n00b question about input and output of a guitar effects box

N00b question about input and output of a guitar effects box:

I have encountered a band which at a show attempted to connect the output jack of an effects box to the guitar and then connect the input jack of the effects box to the guitar amp.

It sounded terrible.

I think there is a good reason why input and output are not interchangeable, but I am not quite sure why, and I found the Guitar World forums to be full of people who don't care about electrical engineering and want the retard explanation, so I came to these forums for help. (Here is an example of a thread on Guitar World forums where the forums members were spamming asking for retard explanation asking what an ohm is:http://www.ultimate-guitar.com/forum/showthread.php?t=1571081&page=1&pp=20).

What is the electrical engineering reason why input and output jack of a guitar effects box can not be mixed and matched incorrectly, only one way works?

Does it have to do with impedence matching to block feedback from the applied effect in the effects box from oscillating back to the guitar pickups in a continuous oscillation?

 

What is the reason that all electronic circuits are designed to only flow correctly in one direction? (I do remember my physics teacher telling me that in a circuit analysis for DC the sign + or - does NOT matter as long as they are opposite of each other, but the current direction DOES MATTER, but that was for DC circuits, and the circuit in question is a guitar amp that uses AC.)

Alternating current flows in two directions oscilating back and forth at a frequency.

Does it have to do with transformers, like alternating current in an electric power transmission line does oscilate back and forth, but the order matters what side of the transformer you are on because one side has a higher voltage and one side has a lower voltage?

 

For me to play devil's advocate, what if the circuit has no such devices that make the signal flow in only one direction, then wouldn't connecting to either input or output work?

Do I have it correct that amplifiers whether they be vacuum tube, transistor, or IC, they all use DC for all 3 of those components, so that is the reason why no amplification occurs if I connect my guitar to the output jack of my guitar amp?

What if the effects box has no components that only let current travel in one way and only uses oscillator circuits to amplitude modulate the guitar signal? Is the reason in that case why the input and output which one chose matters is because you do not want to apply the effect to the original guitar signal before the effect is supposed to be applied?

 

Thanks guys! I think I get it now!

So a passive device that is all AC using only inductors, capacitors, and resistors, is bi-directional.

So a passive device that has DC in any point in time even if the input and output are AC is directional.

So an active device is directional because it uses external power and the external power supply must be DC so as to not add harmonic distortion into the AC signal from the AC wave forms of the AC power supply.

So a passive device that is all AC using only inductors, capacitors, and resistors is directional if a low pass filter is used because "low pass" implies that some current goes one way and some current goes another way.

So tubes, transistors, and ICs must use DC when amplifying a circuit because (1) they only work with DC because "valve" implies current is flowing one way, and (2) AC power supply of amplifier even if possible would cause harmonic distortion from the AC wave forms of the AC power supply. So any circuit with tubes, transitors, and ICs is a directional circuit.

 

Okay, everything that you said makes sense, except I am still confused on one point that you said.

You said that amplifiers use a DC power supply but are otherwise powered by AC or DC pulses?

Can you be more specific? When you say "powered by AC", are you refering to the fact that the amplifer in question is a guitar amp and guitar pickups are generating AC?

Do you mean that the tube or transitor or IC uses a DC power supply to pass the current in one direction through the amplifing component, and the DC current is connected to the AC signal generated by the guitar pickups, so that what passes through the amplifing component when no guitar signal is generated is continous DC, and what passes through the amplifing component when a guitar signal is generated is DC pulses, and each amplifing component has a duplicate wired perfectly out of phase by 90 degrees so that one component will amplify DC pulses for the positive waveform and the other component will amplify DC pulses for the negative waveform and then the DC pulses will be combined back together into AC after the DC pulses have been amplified?

I'll talk about a tube for simplicity. With a tube amp, does the thermionic effect only work with a DC signal? With a tube amp, is the DC power supply what powers the tube heating element just like in a light bulb (Edison got the idea after observing what part of a light bulb burnt out first and his light bulbs were of course using DC), and the DC power supply IS NOT THE SIGNAL, rather the pulses of DC that the AC signal has been converted to 90 degrees out of phase with a pair of tubes using diodes that passes from anode to cathode through the grid heated by the filament IS THE SIGNAL?



I have a new related question: say I want to combine guitar effects pedals to be all in the circuit at the same time, a distortion pedal and a hi-pass filter, what is the correct way to do it?

Could the pedals be wired in series, or would they need to be wired in parallel using a mixer and a splitter?

 

So I have read some tutorials on your forum for AC, the definition of electronics, biasing, transistor theory, and tube theory.

Oh okay, so the reason that not even a passive AC circuit will work the wrong way is because THE WIRE HAS ITS OWN IMPEDENCE IN ADDITION TO THE IMPEDENCE OF THE RESISTOR.

So the reason that an active AC circuit (only analog circuits considered for simplicity) is directional is because tubes and transistors use DC biasing to use a DC control voltage to be directly proportional to the voltage outputed of the tube or transistor provided by the power supply of the tube or transistor since energy can neither be created no destroyed.

So the direction of the circuit analysis for a tube or transistor is:

quiet signal AC (lower voltage)
V
tube or transistor <--bias DC
<--power supply DC
V
louder signal AC (higher voltage)




The simple guitar circuits will be penetrable by me if I can understand how to "fix" Ohm's Law so it works for AC since every guitar circuit uses AC at some point.

So after I have read some tutorials on your forum for AC, is it correct that Ohm's Law works for AC if the voltages are first converted into the rectangular form of a complex number?

So if my guitar amp is 15 watts and the output to its speakers is 16 ohms, how much current in amps does it uses?

If we assumed that my guitar amp used DC, then P=IV and I=P/V and V=IR and P=(I squared)(R) and (I squared)=P/R and I= square root of (P/R) so I=square root of (15 watts/16 ohms) so I= square root of (15/16) amps.

but my guitar amp doesn't use DC...

Does Ohm's Law work if RMS values are used?

Is the 15 watts printed on the guitar amp by the manufacture an RMS value or a peak value?

Is the 16 ohms printed on the back of my guitar amp where the speakers are connected to is that an RMS value or a peak value?

So are complex numbers not needed if RMS or peak values are selected?

If complex numbers are not needed then why did you devote an entire chapter of tutorials to complex numbers?