My suggestion for relays does not provide that function as it was described. That can be added by a modification of the connections. The change will require that all three switches have both normally open AND normally closed contacts. ( an SPDT contact arrangement.)

 

If you step on the same switch it just goes back.

As Adam Savage would say - Well, there's your problem.

Please be more clear in your descriptions. What is "it" and what does "goes back" mean. None of that is useful information for someone trying to reverse-engineer an electronic circuit based solely on text descriptions.

Do you mean that even though the switch is mechanically momentary, the electronics create an alternate-action function: press once to activate a function, release and the function stays activated, press again to release the function (return to the previous or default condition), release the switch and the system stays in the previous or default condition. - ?

If this is correct, I think it is a change from previous descriptions (I might have missed something).

Photos of the internal electronics, both sides of circuit boards, etc. would help.

ak

 

Jsut to clarify...
Just goes back to clean (turns the effect off) or just stays on the existing effect?
[/QUOTE
The switching on the amp is active in the Burn or high gain channel. When you latch a switch that grounds a pin or tip or ring(TRS) it changes a channel to clean or regular gain. When the ground is removed the amp returns to Burn.

 

Jsut to clarify...
Just goes back to clean (turns the effect off) or just stays on the existing effect?

Everything starts with the burn or high gain. If you are on burn and step on a switch that shorts the tip it switches to gain, if you step on the switch that grounds the ring it switches to clean. When all switches are closed it goes back to burn.
I attached a picture of my latest wiring using a 3-button footswitch. by using the NO and NC sides of latching switches I get most of the needed functions. I have gotten really close.

 

My suggestion for relays does not provide that function as it was described. That can be added by a modification of the connections. The change will require that all three switches have both normally open AND normally closed contacts. ( an SPDT contact arrangement.)

I have been able to mock up a 3-button switch using the NO and NC sides of a latching switch set up.

 

Are the three conditions, Burn, Gain, and Clean, mutually exclusive? IOW, is it ever allowed that two conditions are active at the same time, or does selecting any one automatically de-select any/all of the other two?

Put another way: What happens if you step on both the Gain and Clean switches at the same time?

ak

 

Are the three conditions, Burn, Gain, and Clean, mutually exclusive? IOW, is it ever allowed that two conditions are active at the same time, or does selecting any one automatically de-select any/all of the other two?

Put another way: What happens if you step on both the Gain and Clean switches at the same time?

ak

That is the problem, if gain and clean are activated you get no sound. The switching has to be achieved where only one action is active at any given time.

 

That is the problem, if gain and clean are activated you get no sound. The switching has to be achieved where only one action is active at any given time.

So - You want Gain and Clean to be mutually exclusive; whenever one is selected, the other is released. Ahh, clarity.

Next, switches. The logic flows in three steps.

1. With simple electronic circuits, a momentary SPST switch can be turned into just about any type of switch and contact arrangement. So, you're sitting in the power-on default state, Burn, and you press Gain once and hold it down. While it is down, the system switches to Gain mode. BUT, what happens when you release the Gain button? Does the system stay in Gain mode, or revert to Burn mode. Note I'm not interested in how the system used to work. The question here is what functionality do you want going forward. Do you want the system to stay in Gain mode when the Gain button is released (an electronic latch function), or revert to Burn mode (a momentary function)?

IF you want the system to latch in the Gain mode, then there are two options for how to get out of Gain mode.

2. With the system latched in Gain mode, do you want it to go back to Burn mode by pressing the Gain button a 2nd time (electronic alternate-action), or stay in Gain mode if you press the Gain switch again (the simple latch function - once it is latched, repeated switch presses do nothing)?

If you want the system to release the Gain mode and return to Burn mode with the 2nd Gain button press (alternate-action), then we're done.

3. But IF you want the system to stay in Gain mode, then there must be some way of releasing the system back to Burn mode. This calls for a third button that will release everything and return the system to Burn mode. Technically, because one button acts as a kind of reset, this is more like a game show circuit than a radio button circuit, but the results are the same.

The last case would be three buttons, Burn, Gain, and Clean, all mutually exclusive. Pressing any one forces the system into that mode no matter the previous mode.

This looks like one chip, 4 small signal diodes, 5 resistors, and 2 small capacitors (one to decouple power to the chip, and one to force a specific power-on state). The outputs can be an NPN open collector pulling something sown to GND, or a PNP open collector pulling something up to Vcc, or both. Without LED indicators, the circuit would run for years on four AA cells. With LED state indicators, better to use the 5 V from the amp.

ak

 

@Leighz1 could you measure the current from clean to ground, gain to ground and burn to ground. I am guessing they are 0.5mA. Knowing this will possibly simplify the design. Example, we can go directly to a low pin on a logic chip instead of adding transistors.

 

First pass at a guess at the total requirements. Burn is the power-on default state. Pressing any button momentarily latches the system to that mode. Further presses of the same button do nothing. Pressing any other button changes the mode.

C1 creates a power-on reset that forces the system into Burn mode (both outputs "off").

The circuit is flexible, and can be adapted to use whatever logic gates you have available. The CD4093 Schmitt trigger NAND gate can be replaced with a CD4011 standard NAND gate. With circuit adjustments, a CD4002 quad NOR gate can be used. The manual I found says the inputs are TTL compatible. If so for your amp, then the chip can be replaced with a 74LS00 (with pinout adjustments).

Everything to the right of the gates are optional output stages. These can pull an input high or low. As Salts said, you might be able to drive the amp inputs with the gate outputs directly.

ak

 

The required control functions, based on the recent descriptions, can be realized with the three momentary switches, (SPDT), and two small relays that have two sets of normally open contacts. The only additional parts will be the LEDs to indicate the state of the amplifier. It will need power for the relays, but that can be either a wall wart or some batteries. No integrated circuits and no logic diodes An added advantage is that there will be very good isolation.

I am going to be away from the internet for 2 days so probably no more from me until Wednesday.

 

@Leighz1 could you measure the current from clean to ground, gain to ground and burn to ground. I am guessing they are 0.5mA. Knowing this will possibly simplify the design. Example, we can go directly to a low pin on a logic chip instead of adding transistors.

In addition, can you verify ground is really "ground" (and not just a "common" signal return)

 

In addition, can you verify ground is really "ground" (and not just a "common" signal return)

I will check it in the morning, thanks for the input.

 

First pass at a schematic for the relay solution in #31. Clean and almost elegant, if you like that sort of thing.

Note: C1 does not have to be rated for 50 V; that is the part in my design library. Anything 10 V or more is fine.

All Electronics has a store in Van Nuys. Small DPDT, 5 V coil relays:
https://www.allelectronics.com/category/500250/relays/pc-mount-relays/1.html

Another source:
https://www.electronicsurplus.com/r...pole/contact-configuration/dpdt/sort-by/price

ak

 

That is the problem, if gain and clean are activated you get no sound. The switching has to be achieved where only one action is active at any given time.

One other thing...

I think you may have the button functions incorrectly defined.

I think they should be:
1. Boost (or "gain")
2. Burn
3. Crunch

The "Clean" function is implied by neither Burn, or Crunch, activated

So...
When first powered on, and the footswitch cable is plugged in, nothing should be active, and "Clean" should be the power on default state.
Boost should only work when Burn or Crunch is active (because Boost is only used with B/C).
Your requirement that only one function is active at a time implies that the footswitch buttons are momentary
because latched (alternate action) footswitch buttons cannot be automatically reset.

 

Here is page 5.

View attachment 266661

I think that's the wrong manual. The TS has a 1st generation RockMod (based on the photo in post#6) and doesn't have digital switching.

 

One other thing...

I think you may have the button functions incorrectly defined.

I think they should be:
1. Boost (or "gain")
2. Burn
3. Crunch

The "Clean" function is implied by neither Burn, or Crunch, activated

So...
When first powered on, and the footswitch cable is plugged in, nothing should be active, and "Clean" should be the power on default state.
Boost should only work when Burn or Crunch is active (because Boost is only used with B/C).
Your requirement that only one function is active at a time implies that the footswitch buttons are momentary
because latched (alternate action) footswitch buttons cannot be automatically reset.

On this amp Burn is the default.

 

On this amp Burn is the default.

I'm just going by the amplifier front panel selector switch. "Clean" is the first position.



I'm assuming the selector is moved to the "remote" position to use the footswitch.

So...when you plug in the footswitch, and move the selector to "remote", what if "burn" or "crunch" is not active?

 

I'm just going by the amplifier front panel selector switch. "Clean" is the first position.

View attachment 266773

I'm assuming the selector is moved to the "remote" position to use the footswitch.

So...when you plug in the footswitch, and move the selector to "remote", what if "burn" or "crunch" is not active?

You move the selector to Burn to activate the switching capability. From there the shorting of the pins or the TRS components, change from burn to clean or gain depending on what shorting function triggers the channel selection. Burn is the default. The selector only has 3 positions, burn, gain or clean. I know it shows a remote possibility but the selector doesn't go there.

 

You move the selector to Burn to activate the switching capability. From there the shorting of the pins or the TRS components, change from burn to clean or gain depending on what shorting function triggers the channel selection. Burn is the default. The selector only has 3 positions, burn, gain or clean. I know it shows a remote possibility but the selector doesn't go there.

What happened to CRUNCH?