Boss - CE-3 Chorus Ensemble  [schematic]

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Re: Boss CE-3 Chorus

Postby JaylijpeKay » 05 Feb 2010, 21:17

Hey guys,

I need your help. Today i swapped a DOD FX-20-B for a Boss CE-3. Just wanted to try the CE-3 and see how it sounds. Only since a couple of month iv'e been trying different pedals to brighten up my sound. Well, i got screwed over in this swap; the pedal doesnt work.

Let me explain;

I use a 9v battery, and the led light works if i push on the pedal. With the Stereo mode knob on Mono i get a clean sound, no effect on both outputs A and B. BUTTT... if i switch to stereo, i only get a clean sound on the B output, but NO sound on the A (effects) output. Its my amateur, totaly NON-expert assumption that the effect-part of the pedal is broken. How can i figure out what part of the circuitry is broken? Does anyone have expirience with this problem or the pedal? I already checked the insides with the service manual to check if all the wires are connected properly. Thats as far as my knowledge goes. If anyone would be so kind as to shine there light of knowledge over this predicement, id be treully gratefull. If you need i can provide detailed gutshots.

Once again, im totaly new to pedals & circuitry but i see this as a good chance to get started on the art of pedal modding, repairing and maybe pedal building once i get past having no skills at all.

Peace,

Johnny
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Re: Boss CE-3 Chorus

Postby whosyourdaddy » 25 Oct 2010, 16:43

Hey guys,

recently I found out that I've somehow lost CE-3 project pdf :slap: and now I'm thinking of killing myself! [smilie=a_damnit.gif] [smilie=a_help.gif] [smilie=wine.gif]
Anyways, it was posted long time ago on this forum and as you can probably see it's called CE-3-English.pdf.

So, is there anyone on this forum that has same copy? (please pm me to send you my email)

tnx [smilie=rlp_smilie_242.gif]
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Re: Boss CE-3 Chorus

Postby whosyourdaddy » 25 Oct 2010, 19:36

MWichni pointed to viewtopic.php?f=1&t=4453 which has that document.
I suggest you merge that thread with this one. Thanks everybody.
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Re: Boss CE-3 Chorus

Postby MerlynMetal » 26 Oct 2010, 11:55

CE-3 layout and PCB:

Image

Image

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Re: Boss CE-3 Chorus

Postby fws » 01 Nov 2010, 03:52

I just found very old one from 82-83 (black label and knobs), but owner said there is now some dirt in sound it didnt had before, just like some overdrive, so he is selling it as broken. So question is whether anything is really broken and if then is it hard to fix? This one is old ACA 12V powered so I will check with the guy how is he actualy running it, but maybe some ideas?

Another thing is that the guy wants 50 bucks for it, is it worth as much?
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Re: Boss CE-3 Chorus

Postby mictester » 01 Nov 2010, 06:58

fws wrote:Another thing is that the guy wants 50 bucks for it, is it worth as much?


No - especially as it's broken! There might be $15 - 20 worth of parts, including the case and hardware. Given that it's distorting, you might have to spend some $ buying parts to fix it, and you'll have to spend some time doing it. Offer him $5 - $10 and let him push you as high as $15 if you really want the thing!
"Why is it humming?" "Because it doesn't know the words!"
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Re: Boss CE-3 Chorus

Postby Dirk_Hendrik » 01 Nov 2010, 08:08

fws wrote:Another thing is that the guy wants 50 bucks for it, is it worth as much?


It's worth as much as you want to spend on it. It's worth as much as you are certain you'll fix it. If it were an auction I'd easily outbid you with the cheapass lowball amounts Mictester suggests.
Sorry. Plain out of planes.

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Re: Boss CE-3 Chorus

Postby fws » 01 Nov 2010, 21:31

Well that actualy is an auction on polish auction service with "buy now" set on 50, but since Im already content with my current chorus I will try to resist the urge of buying this one. The risk of becoming junkie aka vintage collectioner is way too high :P
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Re: Boss CE-3 Chorus

Postby mictester » 01 Nov 2010, 23:49

Dirk_Hendrik wrote:
fws wrote:Another thing is that the guy wants 50 bucks for it, is it worth as much?


It's worth as much as you want to spend on it. It's worth as much as you are certain you'll fix it. If it were an auction I'd easily outbid you with the cheapass lowball amounts Mictester suggests.


Dirk

The thing is broken. If some clown has tried to power it with 110V AC or even 230V AC, all he'd get is a bunch of shredded PC tracks and fried components! If it was good, known working, reasonable condition, it might be worth as much as $40!

I picked up several old Electro Harmonix pedals in a junk shop recently. They were "sold as seen" and were priced according to the number of knobs and switches on them! None worked properly, but for a total outlay of £33, I got six EH pedals. It took just one pleasant evening to make them all work again, but none of them is as good as I remember!
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Re: Boss CE-3 Chorus

Postby Dirk_Hendrik » 02 Nov 2010, 08:19

Fine,
But that's the price you attach to them. Some, me included, seem to work from a far more certain perspective of being able to fix the bugger, fried or not, and therefore calculate form another perspective than the "price of the parts".
Sorry. Plain out of planes.

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Re: Boss - CE-3 Chorus

Postby jay42 » 28 Jan 2011, 23:38

From looking at the schematics for the CE-2 and CE-3, I think you could mod the 3 to sound like the 2, plus it's got more features. I wish I hadn't sold mine for $25 back in '84. Hated the tinniness. It would be a fun project now.
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Re: Boss - CE-3 Chorus

Postby Pruttelherrie » 19 Nov 2011, 22:34

Hi all,

sorry to dig up this old thread, but I got this CE-3 on my bench. It belongs to a friend of mine who said it was a real tone-sucker, even when bypassed.
I did a sweep with FuzzMeasure (Mac):
Image
Pretty sucky indeed!

Is there any way to solve this? So far I can't see any obvious caps to replace... but then again Jim, I'm a physicist, not an EE!
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Re: Boss - CE-3 Chorus

Postby KindaFuzzy » 20 Nov 2011, 14:50

I've got one of these as well, and it kind of soured me on chorus pedals until I fixed my malekko vibrato. It couldn't hurt to find out how to fix the buffer though, and maybe some tips on how to get rid of the tinniness while you're in there, hopefully someone's done one of these before. I removed a resistor or a diode or something so I could use a normal 9v adapter in mine.
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Re: Boss - CE-3 Chorus

Postby Dirk_Hendrik » 20 Nov 2011, 15:36

Pruttelherrie wrote:Hi all,

sorry to dig up this old thread, but I got this CE-3 on my bench. It belongs to a friend of mine who said it was a real tone-sucker, even when bypassed.
I did a sweep with FuzzMeasure (Mac):
Image
Pretty sucky indeed!

Is there any way to solve this? So far I can't see any obvious caps to replace... but then again Jim, I'm a physicist, not an EE!


When your CE3 responds like this there's either something wrong with your measuring setup or with the pedal. The CE3 may not be the best chorus around but this is dramatically. I've played with a CE3 for years and would never had done if it really had the frequency response of this one.

So I suspect your setup.
I suspect the application compares the in and out signal on a bit level while doing a sweep. So, compare the playsed sample value at the input with the return sample. This instead of doing a proper RMS value compare of the 2. This means that if there's a phase difference between the in and out signal it will show as a frequency dip. IRL the in and out level are of about the same magnitude amplitudewise.

Why the above?
because the problem of the CE3, and many other chorusus, is not in that buffer. It is in the preemphasis (around IC1b) and deemphasis filter(around IC1a) that will cause the in and output signal to be of the same level amplitudewise but gives it a firm, frequencydependent, phase shift. The phaserelation between lower and higher harmonic content gets screwed which one experiences as tonesuck. Your graph subscribes theres something going wrong at the frequencyrange where both filters kick in. However your graph is wrong as it shows incorrect levelbehaviour.

What would be the solution?
Get the preemphasis and deemphasis filtering out of the bypass path. And that's quite an operation.
Sorry. Plain out of planes.

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Re: Boss - CE-3 Chorus

Postby Pruttelherrie » 20 Nov 2011, 16:48

Dirk_Hendrik wrote:When your CE3 responds like this there's either something wrong with your measuring setup or with the pedal. The CE3 may not be the best chorus around but this is dramatically. I've played with a CE3 for years and would never had done if it really had the frequency response of this one.

So I suspect your setup.
I suspect the application compares the in and out signal on a bit level while doing a sweep. So, compare the playsed sample value at the input with the return sample. This instead of doing a proper RMS value compare of the 2. This means that if there's a phase difference between the in and out signal it will show as a frequency dip. IRL the in and out level are of about the same magnitude amplitude wise.

I think I understand what you're saying, but FuzzMeasure does take the phase into account. It actually measures the phase as well as the amplitude:
Image
Image
I included the loopback and the activated-pedal-signal as well. Activated chorus fucks the measurement up pretty bad.

Why the above?
because the problem of the CE3, and many other chorusus, is not in that buffer. It is in the preemphasis (around IC1b) and deemphasis filter(around IC1a) that will cause the in and output signal to be of the same level amplitudewise but gives it a firm, frequencydependent, phase shift. The phaserelation between lower and higher harmonic content gets screwed which one experiences as tonesuck. Your graph subscribes theres something going wrong at the frequencyrange where both filters kick in. However your graph is wrong as it shows incorrect levelbehaviour.

What would be the solution?
Get the preemphasis and deemphasis filtering out of the bypass path. And that's quite an operation.

Hmkay, so what you're saying is that the tonesuck is a fundamental problem with the way the CE-3 works? Then placing it in a True Bypass (tm) loop seems the simplest way to solve this. But then you still get the tonesuck when activated, of course. I just checked it, the tonesuck is really there.
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Re: Boss - CE-3 Chorus

Postby Dirk_Hendrik » 21 Nov 2011, 07:56

Since you do indeed show the phase to be measured correct I'f check the preemphasis filter for proper functioning. It doesn't seem to do the correct High boost that is corrected by the deempahsis filter.

I say tonesuck is a fundamental problem with many chorus and delaypedals utilizing these filters. However the performance of the CE3 you're measuring here is too poor and suggest another problem.
Sorry. Plain out of planes.

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Re: Boss - CE-3 Chorus

Postby Pruttelherrie » 21 Nov 2011, 22:49

I did some more probing and injecting tonight.
The preemphasis filter does some kind of mid bump around 1kHz, is it supposed to be flat towards the higher frequencies? I ended up playing a lot with different values for C6 in the deemphasis filter, 2n2 ~ 3n9 made the overall response better but with a bit of a bump of 2dB around 1.2KHz and a rolloff after 3.5kHz. It sounds better already but could be better I guess.
If I want the preemphasis to have more highs, where should I start? C4 or the lead-containing solder? :D

Thanks for pointing me in the right way Dirk Hendrik, much appreciated!
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Re: Boss - CE-3 Chorus

Postby StratWiz » 29 Apr 2012, 08:20

My BOSS CE-5's output is lower than its input, and its tone is a bit more metallic and less natural even when switched-OFF/bypassed. Otherwise it does great and works well.
Is that normal or common?
Are there any good known mods that can improve its output naturalness & level & switched-OFF/bypass' tone quality/naturalness?
Thanks,
SW
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Re: Boss - CE-3 Chorus

Postby StratWiz » 15 May 2012, 09:42

StratWiz wrote:My BOSS CE-5's output is lower than its input, and its tone is a bit more metallic and less natural even when switched-OFF/bypassed. Otherwise it does great and works well.
Is that normal or common?
Are there any good known mods that can improve its output naturalness & level & switched-OFF/bypass' tone quality/naturalness?
Thanks,
SW


I much improved my CE-5's quality by replacing all the caps on the signal paths by high quality caps, and some of the DC caps directly related to the signal path. One of the caps caused the main gain degradation, that was C13 0.475uF just before the deemphasis amp. I replaced it by 10uF, that fixed the gain and improved the low end. I replaced C32, C33 C35 DC caps for better 8v DC used for the IO transistors (100uF were replaced with 220uF). Its quality significantly improved for both effect & bypass. It is not transparent (I'm very picky), but a lot better than it was.

In my opinion, even with high quality caps non of BOSS pedals is really transparent when effect is off compared to bypassed, they can get close but yet not transparent.. (I modified and tested 6-7 different boss pedal, same result with all).

SW
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Re: Boss - CE-3 Chorus Ensemble

Postby MerlynMetal » 25 May 2015, 23:48

In case the links are not working.

CE3comp.gif


CE3solder.gif
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