Boss ce 1 Chorus Mods

[njkmonty]

since completing my ce 1 clone, i was looking to try out some minor mods. since its just a clone i thought i might try some before boxing up.
Ive done a little reading and come across a couple online, however was hoping for some feedback regarding implementation on a schematic.

here is the full schematic again ...




Here is the more guitar friendly impedance mod .....




Here is the additional chorus depth mod......





True Bypass Mod idea...






any thoughts anyone?

[Mark Hammer]

Though I can't absolutely confirm this, from all outward appearances it would seem that the CE-1 was principally directed at keyboard players who wanted something more portable than a Leslie speaker.  That would explain the input attenuation and low input impedance, better suited to the low output-impedance and levels of keyboards.  Other potential users of the pedal were essentially an afterthought.

One of the problems that introduces is some tone-sucking for guitars, although to be fair many rotating speakers also lose top end, simply because of the way they work.  Another problem introduced is via the noise reduction.  Several pedals from that era use a noise gate arrangement for the wet signal, rather than the companding we tended to see a few years later.  But the threshold for gating may be inappropriate for your instrument level nd there is no means for adjusting it included.  So, you may want to tinker with the gain of IC3, in addition to its decay.

[njkmonty]

ive done the chorus depth mod and its a keeper!

Mark are you suggesting to maybe put a parallel 1 meg resistor with both R11 (470K)  (IC 1 )   and  R73 (470k) (IC 3) ?

i was playing the pedal again today and couldn't put it down, but when playingdrums  with my son noticed the "highs" not cutting through which has made me ponder this "Impedance mod"
i would like to come up with a way of going back and forth from stock  with the least amount of switches and pots

[nickbungus]

Which PCB layout did you use?  I was thinking of making one.  Could it be powered from 9v and charge pumps?

[njkmonty]

i made it with charge pump to test it , then used  lm337 and 317,, surprisingly both sounded the same , very good,  im very happy i stumbled upon it , i can give info if you want it..


http://www.crazy-patroche.com/article-etude-du-chorus-boss-ce1-119548543.html

plus i found a better schematic too elsewhere





this surge pump circuit worked great very quiet..

however i had in series 1 or 2 diodes to drop voltage a little but can help out when you get to that.



one other thing, i like this pedal so much , i read somewhere with a little modification that the circuit could be built around a mn3007 instead, but not sure how to implement yet


i just read again your question,, ive never done it before but i wonder if you could use 2 charge pumps?  one to get 18v , then the other to get bipolar 15v

[nickbungus]

I think my question is (and sorry Njkmonty for hi-jacking your thread), would it be possible to take a normal +9v power input and use charge pumps (or any other method) to get +14v, -14v, +13v and -13v supplies?

I like the guitar impedance mod too.  I want to make a PCB layout that is guitar rig friendly.

[njkmonty]

i was warned against any charge pump on this  introducing heterodyning, or whatever that is !  it was clean, and sounded great, when my regulators arrived  i just used them , but i cant see why 2 wouldn't work. 9v - 18v -  15/-15
i previously made an early version of madbeans mxr flanger using a surge pump, and it was noisy and problematic.  after he revised his next board with modifications to the surge circuit mine sounded great , since then i use that version for  + 15v.

what im saying is the circuit around the chip has resulted in good and crappy results. Moosapotomuses ada flanger mn3007 version for example worked great for me too.

i also got the slightly lower voltages adding some 1n400x  diodes in series on each rail.  , but it took me a while to figure out that the diodes must face the opposite way on the negative 15v side!

[daz061]

i made it with charge pump to test it , then used  lm337 and 317,, surprisingly both sounded the same , very good,  im very happy i stumbled upon it , i can give info if you want it..


http://www.crazy-patroche.com/article-etude-du-chorus-boss-ce1-119548543.html

plus i found a better schematic too elsewhere



From that +/-15v where are you getteing the 13 and 14v from?



this surge pump circuit worked great very quiet..

however i had in series 1 or 2 diodes to drop voltage a little but can help out when you get to that.



one other thing, i like this pedal so much , i read somewhere with a little modification that the circuit could be built around a mn3007 instead, but not sure how to implement yet


i just read again your question,, ive never done it before but i wonder if you could use 2 charge pumps?  one to get 18v , then the other to get bipolar 15v

[njkmonty]

[nickbungus]

Just a quick update on the mod Aussie Nick (njkmonty) suggested on adding a depth control to the Chorus.  I did this on my working board and it works excellently.  This must be the easiest mod ever and I dont understand why it wasnt on the original schematic.  I did it all offboard.