Tuesday, 1 July 2014

Boss CE-2B

And I may as well add this one as a separate layout so we know what versions the comments are based on.  This changes a cap value and adds an Effect Level pot to the CE-2.  If you want to add an Effect Level pot to the guitar CE-2, just use this layout and swap the 12n cap to the left of Q3 for a 33n.  Or if you want the option of using both, use a DPDT on/on toggle like this:

1---4
2---5
3---6

Solder a 12n between 1 and 4, solder a 33n between 3 and 6, and connect wires 2 and 5 to the holes that the 12n should have connected to on the board.

This obviously isn't yet verified but it's so close to the guitar version that it will be good to go.

The BOSS Bass Chorus CE-2B is designed specially for a bass guitar, giving you the best result when used with a bass guitar.

The Rate, Depth and the Effect Level knobs serve to create various chorus effects.








29 comments:

  1. guess i'll build this for my bass player....just keep up with you!!

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  2. awesome mark. with this and the small clone i'm finally going to have some amazing chorus pedals. i just placed an order for all the IC's i didn't have. freaking awesome.

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  3. Could you tell me which mods are referred to when it says "with mods?"

    Also, and this might be more complex than can be covered here, is there an easy way to make this (or another chorus pedal) into a stereo chorus? I know I could build two and run them in parallel, but I'm assuming that a true stereo chorus works differently--kind of like a stereo panning delay works different than two delays run in parallel. I'm guessing this would require re-engineering the circuit, but figured I'd ask just in case it is more simple.
    Thanks!

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    1. The original didn't have the Vibe switch, Intensity switch or the rate LED which also increases the depth.

      As far as a stereo option goes, a lot of information can be inferred from the CE-3 schematic. The CE-3 is basically a stereo version of the CE-2 but using an MN3207 instead of MN3007, the rest of the parts are very similar (close enough that I've already done a mono version of the CE-3 which I haven't posted yet). So I may add a stereo daughterboard for the CE-2.

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    2. Reckon you'll ever post that ce3 layout? Im dying to make a mn3207 chorus

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  4. Thanks! This could replace my old Ibanez CS9 stereo chorus that boosts the volume too much.

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  5. Hi Mark.
    I want to start using 2pdt instead of 3pdt. Save some cash. Do you have a pix of standard wiring for any of your effects, with LED?
    jeff

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  6. Hi Jeff. Not with DPDTs. The switch has to perform 3 jobs
    Guitar in to effect
    Effect out to amp
    On/Off LED status.

    Using a DTDP will only achieve 2 of those 3 tasks without using another circuit to specifically drive the LED found here

    http://tagboardeffects.blogspot.co.uk/2014/01/millennium-bypass-2.html.

    But with the extra cash in parts plus assembly time, I'd personally just stick with the common 3PDT footswitches. I hate wiring enough already to have to introduce more!

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  7. I'm using a DPDT in the CE-2 I just finished building yesterday. I added the wet level control as per the ce-2b schematic, then I realised if I cut the wet totally, then only the dry goes to the output. So, I put one half of the DPDT on the wet line between R22 (47K) resistor and the mix input to the opamp achieving in effect what Boss does with JFET trannies. The other half of the switch is the ground for the LED.
    For other effects I\m building where true bypass is needed (rather than a wet/dry mix) I'll use DPDT and millennium bypass. It isn't the price of the 3PDT switches its the damn size of them thats the problem.

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    1. Yes that pretty much mimics what Boss do. I think it was a strange choice from them considering the signal will always be going through the pre-emphasis and de-emphasis filters rather than just a buffer, especially considering that it would have been easy for them to take the bypass feed after the input buffer like they do with most of their pedals, but it does make the build that little bit more authentic I suppose. Maybe it's with things like this that Boss got the reputation for their buffered bypass colouring the tone.

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    2. Good point. The filters are changing the tone somewhat, I'll have to do an A/B test to see how exactly. And to be honest, my clone is somewhat noisy, could be all that wiring to the DPDT and extra pot, which are not shielded currently.

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  8. BTW - I used a DPST toggle for the filter caps, with a 12nf which is always in (for bass spec) and a 22nf in series with the switch (which is parallel to the 12nf) for guitar specs. I don't hear a lot of difference playing the guitar and toggling this switch, but it affects the bass guitar's frequency response for sure.

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  9. Hey Mark, just wondering if I can just add the 2 leads for the mix control from this layout to the same spots on the regular CE-2 layout. I noticed this layout has a few differences in component location, but i've already got my board almost done and adding the mix control was an afterthought. Thanks.

    -Ryan

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    1. You can do it, but it will be a bit of a chop job. Just disconnect the top of the 47K which connects to IC1 pin 6, and solder a wire from it directly to Effect Level 3, then connect Effect Level 2 to the right hand side of the 6n8 on the IC1 pin 6 row. That's it.

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    2. Thanks for the quick reply Mark! You're a lifesaver.

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    3. Also, couldn't I just add the cut on Row 2 and then remove the old 47K and solder a new one between rows 2 and 9 like in the CE-2B layout? And then connect the two Effects Level wires as normal?

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    4. You can connect the top of that 47K to the mix pot in any way you like, but to have an open path to the second row you'll need to shift around other components which may be a pain if you have that part of it built up already. If you haven't got that part built up yet then you can do it exactly as per the CE-2B but with CE-2 values for the cap preceding the 47K

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    5. Just wondering...will a 200k rev log pot work for the Effects Level? Tayda only carries 200k and 500k, no 250k. Thanks again.

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    6. curious to know if anyone can officially say this is a verified layout? would nice to have another verified bass pedal.

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  10. Okay...so I populated the board, hooked up the in/out/ground/9v, pots and vibe switch (ditching the Intensity switch)...power it up, and I'm getting some weird gated distortion. Pretty quiet as well. When I flick the Vibe switch one way, I get that distortion. The other way, just my clean guitar..kind of. It seems like the mix knob still adds a bit of distortion to it, so I'm assuming that's the normal mode, with the more intense mode being the Vibrato mode.

    Where should I set the pots when checking pin voltages on the IC's and trannies? Do you have any idea what could be causing this? Trim pot is set so the reference voltage is 4.5V +/- 0.1V on all IC's.

    Thanks in advance for any help you can offer.

    -Ryan

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  11. And after running a razor blade between all the tracks, it's working. Must have had a bridge somewhere...

    This thing sounds really good. One thing though...on some settings I'm getting quite a bit of..clock noise? ticking? I don't know the right terminology for it. It's a ticking in time with the Rate. Could that just be my sloppy test wiring (don't have it boxed...it's a bit of a mess right now)? It's only Really noticeable on the higher speed settings...

    -Ryan

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  12. I thought i'd share a few notes.. Build this about a week ago with 33n instead of 12n for guitar values. The enclosure for this circuit has its clearcoat on and i'll just wait 'till tomorrow for it to dry. Anyway. Been playing with the circuit on my test box and noticed couple of things that i felt that needed to be addressed. The chorus/vibe switch is unusable with effect mix pot. As the switch in vibe position cuts the clean signal from getting to the output mixer amp, there's nothing for the effect mix pot to mix the chorused signal with. Meaning that the pot in vibe mode acts just as a volume - from clockwise = unity to lower levels. This being the case, i just soldered a piece of wire to bypass the chorus/vibe as always on chorus mode.

    Next up was the LFO rate. I've always felt that too slow LFO speeds are annoying feature of all Boss choruses. As we have a depth switch that changes the depth between stock and wild detuned depths, i thought why not do the same thing for the LFO rate range. The 1M resistor coming from Rate 2 to IC2 pin 6 is the one component that determines the range of our rate pot. So i took it out and put 1M and 270K resistors on a 2PDT On-On switch. The 1M side gives the stock range, while 270K changes the pot sweep from slow to near ring mod speeds.

    A few months back i built Madbean's Pork Barrel PCB and noticed that using a pulsing LED to get more depth mod was a bad idea. The additional depth kills the greatness of the chorus. Besides this layout has a switch for it.. So i decided to see if the LFO was strong enough to drive the LED in parallel with 4K7 without adding any depth. I soldered the stock value of 4K7 from between D1 and 22K LED resistor to ground and swapped the 22K for 8K2. Yup. It drives my 5mm white LED with no issues and still has the depth as stock.

    That's it. Possibly the greatest analog chorus one can build.
    +m

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    1. I've also noticed that the 100n at the bottom of the layout also affects the maximum rate. Lowered it to about 80n to push the pedal just into Leslie-esque territory. Has a nice ramp-up too...might put that on a footswitch next time for a "fast/slow" leslie deal...

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    2. I'll be adding a mod for these soon, thanks to Miro for sharing the info

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  13. Hey guys...I've noticed something odd with the pedal...if I plug it in after a buffered pedal, everything works flawlessly. But without a buffer in front, it loses a Large amount of signal and gives a wooshing sound when bypassed...any ideas?

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    1. This has an input buffer so I'm not sure what the problem could be, unless this buffer works better with a low impedance output from another buffer. Are you voltages all ok or does anything look suspect around Q1?

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    2. What should I be seeing at Q1?

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  14. Gentlemen. Has anyone verified this oldie? If not I will be tackling it in a month or two.

    Cheers!

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    1. I've built one. Check my notes a few comment posts up.
      +m

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