Tube Amp MODs : The V1 PolyMorph | Easy | Cheap | Glorious!!

[@WaylonMcPhersonGuitar]

Love this Mod! Simple but very Powerful!!

[@giulioluzzardi7632]

Waylon, can I just try various caps at that point without having to change the Resistor value? Thanks..

[@oliverlangrall2014]

I'm looking at the schematic for the orange Micro Terror and 8 goes straight to ground. I know it's not a full tube amp but can this mod be done to the Micro Terror? I've never modded an amp before so I thought I would try on a cheap one hehe. Here's the schematic if you're interested, maybe I'm reading it wrong or maybe the circuit isn't traced correctly. drive.google.com/drive/folders/1g9wfa2V6Wt_q-ImJeZs3KuYknL_G4_X9

[@WaylonMcPhersonGuitar]

@@giulioluzzardi7632 Yes, you can

[@WaylonMcPhersonGuitar]

@@oliverlangrall2014 Unfortunately, it does not look like you can install the mod on this amp, cool amp though :)

[@oliverlangrall2014]

@@WaylonMcPhersonGuitar thanks!

[@Johnny3three]

I've been building custom electric guitars and pickups for over 20 years, and an instrument tech even longer, and this guy constantly teaches me stuff that blows my mind. Admittedly I'm no electrical engineer by a long shot, but I never have a hard time following him. That's the sign of a great teacher that actually knows what he's talking about

[@satanbane]

I do something very similar in my preamp design, with a 3-way switch, but I change the resistor as well as the cap. It's really no more complex, and lets you get quite close to the exact Fender and Marshall front end circuits. My circuit has a 2.7k resistor always present. Then, in "M" position, it parallels a 680n cap. In "F" position, it parallels both a 25u (or 22u) cap, and a 3.3k resistor. The result is pretty close to Fender's 1.5k. The middle position just leaves the 2.7k resistor, no cap, which is also a useful voicing. Glad to hear that other people are into this convertible front end concept!

[@giulioluzzardi7632]

Thanks for sharing, like the 3 way switch idea.

[@WolfgangSambs]

Thank you for sharing!

[@catherinemacleod4985]

I'm impressed. The EP3 mod really makes single-coil pickups shine. Every Strat player should investigate this. Absolutely beautiful sounds. Love to hear a P90 through this.

[@dustinayres5456]

My thoughts exactly. I play a jazzmaster through a twin and as soon as I heard the EP3 I told my girlfriend listen to this! I need that sound, it'll go good for what I play and write.

[@mikedwiles]

I was skeptical until I heard what you did. I was super impressed with the sound of the Fender mod. It really sounds like a cranked Super Reverb. Also, the Marshall sounds were very good. It sounded great all around. But I was really impressed with how well the driven sounds match the originals. Congratulations!

[@giulioluzzardi7632]

Your channel is fab. The Ep3 really keeps the character of the pickups. The single coils sounded bold and clear. BTW, mid 80s London met a Mr G who used to work with Vox building cabinets. Mr G told me that the Beatles had Fender style circuits modded into their Voxs. If it's true this must be one if the steps to getting there(Mr G was basically hinting that the Vox cabs the Beatles used had Fender amps inside). Don't know if it's true but I was a young sprogg and at that time very few players even knew how to change a V1 or what type to use...so it was all voodoo to me! Keep reminding us all about "Safety" every video, even experienced Technicians can be distracted or forget.Thanks again.

[@rocketpigrecords3719]

I could see it. The Vox circuit/build was temperamental for live use, and there you are with all the pots, tube sockets etc sitting there waiting for a 2 knob Fender circuit to be put in with very little effort. Hell, they could just rent one & their tech could have a functioning board going within hours or days. Depending on how many specific value caps, resistors etc they needed and how long it would take to hunt down. All while appearing to run "UK Built" amps, and giving their copycats the fits - wondering why they can't get "that" sound.

[@giulioluzzardi7632]

I knew Mr G was letting me into a "Trade secret" but I was too young and naive to tinker with amps. I am going to give this mod a go (22nf) on a Champ style combo, thanks.

[@nikolagenov8881]

Great demo!!! For me the Marshall mode rules on all three types of sounds!

[@PaddyMc5th]

Agreed, the EP3 setting sounded great through some good headphones, tempted to try this on a Marshall Origin 20 head. Great videos, great channel.

[@daves6851]

My MesaBoogie is like that EP3. I plugged up a tube fender and a Marshall combo to get closer to that sound in the 80s, then I heard a Mesa, that was it. I have been using a Subway Rocket ever since.

[@MrHellfinger]

Doesn't have a 12 inch speaker, reverb or tremelo, but I have loved my Subway Rocket for 28 years now. Gigged it hard for many years and even played a huge theater recently. Sometimes I enjoy having a modded TubeScreamer in front of the pre-amp to drive it a little harder. Otherwise, I am normally just straight cable from guitar to amp. FX loop gives me my reverb and stuff. I suppose I could get an extension cab for a 12" but haven't bothered.

[@williambock1821]

Cool! Definitely convincing tones for a couple bypass caps on a three way switch. The EP booster PCB on a popular diy pedal site (easy to figure out the name)is really cool. Lots of fun switcheroos on it available on the top. Not just dip switches inside. Very useful pedal. Dig that Strat style guitar ya got there ,too.

[@robertdonosobuchner3129]

The EP3 mode sounds really good! Very inspiring video!

[@WaylonMcPhersonGuitar]

Thanks!

[@waynegram8907]

WAYLON, Look into the Bernie Marsden Marshall mods they changed the capacitor values which make it has extra bite per each stage which sounds really good. Make a video lesson about it, its simple just the coupling capacitor values are changed per each stage. EVH Jose Arredondo mods using silicon diodes around V1 tube is also an easy mod which you should look into doing a video lesson about it. This diode mod was used for Mick Marrs Motley Crue and many other 80's guitarist.

[@giulioluzzardi7632]

Good to know. Before the 80s all this was handled by a "Tech" who spent most of the day in a little room in a Music shop or Factory and no-one wanted to fix thier own gear let alone mods..most of the tones we like were created by lucky accidents.

[@chrisgmurray3622]

I had diodes installed at the inputs on my old Marshall Super Lead 100, by Paul Crowther ,in 1979, and it sounded quite good at lower volumes, if a bit woolly. I eventually got him to take them out because I could no longer get a good clean tone as before. Maybe if I'd had them in only one input it could have worked better with an a/b switch, but in those days there weren't very many specialised signal switching foot pedals available and I'd have had to have one custom built..., not difficult, but in those days, a bit of a pfaff for me to organise. I realise this was more of a Jose clipping mod than what you demonstrate here but this is what the JCM 800 series sound was sort of like.

[@waynegram8907]

@@chrisgmurray3622 Paul Crowther might have copied the diode mod from Jose Arredondo since it was done on EVH plexi amplifiers I think in 1976 on the first Van Halen Album. The Diode mod sounds really good because its going some type of threshold clipping with the 1st preamp tube V1. DOD made an A/B box pedal when you can switch input ports on your amplifiers back in the 80's.

[@Beelzehump]

@@waynegram8907 Not really, Jose's clipping happens after V2, before the tonestack and not on the input. And btw, eddie's amp just had a 470u cap on V2, the rest is stock, the sag is the variac feeding only around 90v to the amp. First album, from 1978, sounds different in part because there was one JBL speaker being mic'd alongside the greenbacks.

[@waynegram8907]

@@Beelzehump Which year did Jose add the clipping diodes to EVH amps? I thought it was done before the Van Halen II album

[@antoniushalim2829]

Thank you for posting. Food for thought, Informative 👍

[@jcugnoni]

Cool mod. I actually made an amp where each stage can be tuned with switches for cathode bypass cap and bias resistor. Combined with parallel / series v1/v2 switch, it can get a wide variety of tone.. a kind of analog tube modeler in a sense;-)

[@stepath18]

Very cool Mod! Could this work on a transistor amp by changing the capacitor of input transistor?

[@WaylonMcPhersonGuitar]

Yes, if your amps 1st stage is a Bipolar or Jfet gain stage then changing the bypass capacitor will give similar results. You may have to experiment a bit, make sure you do it safely as well :)

[@GregoryMerritt-o1f]

That's a seriously cool ass guitar.

[@Theansilgregoryshow]

22uf 1.8k increases gain and bass filter to 4hz. 1uf 1.8k gives 88hz filter 22nf 1.8k is 4khz filter If you would really like to open app the flexibility of the amp. Pull the 220k for a 150k. Change 2nd stage to a 150k add in a 1uf cathode cap. Third stage disconnect the cathode follower add in an irf820. Use the second tube stage as a recovery/ boost or gain stage. Put an ldr in there as a negative feedback loop and you have options for compression or add an lfo you have tremolo.

[@goodbyepolarbears172]

Checked the Bugera V22 schematic and happily found the mod is already pre-done! 😊

[@WaylonMcPhersonGuitar]

Cool, I just pulled the V22 schematic and it has a 22uf Cathode Bypass Cap on V1, that's the one you can change if you want some different tonal options, cheers!

[@scottseale]

@@WaylonMcPhersonGuitarIs that cap ref number C 25 on the v22 schematic?

[@WaylonMcPhersonGuitar]

@@scottseale On my schematic it's C11, C25 is also a cathode bypass cap but further along the signal path just before the EQ

[@Pablo-nc6qu]

Thank you for this information, extremely useful and well explained. Nice playing too bro. Cheers ✌️ Edit: I subbed 👍

[@robbo4858]

Nice simple mod.... what did it sound like BEFORE the mod was installed ?

[@apparentlysmarterthanyou3446]

Look for the amp model on youtube and watch one of the hundreds of videos available on it? I don't know, just an idea.

[@jwstout007]

3:57 that made my eyes water a little ;)

[@guydouglas6094]

Yeah, it kinda looked cool. Has anybody done that?

[@jwstout007]

@guydouglas6094 nnnnnnnooooo dude! But also, probably ;)

[@oldguyjammin9732]

Cool!! What values did you end up using?

[@juansolanas]

Great!!! I will do it! Thanks!!!🎉🎉🎉

[@WaylonMcPhersonGuitar]

Let me know how it goes!

[@BataraKado]

your channel made me become the first to create a multi capacitor multi switch, yeah, i got three different capacitors on my les paul now i have the ability to go bright, dark and even setup a shortout option so if i use high gain on the shortout option it allows for a more cleaner and half output so it makes it change so much, mod your guitars and find your hidden tones..] if anyone uses this multi capacitor mod please shout me out as i did create it.

[@K707OR30]

Did a mod similar to this on my jtm45 reissue. One side of the switch is stock setup with the tied cathodes on v1 and v2. The up position separates the cathodes and adds a bypass cap on v2 which normally doesn’t have one. Gets it a little bit closer to 1959/1987 preamp territory although obviously not super close because of the totally different tone stack topologies.

[@copperaudio9664]

Sounds great - thanks for sharing.

[@rocketpigrecords3719]

Iirc, the JCA20 is the Crunch channel of a JCA 50, correct? I have 50 combo, and I was wondering if the gain channel could be independent of this mod? As in, this shapes the Crunch channel and leaves the Gain channel stock? Either way, since the stock amp is such an underrated beast itself, I think I'm going to adapt this into a 3 dpdt switch mod. Crunch or Clean Clean: Fender or EP3 Crunch: Marshall or Soldano (stock) Maybe add a Marshall/HR50+ (stock) switch on the gain channel, too. Fix the FX loop, and I don't know what more you could ask from an amp. Killer video, good tones, thanks.

[@tommymartinez1788]

I saw this in a Kendrick design. If I remember right he called his Fender, Vox, Marshall. Don't remember the capacitor values. Nice to hear it again

[@gooseabuse]

This made me think of hovercraft amps, they turned modding these amps into a whole business essentially.

[@rocketpigrecords3719]

Epic, too. They have kits for damn near anything. I'll probably end up buying more of these to mod, but I really like the JCA50 as-is. Bryce at Epic knows his stuff and has excellent customer service - he must, because he was really nice to me, and I haven't spent a dime with him yet.

[@gooseabuse]

@@rocketpigrecords3719 Never heard of them, sounds interesting. It's called Epic amps? I'm pretty sure Hovercraft has shut down, unfortunately.

[@rocketpigrecords3719]

@gooseabuse yeah, Epic Amplification. You can find some demos on their channel, and low_e has several demos of his amps with their mods on his.

[@NINEWALKING]

Now, indeed, the voicing can be changed with the different bypass capacity. Though it is not just a simple thing. If you are in the bright channel of some Marshall amplifiers, they will have extremely small coupling cap in that channel, and it will make way less difference as if it would be the standard 22nF coupling cap. So you would need to change that as well because 2.2nF ain't gonna let lows true. The second thing is that sure bypass cap adds gain and changes voicing, but it changes signal by applying certain low-end EQ curves. No bypass cap gives linear full range response but with lower gain. The point is that a good amplifier designer has taken whole parts of the schematics in calculation. With things as complex as they are in the world of electric guitars, everything matters, and everything is also dependent on other things. Plus, things have one effect at one level and different effects at different levels. Like when you push lows first they get louder. Though once the amplifier can't make them louder, it compresses, and other ranges get louder, and the complete tone is different. That compression could be nice and musical or just crap. Like treble booster or fuzz. With clean settings, it might be awful and harsh. Once compression hits the needed level, it suddenly becomes smooth, creamy, and musical. The very same things are true with designing amplifiers. You can go all to the output section, and the amplifier will have one character, and dependent on the solution used, it can be a very different amplifier at the end. Use stiff power supply, big iron, powerfully output section, and your amplifier will sound different. Use just a bit smaller output transformer, and it will start saturating and sound different. Use less filtering and looser power supply, and it will be a completely different amplifier. Sure, experiment and choose what you like. Just don't cone back running when things get wrong. I can't even count the number of cases where people want to return their amplifiers to stock and ask professionals to do it. You tell them that bad idea. They say, but it works. And it works until exactly what you told them will happen happens. If you want to experiment, sure learn about everything you can and get good.

[@liquidsmokemustang1537]

Cool mod. I’ve got a Peavey Classic 20 mini head I’d like to do this with.

[@WaylonMcPhersonGuitar]

Cool! Let me know if you try it!

[@liquidsmokemustang1537]

@ Will do. I like the Peavey stock but, adding the Fender and EP tone would be pretty cool. You didn’t cover the switch so I just need a SP3T and the corresponding caps correct?

[@GaryGraham-sx4pm]

cathode bypass capacitor limits a cathode biased tube's own local feedback, down to whatever frequency the capacitor suppresses. (the inductance of a wire-wound cathode resistor dampens low frequency local feedback and increases low end, [in more liner-optimized music reproduction designs]).

[@o.gu.1354]

I'm glad - at least one who comments and has an idea of electronic circuits! Greetings!

[@GaryGraham-sx4pm]

@@o.gu.1354 :) been building and modding guitar amps since 1965 .

[@cheesequake38]

I have always found when drilling holes into a metal tube amp chassis. If i take the metal shavings and sprinkle them like parmesan cheese into the preamp section, The Grim Rreaper taps me on the shoulder, And says {are you sure about that }. If i place a metal shaving in the power amp section , the Grim Reaper, takes my hand and says { your coming with me ! } This might sound funny to those who know but SERIOUSLY do not mess with a tube amp unless you really really know for sure know what you are messing with. These tube amps can kill you faster than you can imagine. One slip of touching the wrong thing at the wrong spot and your heart will stop beating. You wont die from the shock but it will make your heart stop. YOU HAVE BEEN WARNED!

[@kennethcohagen3539]

Now I’ve got to find a schematic for my amp. I’ve looked before, but won luck.

[@chrisbc61]

Waylon that symbol means 'microfarad' not 'nanofarad' so it's 1000 times larger value. It looks like 'u' but it has a tail in front , it's the greek character 'mu'.

[@WaylonMcPhersonGuitar]

It's a .68uf or 680nf both are the same, I often convert things from uf to nf, cheers!

[@user-zx5gg8od6l]

id personally want something like this but variable

[@dustinayres5456]

The EP3 Was absolutely my favorite tone. I have a fender twin reverb reissue and I know I can do the mod, just what exactly did you do to the v1? Or at least how do I get the twin to sound like the Ep3? I'd like to give this a try. Thanks in advance.

[@samizdat113]

I really like it.

[@void_snw]

No no no you gotta buy tons of tubes and try them all until youre convinced of a change to get tonal difference! Cant just change the actual circuit, where would we ever get with that? :p

[@bavarianmonkey8326]

Tubes have to be NOS and handselected of course. Otherwise, you cannot even hear the changes introduced by the soldering Iron 😂

[@darrenfoxwell7831]

just built a new pedal and sold most all of my over drive pedals echoplex and pre amp excluded Its called a 5E3 and its got a speaker too

[@void_snw]

@@darrenfoxwell7831 🤣

[@donald-parker]

I wonder if there is such a thing as a variable capacitor that could span the range of values you want, but instead of discrete different values you could have a knob like a pot for continuous changes?

[@Tmoyd51]

no switch position for the original sound of the amp ?

[@eyeball226]

I'd love a bit more technical explanation about how this works. I get that it's bypassing that resistor, so for higher frequencies it's like there's less resistance than there is for lower frequencies. What I'm curious about is the why and a bit more of a generalised explanation about what changing the value does to the sound, rather than just copying values from existing amps. Great video, I hope you do a follow-up. p.s. For the comparisons I think it might have been more helpful to switch through each voicing at the same gain level, then increase the gain and switch through them again. After all, it's the voicings we're meant to be comparing, not the gain levels!

[@hrsey71]

essentially, changing the value of the cap is allowing more or less input signal to pass through into V1. the more signal you let into V1, the more "gain" you will get once that signal is amplified through the preamp stages.

[@orbitaljellyfish808]

Totally agree... I’d only add a request to include a humbucker guitar. Cutting the video together with A/B would also work. Maybe later I’ll post all the times so we can use links for a/b. Technically speaking I’m pretty sure cap values have specific correlation with eq ranges, like high/low pass filters, but different… and how it’s wired will affect how intensive that effect is.

[@eyeball226]

@@hrsey71 But the fact it's a cap means it'll be different for different frequencies, so this isn't just a flat change in gain.

[@GaryGraham-sx4pm]

cathode bypass capacitor limits a tube's own (gain reducing) local feedback, down to whatever frequency the capacitor suppresses.

[@nibel13]

For this mod I just need a SP3T and the corresponding caps in the amp?

[@MrHellfinger]

Looks that way, yes. Just lift the ground side of the stock cap, then wire all 3 caps back to the same point still connected. Then connect each loose end of the caps to each 3T point on the switch. Connect the ground side to the single pole SP part of the switch. Super easy mod that seems kinda cool. Hardest thing might be deciding where to drill the hole :)

[@gwoodtones]

Can you make a video where you actually do that replacement to see how we have to do that practically?

[@Reyvil777]

ima check if this can be done in my vox ac15, maybe turn it to a marshally amp 😮

[@jamesrobertson9597]

FYI, uF is microFarad, not nanoFarad.

[@WaylonMcPhersonGuitar]

680nf is the same as .68uf, I just convert uf to nf on the fly sometimes :)

[@dananthony6258]

What’s the best pedal to make a blues jr deluxe sound like a jtm 45 ?

[@antoniushalim2829]

Would this mod would still work for single ended amp i.e champ style amp ?

[@Mark70609]

I know from personal experience that You Tube compresses the signal, I didn’t we were hearing the same thing.

[@michaelstankiewitch5391]

the 1uf with the 1.8k is already the marshall tone because the cap value is referenced to the resistor .do the math

[@Peterbrendanalbert]

Makes me wonder why manufacturers don't add a 5 way switch with different values to scroll through if it's so cheap. Seems like a no brainer to me..??? What am I missing?

[@Skoora]

I didn’t know sheep played amps.

[@Satchmoeddie]

An EP3 is not tube based and it never ever was. That would be an EP1 or an EP2. I have a mod that changes the tone stack of a Fender to scoop more like a Marshall amp, but the gain will be about 3 or 4 dB down. If you have the OLD plug into the wall Boss GE10 that will drive an amp into clipping like an EP3 pedal. Instead of 9VDC those old GE 10s run at 26 VDC so lots more gain and headroom. Van Halen used the GE10s to push his Marshall amps, with lots of midrange.

[@RickMcCargar]

Isn't the cap just before 3 minutes a microfarad not nanofarad cap? You say it twice..

[@WaylonMcPhersonGuitar]

It's a .68uf or 680nf both are the same, I often convert things from uf to nf, cheers!

[@Tech-gu5ge]

Why not just lift the bypass cap completely? Bypass resistor sets the gain for the stage, bypass cap EQs it.

[@steveymoon]

It only costs about ten sints? 😋

[@WaylonMcPhersonGuitar]

That sexy New Zealand accent breaking hearts around the world :)

[@steveymoon]

@WaylonMcPhersonGuitar - love it. 😋

[@davidlong1786]

I wish those that mod amps would run frequency response software to prove or show what the changes do.

[@1176hambone]

Hi gain on neck is stupid. be realistic.

[@NINEWALKING]

Opening the tube amplifier and saying to people who have no experience it is safe because you are not working with the high voltage? Curios approach, indeed.

[@void_snw]

While not wrong, you're still opening a box where touching the wrong thing can totally fuck you up or even kill you. I agree, not advisable.

[@darrenfoxwell7831]

He refers you to instructional videos he has allready done if your not sure. I dont know how much clearer you can be.I have a personal grudge against and report people who dont give proper advice in this regard.Dude listen to what he says at that the start cheers👍

[@GaryGraham-sx4pm]

400 volt electrolytic capacitors can store a very surprising voltage for weeks after an amp is turned off and unplugged. high tension capacitors in most amps are bypassed with bleed resistors, 470K 1W, for discharge to a safe voltage within about half an hour. after unplugging the amp, use a multimeter set to 500volt DC to measure across any high voltage capacitors, if more than twenty or thirty volts; touch a 100ohm 5watt resistor across the capacitor for twenty seconds, then you're good to go.

[@NINEWALKING]

@GaryGraham-sx4pm Most amplifiers use 220k discharge caps. Plus, amplifiers that use very high first node B+ voltage tend to use two caps or two full cans in series to be able to handle high voltages. Then, they have to have additional strapping resistors that act as the voltage divider and make sure they are discharging caps after the amplifier is turned off. I build, and I have designed amplifiers. I can literally write a book about every single part of the amplifiers and name all functions of every part. Because many parts in amplifiers have a few functions depending on how you look at them. Take the coupling caps. They prevent positive voltage to open the grid of the next stage, but they do allow mudic signal to pass. Their capacity will shape the lowest end of the signal, too. Like in some Marshall amplifiers, normal channel will have 22nF, and the bright channel will have 2.2nF rolling off the low end. Or plate resistor on preamp tube triode. It has more functions as well. Anyhow, you take it tube amplifiers are complex and dangerous beasts. Some of them are just scarry. Take any monster with 4 KT88 tubes. Voltages are inssine. Take Hiwatt power supply for such amplifiers. Those will not just puncture your skin like a needle if your finger gets too close. Those will not just shock you. Those are seriously dangerous. Often, they have 300uF effective filtering capacity where the first node has 100uF at voltages north of 500V DC. That enough starred energy to do some serious damage. Plus thise transformers can put out 1.3A on HT tap! Insaine. Even 100Watt amplifiers have 0.4A on high voltage tap plus caps. Usually under 500V but not that far away. 450 to 475V mostly. At high DC voltages already a few mA are already extremely dangerous. 10 mA and your chances are getting worse. Even single ended 5 yo 6 Watt amplifiers with single EL84 or 6V6 in yhr output will have 250 to 300V. That is already enough for very unpleasant and dangerous accidents. 12 to 22 Watt amplifiers have 300 Plus volt always. Anything with 400V is just scarry. People who are not trained to work with such scarry things should not open amplifiers ever. Even if they watch 10000 videos.

[@void_snw]

@@NINEWALKING what's insane to me is that in overall electric work our guitar amps are considered pretty much puny little low voltage devices lol. I would NOT want to be one of the guys working around 10kV+ shit, like DAMN bro.

[@LIKEFUNK]

Not smart in my opinion to try a home diy on a device that can kill you, best left to a qualified person....electricity can kill a person stone dead -and it's ....silent.....odourless....and doesn't give anyone a hint, simply never worth it as a diy unqualified.

[@AriaMusicVibe]

Trust the corporations instead. Samsung phones being recalled after they explode and set on fire. Suicide nets around apple manufacturing facilities to stop the workers from jumping to their end. Built in obsolescence. Yes definitely, don't bother to learn how to do things. Don't critical think. Trust the corporations.

[@SwiftFieldMusic-i6n]

Get a friggen grip... he even mentions another video he's done on safety around amps in the video to help with this. If your not confident or capable (and not willing to check over a safety video) don't do it.... same goes with driving a vehicle!!! kzbin.info/www/bejne/gXecnmWFf5prras

[@MrHellfinger]

If someone doesn't have common sense enough to unplug the thing before working on it, they should just stick to watching TV. There is no such thing as a 'qualified person' when it comes to doing any of this. Tons of people have built, repaired and modified tube amps, TVs, radios, etc. on their own (DIY) for over a century now. Some with formal training, most without. If you're afraid of working on this stuff, you should probably just watch other people do it.

[@LIKEFUNK]

@@MrHellfinger You obviously don't seem to be aware that capacitors hold/store power within them for hours in most cases and depending on the size/type can produce a serious electrical shock or worse if not professionally respected when working on most guitar amps, not to mention they can and do actually explode causing injury, imagine if one popped in front of your eyes/face for example.

[@MrHellfinger]

@@LIKEFUNK AGAIN if you are too scared, or TOO STOOPID, then go watch Footy On TV.

[@karldettling5981]

There is a tone stacker program online you can use to get an idea of what cap changing will do to your amp. I have never used it but i think it would really help out?

[@smithcustomguitarco]

that will alter the voicing of the amp as well, but after the first gain stage. it will also alter the effect of the eq knobs. the mod here affects the voicing of the first gain stage itself.