the amp? Besides that, there are 3 diferent tube references 12AX7A, 12AX7B and 12AX7C what is the difference between the tree tubes? any information you can give me would be most apreciated. tahnks in advance.

[@marcusbrown1767]

This can be done on any tube pre amp? My pre amp tubes barely glow and is low on volume compared to other side.

[@casey43]

That's a nice twin the first two tubes are for each Channel unlike most tweed amps this amps Channels are not sharing the same preamp valve. Usually each channel uses one side of the valve on the first one on the right. It's placed on the right farthest away from the power transformer for a reason beacause of 60 cycle hum. The next two tubes are aloud to be microphonic because they do a different function in the amp. So an easy fix is moving them around. Just because a tube is microphonic. Doesn't mean it's bad it actually give the amp more lively sound as long as it's not rattling or ringing. Also log plate 12ax7's tend to be more microphonic than short plate ones. Ps - don't bang on your tubes or move your amp around when there on or hot that is how they become microphonic and rattle. Get tube rings they help!

[@renatopasqualini5989]

+Casey Jones Thanks for the tips! Yea I ended up replacing all the tubes down the road because it was about due to replace (I play pretty hard, and have the power tubes biased pretty hot). Unfortunately this Tweed twin is going into repair because a transistor got burned out and the whole amp shut off. Been using my Blues jr. for now. Love that amp too! Thanks again for the tips, cheers!

[@papahjoshscene4234]

I have a vox vt30, but now there is a problem. if I play for 30 minutes, the sound suddenly decreases and hoarse. what's the problem?? Please help me. Thank you

[@Funkfreed]

Is that hissing sound because of bad tubes? I have one of those joyo bantamp and I get hiss even in clean mode at 8 oclock volume

[@KunchangLeeMusic]

How much pressure is required to replace a preamp tube - I tried wiggling in the new tube while applying gentle but firm pressure but it just doesn’t seem to go in - do I need to press in really hard ? Just doesn’t feel right cuz all the videos I see of people replacing tubes - it seems to be very little effort -

[@billwilliams6338]

RENATO PASQUALINI, the B+ voltage is at 450vdc and if you increase it to 600vdc will this increase the AC ripple voltage and output wattage of the amplifier?

[@Vivelabretagnelibre]

Good video, thanks, very helpful. I've got trouble with my Marshall TSL, no sound at all, and a burn smell...the 2 fuses look OK...I changed all tubes 4 months ago, everything was perfect until the last time I used the Amp...I don't know...do you have an idea ? thanks for your help...

[@AAgunner]

Don't know about guitar amps, but my hifi tube amp made it VERY obvious to me when one of my power tubes died! The most horrid cracking and popping noises, followed by a loud honking noise coming from the left speaker when turning off the power to the amp. Scared the shit out of me!

[@WillyMcCoy50]

Love the amp. Either it is an old tweed that has been heavily modded or it is an reissue ..... old Fender tweeds do not have ceramic tube sockets. I have an old Supro s6650 with its original tubes that I haven't played or fired up for over 25 years. As soon as I can I will have it checked and serviced along with a three prong upgrade. I wish I had ceramic sockets. $$$$$ If tubes need to be changed every year I would suggest looking at the biasing. I would also suggest playing it as needed and have a practice amp from Goodwill for home use.

[@renatopasqualini5989]

Thanks man! Yea I love this amp, it's my number 1 for sure! It was a reissue the custom shop had in the early 2000's. This one is a 2006 model. I think the custom shop is bringing them back, but they don't have the Ted Weber speakers in them. It sounds amazing!

[@kyleelrod3008]

This method works but I dont hear anything wrong with this amp did it sound better when you changed the preamps?

[@themodularmodular]

So how was it, did you really solved it? cos I couldn't really hear the noise when you tap the "culprits". What 12ax7 did you get? I too currently have harsh sounds when I hit the amp harder with pedals and these tubes (Tung Sols reissue) are only few months old and I didn't even play that hard/much, whereas the JJs that I had there before were crackly when I smack the string hard or pushed hard too. A little different. Thanks!

[@oscardejesus4490]

4:31 the best part of the vid

[@danielauen7790]

Is 4 years long enough for the lethal voltage to clear out?

[@pedromartinazzo5036]

Daniel Auen Yes. The capacitors usually discharge in a couple months

[@edgararreola1317]

xd

[@97warlock]

My Peavey amp head is making aloud Hum & thats with nothing plugged into the amp. And when i do plug my guitar in I have to CRANK the volumes and its barely louder than speaking volume. Any guess if its a tube or not?

[@AMGL1989]

Did your problems go away when you changed them out? I'm not sure if one of my preamp tubes are microphone or if my pickup. It's been squealing at high gain.

[@renatopasqualini5989]

+Ariel Gomez Yes they did :). Not sure what the squealing sound could be from.

[@xanthurian]

oil is only bad with halogen lamps. The temperature isn't all that high unless you bias them too hot.

[@davidtfitzphoto]

Which ground connection is that hanging loose on the left side of the amp?

[@renatopasqualini5989]

The regular ground cable. It's actually very short according to me and my amp tech. Cheers!

[@atulsharma4501]

Hi Renato , wonderful video i'm new to tube amps, so i have a laney 200v hybrid amp, i cant get much gain out of it, what pedal so i need to use ? or do i need a attenuator ? should i consider changing the preamp valve ?

[@renatopasqualini5989]

+Atul Sharma. Hey there! Yea don't worry about the amp to get any kind of overdrive for now. Sure there's tubes that have more gain in the preamp section, such a 12Ax7, while a 12Ay7 is more of a traditional 50's-60's sound. However, your amp needs to be able to take those tubes, some amps don't like to switch to different kinds of preamp tubes, (bottom line, don't worry about the preamp tubes). I would get an overdrive pedal. My favorite kinds are based off a klon and the ones based off tube screamers. I use a Mad Professor Sweet honey Overdrive and a Mad Professor Little Green Wonder. They make 2 versions, a hand-wired kind and a factory pressed circuit board version (non hand-wired). Depending on your price range you can get the same tone. I recommend hand wired as much as possible just because I've had the Sweet honey hand wired for 6 years and it hasn't given me any problems. The little green wonder hopefully lives up to it's brother! Hope that helps! Cheers!

[@atulsharma4501]

Hi Renato, Thanks for the response, i appreciate it :) ill consider buying there pedals, but there are different kinds of ecc83 valves, do these different kinds of valves give me different gains ?, i know that 12AX7 is 100 for the gain

[@renatopasqualini5989]

I haven't heard of any ecc83 valves. I do know of el84's and el34's, but those are power valves (or tubes). Those can never be changed, so make sure you stick to the type that's in your amp already when you want to switch those ones out (usually 2 or 4). I highly recommend you just look at pedals to get the sound you want, I wouldn't worry about doing things with the amp right now. Hope this helps! Cheers!

[@silasfatchett5693]

ECC83 is the European designation for the 12AX7.

[@Menatss]

I just got a brand new tube amp and I put them in. After I turned it on whenever my bass knob and volume are changed there's a very loud humming noise. Still new at this and would like some help. Did I maybe put in a Pre amp tube in a little off or was it maybe a bad tube?

[@renatopasqualini5989]

+Mentas. I would maybe first try to plug the amp in another outlet to see if maybe that cleans up the humming. Also, if you put in new power tubes without a proper bias job, that may be your first culprit. Hope this helps! Cheers!

[@Menatss]

Thanks for the tips. I don't have any other guitar cords and at some points the hum stops in a certain position the way I hold the guitar. I think it might actually be a faulty cord. I've had it for a really long time and it hums on my other amp as well. I think I found the problem.

[@jegr3398]

How does geting oil on the glass cause them to fail? The oil doesn't eat through the glass. Sounds like BS

[@Gary.Abusey]

It's the same with automotive light bulbs, the oils lead to "hot spots." Overheats the tube and they don't last as long

[@eldrinpaulgok-ong3450]

I have a laney cub 10 and the gain knob doesnt work anymore but I cant hear anything even if I put the volume knob at 10. but if I crank up both gain and volume knob, I hear the clean sound. but considering that I cranked them both to 10, it still sounds quieter than before. I still hear alot of distortion when using my boss overdrive/distortion stompbox though like nothing changed.. so weird..

[@Denvermorgan2000]

Be careful about doing this at high volume start at lower volumes and work your way up sometimes you can get hit with a very loud bang if you have a short or a really bad tube or a tube that’s very microphonic and your hand will not damage a tube but you might burn your self if it’s hot.

[@davidkenneth3983]

What you tiuching it with your fingers when its hot do you stick your hand in the toaster no wait let it cool .or grab that hoty and hold on.

[@davidkenneth3983]

Everthing is apreciated .

[@MrPyroguru]

I actually touched my tubes with my fingers. Will they fail now? I was inspecting the tubes because there is popping and crackling when playing guitar. I have a Marshall 40 Watt DSL. What should I do? What is the problem?

[@atcaleb]

Touch all you want. Old equipment always has grungy dusty dirty tubes installed. This isnt a halogen light bulb, it will be fine. Clean tubes look nice and dont smell funky when they light. Your fingers wont hurt your tubes.

[@MrPyroguru]

Caleb Welte What is causing the horrible popping when touching the amplifier on top?

[@atcaleb]

I'm sorry I don't know. It could be a number of things. Buy deoxit and put a small amount into the input jack and plug in and pull out the plug a few times with the amp off of coarse. If that don't fix it IDK where to start from this end. I doubt it will fix it, but it might.

[@renatopasqualini5989]

Hi Michael. Yea your tubes won't fail if you touch them a few times, however, if you are working on them and touching them constantly, any oil that is left on the tubes will cause them to fail prematurely. Couple of things I would advise: 1. I would not "touch them all you want" YES they WILL burn you. This is gas being heated in a glass tube, it's not advised to touch them while the amp is on or if you just turned the amp off. Wait a few minutes for them to cool down before doing that. 2. Please DO NOT pour anything into the input jack! The popping sound is either one of these 2 things. The tubes (most of the time they go bad, they don't last forever. Or there's dust in the input jacks, or in the tube sockets. You can actually carefully take the tube out, and use a air duster and blow any dust out. (This has been the case for me many times)

[@justingreen3530]

Simply not true. You are thinking of halogen light bulbs. There is no evidence anywhere that oils on your finger will hurt your tubes at all. simply made up.

[@krustybuzzard2477]

I pin a 59 fender twin that the bright input jacks don't work normal channel is good any suggestions?

[@marazomarazo6429]

probably preamp tube or wiring from jack

[@nor4277]

How much power does that amp put out ,it seems to be a very well put together amp ,clean ,how about a good vintage tube tester .

[@The2bdkid]

Can a microphonic tube start to feed back from the speaker sound?

[@silasfatchett5693]

Yes.

[@riffsnreviews]

Yes it can, and to find out if it's a tube or not, cut the volume on your guitar, hit the amp chassis if it rings and feeds back, you've got a microphonic tube (or a bad capacitor but most likely not). What this video is demonstrating *is not* a microphonic tube, it's a loud tube but definitely not microphonic. If he had have swapped the 2 over for the other 2 he would have been fine.

[@WithoutAChance64]

If a tube does not glow when you turn it on, is it a bad tube?

[@ashscott6068]

No. Or yes. The filaments that make the glow, are a totally different circuit to the rest of the tube. The amp won't work if the filaments aren't working, but that doesn't mean it's a bad tube. If none of the tubes glow, it's probably the filament power supply - those thick twisted wires that run to every tube. If you're getting around 6.3 volts across those, then it's the tube. If the heater in one tube fails, it won't affect the others. They should still work. Bear in mind that some tubes have the heater filament tucked away where you can't necessarily see a glow. If none of the tubes are glowing, check the filament wires to make sure you have continuity all the way along. At some point along those wires, there will be 2 big resistors, both connected to the filament wires on one side, and to ground on the other. Replace those. They often burn up. The amp usually still works if they do, but is very noisy. If you get no voltage at all across the filament, but there's no obvious break in continuity, then you got the absolute worst case scenario: The actual filament winding on the mains transformer is dead, and you need a new mains transformer. (Unless your filaments are powered by a separate transformer, in which case you just need to replace that) But no, a tube does not have to visibly glow, to be a good tube

[@Bairov]

Just got a budda SD18 and the v1 tube is visibly bright. The other two have me wondering. Not sure if they work, but the amp runs quietly 🤔

[@WithoutAChance64]

@@ashscott6068 thank you for your knowledgeable reply 👌

[@hadikayanuar1367]

My tube preamp sound "ting ting ting" when i test like you, are bad?

[@TheApsodist]

Bad

[@KevinPlaysGuitar]

I got a question: so if you can hear the tubes making the popping noise when you hit it through the amp, does it means that it's a bad tube?

[@ryantoomey611]

No, that is perfectly normal. It is called "micro-phonics" it is due to the metal parts inside the tube vibrating which causes a resonance, doesn't necessarily mean they are bad. Usually when a tube goes "bad" the filament burns out or the cathode depletes.

[@Jonathan-L]

I think it takes a trained ear to hear if the tube is microphonic with the chopstick / pencil test. Is there any more definitive way to determine which tubes are bad?

[@renatopasqualini5989]

+Jonathan L Hi Jonathan, yea this video doesn't do the best justice in picking up the audio in the room. However, tapping the preamp tubes and seeing if they cause echo, feedback, or a reverb-like effect will be a sure find that that tube is microphonic. The preamp tubes that usually go bad by the way are the first preamp tubes in your amp. The first and second preamp tubes in this video was for sure microphonic. I wouldn't say you need a trained ear to tell when tubes are starting to go bad, however, power tubes also have their signs as well. Some of those signs are, loss of volume, and muddiness or dullness in tone. Hope this helps. Cheers!

[@daivajurkeviciute5771]

Renato Pasqualini, i think you just helped me a lot, dude! My fender blues junior have lost the bass and i was thinking if i'm imagining it or there's something wrong with the tubes..And guess what? One of the tubes have that reverbish sound on the full volume.. I would describe that sound like drops of water are falling in to a big metal bowl. Gonna try to replace it, thank you!

[@Halliday7895]

touch the tubes all you want ...that was only true about old fashioned tubes from a long time ago. the finger oils would cause uneven heating of the glass surface and it'd shorten its lifespan. modern tubes can be touched as long as they aren't too hot to touch....

[@mekakorpse]

About that warning at the beginning of this video.. If you discard the plug from your amp, and then try to power it on, shouldnt it "deplete remaining voltage"? I'm definitely not an electrician neither have opened an amp. I've heard that this should be done to computer when touching parts inside it.

[@justinpaquette224]

A amp tech told me to unplug the amp while strumming a plugged in guitar, to drain the filter caps. I don't know how safe it is, but I can see how that could make sense

[@mekakorpse]

@@justinpaquette224 shouldn't a tube amp been put to standby mode for a while before taking power off?

[@justinpaquette224]

@@mekakorpse It might be a good idea, but I think its more important when you are turning the amp on

[@degingerninja]

I’d replace the electro caps now

[@tobiasrechsteiner8459]

"Touch these and you're dead" ... OK! Do I have to take that rear cover off or did you just do that to check the cables and solder n stuff? Very good I am going to give it a try since i suspect one or two tubes to have failed in one of my amps. Thanks for the demo

[@pedromartinazzo5036]

Tobias Rechsteiner Dont do it. If you touch a charged capacitor you can actually die. Even if the amp is turned off

[@KawiMusician]

thanks man..appreciate the help

[@casey43]

One more thing you should research what a rectifier does and you would not tap on it ever again! Take one of those out and that amp will sound like pure bliss

[@SkyLukewater]

What does a rectifier tube do? I just got my new amp and it has one but I've never had an amp with one before.

[@rustyzipperband]

Does anyone know if Marshall tubes are all shit? I just tested my tubes and they all seem to make these noises. I might not be hearing the sound on this video right but thats what it sounds like to me. Some of them sound more quiet than others. Just a light tap out of the speakers. Others are much louder. Should there be any sound coming out of the speakers? I'm kinda concerned because I have a gig coming up in a couple days and I know I should have gotten spares but damnit I didnt. I noticed it at my last show that it was sounding like shit then learned about this tapping test. Anyone have any advice? I sure would appreciate it. Thanks Marshall JVM410H Different Michael Williams than previous btw

[@chenks54]

To my understanding, Marshall do not make tubes, they buy in their tubes from other manufacturers who put the 'Marshall' logo on the tubes. Sometimes the original manufacturer's logo may be left on, other times not. Have a look on your tubes for evidence of another manufacturer's logo . . . like Sovtek for example. I've never used them (haven't had to replace any tubes yet!), but I've been told that JJ tubes represent good value for money, and produce excellent results in Marshall amps. Don't just take my word for it, speak to other musicians preferably those who use Marshall valve amps as part of their kit. sorry I can't be of more help.

[@3r1ck901]

I think jj's r just bad i had my vox re tubed less than a year ago n my amp is starting to pick up those crackling noises u had in urs, anyway great video I needed a refreshment about checking tubes

[@renatopasqualini5989]

+Erick Hernandez Thanks Erick! Yea tubes can go bad at unpredictable times. I just recently had to put in new tubes a month ago. Based on the way you play and how you bias your tubes (hot), they can burn out surprisingly fast. I would say the crackling is a sign that the tubes are already going bad. Hope that helps. Cheers!

[@philosophicallyspeaking6463]

These aren't halogen bulbs. You can't damage them by touching them, oily hands or not.

[@johnsimms3957]

I don't think it's good for the tubes or the sockets to tap on the tubes.

[@renatopasqualini5989]

+John Simms It should be ok, if you don't bang the tubes too hard. I ended up just replacing all the tubes btw. Cheers!

[@blakehatton4990]

@@SteveRyan1965 you shouldn't hear anything come out of your speaker when you tap the tubes. When he tapped the bad tubes the noise came through the speaker.

[@renatopasqualini5989]

Thanks for all the comments! Making another video soon to grow the channel. Any ideas or suggestions feel free to leave them here! Cheers!

[@brentholladay3113]

Like a mechanic who only kicks the car to see what’s wrong

[@Shadowman-1960]

Tapping once or twice on tubes to find microphonic tubes is understandable but unnecessary tapping on tubes will damage and eventually ruin them, so all that tapping was about as intelligent as thinking handling a tube with a bare hand will harm it.

[@paulmurro9304]

First always have the schematic for your model and series of amp . there's notes on them telling how to set up the amp to bias it and where to place control levels while testing ,NO ALL THE WAY UP !!! 2 ND RULE OF THUMB V1& V2 ( the one's on your far right looking at the back ) will fail or cause noise problems just Always travel with an extra 12Ax7,v1 and swap it out if problems still persist replace old v1 tube and repeat procedure with v2. Please turn off amp,let tube cool also Unplug from mains !!! PLEASE Note ,Tube Amps Can Kill if you're not experienced. I'M a retired broadcasting CEO and guitar player.

[@loosingparts6159]

Did anyone else notice the disconnected ground wire on the left ? Ugh.

[@renatopasqualini5989]

Probably because I needed to disconnect it to get the back panel off.

[@thespiritof76..]

Someone has been over informing you... You can handle your tube with bare hands.. unless thee stilll Hot! Then you want gloves

[@nigel900]

Won’t fail if you touch them.

[@internationalmasterspeaker1879]

Wow idol very nice 1

[@davidosbiston9699]

mine sounded harsh on clean

[@MrDavidschloss]

hang on im gonna get my tube gloves….

[@Banjoandguns]

Instead of damaging your equipment and testing it the wrong way. Think about the time you hit a light bulb and it went out. Spend a couple $ on a tester. eBay has old tube testers for 100$-200$

[@renatopasqualini5989]

+Christopher OTrust me, tapping a preamp tube isn't going to damage this amp. You don't have t spend that much money for something to test a preamp tube, but yea they do come in handy.

[@CHAOSMOVEMENT]

Tapping a tube is a rediculous diagnosis test. I can't begin to tell you how many times customers of mine have called me and said, "I tapped my tubes like it said on the internet, and now ALL my tubes are microphonic"....

[@renatopasqualini5989]

+Chaos Entertainment Well that quote is just not accurate, isn't it? If you tap a microphonic tube, it will give a responsive to that tapping. Microphonic tubes tend to be the preamp tubes, so when you tap one and it gives you a response, I believe that's a most likely way of finding the culprit. I wouldn't say what I did is a "rediculous" diagnosis test, it's actually a really good way of finding a bad tube without fetching a lot of money on a tube testing device. You're going to eventually replace all the tubes, so spending money on a diagnosis on your preamp tubes really seems ridiculous to me to be frank. It's not more complicated than that and when you find a microphonic tube, it doesn't mean all the tubes in the amp are bad. "I tapped my tubes like it said on the internet, and ALL my tubes are microphonic" That's just not correct. I hope you tell your customers that. Cheers!

[@CHAOSMOVEMENT]

Do your research. You may get away with it many times, but all of the real life experience that has shown it can drive a tube into a microphonic state aren't inaccurate.

[@renatopasqualini5989]

What's the point? If you're getting high pitch noise, or unusual feedback, and you find a microphonic preamp tube, that's most likely the culprit. So it's time to swap that tube out. I'm sorry, but I can't believe every customer's tubes have become microphonic by tapping them. That's probable, but unlikely. Cheers!

[@riffsnreviews]

"If you tap a microphonic tube, it will give a responsive to that tapping. Microphonic tubes tend to be the preamp tubes, so when you tap one and it gives you a response, I believe that's a most likely way of finding the culprit." This is just not correct... A ringing tube is microphonic, if it amplifies your the thud of the tapping it isn't, all tubes are somewhat microphonic when you tap them by design, especially the louder the amp is and microphony will vary depending on amp as well A tube recreating the sound of you hitting it *is not* microphony... and it's true some tubes will be dead silent some will not be, because they aren't all made equal, that doesn't mean that the loud tube is microphonic, actually that is one way you test for what tube you want to put in V1, the less microphonic of all is what you want at your input, same goes for the PI, you'd want a quite tube in that position as well. Microphony is when you get feedback from the tube. But yeah hitting them repeatedly will make them microphonic at one point thats for sure.

[@sohailahmedrizvi9231]

Not Properly Shown And Explained, I Could not Differentiate Between Bad and Good Tubes, Camera Was On a Different Side While Hitting Tubes By Stick, It was A Mith , Needs Full Attention Of The Video Maker To The Subject. Thnkx pls Try to Improve .

[@davidkenneth3983]

You ok you dont seem to know anything

[@timm.6391]

Get the Russian tubes instead of Slovakian

[@nathanchamness1778]

Get to the point man!

[@valvoxvo2755]

stupid way of testing

[@Fendera1]

and whats the better way? tell us

[@DrVulatar]

Four year's have past, and he hasn't told us the right way of testing

[@TheCleaner6969]

@@DrVulatar That's cause he has none.

[@guitarpedals2699]

Good info thank you man