hey everybody how's it going 大家好
in this video I'm gonna be going over the basics of guitar electronics 本视频中 我要讲解吉他电路的基础
I did have a video of this up but there was a mistake in it 我之前做过这种视频 但当中存在一个错误
thank you big and woo-hoo-hoo pointed it out 感谢“大大”和“呜呼呼”指出了问题
what ended up happening is 最后的状况是
considered me going by what I knew 当时感觉我是 凭借自己的所学
I kind of went into autopilot mode 有点进入“自动驾驶”模式
and I was only focusing on a certain portion of the schematic 我只看到了 电路图的某些部分
and I was thinking incorrectly and then so when I was doing that 我当时想法不对 当时我在讲这些
and I was stuck describing what was happening I was actually incorrect 我的描述 实际是不正确的
so I decided let me redo it because I don't want to give you guys bad information 所以我决定重讲 因为我不想误人子弟
so that's what this is all about I'm redoing it 那么 这就是我要重讲的内容
okay so if you've already seen the video the first time 如果你上次看过这个视频了
nothing much has changed except just a little bit about the volume control 这次大体不变 只有音量控制方面有出入
you don't have to watch it yet so anyway 你不是一定要再看一次
before I actually start doing this video 在我录这个视频之前
I want to go over what electricity is 我要温习
just in case people don't know right I
know it sounds so silly but what causes
electricity
well electricity comes from the word
basically electron right electricity
electron right well that we have to go
to the atom to find the electron and
instead of drawing what is it twenty
seven twenty eight is twenty eight
twenty is it 28 or 29 copper copper
twenty-eight twenty-nine thirty is zinc
so copper is 29 so instead of drawing 29
instead of drawing 29 protons and
neutrons and 29 electrons I'm going to
just do two now this is helium but it
doesn't make a difference because the
idea is the same now you're not gonna
have any like helium wires but I'm just
doing this to show an example okay so we
have a helium atom here we have two
protons two neutrons and we have two
electrons the protons they are
positively charged the electrons are
negatively charged the neutrons are
supposed to be inert in other words they
don't do anything kind of like a
brother-in-law and these electrons
always fly around and
they're doing all sorts of cool stuff
doing their Indianapolis 500 on here but
see we have two to two everything's
balanced they're happy it's not doing
anything it's an uncharged state but if
I end up inducing another electron here
I force another electron right here this
is now imbalanced technically this would
be a helium ion and because it's
negatively charged and this is
unbalanced it doesn't want it doesn't
want this so it's going to try to get
rid of this one to the to the next atom
that is next to it which would be like
this guy okay and it's gonna say you
take it I don't want this and this guy's
gonna say well I don't want this and
it's going to go to the next one and
you're going to say well why doesn't
this guy right here just give it back to
this dude why isn't you know just like
stuck in the middle the reason why is
because there's a current flow in other
words there's a certain level of force
of electrons coming like a certain
direction in this case we have a bunch
electrons going this way so by the time
this one ends up getting this one it
hands it over there's already another
one here the guy over here doesn't have
one so as long as there is more
electrons on one side or a force a
certain voltage right on one side it's
always going to go in the other
direction okay it's always going to go
in the other direction that's the first
thing that's electron flow that is
electricity okay there are three things
to remember about electricity
you have volts you have amps and you have resistance okay 电压、电流、电阻
volts is the amount of pressure that
it's the potential it's it's it's what
they call electro-motive force right
it's it's the pressure if you think of a
typical explanation of this would be
like a garden hose so if you have your
garden hose and it's hanging out in the
backyard and you can you have it hooked
up to your your spigot and everything
like that and this is coming out of the
wall and you go ahead and you turn this
knob on just a little bit right it's
going to kind of just trickle out right
there now if it trickles out that would
be very low pressure right there's not a
lot of pressure in it's just trickling
out so that would be low voltage but if
you turn this thing all the way up and
the stuff just started spraying out like
this that's high pressure that's high
voltage so that's what voltage is it's
the pressure of the electron flow amps
is the current okay and the current is
measured in amps or amperes and the
current is the amount that's coming out
so think of it kind of like this if I
had if I had a bottle of wine and I
turned it upside down like this there's
this is a very small opening so the
amount of wine that could come out at
one time would not be very much because
simply wait well I'm not gonna bring up
the vacuum but the amount of wine could
there couldn't be a lot just simply
because this is a small opening right we
can consider this a low current like low
amperage but if I turned a bucket upside
down on the other hand like this a huge
amount could come out that would be high
amps right because the amount that's
coming out is much larger the amount
that's coming out it has really nothing
to do with pressure has to do with the
amount right but when you mix the
pressure and the amps and stuff like
that you're going to end up finding that
they have a relationship between them
and then that is what's known as Holmes
law I'll talk about this a little bit
later and it all it is is this that
there is a relationship between voltage
current and resistance okay that's all
it is I'll talk about that a little bit
more here in a second what about
resistance resistance is exactly that if
I came up and I stepped on this hose
even when it was full blast tonight and
I'm holding it down it reduces the
amount of liquid that can be forced out
of here and so what would end up
happening is it would kind of start
trickling out or at least it wouldn't be
as strong as this even though there's a
lot of
sure back here right same thing that's
resistance okay resistance does just
that it resists current flow let's go
ahead and go over this so we have a pick
up this is going to be our pick up
anywhere you see a black line the black
lines are going to be representing like
wires or leads or something along those
lines everywhere that you see one of
these like little circles consider that
like the the spot where you on the back
of a potentiometer where you have the
three leads just consider it that there
actually should be one right here but I
didn't drive anywhere that you see this
symbol where it kind of looks like kind
of like a triangle little bit right here
that means ground and so it's assumed
it's assumed that this this this and
this are all connected to one another
the reason why you don't actually draw
the wires is because if you did it would
look really bad and be hard to tell what
but you know what's going on when you
see a squiggly line like this that means
it's a resistor and if you see the arrow
it means it's a variable resistor and in
this case we're going to be dealing with
potentiometers or they call them pots
when you see this sign right here
that's a capacitor when you see this
this means AC current NC current okay so
real quick like I'm going to go over
this section and the end portion I'm
going to go over the tone okay
the pick up I've got I've made videos
about this before but the way that the
pickup works is you have magnets inside
of it and there's coils around these
magnets and then this magnetic field
goes through the coils and above above
the coil as well when you get a string
or anything metal and you move it inside
there it causes the electrons to move
back and forth in sync with whatever's
moving and then it creates an
alternating current okay if you want to
know more exactly about how that stuff
works go to my other videos about how
pickups work or you can look at the
video called art pickups and microphonic
my video called that
we have an AC current coming up AC
current just means that it's constantly
going positive negative positive
negative positive negative it's going
back and forth at different frequencies
okay and frequency in this case don't
think of it like pitch you know think of
it more along the lines of how frequent
something is happening
yeah and it's important if we saw the
actual wave form that comes out of the
pickup it might look something like this
like something strange like that okay
now what this would actually represent
would be a multitude of frequencies
you know we this this tall one and this
one might represent a hundred and ten
Hertz and a hurts as is just the measure
it's a measurement of frequency its how
often something happens per second so if
it's a hundred and ten Hertz that means
that it's oscillating 110 times per
second this one might be something like
two hundred and twenty Hertz or
something so this is this is oscillating
faster than the 110 this might be
something like a thousand two hundred or
something I'm just making these numbers
up now waves can travel through each
other this is this would symbolize a
bunch of different frequencies kind of
just shooting through the line all at
the same time they're superimposed on
top of one another so that's what this
looks like but it's important to
understand that they're within this
signal there's a multitude of
frequencies some of them are going to be
very slow like this some of them are
going to be very fast like this but
they're they're on top of one another
okay they're they're superimposed this
is going to be important when it comes
to how the tone the tone circuit works
so we have the the the current the
signal coming through like this
electricity wants to take the path of
least resistance all right so it's gonna
cruise over this way and we get over to
this point and you can see that there's
part of it that's going to shoot over
here to the tone circuit
but there's also a part of it that goes
up to the variable resistor this is
called a wiper blade this this is a
blade that can move back and forth
if this resistor is 500 K it would mean
that on this side would be 500 I'm sorry
this 500 this side would be 0 okay at
least what I'm talking about here
it can actually be flipped the other way
around too so this wiper blade can move
back and forth on top of this this
resistor within the potentiometer and it
will cause the resistance to vary that's
why they'll call it a variable resistor
so if this wiper is dead center and this
is 500 K it would stand to reason that
it's about 250 K currently if I turned
it down and be like 100 K by one up
closer to 500 it'd be close you know
it'd be like 400 now that is if you have
what is known as a linear pot they come
an audio taper and linear taper
I'm sorry linear and audio taper and the
difference is like this a tone is a
linear pot and what that means is on a
scale from like if this is 0 this is 500
linear means like it is divided equally
all the way across it so if you move the
white or dead center it would be 250 K
because everything is divided equally
the resistance is divided equally when
it comes to a audio taper it is not like
that an audio taper would be more along
the lines of something like this okay
where 250 K might be closer to here okay
and so from here to the 250 K there's
much more play so you can kind of fine
tune a little bit more that's the
difference between an audio taper and a
linear taper and the the linear is
usually used on tone you can put it on
volume
but typically they'll use an audio tape
for that so since this is an audio taper
this would not be at 250 K this would
probably because closer to like maybe a
hundred or 75 K or something okay
but in order for this signal to come
over here to the output which would go
to your amplifier this is your jack
right it has to we've got a ground here
which is connected these two are
connected so we have we have one of the
wires coming to ground that goes
directly to the amplifier so we're good
there but the other signal has to get
over to the hot portion of it and that's
where we've got this resistor right here
now this is what is known as a voltage
divider and what that basically means is
this this is actually parallel this is
what's known as a parallel circuit so if
you got this and kind of turned it this
way you would see that this is ground
and this is ground so in a way in a way
actually not in a way it is these two
wires are actually connected okay so
it's it's parallel and by moving the
wiper back and forth what you're doing
is you're dividing the amount of voltage
that's here between going to ground and
then the other one going to out well if
it if it ends up going to ground right
what you're doing is it's pretty much
the same thing as just kind of shorting
this here that's that's the first thing
but another thing that you're doing is
if this wiper gets closer to this way
the hut it's like it jumps straight over
here to the ground so it's a dead short
and so you're not gonna hear any sound
so this is why when you end up turning
this guy all the way over to this side
there is no sound it's because it's a
dead short but if you have it over here
what happens is it the electricity
shoots up over here cruises down comes
out and this is at full volume but
you'll notice that the resistor and the
ground are still in the circuit okay
they're still in the circuit so it plays
a little bit of a role when it comes to
how much how much signal gets bled out
in other words if if you have 500 K and
remember electricity does
take the path of least resistance so
with this if we could imagine that this
guy is like this the wipers like that
and let's just say that there's zero
resistance here this signal would much
rather just go straight out it would
much rather do that it's easier but at
the same time there's going to be a
little bit of leakage going through this
this 500k so some of the signal is going
to come over here to ground it's gonna
leak just a little bit okay
just a little bit so if you ended up
having 250 K that's less resistance and
then that's gonna end up causing a
little bit more leakage a mega ohm since
it's it's higher resistance it would
actually decrease it how much how much
leakage are we getting how much drain
not much not much probably not enough to
worry about okay there's some people
that would swear they're gonna swear by
it they're gonna say oh my god I can
hear a difference between this amount
and this amount and hmm I mean I've
never I've never really been able to
hear the difference that doesn't mean
that you can't I'm just saying I've
never really been able to hear a
difference when this thing is fully open
it's fully open right but you will get a
little drain like that so when you hear
people talking about the drain on a
potentiometer they'll say well you know
it takes on some of the highs a little
bit more the highs away does this is
that that's what they're talking about
but that's how the volume works it's
pretty much like a dead short or it's
fully open with a little bit of bleed so
that's how the volume works but what
happens is we have this signal right
here these are tied together chews down
to this next potentiometer and through
here we have another variable resistor
another 500k just for the sake of
argument you can use any value that you
want on these really it'll change how it
performs but it'll it'll do the same
thing we have another 500k this light's
not hooked up to anything so this is
more like series this is parallel
because these guys these two guys are
hooked together this doesn't have
anything pumped up to it so this is
series and what happens is we have a
wiper here that goes to a capacitor this
is not an electrolytic capacitor in
other words it's not a polar icecap ass
this is one that's unpolarized the
signal shoots through here and depending
on where this wiper is if it's straight
over here it's going to be just like it
was over here where there's like no
resistance to just go straight into the
capacitor if that's the case you're
going to get it's like the the tone knob
is turned all the way on in other words
it's robbing all those high frequencies
if it's over here it's like it's turned
off because once again electricity is
going to take the path of least
resistance and with this 500 K that's
asking an awful lot of this small signal
to get through the 500 K but there is
there is a relationship between the
resistance and the value of the
capacitor this is what is known as an R
C circuit this is a resistor capacitor
circuit this is a low-pass filter this
allows the low frequencies to pass
through but at the highs go to ground
and I'm gonna explain that here in a
second it's just important right now to
understand that this signal comes here
depending on how much resistance we have
is going to determine you know how much
signal how slow all that other stuff is
going to be shooting through here it's
going to come up this way and then
depending on the frequency and the value
of this and the value of this is what's
going to determine what frequencies get
bled out they go to ground
it's like shorting out only those
frequencies so what we have to do is we
have to understand how a capacitor works
that's what I've got these guys here for
just look at the top one now this would
be one of the wires from the capacitor
this would be the other this would be
like a plate and this would be a plate
and there's a gap in the middle it could
have paper liquid or something but
there's some dielectric compound
typically that's in the middle of this
and which prevents these guys from
touching now on this side on this plate
you'll see that we have a positive and
negative a positive and negative a
positive negative positive negative it's
an equal number in other words there's
no charge and the same thing with this
side there's no charge because there's
no power to this but if I were to get a
battery and I were to stick it where
positive was here negative was here what
would end up happening is remember
opposites
attract and 'likes repel right so what
happens is the negative portion of this
sits there and says hey cool positive
right and so they kind of neutralize
themselves but then this gets built up
with a really really strong positive
charge and the same thing happens over
here on the negative because the
negatives and the positives are going to
be attracted to one another so this
becomes this becomes charged now what
ends up happening is at this point since
this is positive and this is positive
these guys are going to repel one
another in other words it's almost like
this this right here is almost kind of
like a on and off switch and when it's
charged like this it's the same thing as
like turning the lights off and then
when you remove this and it turns into
this thing it's like the light turns
back on again because this is acting
kind of like a switch kind of like a
gate right well what happens this is on
a DC current that's like if I put a
battery but we're dealing with an AC
current so if I ended up switching this
to negative and I switch this one to
positive right I went like this and I
went like this which is exactly what
would happen with an AC current because
it can go positive negative positive
negative positive and different speeds
of frequencies now we have the negative
we have the positive here these are
going to be attracted to this and this
is going to be attracted to that and
then all of a sudden these guys are
going to flip positions so all of this
would become negative and all this would
become positive and then it would stop
once again it would create that that
that that barrier for electrons for to
pass back and forth so what ends up
happening with this well depending on
the value of the capacitor which is in
farads and typically you're going to
find like microfarads or pico farads or
nano farad that type of stuff because if
air adds actually quite it's a large
it's a large amount of charge but these
guys are like little batteries this
tells you right here the amount of
farads
that this basically has but there's also
other properties to a
pastor but right now we're only going to
focus on this depending on the value of
this size of the capacitor all sorts of
stuff is going to determine plus the
resistance and plus the amount of juice
going to it etc there's there's factors
involved but depending on all that is
what is going to determine how fast
these plates get into this state how
fast they charge up now if it's a very
very large capacitor it's going to take
longer for the thing to charge up right
but also if you have resistance more
resistance it's going to take longer for
it to charge up when you have little
resistance like if you move the wiper
over here it doesn't take as long to
charge up so what is what does this mean
well these cannot instantaneously switch
back and forth that it takes its micro
we're dealing with you know just a
fraction of a second on how fast these
are but it can't do it real fast right
depending on the size of it and the
resistance and other stuff it changes
the speed of which this stuff can go
back and forth well if it's in a state
that's similar to this electrons pretty
much can get kind of passed through it
now if it passes through it's like
grounding out right and technically
electrons don't really pass like AC
current really doesn't pass through a
capacitor it looks like it does and it
acts like it does but it it kind of
really doesn't right not that that's
really important but I'm going to be
using passing through just so you kind
understand what's happening here if it's
in this configuration something like
that it's much easier for the signal to
go straight to ground if it is in this
the it's gonna block it's gonna block
anything positive coming this way right
it's that's just way it is anything
negative on the other hand it's gonna
sit there and say I'll take it
I'll take it okay so why is that
important why does it why's the tone do
what it does well this is a low
frequency this
very low this would be like hitting your
low E string or something along those
lines the lowest fundamental note I'm
sorry the ferret the the lowest
fundamental frequency within the e
string itself right this is so slow that
the capacitor has time to change its
charge enough to block this so what
happens is this cannot go through and go
to ground it can't right well I mean a
little bit will but not much right it
blocks it because of this this
alternates so fast a high frequency this
can't keep up and because it can't keep
up these pass through and it goes to
ground right so you can change all that
stuff though by altering the resistance
with the wiper that ultimately is how
your tone works that's pretty much it
and doesn't matter if you have you know
three pickups and through two tones and
two volumes or whatever it doesn't make
a difference because all of this the
principles are the same nothing changes
right and hopefully I explained that in
a way that makes sense
hopefully I didn't make any errors this
time I bet I was trying to consciously
not go on autopilot like I did the first
time
let me see is there anything else oh the
one thing that I did want to talk about
which I did in the first one and it's
it's about capacitor values right
some people will talk about well which
type of capacitor value is best some
will say well a point zero two two is
grade or a point zero four seven is
great under these conditions and you're
going to hear a lot of you're going to
hear a lot of different opinions on it
and really it is kind of opinion based
when it comes to the type of capacitor
remember in electronics values or values
right the same thing when it comes to
resistance and stuff values or values
there is a thing in electricity known as
Ohm's law which basically states that
there is a relationship between voltage
current and resist
and if you basically if you have two of
them you can figure out the other right
by either multiplying or dividing or or
whatever but this always holds true and
the same thing is true when it comes to
capacitors and I mean you wouldn't use
Ohm's law really for capacitance but
it's also true for capacitors values are
values when a capacitor gets older it
starts deteriorating and it loses it
loses some of its effectiveness and its
performance right when it gets older the
ones that they're making nowadays are
much better than the ones that they used
to make a long time ago the reason why
I'm bringing this up is because there's
some people out there that are going to
swear to you that if you want to have a
vintage tone anyone everything sounds so
great you have to go and you have to buy
these old bumblebee capacitors that were
taken out of old guitars and stuff right
because they're just so much better
there's just so much better these ones
because they were made in Soviet Union
or they were made in wherever right and
they're just so much better no no no
values are values right so whatever that
capacitor can do whatever its values are
you can buy a brand new one that will
actually work just as good if not better
and it'll last longer and it's going to
be remarkably cheaper you can get in a
brand new capacitor for 80 cents right
you buy one of those bumblebees from one
of those those snake oil salesmen or
whatever like on eBay or whatever you
might spend 80 bucks hundred whatever
depending on the the person is trying to
sell it and the hype they're putting
behind this special one-of-a-kind you
can't buy anymore you know super 1959
out of Buddy Holly's fender type you
know capacitor capacitor is a capacitor
right when it comes to the values the
values are the values don't get caught
up in that whole thing about it has to
be this it has to be that values are
values it's and the values are going to
tell you what if the performance is and
before you buy anything like this or you
buy anything like this typically if you
if you buy it from somewhere that is
reputable they're going to give you the
spec sheets on it they're going to tell
you what the actual
these are going to tell you the
tolerances and stuff when it comes to
your potentiometers any resistor they
have what they call tolerances which
basically means this it might be stamped
and it'll say 500k but it might it might
say you know 5% tolerance 10% tolerance
which means give or take 10% right in
other words the total amount over here
could be 520 okay or something like that
but it could also be something along the
lines of like you know 472 K or
something so they're just saying look
there's the possibility it's not going
to be exactly like this the more
expensive you get the more accurate they
are a few a few ohms isn't going to kill
you right a few ohms you're not getting
here you and I can hear difference so
that's not a big deal when it when it
comes to your capacitor and stuff a
little bit of changing here and there's
you're not going to notice a difference
and for the people that say that they
can hear a difference between the old
bumblebee ones and the newer ones I
guarantee you if we have the exact same
values right apples and apples and
oranges and oranges the exact same
values and I swapped out and I had two
guitars that were identical and and I
played them they could not tell the
difference which one was which because
values are values that's the cool thing
about electronics it's it's almost just
like math where it's like whatever the
number you get that's the number you get
right there is no there's no opinion or
anything like that there's nothing
that's really debatable I mean the
function of something you can kind of
debate but you know the reality is is
after you look at the schematic long
enough and you follow the current flow
you'll know you'll know that it's not
debatable right keep it like know you're
trying to tell me it's like this but the
reality is is look it can only do this
and under these given laws and under
these given numbers boom it's the only
thing that can happen so it's not
opinion based and you're gonna find that
when you go on a lot of these forums and
stuff like that they're going to be
trying to throw a pinion based
electronics at you and that's not the
way it works