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On amps with a loop as you know the Send is the signal from the preamp section and the Return is the Power Amp section. Let’s assume a guitar is plugged into the Input of the amp. Once the return is engaged the front end cuts out. Is there some way to run a Tone Box in the loop that acts as an A/B box. For example: Let’s say someone is using the 4 wire method and they plug into the Tone Box which will double as an A/B box. You’ll have 4 cables but you’ll switch from the front input to the return jack.
My thoughts.
Use a “ToneTWEQ” and a “Sho’ Nuff” and then make it switch A/B.
Any thoughts?
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toTo clarify you are trying to build a Sho’Nuff/Tone EQ that you can also use as an A/B box? Are you trying to send a boosted signal to one and and the totally clean signal to another amp, or do you just want to the ability to send your guitar signal down one path (A); which goes through the Tone Box effect + plus what ever other effects you put in that path, then also have the option to foot switch to a second path (B) which bypasses all effects including the one in the tone box (Sho’Nuff/Tone EQ) and send your guitar signal straight to the amp input?
At any rate, I feel like that if you built the Paramix from here, that has the adaptability and I/O that you would need to split your guitar signal, send it wherever, then combine it back to go into your amp
you might give this https://guitarpcb.com/wp-content/uploads/2018/06/BD_ParaMix.pdf a read to see if it helps answer your questions!
I am unfamiliar with the ways of the four-cable method, so I sought counsel from the Metal Godz. I offered a sacrifice and waited in the shadows for their answer to be revealed. In time, their whispers reached me, and this is what they said.
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Yes, you can set up a Tone Box to act as an A/B switch in the effects loop of an amp, allowing you to toggle between the amp’s front input (preamp section) and the return jack (power amp section) when using the 4-cable method.
Here’s how you can do it:
- A/B Switching Circuit: The Tone Box would need an A/B switch to toggle between sending the guitar signal directly into the front of the amp (Input) or into the Return of the effects loop (bypassing the preamp).
- Wiring Setup:
- Input: Plug the guitar into the Tone Box.
- A Output: Connect to the amp’s Input (front panel). This sends the guitar signal through the preamp section.
- B Output: Connect to the amp’s Return jack. This bypasses the preamp and sends the signal directly into the power amp.
- 4-Cable Method:
- Cable 1: Guitar to Tone Box input.
- Cable 2: Tone Box “A” Output to amp’s Input (front panel).
- Cable 3: Amp’s Send jack to the Tone Box input (if the Tone Box has an effects input).
- Cable 4: Tone Box “B” Output to the amp’s Return jack.
- Operation:
- When the A/B switch is in position “A,” the guitar signal flows through the amp’s preamp section, allowing you to use the amp’s front controls (gain, EQ, etc.).
- When switched to position “B,” the guitar signal bypasses the preamp and goes directly into the power amp section via the Return jack.
Advantages:
- Versatility: This setup lets you easily switch between the amp’s natural tone (using the preamp) and an external preamp or pedal setup (through the power amp), giving you a broader range of tones.
- Signal Routing: The Tone Box acting as an A/B switch simplifies your rig, eliminating the need to manually plug and unplug cables during a performance.
Considerations:
- True Bypass: Ensure that the Tone Box is true bypass or has minimal impact on your signal when switching.
- Signal Levels: Be mindful of signal levels when switching, as the return might need a different input level than the front input. Some buffering or level adjustment might be necessary.
This configuration offers a flexible way to integrate different preamps or effects into your rig, making your amp even more versatile.
Thank you for the sacrifice.
Great information!
Barry, do you have anything I can build this with?
Brent, I looked at the Paramix, it looks like that could be a good choice.
The Paramix could be beneficial for a number of reasons.
It has a Phase switch as well as buffering and mixing.
I’m not an expert on the four-cable method, and to be honest, I hadn’t really considered it before, so I might be misunderstanding you. When you mentioned using the Paramix, I don’t see the need for an A/B switch in this case. You could place the preamps in the Paramix loop to switch them in and out as needed. Plus, there’s an advantage to having the loop in parallel, and since the Paramix has a phase switch, it doesn’t matter how many effects you run or how often you switch them out for different ones. Any potential phase issue can be resolved with just the flick of a switch.
Totally get what you’re going for. Using a switcher like the ToneTWEQ and Sho’ Nuff in the loop sounds like a great plan. Just make sure the switcher you’re using can handle the signal properly—sometimes switching can affect tone or add noise if it’s not up to par. I’ve had good luck with switchers that are designed to maintain signal integrity, so just double-check the specs and you should be set!
Hello. On the Paramix, what am I looking for listening for using the phase inverter toggle? I don’t really have a way to test this pedal fully. Currently, I get Dry Gain and Dry signals, but Wet doesn’t seem to do anything nor does the phase inverter toggle. I double checked all of the wiring and it looks correct. I have the IN/OUT plugged in only to the guitar and amp.
The phase toggle will be pretty hard articulate if you don’t have more information about what it’s plugged into. The phase inverter toggle takes whatever phase the input signal is and flips it. Therefore you need to know what phase the signal is in coming into the Paramix. What determines the final phase of the signal is made up of several things, but amounts to the specific combinations of particular pedal circuits you have going into the Paramix and also what order they are in.
To confuse you more 🙁 often times the the signal going into the Paramix will be in phase anyways because none of the circuits before it (or the final output the circuits sum to “in phase”) invert the phase……..thus flipping the phase inverter would actually be detrimental to your tone. But its subtle at best (subjectively to me) and there are lots of well known pedals that output an out of phase/inverted signal anyways. So there is that about the phase switch
As far as the wet gain goes the Paramix has an effects loop. Here you can take whatever signal is coming from the input and then send it to whatever pedals are in said efx loop on the Paramix. The signal then goes to the return of that loop. This if your “wet” signal. The “dry” is simply the input from the “in”. Using the wet and dry gain knobs you can adjust the relative levels of each signal to taste, then using the mix knob you can gradually blend your wet signal with the dry signal. Fully CW, the mix is 100% wet, fully CCW the signal is 100% dry. Noon is 50/50, etc. The blended singal is finally sent to the output when you can go straight to you amplifier, or even into another section of pedals if you like.
At this point and this point only should you consider the phase switch, as we need to consider the summed signal’s phase going to the output. In the simplest terms if its in phase leave it be, if its out of phase flip the switch. To honest the explanation of phase and how it relates to sounds and our perception of it is pretty complex, but I think Barry has whether or not the final signal is in phase for most of the circuits from guitarPCB, so if your pedal chain is relatively small it shouldn’t be hard to figure if your Paramix output is in or out of phase!
Two great ways to use a Paramix:
1- Put a distortion like a 250 or RAT or any drive pedal in the efx loop of Paramix and set it to 100% wet, add a little bit of dry signal back into the wet distortion signal. This will return some bass frequencies back into your signal that are often rolled off in pedals like RAT, Distortion+, DoD 250. Now you pedal setup is “bass ready” and you tweak it as you need it.
2- Take reverbs/delays or other time based modulations and stack them in the effects loop. These time based affects are in parallel to your input signal and can be precisely dialed in to blend perfectly with your main signal.
bonus use 1: Use the send of the EFX loop on the paramix as a 2nd output for stereo rigs. bonus use 2: Use the return jack on the efx loop to mix in another guitar input, OR down mix a stereo pedal into mono. All of this while keeping things in phase.
super useful little device actually!
Brent, that’s an amazing answer! Thank you for your help. All of this makes sense and I can test some of these. Thanks again. Darren
Awesome Darren! Glad I was able to shed some light on it.
I tried really hard to be as “to the point” as possible. I work in the engineering field and the last thing I wanted to do was to put someone through the kinds of lectures on discrete electronics that I had to sit though in college LOL! The whole phase topic IS really interesting however, and actually plays a fairly critical role in the vast audio universe, especially in live sound applications. So, if you ever want to give your brain a solid workout I totally recommend watching some YT or doing some deep Wiki reading on the subject!
one last side note on phase: If you are running your pedal rig into a modeler or amp connected to a load box and not using a speaker cab (your taking the line out from the modeler/load box and going into a mixer/Audio interface) AND you will ultimately bring that line signal from the mixer/interface into a channel of your DAW then consider this – once the signal is “in your computer” i.e. it has gone though AD conversion and is now “bits'” instead of an analog waveform, in some but not all cases your DAW either automatically accounts for and adjusts phase relationships , or its pretty simple to “flip” the phase in post processing. I’m starting to ramble and we are going down a rabbit hole at this point, but it should be noted that there are many ways and places you can “fix” phase if at all’
That brings me to my very last comment on the matter…..I swear. Phase mis-alignment isn’t necessarily a “dirty word” or bad thing. In fact lots of producers and musicians intentionally flip or otherwise manipulate phase to exploit some cool effect that can be generated (we are familiar with phaser pedals yes?). My favorite phase related tid-bit of music trivia is the story of Kirk Hammett’s “Greeny” Les Paul. Long story short his tech was repairing a Les Paul that Kirk was using at the time and when the pick-ups were replaced the tech accidentally installed one of the humbuckers upside down. As a result the signal of the guitar in certain positions was out of phase. When Kirk used the guitar he immediately noticed that it sounded different, but he liked the way it sounded so much he told his tech to leave it and that tone became something he is really well known for as an artist.
This concludes part II of my musings on phase and audio signals…..im for real done now
Here is how to correct phase in post in Logic (I assume similar in other DAWs):
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