A long shot......marshall pedl 91016...

[whomeno]

I'm looking to build a 91016 foot switch for a dsl40cr. Hard to find and the price is out of this world at 200.00 for a foot switch.
dose any one here have one. that they could do a schmatic on? Going to get the amp in a few mouths will not be able to afford the foot switch.
Thanks

[codycale]

I am also interested in this same thing.  If anyone has one that they could post a schematic or pictures of, it would be greatly appreciated.

[pinkjimiphoton]

is there some special vegematic function this fs provides?

usually anything marshall is just short to ground for each segment. if its using a din/midi style plug, its still fairly easy to figure out usually once ya have the amp in front of you.

not familiar with the amp in question, so, need more info... what's the plug look like? jack? how many functions does it support? etc etc

that will get us a lot further than just a model number

[pete74]

Bump. 
Does anyone know what's being done in this FS?    From what I've seen it's using a standard mono 1/4" cord/jack to handle 6 switches.   

The 2 button switch that comes with the amp is TRS which makes sense.   But the 6 button one plugs in the same jack on the back of the amp.   

[pinkjimiphoton]

thats weird, 6 functions on one trs?  i'm betting it has to do with voltage levels... different voltages may tell the amp what to do.. in that case, its usually diodes on some of the switches, so each switch presents two different voltage levels, or maybe even three... sounds crazy and weird but it should work.
i'm not familiar with the switch, but have ya tried contacting marshall directly?

[pete74]

thats weird, 6 functions on one trs?  i'm betting it has to do with voltage levels... different voltages may tell the amp what to do.. in that case, its usually diodes on some of the switches, so each switch presents two different voltage levels, or maybe even three... sounds crazy and weird but it should work.
i'm not familiar with the switch, but have ya tried contacting marshall directly?

I personally haven't, but have read many comments that they won't disclose any of these details.   One thing I just thought of though, the amp provides some power to the fs as the stock one has LEDs and no other power source.....

[LAAF]

Has anyone made their own 6-Way pedal using the MIDI interface? Seems quite possible and customizable at a low cost. Now that I'm retired I may want to design one, but it would be nice to leverage work that has already been done.

[LAAF]

Well I couldn't wait, so I built my own MIDI version. Seems to work quite well now with some code changes.

https://youtu.be/yKC5l1sZTKw?si=mrrGjBgXTF8QsTCF

[R.G.]

There are a lot of ways to get many functions with only a TRS footswitch, but they are not simple. There is most probably a controller/processor involved at either the amp end, possibly at the footswitch end as well. Sensing a tap on a string of resistors is probably the cheapest way to manufacture the pedal, so it's likely to be what is really in there, but an alternate, and nearly as cheap way is to put a microcontroller in the pedal and have it just send ASCII or Morse code or some such, probably proprietary and encrypted messages back to the amp. If it's string-of-resistors, finding one and hacking it open solves the problem. One good choice is to make friends with a respected (and probably backlogged) amplifier repair tech.

[LAAF]

Since they need to run the LEDs reliably, my guess is that they are modulating data on a DC level known as Power Line Communication (PLC). The DC level is used for powering the electronics (microcontroller and LEDs) and the data is then AC coupled to the power line.

[marcelomd]

Hi,
This is the schematic for the DSL40: https://music-electronics-forum.com/filedata/fetch?id=849830&d=1528852809

Let's see...
- Tip, ring and sleeve are connected to pins of a microcontroller. They have pullups to 5V;
- One of the pins can be used as an analog input, but I don't believe it is used as such;
- No dedicated 5V to power the footswitch, which more or less rules out a microcontroller there;
- Sleeve can be dis/connected to ground via EFFECTS SW;

So
- We can operate the footswitch like a keyboard matrix;
- We can have different buttons short different combinations of the uC pins;
- Maaaybe the ADC pin is used as such and each button presents a different voltage;

EDIT: Found an incomplete schematic of the DSL100 that has +12V, Ground and a "FSW" net connected to the footswitch jack. It doesn't show where it's connected, but points to power and one serial data line.

[LAAF]

That schematic may be for an earlier model and doesn't match my DSL40CR.

I did find the schematic for the DSL40CR and it looks like the footswitch (in the 2 wire interface mode) uses +12V through a 150 ohm resistor to provide a soft DC to the footswitch. It doesn't need much power so it likely uses a simple diode to a cap (charge pump) to hold enough charge to run the electronics. The DC level is maintained because the duty cycle (ON time to OFF time) is high.  Bidirectional data is then transmitted on the same line to/from the footswitch. The FSW_TX signal (in the schematic) from the DFX microcontroller (STM8S005K6) switches a FET to drive the line to ground with serial data. For reading, the FSW_RX line is resistor isolated (4.7k) and clamped with a 3.3V zener for protection to the input of the microcontroller. So data is completely serial for this footswitch and allows for many states to be transmitted/received on the same wire. Since there are no other control signals they are likely using start/stop bits like the MIDI interface and other asychronous serial comm designs.

When the 2 button footswitch is used, the TRS plug just provides two DC states the the micro.

[PRR]

schematic for the DSL40CR and it looks like the footswitch

Is this your device?
https://forum.arduino.cc/t/5-button-marshall-dsl40cr-footswtich-controller/531856

5 Button Marshall DSL40CR Footswtich Controller
Using Arduino
I am building a 5 way footswitch pedal for a Marshall 40CR amplifier using Arduino and a MIDI out.
I have included my code and a schematic(Created with DIYLC software (http://diylc.org

If so, it is not a half-passive switch/lamp rig but sends MIDI messages. (I think you knew this but is good to see a fuller explanation.)

Buy easier than DIY? The switch lists for $99 on a US musicians' site but "Out of stock". Thomann says $88 and seems to be selling some: https://www.thomannmusic.com/marshall_pedl_91016_footswitch.htm  ***Ah, "Sadly we cannot deliver Marshall products to your country"

However this is MIDI and you guys say TRS??

[LAAF]

Buying is definitely easier than DIY, but only if you can find it.

The one I was working on is similar to the one you linked, but mine has 6 switches, debounce logic, individual tracking of the 4 channels for Master Select/FX Loop states and saves settings to NV memory. This is indeed a MIDI Only design. However, I did try to emulate the functionality of the 91016.

The PEDL-91016 is completely different electrically and uses the description I gave above with power/Rx/Tx all on a single line. I'm wondering if Marshall is having yield problems or issues with the pedal and that's why it's slow to roll out. After all this time they are still backordered.

My TRS comment refers to the 2-button switch that comes with the amp, which is a simple circuit (just switches & LEDs).

[R.G.]

The PEDL-91016 is completely different electrically and uses the description I gave above with power/Rx/Tx all on a single line. I'm wondering if Marshall is having yield problems or issues with the pedal and that's why it's slow to roll out. After all this time they are still backordered.

Given the description, it might be that Marshall is having licensing problems with the owners of the 1Wire communications protocol. 1Wire is power/RX/TX  on a single wire, plus a ground. It's a handy protocol. I use DS18B20s all over the place for temperature sensing.