Xenyx 802 Insert Mod

Yes, you read the title right. A channel insert on the ubiquitous Behringer 802. Why? Because I could. That, and I scored a DBX 363X noise gate on eBay for $20 and for some reason wanted to use it with this mixer. I have other mixers, I have better mixers, and I have mixers with inserts. But hey, let’s take the road less travelled. . . It’s bothered me for a while, that one of the most common mixers around didn’t have an insert. And since it has a LINE IN on the two XLR channels, the mechanical part of the modification is already done! No holes to drill, no odd placement of the jack. Just a mislabeled input when you’re done. Since you can’t use both jacks at the same time, and any “real” mic will have an XLR anyway, why not just use the jack that’s already there?

I’ll probably do another post (or video) on how to be a cheap@$$ setting up little podcast studio. Just to add a little perspective on this, here’s how I have this mixer setup. Chan 1 has a AKG Perception 220 as the main mic. There’s a dynamic E4000S mic on Chan 2, sound effects come in from a freebie Kindle Fire to the Stereo Return, my iPhone 6s connects to Chan 5/6, and uses FX Send in a “mix minus” setup. That leaves Chan 4/5 as a spare channel. The whole mess with mixer, gate, mics, cables, headphones, shock mount and mic booms cost me less than $200! And before you ask, it’s a lot of eBay, and a lot of waiting for something to go for cheap. With this setup I could have two people “in studio”, one on the phone, and add sound effects as needed to keep it interesting. Recording is done with and old unused, unloved castoff iPhone 5.

WARNING !!

This mod has rattled around in the back of my head for over a year. Over the holidays I decided to take a whack at it. What follows is not trivial, not for the inexperienced, but it does work. If you attempt this and ruin your mixer, don’t blame me!! You’ve been warned. It’s not just a “cut a trace and solder a jumper over to there”. Well, it kind of is, but it’s an enormous PITA to get to that point, lots of cuts to make, and a five pin jack you have to get out of the board first. That said, if you have decent soldering and desoldering skills, aren’t afraid to take an Exacto knife to the PC board, have a few resistors and wire for jumpers, and some basic tools, you should be able add an insert or two to your 802.

I’ll include pictures, schematics, and notes/instructions on how to perform the mod. It won’t be step-by-step, but face it, if you need really really detailed instructions you may want to find someone who can do the mod for you.

PARTS/TOOLS NEEDED

One 120 ohm ¼ watt resistor (100 ohm will work)

Ohm meter for testing (Harbor Freight #63759 is fine ~ $7)

8” of small (28 ga) hookup wire

#1 and #2 Phillips Screwdriver

11mm socket or Pliers

Wire cutters / strippers

Exacto knife with a pointed blade

Soldering iron with a fine tip + solder

Solder wick or Solder Vac

10X magnifier (optional)

BONUS MOD: Move the FX to pre-fader

Need one 4K to 10K ohm resistor (or fine wire)

DISASSEMBLY

To pull the mixer apart, first remove all the knobs. Remove the six screws on the bottom, four on the sides, and eleven on the top. Next remove the fourteen nuts and washers on the ¼” jacks. An 11mm socket will make this part much easier, but you can use pliers if you’re careful. Remove one or two adjacent nuts at a time so you can invert the mixer and shake the washers off into your hand. If you decide to shake them all off at once, there’s a good chance some washers will make it to the floor never to be seen again. Just sayin’. Now you can wiggle the board out of the case. There are no wires to get caught, but you may have to flex the case a little to get the board out. Now you should have this.

If you flip the board over so the knobs and jacks face the table (down), and the power connector is away from you, it should look like the picture below. Most of the “magic” is going to happen in the upper righthand corner of the board. First, you need to remove X8. X8 is the ¼” LINE IN jack for Channel 1. You can use a solder vac, or solder wick, just take your time and be careful to not overheat and destroy the board in the process. If the plating in the holes comes out, it’s not a big deal. Only pin 1 (GND) keeps its original connection after the mod. Traces will be cut to isolate pins 3 and 4, and pins 2 and 5 will be isolated at the pin. In the original config, pins 2 and 5 are grounded, and need to be isolated for the mod to work. Be careful not to damage R32 and R33 as these remain in the circuit after the changes. The capacitors C4 and C5 need to be grounded later on to “fill the hole” in the circuit where the jack used to be.

Now might be a good time to toss in some schematics so we can see what we’re starting with and where we’re going. The front end of most small format Behringer mixers is virtually identical. This mod can be done on a UB802, Xenyx802, as well as the 1002 and 1202 versions. The individual part numbers on the schematic will change, but the circuits are identical.

I copied the insert connections from a schematic of my SL2442FX-PRO. We’re just inserting the 5-pin jack between the preamp output, and the EQ fiddly bits. In effect, we’re cutting the wire between those two points, and inserting the jack. When the insert is not being used, the two ends of the wire are connected. This is accomplished with the shorting bars (pins 2 & 5) in the ¼” jack. When we plug in an insert cable, it breaks the wire, and connects the TIP of the TRS cable to the preamp side, and sends it out to the outboard device. In my case it’s the DBX 363X. The line coming back from DBX then connects to the RING of the jack and passes the processed signal on to the EQ and the rest of the mixer. The ground of the jack is shared by both. Here’s the schematic of the original front end of the 802.

You’re going to break the connection between R52 and C41 (the red X). The point where R52 connects to C19 (lower red dot) will go to the TIP connection of X8 (pin 3) through a 120 ohm resistor. The point where C41 connects to R77 (top red dot) will go to the RING connection of X8 (pin 4). Since we’ve now disconnected the pins to X8 (skinny red oval on the left) we will need to install a jumper from the + side of C4 & C5 to ground. Below is the schematic after the mod has been completed.

MODIFICATIONS (LET THE CUTTING BEGIN)

In this schematic above you can see X8 has moved from the left to the center of the drawing. The EQ has been pushed to the right and the new INSERT jack is in between the preamp output and the EQ input. It’s likely you could ignore grounding C4 & C5, but it’s just bad practice to leave an “antenna” on the inputs to pick up noise. As I warned, it looks easy on paper, but when you get down into the guts of it, the difficulty starts to increase. Once you have X8 out of the mixer it should look like the picture below. Now we start cutting things.

This is the “top” side of the board, upper left corner, with the X8 ¼” jack removed. Surgery needs to be performed on pins 2, 3 and 5 with the Exacto knife. In the circle next to pin 3 you can see that the thin horizontal trace has been scraped away. On pins 2 and 5 there are four points that need to be cut away. You can see these points on pin1, the green is the exposed board and the yellow is the copper covered with solder mask. You need to isolate the circle around the hole from the rest of the ground plane on the board. NOTE: Pins 2 and 5 are grounded on both sides of the board. To remove copper, I try to make two small parallel cuts through the copper, about 1/32” apart. Then scrape off the copper between the two cuts. There’s no need to scrape very deep, the copper is very thin. You may want to practice this on a junk circuit board before you take a knife to your mixer. Now for the other side . . .

There will be a lot going on with the picture above. First, cut the trace between pin 4 and the positive side of C4 (cut near the red X). Next you need to isolate pins 2 and 5. This means cutting away the copper connecting the center circle to the rest of the ground plane. It’s a little difficult to see in this pic, but pin 5 has the copper removed, pin 2 is still connected to the ground plane. If you look at the connection labeled GND in the picture you can clearly see the four points from the ground plane that connect to the inner circle of the connection. They are similar to the ones you need to cut away on pins 2 and 5. Look at the inverted U shaped jumper between C4 and C5, I used a piece of cutoff resistor lead to both ground and tie together the positive sides of C4 and C5. I scraped the solder mask off the ground plane just above C5 and used a “solder blob” to connect the positive of C5 to ground, and then used the jumper wire to the + of C4. It may be easier to jumper directly from the positive side of both C4 and C5 to the pad labeled as GND with two small wires (from the two small red dots to the big red dot).

There is one last cut to make. If you look at the picture above, there is a small circle in along the middle right side. It’s below IC6 on the very outside edge of the board. There’s a little “dog leg” in the trace, cut out a small piece of the trace near this dog leg (the red X in a circle). This cut disconnects the preamp output from the EQ input. Now to check if we got the pins on X8 isolated.

TESTING TO SEE IF YOU’RE READY PUT IT BACK TOGETHER

Using an ohm meter test all 5 pin connections to ground. Flip the board over again so you’re looking at the back. Place one lead from the meter on the solder joint marked GND in the previous picture. With the other meter lead touch all five pin locations by poking the lead in the holes where the pins used to be. Pin 1 should show less than an ohm, the other four should show no connection. Also check there is no connection from pin 4 to the positive side of C4 (right red dot), and from pin 3 to the positive side of C5 (left red dot).

If readings are not what you expect, go back and check both sides of the board, pin 3 is the trace cut on the front side of the board. Pin 4 is the trace cut on the back side of the board. Pins 2 and 5 are connected to ground on both the front and back of the board. Pins 2 and 5 are the most likely to have issues. You may want to take a look with a 10x magnifier to see where there is copper you still need to remove.

NOW PUT IT BACK TOGETHER

Reinstall and resolder the X8 jack removed earlier. Make sure it’s pushed all the way in, and flush with the other jacks before soldering. If it’s crooked, or two high, the case may not go back together. Solder all five pins on X8. At this point you may want to use the meter to check the pins are still isolated as before. Also, pins 2 and 3 should show connected to each other, and pins 3 and 4 will be connected together as well. This from the shorting bars inside the jack. Once the jack is installed we can move on to wiring.

1) Solder a jumper (or jumpers) from the + sides of C4 and C5 to ground.

2) Solder a jumper from pin 2 to pin 4, and a jumper from pin 3 to pin 5 on X8.

3) The next jumper will go from point below IC6 (near the top of R76) to pin 3 or pin 5.

4) Finally, solder the 120 ohm resistor from the point in the picture just above IC6, to either pin 2 or pin 4. I covered the leads of the resistor with heat shrink, but you could use the jacket stripped off of your jumper wire. Or cover the board with some electrical tape to prevent shorting of the leads.

If all has gone well you should now have a working insert jack on Channel 1 of your mixer. If you have something non-conductive to set the board on, I would test it before it’s reassembled. Nothing guarantees a failure like putting all the screws back in before you test it!

Now you could do the mod to Channel 2. Just repeat the process about an inch to the left 😊 You’ll have to find the points with the help of the schematic, but the layout is almost identical to Channel 1. Below is what my mod looks like. If you look carefully, the wire colors do not match. After I was done, and testing it, I realized I had the wiring backwards. The TIP was return and the RING was send. I just had to switch the jumpers on X8 to make it work as intended.

FINISHING UP

Re-install the board in the case, put in the 11 screws on top, fasten the sides and bottom cover, spin on the 14 nuts and washers for the ¼” jacks, add the knobs and you’re done. You do remember which knobs go where, right? So that’s it. Enjoy using the insert to run a noise gate, or compressor, or outboard reverb, delay, etc, etc. You can also “one-click” the insert jack and get a direct out. Not sure how useful that is on a mixer this small, but it might be good for something. If that wasn’t enough for you, go ahead and add an insert to Channel 2!

And now. . .

THE BONUS MOD !! PRE FADER FX

I claim no credit for this one, it’s several places on the web, this is just my take on it. You cut the trace from the wiper on the FX pot for Channel 1. Then reconnect it with 4 to 10K resistor. This will move the feed for the FX for the channel from post fader to pre fader. Originally this is connected to the “top” of the PAN pot through a 5.1K resistor. The mod will move it from the pan pot to the connection of R115 and C69. That will feed it from the output of the EQ section. For the first option (picture below) cut the trace at the red X and add the resistor as shown. Or, cut at the green X and run a wire jumper. The first option is drawn in red, the second is green. Just remember it’s one or the other, NOT both! I found it much easier to solder in a resistor. So unless you have an extremely small iron, and very fine wire, go for the resistor option. Your choice, but I’ll go for easy and splurge on a $0.02 part!

And below it my version of it. Those with a sharp eye will notice that the resistor installed is a (grn/brn/org) 51K !! Is that last band red or orange? Ooooops! That was a mistake, it worked, but I had to crank up the FX much further than I thought I should have to. When I was taking pics for this tutorial, I noticed the error and changed the resistor. And, of course, I couldn’t find a (grn/brn/red)5.1K, and instead used a more common (yel/vio/red) 4.7K, it works just fine.

If you’re a little hesitant to do the full insert mod, the pre fader FX mod will still let you use external gear, but it will need two channels. To do that, connect your mic to Channel 1, connect the FX SEND on the mixer to the input of the outboard gear. Then return the outboard gear to Channel 4 as mono. Now when you use the mixer, turn the level on Channel 1 all the way down, turn Channel 1 FX to 0dB, and use the level on Channel 4 to mix the mic that is plugged in on Channel 1. You’ll still need to set the gain on Channel 1. Twist the knobs until you’re happy! Got all that?

The downside is that it uses two channels for one mic, and uses the FX send, so you can’t do both outboard gear and a mix minus for a phone, skype, etc at the same time with just the pre fader mod. But you may want to start with just the pre fader FX mod, then convert the LINE IN to an INSERT for when you need more out of (or into) your 802. That said, you can also shop eBay, Reverb.com or Guitar Center for a bigger, better used mixer. As I type this there is a Mackie DFX-12 for $100 (4 XLR's w/inserts, FX) for $100, and a X1622USB (4 XLR's w/inserts, FX, USB) on eBay for $169. But that’s more than three times what I paid for the 802, but it’s up to you.

Mod it ‘til it breaks, Oxcart124@gmail

02jan21