CE2 mod idea / questions (schematic check)

[Matt]

Is it possible to have 2 separate switchable LFOs on a Boss CE2?  My idea is to have one set for chorus and the other set for leslie type sounds. My concern is that would be more likely to tick because of the extra current draw.  I was also thinking that I could have the power to the LFO 1 shut off when I'm using LFO 2 as a way to remedy this. 

Thanks in advance,
Matt

[LaceSensor]

Just build it with two rate pots, and put the pots on a switch. Thats the most simple way to achieve it.
you may have to compromise on the depth control depending how you like your slow sound, to not make it too crazy on the fast setting.

Having said all this, I never found the CE-2 went that fast to approximate those fabled leslie tones.

YMMV

[Matt]

Just build it with two rate pots, and put the pots on a switch. Thats the most simple way to achieve it.
you may have to compromise on the depth control depending how you like your slow sound, to not make it too crazy on the fast setting.

Having said all this, I never found the CE-2 went that fast to approximate those fabled leslie tones.

YMMV

That's the thing, I wanted to be able to switch the depth and rate at the very least.  Ideally I also wanted to switch a cap as well, that way I could have a faster range for the leslie side.

[LaceSensor]

Depending how the pots are connected, a rotary switch perhaps. But that's can't be footswitches of course.

Just build 2 in one box. To be frank...

[Scruffie]

Shrink the value of the 100nF between pins 6 & 7 of the LFO, will increase the speed and range of speeds and for depth you could alter the delay time by changing the 47pF, larger for more delay (more apparent depth) and vice versa.

Yes you could build 2 x LFOs if you wanted... couldn't say if it would necessarily add tick in your build but if you did it with properly filtered power and good layout no reason it should and you could always use your idea of shutting off power to the other as you switched.

[Matt]

Depending how the pots are connected, a rotary switch perhaps. But that's can't be footswitches of course.

Just build 2 in one box. To be frank...

I thought about 2 pcbs but I was trying to build this without the extra cost.

Shrink the value of the 100nF between pins 6 & 7 of the LFO, will increase the speed and range of speeds and for depth you could alter the delay time by changing the 47pF, larger for more delay (more apparent depth) and vice versa.

Yes you could build 2 x LFOs if you wanted... couldn't say if it would necessarily add tick in your build but if you did it with properly filtered power and good layout no reason it should and you could always use your idea of shutting off power to the other as you switched.

I've started the schematic in eagle. I figured that as long as I don't get a "pop" when switching between LFOs, ( because of the power being turned off for one and on for the other) it should work.

I appreciate everyone's time, input and help with this!

[Matt]

Ok, so I finished the schematic.  If someone could check it and make sure I didnt make any mistakes, it would be much appreciated.  Also, any concerns? I used the Pork Barrel part numbers and schematic since most people on this forum, Im assuming, would be most familiar with it.

Thanks in advance!
Matt

[BrownMagicMurad]

Ok, so I finished the schematic.  If someone could check it and make sure I didnt make any mistakes, it would be much appreciated.  Also, any concerns? I used the Pork Barrel part numbers and schematic since most people on this forum, Im assuming, would be most familiar with it.

Thanks in advance!
Matt

You're over thinking this.

In this scheme that you've devised, you don't need to switch the power to the LFO's, nor should you. As a rule of thumb, switch the ground, not the hot. Look at how LED's are switched, you toggle the ground.

That said, switching power to the LFO will likely cause a nasty pop. Try this. Set the pedal up and strum a chord through it. While the chord rings out, unplug the power to the pedal, then plug it back in. What do you hear? POP. You're likely to incur the same effect if you switch the power to your LFO.

Additionally, LFO's require a "moment" to start oscillating once connected to power. So switching the power to them will not give you a seamless switch, which I'm assuming is one of your design criteria.

In your scheme, you could simply switch the output from the LFO. I don't see a reason why having 2 LFO's oscillating, with only one being utilized would be an issue. Noise? Maybe, but that can be mitigated. Would the noise from another LFO be more offensive than the noise of a pop? Probably not.

But wait. Why do we have 2 LFO's anyway? To switch speed, range, depth, AND LED's on the same 3PDT switch? Hmmmm, I think we can devise something clever. To have 2 dedicated LFO's for this task seems...inelegant.

Ok, so what determines the speed? A voltage divider. We have a pot that is simultaneously increasing the shunt resistance while decreasing the series resistance as we turn the Rate Knob up. Now, what if we were to switch just the shunt resistance, but keep the series resistance fixed? It's still a voltage divider, right? Maybe we use a log or reverse log taper pot instead of linear to compensate for the change in the resistance taper.

Ok, so that's 1 "row" from our 3PDT. Now depth? Another voltage divider? See above.

2 Rows gone. 3rd Probably has to go to our setting indicator LED. But...

But this cap...We're out of switch lugs, so let's think for a minute. A user above suggested that the CE-2 doesn't get quite fast enough to get into Leslie territory. Fair. Decrease the cap size, and we get a speed that's more appropriate for that Leslie swirl. This affects the whole range of speeds available on our Rate Knob, so bumping the range up reduces our lowest available speeds. But...will they necessarily be missed? Sure, you get a nice doubling effect when the rate is super low, but are you honestly going to be switching between a super slow chorus up to a much more rapid Leslie-esque rate? If no, it might simplify things greatly if you can possibly find a cap value that shifts the range up to where you want it, but doesn't sacrifice low speeds that are available to you when footswitched. Because remember, if you want those sounds to be available, you can always throw that cap on a toggle switch and save on precious 3PDT Real estate. If you're REALLY insistent on having the whole range available to you, then get a 4PDT.

This solution may not be for you, but it is certainly something to experiment with.

Bonus! Futz with the value of the 33pF capacitor on the clock to mess with the delay time. You start to creep into flanger territory if you reduce the delay time, which I think is pretty characteristic of a real Leslie.

Good luck!

[Matt]

Ok, so I finished the schematic.  If someone could check it and make sure I didnt make any mistakes, it would be much appreciated.  Also, any concerns? I used the Pork Barrel part numbers and schematic since most people on this forum, Im assuming, would be most familiar with it.

Thanks in advance!
Matt

You're over thinking this.

In this scheme that you've devised, you don't need to switch the power to the LFO's, nor should you. As a rule of thumb, switch the ground, not the hot. Look at how LED's are switched, you toggle the ground.

That said, switching power to the LFO will likely cause a nasty pop. Try this. Set the pedal up and strum a chord through it. While the chord rings out, unplug the power to the pedal, then plug it back in. What do you hear? POP. You're likely to incur the same effect if you switch the power to your LFO.

Additionally, LFO's require a "moment" to start oscillating once connected to power. So switching the power to them will not give you a seamless switch, which I'm assuming is one of your design criteria.

In your scheme, you could simply switch the output from the LFO. I don't see a reason why having 2 LFO's oscillating, with only one being utilized would be an issue. Noise? Maybe, but that can be mitigated. Would the noise from another LFO be more offensive than the noise of a pop? Probably not.

But wait. Why do we have 2 LFO's anyway? To switch speed, range, depth, AND LED's on the same 3PDT switch? Hmmmm, I think we can devise something clever. To have 2 dedicated LFO's for this task seems...inelegant.

Ok, so what determines the speed? A voltage divider. We have a pot that is simultaneously increasing the shunt resistance while decreasing the series resistance as we turn the Rate Knob up. Now, what if we were to switch just the shunt resistance, but keep the series resistance fixed? It's still a voltage divider, right? Maybe we use a log or reverse log taper pot instead of linear to compensate for the change in the resistance taper.

Ok, so that's 1 "row" from our 3PDT. Now depth? Another voltage divider? See above.

2 Rows gone. 3rd Probably has to go to our setting indicator LED. But...

But this cap...We're out of switch lugs, so let's think for a minute. A user above suggested that the CE-2 doesn't get quite fast enough to get into Leslie territory. Fair. Decrease the cap size, and we get a speed that's more appropriate for that Leslie swirl. This affects the whole range of speeds available on our Rate Knob, so bumping the range up reduces our lowest available speeds. But...will they necessarily be missed? Sure, you get a nice doubling effect when the rate is super low, but are you honestly going to be switching between a super slow chorus up to a much more rapid Leslie-esque rate? If no, it might simplify things greatly if you can possibly find a cap value that shifts the range up to where you want it, but doesn't sacrifice low speeds that are available to you when footswitched. Because remember, if you want those sounds to be available, you can always throw that cap on a toggle switch and save on precious 3PDT Real estate. If you're REALLY insistent on having the whole range available to you, then get a 4PDT.

This solution may not be for you, but it is certainly something to experiment with.

Bonus! Futz with the value of the 33pF capacitor on the clock to mess with the delay time. You start to creep into flanger territory if you reduce the delay time, which I think is pretty characteristic of a real Leslie.

Good luck!

Thanks for the input!  Lots of good ideas. I'll breadboard this mess and we how it all works out.  Thanks again!