Build your own Beta Lead footswitch

[kingnimrod]

OK, after giving up on the chance of finding a footswitch for my Beta Lead, I decided to make my own using the schematic available on this site. I am starting this thread as a service to help out those who want to do the same. That said, you will need to have some experience soldering, stripping wire, building circuits on boards, etc. It's pretty simple, but attempt this ONLY AT YOUR OWN RISK. I do not advise that you undertake this project unless you are confident with what you're doing. Otherwise, have an amp tech build it for you. Please note that if you want to replace the socket/jack assembly, you must remove the existing jack from the amp head, so you will have to partially disassemble the head unit to remove it.  The CB radio type connector I used will slip over the pins in the existing socket, but it does not make a usable connection. Otherwise, you can order a connector to fit the original jack if it is functional (links in parts list).

This is not a cheap build. I bought from a local electronics supply store, so my materials cost from $60-70.

TOOLS YOU WILL NEED
- pencil tip soldering iron
- rosin core solder
- small hobby/electrician screwdriver set
- large screwdriver
- electric drill
- Irwin Unibit #1 stepped drill bit
- wire stripper
- small wire snips
- needle nose pliers
- helping hand (solid base with movable clips & magnifying glass)
- electrical tape
- scissors
- heat shrink tubing
- dremel tool with cutting disc and sanding wheel

PARTS LIST
- Hammond 1590 PBK aluminum enclosure (this model is powder-coated black)
- self-adhesive rubber feet for box bottom. I used 2 large and 2 small to angle the box
- 10 - 15 foot length of medium to heavy duty 3-conductor shielded cable that has braided wire to shield for ground
- 1/2" press-in cable clip. Not sure what it's called, but it holds the cable tight in the opening to the enclosure
- terminal strip for grounding
- 1/2" long 1/8" machine screw with nut for mounting terminal strip
- yellow, green and red LEDs
- LED mounting rings (I used the cheap plastic type)
- rubber or cloth-coated wire
- bare copper wire (non-braided) (optional)
- small printed circuit board. I used the Radio Shack type that can be split into two easily
- 3 heavy duty Carling brand SPST (on/off) metal switches. Do not get momentary switches!
- one 330 ohm resistor (R1 in schematic)
- one 150 ohm resistor (R2 in schematic)
- one 560 ohm resistor (R3 in schematic)
- two 1N 458 diodes (CR4 & CR5 in schematic)

if you want to replace the jack/socket assembly with a CB radio type 4 pin connector (as shown in this build):

- 4 pin socket (cb radio socket) to replace connector on amp head
- 4 pin connector (cb radio microphone connector type) to attach to 1 end of cable

if you want to use the correct replacement parts for the connector cable (no disassembly of the head required) :
- plastic connector housing
- 4 socket contacts
- cable clamp

use this schematic as your guide. You will mount the 3 resistors and 2 diodes on the PCB. Do not mount the LEDs directly on the PCB.

[kingnimrod]

ENCLOSURE LAYOUT

I chose to layout out my 3 switches and 3 LEDs from left to right as follows:

REVERB       CHANNEL SELECT      BOTH




you can lay yours out however you'd like, just remember to wire it to the correct points on the PCB

on my enclosure, I chose to mount the LEDS at the halfway point on the top (about 1.5" from the edge). My channel select LEDs (red and green) are in the center of the enclosure, so I marked the halfway point lengthwise and positioned them about .5" APART. I positioned the "both" yellow LED 3/4" from the right edge.

For the switches, I measured 3/4" from the lower edge of the top of the enclosure, and marked one point in the center lengthwise for the middle switch, and 3/4" in from left and right for the other 2 switches.

Mark your drilling positions and drill a small pilot hole centered on each point with a small drill bit. Measure your switches and LED mounting clips, and drill your holes in the enclosure to the appropriate step on your Unibit drill bit.

Measure the width of the push-in clip that will hold the cable tight coming into the back of the enclosure, and drill a centered hole 3/4" from the bottom in the back of the enclosure.

Drill a 1/8" hole in the back of the enclosure, halfway up from the bottom and 3/4" from the left or right edge. You will want this to be on the same side (left or right) that your reverb switch will be, since there is not an LED getting in the way. You will use this hole to mount your terminal strip to with your 1/8" machine screw and nut.

RUNNING THE CABLE INTO THE ENCLOSURE

Taking one end of your cable, strip about 2" of the outer rubber coating off. Using your wire snips, cut and peel away the shielding as well. Strip enough of the coating from the ends of each of the 3 conductor wires so you can make connections inside the box. Go ahead and run the cable through the mounting clip to where the rubber outer coating starts, and push the clip into the hole in the back of the enclosure to secure it tightly. Make your decision now and write down what color conductor from your cable corresponds to each part of the circuit. Write these down and make sure that they match up to the numbers shown in the schematic, and how you solder the connector to the other end of the cable later.

MOUNT LEDs & SWITCHES

Push in your LED mounting clips. Go ahead and attach some wire to each leg of the LED (keep track of positive/negative). I like to snip my LED legs short, wrap wires and solder, then slip some heat shrink tubing over the connection to keep it from touching other wires. Pop in your LEDS into the appropriate positions.

Mount your 3 SPST switches in the box.

PCB ASSEMBLY

Solder a bare copper wire across the top of the PCB. This will be your common ground point. You can also run all your ground wires directly to the terminal strip if you wish.

Solder the resistors and diodes onto the PCB so that they correspond to the placement as shown in the schematic. Double check to make sure you are orienting your positives/negatives correctly.

Solder the appropriate wires from the LEDS and switches to the correct places on the PCB.

Wire the ground from the PCB (or all ground points as separate leads) to the terminal strip. Make sure the terminal strip has a connection between where the ground wire(s) attaches and the mounting terminal that touches the inside metal of the enclosure. You may need to solder a small wire between these two points. Mount the terminal strip to the inside of the enclosure.

Before you close the lid, make sure that you orient the PCB so that its connections do not touch any exposed wire or the metal of the inside of the enclosure itself. I used a rubber adhesive foot as a standoff.

CLOSE IT UP

Close the enclosure and tighten the screws. Attach the rubber adhesive feet. I used larger feet in the rear to tilt the box, making it a little easier to punch the switches.

ATTACHING THE CONNECTOR TO THE CABLE (CB TYPE 4-PIN CONNECTOR)

on the other end of the cable, strip a little less than an inch of the outer coating and shielding, and expose enough of each conductor to make solder points inside the connector.

Disassemble the connector, and slide the main body of the connector a few inches down the body of the cable for now. Check to make sure that when the screws on the connector's collar are tightened, that it will be a tight fit on the cable. I had to use some heat shrink tubing around the end of my cable to make a good fit.

Solder each conductor to the appropriate numbered pin terminal on the detached connector head. This is a bit tricky, as both the wire and pin terminals are very small. Once your connections are soldered, reinsert the connector head into the connector body, and replace the screw that holds it together. Tighten the collar screws so that the connector is firmly attached to the cable. If not, you risk ripping the leads from the pin terminals when you pull on the cable.

ATTACHING THE CONNECTOR TO THE CABLE (ORIGINAL PLASTIC CONNECTOR TYPE)

slide the cable clamp onto the cable

solder your 4 wires into the socket type connection pins

insert these sockets through the back of the plastic connector housing, into the appropriate numbered holes.

Attach cable clamp to connector housing.



congratulations! your footswitch is finished. Now to the hard part.

[kingnimrod]

 NOTE: THE FOLLOWING PART IS ONLY NECESSARY IF YOU DECIDE TO REPLACE THE CONNECTOR AND SOCKET ASSEMBLY WITH CB RADIO TYPE CONNECTORS.

The most difficult/messy part of this project is replacing the 4 pin socket in the head itself. This requires disassembly of the head casing, and some delicate work on the guts.

First, make sure that your new 4 pin socket matches the connector from your footswitch cable. You should purchase the connector and socket as a matching set. For this build I used a CB radio microphone connector/socket assembly.

HEAD DISASSEMBLY

Unscrew the 4 screws in the top of the head cabinet, then carefully slide the head unit out the BACK of the cabinet. It's hard to avoid scratching the inside, and better for this reason to slide it out the back where it won't be so noticeable. DO NOT use the power cord wrap as handles for pulling out the head. These can break if you're not careful. Lay the unit on a towel or other soft surface.

On the top of the head case, remove the screws on the left and right side. Carefully flip the head over, and remove the 8 philips screws along the edges. Don't remove the slot head screws in the middle - these hold the reverb pan in, so just leave them alone.

With the head still resting upside down, and the back of the unit facing you, remove the loose casing and set it upright behind the unit. The wires are long enough to allow it.

Be careful not to touch the large transformer or any of the circuit board components of the amp. Note that the large cylinder capacitors could potentially be a shock hazard as well, so take special care not to touch them.

REMOVE THE OLD SOCKET

With a small screwdriver, remove the 4 pin footswitch socket from the rear of the head. Retain the screws/nuts in a safe place.

Pull this socket plate up from the inside, and lay some paper towel or paper over the circuit boards in the amp. You are about to perform surgery with your dremel tool. But first, write down which color wire corresponds to what number on the socket assembly where the wires go in. These correspond to the same numbers in your footswitch schematic. It is imperative that you connect these wires to the correct numbered pins on your new socket.

TIME TO CUT

Attach a cutting disc to your dremel, and cut at the base of the cylinder of the plastic socket piece on the side where the wires are attached. Your goal is going to to be to end up with the square plate of plastic to use as a mounting base for your new socket. Make sure to wear safety goggles, and cut slowly. As you cut, your wires may come loose, but it may be difficult as they are attached to metal pins inside the plastic cylinder. Once you have cut the square plate and socket cylinder loose, set that aside and finish removing the wires from the cylinder piece. If you apply any pressure, make sure you don't yank on the circuit boards of the amp! Once your wires are free, strip a small bit of the ends of each bare for soldering to the new jack terminal pins.

Pick up the old plastic plate/socket and your dremel tool again, and cut the socket cylinder away from the square plate. Your goal is to end up with just the square plate. It's likely that you'll end up with a plate with 4 small holes in the center. Use your drill and unibit to enlarge these into one centered hole, then attach your sanding cylinder attachment to the dremel to create a large enough hole in the middle of the square plastic plate to attach your new socket assembly to. Make sure to measure carefully, so you don't make the hole too big. This is your socket mounting plate, and you will reattach it to the amp head case with the same old screws.

BUILDING THE NEW SOCKET ASSEMBLY

Attach your new 4 pin socket to the square plastic mounting plate. The hole in the plate should be big enough to push the back end through and catch on the collar/flange of the socket body. Screw the socket washer and nut on the threads on the other side of the mounting plate.

Solder the wires to their appropriate numbered pin terminals. This is difficult, as the wires / terminals are very small and close together. Take care not to glob solder between wires or terminals. Wrap each new connection with an individual piece of electricla tape, then wrap electrical tape around the whole wire/socket assembly base.

REASSEMBLE

Screw the socket plate back into the amp case using the old screws/nuts.

Replace the outer casing, and reattach all 14 screws.

Slide amp head carefully into the cabinet, again from the BACK of the cabinet.

Reattach top cabinet mounting screws.

[kingnimrod]

USING YOUR NEW FOOTSWITCH

Plug footswitch cable into the new socket, and screw down connector collar tightly. This makes for a secure connection.

Plug your guitar cable into the "both" jack on the front of the amp. Turn the amp on.

Your new footswitch controls and displays the current channel(s) being used. The channel selector switch will switch between A and B channels. The "both" switch will activate both channels. Note that you can still use the selector switch between A and B while "both" is active, allowing you to go from "both" to a different channel selection once you disengage the "both" switch. Your selected channel LED will still light up while "both" is engaged.

The reverb switch simply engages/disengages the reverb on the amp. There is no LED for it.

Now you're able to enjoy the full possibilities of the amp. Enjoy!

[kingnimrod]

PHOTOS

new socket on rear of head


new cable/connector attached to socket


footswitch top


footswitch rear


bottom - note different sizes of rubber feet

[loudthud]

The search function doesn't work as good as I would like but... look at this:

https://forum.sunnstillshines.online/index.php?topic=3694.0

[kingnimrod]

oohhhhh.....

(SLAPS FOREHEAD)

Well, thanks for pointing that out. I've modified the build thread with direct links to those parts. I think I had seen that thread before, but the Allied website was down for reconstruction and I forgot to check back with them before diving in with an improvised replacement.

To make myself feel a bit better, I'll point out that my new socket is made of shiny pretty metal.

By the way, if your existing socket in the head is shot, it would be far easier to replace it with my method - those pin connectors are a bear to deal with. I'm even halfway glad I didn't have to deal with the connection sockets on the connector end.

[LEADSOLDERHUFFER]

if you had the proper crimping tool the pins would go on with little effort and you would'nt be pokin around in the head for nothin.
i have crimped a billion harness's and its not fun, but what your saying is obsurd, although the crimping tools can cost a billion trillion dollars if they're made outa hard tool steel in japan etc.

[letsneck]

I have a few questions about the build on this footswitch. I want to know if the reverb function is activated when the switch is in the closed position (connection is made) or in the open position (when connection is removed). I hope someone can help with this.

Also, the pin locations are different on the schematic than they are on the plug end. When I insert the pins, do I follow the numbers on the schematic and just forget about the location on the diagram, or do I follow location on the diagram and just forget about the numbers on the plug end. Looking at the plug end from the back side (where the pins are inserted) the numbers are as follows.. the number 1 is at what we will call the top (because the number is upright) number 2 is to the left, number 3 is to the right, and 4 is at the bottom. This has to be the most frustration part of the build for me.

 I don't know if the numbering is just off due to a different manufacturer of the plug end, or if SUNN just disregarded the number system on the plug end and drew up the schematic out of convenience, without regard for matching up the pins' numbers in the diagram with the numbers on the plug end.

Also, I noticed that the LED's positive leads are run to ground, which is reversed from how the LED's my other footswitch are run. Negative leads are run to ground. It is a generic footswitch that is supposed to work with most amps with a 1/4" stereo jack. Please let me know as soon as you can. I am right in the middle of this build, soldering iron smoldering, along with my temper at this moment. I haven't gotten pissed off enough to throw anything yet (LOL), but enough to take a break to write this post .

I will greatly appreciate anyone with greatness, who is up to the challenge of taking on this multifaceted question.

[loudthud]

Closing the switch turns the reverb off. That way it still works after you lose your original footswitch

[letsneck]

Closing the switch turns the reverb off. That way it still works after you lose your original footswitch

That's very funny, 'cause most of us do lose our footswitches. Mine is probably in a deep dark crevice in my tomb of a room. So the reverb is active when the 2 leads going to the reverb switch are not making contact, right? I got confused, because looking at the schematic, it shows the switch in the open position. I thought it  meant that the reverb was not active until the switch was closed. I want to add a battery, so I want to make sure I wire it to the correct side of the switch.

[letsneck]

   I'm still trying to figure out the correct pin placement for this DIY project. As seen in the image below, the pin locations are numbered on the schematics differently than on the plug and jack from allied electronics.

 Please tell me how to place the pins correctly. The pictures of the Jack and Plug, with the red numbers, are views from the front. I need to know how to place the pins from the back. I have all 4 pins soldered to the wires, I just need to know where to stick them. I am sure I will get a bunch of comments on that statement. If you must leave a humorous comment in reference to which holes to stick them in, that is fine, but please include a serious answer to the question as well. LOL Thank you in advance. Once I figure this part out I get to try it out. Thanks

[loudthud]

I'd just go with the pin numbers as marked on the jack and plug. I can tell you that on my Beta Lead amp pin 4 as marked on the connector is ground and pin 2 is the reverb. If 1 and 3 are reversed you can just reverse the wires inside the footswitch. The reverb switch literally shorts the reverb signal to ground so you'll need a double pole switch to incorporate an LED and battery.

Keywords: Beta Lead Bass Footswitch Schematic

[dblotii]

Could you recommend an easier-to-find diode than the 1n458?   Perhaps one available at RadioShack or PE?  What is the critical parameter?  I am guessing that any small diode above a cerain voltage rating would work.