Boss BE-5

I got this as a gift from the relative who had it sitting around for years without being used. And finally after 5 or so more years of doing nothing at my place I got to play more with it. The very first impression didn’t promise much – plastic enclosure and crappy feeling plastic switches. But upon closer look, this thing is not bad at all. Back in the day, multi-effect pedals were basically just a couple of standard pedals jammed in the same box, unlike modern digital simulators that just try to digitally emulate the sound of the actual pedals.

Signal chain goes from right to left, let’s see what’s inside?

  • Compressor – looking at controls, I assume that it’s close to CS-3 realm. Early CS-3 had uPC1252 chip that I found inside the BE-5, so it adds up.
  • Overdrive/Distortion – compared the schematic and it seems to be very close to OS-2.
  • Simple noise suppressor.
  • Digital Delay – MN51010RBA based, similar to highly acclaimed early DD-3.
  • Chorus – analog BBD (based around Panasonic MN3207/MN3102) chorus very similar to CE-2 but with stereo output (if used in stereo mode, one channel is dry).
  • Input
  • Tuner out
  • FX loop send/receive jacks between noise gate and the delay
  • Mono and stereo out

I really like having FX loop because it adds a lot of versatility. For example, you can connect guitar -> BE-5 input -> BE-5 send -> Amp in -> Amp send -> BE-5 return -> BE-5 out -> Amp return. That allows you to place compressor and overdrive in front of the amp and place delay and chorus in your amp’s FX-loop. Or, it can be used the same way to place compressor and overdrive in front of a tube preamp and have the delay and chorus after the tube preamp.


I’m not a big compressor user, mostly because I don’t know how to use it properly. BE-5 compressor seems to be doing to job just fine, but my unit developed a slight fuzzy overtone that is audible at any level of compression. It’s not bad when playing through an amplifier, especially if using overdrive, but I can definitely hear it when playing clean through the headphones.


Just like the OS-2, this actually has two circuits inside with a pot to blend between the two. It’s a great idea because you can have the distortion or overdrive, but also everything in between, just by blending them together. Distortion side is similar to DS-1, with two clipping diodes after the first op-amp stage, producing harsher clipping. The overdrive side resembles SD-1 with asymmetrical clipping diodes (2+1) in the feedback loop of the gain stage, producing softer clipping. It’s really useful, can be used on a clean channel of the amp or to push an already overdriven amp into saturated goodness.

Noise Suppressor

It’s a very stripped down version having only Threshold knob, but it does the job without killing tone too much. There is no bypass switch for noise suppressor, so you can only turn it all the way down. However, it still seems to cut some noise even turned down.

Digital Delay

Delay is a very simple, but effective clean digital delay as you’d expect from Boss, very similar to DD-3 but with slightly longer maximum delay. There’s no tap tempo or tone control, just simple controls for setting level of echoes, number of repeats and delay time (up to one second). Repeats are very clean with no added noise. Older DD-3 pedals that share the circuit with BE-5 are sought after for their clean and natural sound that still has some warmth and doesn’t sound sterile.


Chorus is a BBD-based circuit built around Panasonic MN3207 and MN3102 BBD chips. Those chips are still highly desirable. It features rate and depth controls without any tone shaping, just like CE-2. Sound ranges from subtle chorus that can add dimension to distorted chords (think Zakk Wylde or Petrucci) or lush deep chorus suitable for three-dimensional cleans, especially with a little of delay added. It’s really nice sounding, simple chorus.

What’s really cool about it is the stereo output, but not necessarily for using stereo. There are two mono output plugs labeled A and B. When only Output A is used, the pedal mixes dry signal with modulated vibrato signal, producing chorus effect. But when both Output A and Output B are plugged in, the pedal splits dry and vibrato signals, sending vibrato to Output A and dry to Output B. So we can fake chorus/vibrato switch simply by plugging a mono jack in the Output B jack (without using the dry output if we don’t need it) and what we’re left with on Output A is a very nice vibrato effect. Very cool!


As you’d expect from a cheap-ish plastic pedal, it’s not built like tank. Everything is packed on a big PCB and circuit layout is not great. It looks like someone arranged pots and jacks where they wanted them to be and left the auto-router algorithm (from the 80s) to layout everything else. Digital delay chip is all the way on the other side of the board, right next to the compressor circuit, there’s gazillion of jumpers and other stuff that indicates that not much effort was put into making a nice layout. Luckily, it’s not bad enough to cause any noise issues.

As far as components, I cannot complain, given that it works more than 25 years after it was made. It hasn’t been used much, at least not in the last decade, but the old Sanyo electrolytics seem to hold well. I’m considering re-capping it in the near future just as a precaution. Most of the pots are good, but few started crackling when turned. Cleaning them might help, but it’s not a big deal. Enclosure is made of plastic and although it’s ugly as hell, it tough plastic. Surprisingly, the inside of the enclosure is made of conductive plastic that is slightly gray-ish, compared to the black outer layer. I was surprised to find that it doesn’t produce any noise even in the plastic enclosure, but conductive plastic shell helps shield the circuit from noise.

Switching Problems

When I got it some of the switches were problematic, took a couple of clicks to turn the effect on or off. I took it apart and found that cheap plastic actuator was worn off and wasn’t making a good contact with the small momentary switch on the board. It’s an easy problem to fix, I just put a drop of epoxy on each of the actuators exactly on the place that makes contact with the switch when pressed (see below). That solved the problem.

After a couple of years, it started having switching issues again, so I started with the most likely culprit and replaced the 4 miniature switches. Luckily, it fixed the issue, so I didn’t have to dig deeper. I couldn’t find exactly the same square switches, but I found very similar rectangular ones that have the same pinout and same height and they work flawlessly.

What I Like About It?

For a cheap plastic box it sounds surprisingly good. Every effect inside is very usable, obviously taken from standalone Boss pedals from that period. FX loop is great thing to have.

What I Don’t Like About It?

I hate the of the plastic enclosure and those plastic switches feel horrid to press. I’m considering doing a complete rehousing into a metal enclosure with proper off-board metal foot-switches.

What Would Be Nice To Have?

Having simulated headphone and/or direct record out would be useful. Then it could be used even on its own.

Video Clips

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Useful Documentation
25 Responses to “Boss BE-5”
  1. Phil says:

    I’m missing a knob (potentiometer knob) on mine. I’m wondering if there’s a shaft size, or standard part reference I could use to find one on Aliexpress?

    • bancika says:

      I think they are 6mm D shaft…you can measure the diameter of the pot shaft where you have a missing knob. Also it should be D shape with flat surface…the alternative is knurled shaft, but you can easily tell the difference just by looking at it

  2. Fredoline says:

    What number or code for diode (D19) that boss be5 used?.my boss be5 diode are burnout..split in half..

  3. Adam says:

    To the user name mark said he bought a power supply for his unit and it didn’t work did you happen to notice the polarity of the plug in is negative on the inside pin on the be5 maybe switch the wires around on your power supply and try again

  4. I’ve had one of these for years and it’s always been in my closet. When I finally took it out and bought a new power supply for it, it would not turn on. Any suggestions as to what it might be and how to solve it are welcome. I’m assuming it’s probably some simple item that I can easily fix myself.

    • bancika says:

      I would open it up and measure voltage across a few of the filter capacitors. MAybe there’s a break somewhere or a leaky capacitor. The whole circuit is on the board so it’s easy to access.

  5. Bill says:

    I have what is probably a hopelessly naive question. I have a be5, a blackstar htr with no effects loop, and a pedal board with wah, 2 overdrives, tremelo, and ambient reverb. is there any way I could use the be5 effects loop to integrate the signal chain in the right order (wah, compressor, and od before modulation and delay/reverb). any advice much appreciated🙏

    • bancika says:

      why not go with wah -> comp -> OD -> BE5 -> htr and keep the htr on the clean side.

  6. Lee says:

    I bought one new in the 1980s and have used it regularly ever since. I agree that the cheap plastic case and pedals are a bit let-down, however the unit has worked without fault for over 35 years. I’ve learned a lot from your article here, so many thanks for that!

  7. Maurizio Firmani says:

    Nice to see again my first (and unique!) multi-effect pedal board! I gave it to an old friend of mine when I quit with elecrtic guitar, but I enjoyed very much playing with that. A nice tool for beginner.

  8. Rollasoc says:

    Bought one of these new, in the late ’80s. Sold it about 10 years ago (for about £100) and then regretted it. Bought one of Ebay for £10 a while ago, with missing knobs. Got a friend to print me some (different) knobs with his 3d printer. Nice to have it back again

  9. Marc says:

    Got one of these years ago and its been in my closet ever since. Finally pulled it out and bought a new power supply for it, but when I tried it will not power on. I’m assuming its probably some simple thing that I can probably fix myself – any ideas what it might be and how I can troubleshoot it? Thanks!

  10. Bear says:

    I have had one of these for nearly 30 years. I just found it in the Cupboard & dusted it off. It works as well as the day i bought it. many hours of enjoyment out of it.

  11. timmy says:

    Can you please indicate where you found the new switches? I’m searching but not having much luck finding something small enough. Thanks!

  12. AJ says:

    picked one of these up without a power cable for $10. Killer unit.

    • bancika says:

      Ha, for 10 bucks it’s a steal. People can’t see past the ugly plastic exterior, it’s a great unit!

  13. Polymath says:

    Please anyone have the answer for my question , when i try to use the B output all the effects work only the chorus the led it’s on but no chorus effect but the A output the chorus work , is it normal ? Plz help

    • bancika says:

      yes, that’s normal. When you plug something into B, chorus gets split into vibrato that is sent to output A and dry signal that goes out to B. If you plug something in B and use A as output, you should hear vibrato only.

  14. another great thing about these is if you plug a 1/4″ plug into the “mono” output, the chorus becomes a great vibe!
    i highly advise making the diode clipper asymetrical, and using a GE diode in one position.. really brings it more to life.
    rock on!

  15. Phil says:

    Hi, I have one of these, and, for the most part, love it. Not my favourite OD sound, but it’s usable. My problem is with the compressor, which has gotten so noisy, I find it unusable, other than with heavy distortion. Sort of a buzzy quality. Any ideas what I should look at? I’m not an electronics expert, but I’ve wired new pickups into my guitars, so I have a bit of a clue, and willingness to open things up and tinker.
    I also have a BE-5B which has a nice quiet limiter circuit that used to sound similar to the BE-5’s until that one got noisier.

    • PeterK says:

      I got one of these off ebay. I was disappointed that the compression sounded a little distorted or ‘fuzzy’. I checked out youtube demos and they all sounded fine with none of the fuzzyness I was getting. So there was obviously something wrong. I checked out the circuit diagram and changed the upc1252 (again bought off ebay).
      Totally cured it!

      • Bobby says:

        I’m about to buy my first boss be5 built in the late eighties. $45.00 …..EBay says it tested out good. Wish me luck. Bob

  16. Evert albers says:

    Thanks for the info. I plan to buy one 2nd hand and this is what I neeeded to know.

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    The idea behind this site is to share my experience with Do It Yourself approach to guitars, amplifiers and pedals. Whether you want to save a couple of bucks by performing a mod or upgrade yourself instead of paying a tech, or want to build your own piece of gear from scratch, I'm sure you will find something interesting here. Also, this is the home of DIY Layout Creator, a free piece of software for drawing circuit layouts and schematics, written with DIY enthusiasts in mind.