Boss - CE-1 Chorus Ensemble  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Frabbio
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Post by Frabbio »

Nice sounding! I'm currently developing a new layout including a charge pump with LT1054 to get the dual supply from 9 volts, and i'd like to know what transistor you subbed in your build. Thank you :)

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lufox15
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Post by lufox15 »

Hi, well i don't remember which transistors i replaced but i use this page for searching the replacements:
http://english.electronica-pt.com/
i remember that i need replace the two voltage regulators of the power stage, cause i don't found it here, and the others was the same code i guess.
I saw another topic of another page where they trying to replace the bipolar powersupply for a charge pump, but they have too many problems i guess and the topic is open yet. the page is:
http://www.guitarrista.com/phpbbforum/v ... &start=630

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Post by Frabbio »

I understand,thank you very much :)
Before i develop the layout i'd like to know if i can use a dual opamp for IC1 and IC3, because on the schematic these are fed differently, and i don't know if it's that important for the sound.
If anyone can confirm these equivalences i can start :)
2Sa733Q-->BC557
2SC900F-->BC549
2SA493-->BC560
2SC536-->2SC945
Regards to the dual supply i will use a lt1054 instead of the classic 7660 or max1044, in this application is far superior imho.

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lufox15
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Post by lufox15 »

i just can confirm the 2SC900F-->BC549

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Post by lufox15 »

news about CE-1 without a Transfo?

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Post by hruki »

pz wrote:The power transformer has 2x18.5V AC secondaries (loaded), as it is written on the schematic. The overall measured differences in the voltages against the values on the schematic were about +/- 0.7V.
Here's some photos:
I burned transformer in my CE-1 :-(
Can someone please tell me what should I look for (model / specifications) to replace it? Any idea where to buy the thing?
Thanks a lot for your answer...

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Post by sinner »

Necro bump!

I'm working on set of replica files for this.

Main job (layout) is done, I'm on check over stage right now

I'm going to do it similar way as I did with my univibe files, with marked (highlighted) circuit blocks.

The problem is, I'm not really familiar with time based FX's

To what circuit blocks CE-1 can be broken in to?

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Post by blackbunny »

I have a CE-1. Do you need any images? Or mainly discussion of the CE-1 schematic?

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Post by sinner »

Yes, that would be really nice of you. Maybe few overal pcb shoots for now, just to chec the spec. I have found two slightly different Ce-1 schematic, and i suspect there is at least two more ce1 variants. Roland was doing revisions of other products quite often

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Post by sinner »

... Some components ware on the trace side, i wont even esk you to take it apart - its old and fragile, but maybe you could chec it out somehow with a mirror, or something?

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Post by Govmnt_Lacky »

sinner wrote:To what circuit blocks CE-1 can be broken in to?
Power section
LFO Section
Delay Section (BBD and Clock)
Audio Section (Input and Output audio processing)

Good Luck :D

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Post by sinner »

Electrosmash.com did really nice CE-2 circuit analysis http://www.electrosmash.com/boss-ce-2-analysis

I'm trying to find similarities to CE-1

This will take me some ;) I don't feel rushed on the other hand - I still have no MN3002, and I won't publish my files till then ;)

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Post by sinner »

...but - what I can show now, is the schematic redraw.

As you see it'd direct redraw from (one of) factory schematic

Factory (one of two) are low quality and hard to read. I tried to keep original part numbers, but ones again - factory schemo is difficult to read and part numbers can varies. There is no double part numbers AFAIK.

Please note this is pre version, I still need to compare it to the board values.

The final versions will be with all value differences pointed out and clearly highlighted, also broken into circuit blocks

I like to triple check the thinks Im doing, so the final version may take me some time to finish

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Post by Scruffie »

Input - Splits to Threshold/Input Level Control (Travels round to other side of BBD via OpAmp to FET) Dry Mix and Input Filtering - Splits off to Input Level Detector and BBD, Output Filtering - Output

Downwards, Clock/VCO & LFO

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Post by blackbunny »

The only components on the track side are 2 pairs of back-to-back silicon SS diodes.
One pair is soldered from the input hot to the ground buss, and the other pair from the L / mono output to the ground buss.
Attachments
CE-1 PCB diodes_small.jpg

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Post by blackbunny »

More PCB shots.
Attachments
CE-1 Components Sml 02.jpg
CE-1 Components Sml 01.jpg
CE-1 PCB tracks Sml 01.jpg

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Post by sinner »

The only offboard components are two output resistors (470r) and 220k resistor across vibrato rate pot?

Can you list the pot values?

Diodes on input are interesting, schematic (later edition/revision) shows them only on outputs, just after 470r output resistors.

I have just my smartphone with me today, so im unable to look on other picts i have

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Post by blackbunny »

On my CE-1 there is a 470r offboard resistor connected to the L/Mono (green) output wire and another 470r for the input (blue) wire.
There is a 220k resistor across the CW and middle legs of the Vibrato Rate pot.

Pot values are 100KC (Vibrato Rate), 50KB (Vibrato Depth), 10KB (Chorus Intensity) and 50KA (Level Control), looking from left to right in this photo:
Attachments
CE-1 Wiring 01-small.jpg

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Post by sinner »

Weird, schematic shows 470r and diodes attached to outputs only. There is no 470r and series back to back diodes on input. You sure you got it right?

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Post by blackbunny »

sinner wrote:Weird, schematic shows 470r and diodes attached to outputs only. There is no 470r and series back to back diodes on input. You sure you got it right?
I just checked my PCB against the schematics and you are right! The 470r resistors and diode pairs should be on the left & right outputs. :slap:
Someone has replaced the left and right output jacks before I bought the pedal, and changed the lead for the right output with the lead for the input, then moved them across to the correct solder lugs on the board and re-soldered them. I have now re-wired them to match the schematics.

I never checked that before in the 2 years since I bought the CE-1, because it still works fine and sounds great. :oops: Thanks Sinner!

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