Diy Chorus suggestions?

[birt]

A proffesional musician asked me if i could build an analog chorus wich is capable of subtle i-know-its-there-but-its-not-obvious sounds such (i believe the boss ce-1 was great at that) as well as an over the top underwater sound. he has no need for cheesy inbetween stuff.

any hints?

[MartyMart]

Sounds like he needs a ROG Slitter Blender:   http://www.runoffgroove.com/splitter-blend.html
Makes any Chorus/Flanger behave like an effect wired to a mixing desk, using "send/return"
jacks.
You can "blend in" as much/as little "chorus" signal as you like compared to "dry" gtr !!
V- cool

Marty.

[nelson]

could use a paralooper......

Small clone chorus at tonepad.

There does seem to be a lack of DIY chorus projects...

I did a layout for the EH Clone theory. Havent had time to verify it yet. I should really redo the layout too, its too big. Just fits in a 1590BB.

There is also the EH echoflanger layout I did. Bit overkill for your needs though. It does to subtle to complete crazyness. My favourite chorus so far.

[birt]

he also mentioned he likes the chorus sound from some kind of EHX delay pedal

[moosapotamus]

I'll second the Small Clone. Lots of good mods to make it produce a much wider range of effects, too.
http://www.moosapotamus.com/wavy/wavy.htm

~ Charlie

[RickL]

I did a layout for the EH Clone theory. Havent had time to verify it yet. I should really redo the layout too, its too big. Just fits in a 1590BB.

I'm in the prossess of building this right now. I'm not sure if I'm using the most recent version of the layout, but the version I have has all of the ICs with a width of 0.3" instead of 0.4". I'm building using 4ms' CBCB method so it was fairly easy to drill all the holes on one side of each chip 0.1" further over but if you etch a board it will be more awkward.

I should be finished it by early this week but probably won't get a chance to post a review until late in the week (working out of town).

[KORGULL]

Small Clone with the cap switching mod (Tonepad).

[nelson]

I did a layout for the EH Clone theory. Havent had time to verify it yet. I should really redo the layout too, its too big. Just fits in a 1590BB.

I'm in the prossess of building this right now. I'm not sure if I'm using the most recent version of the layout, but the version I have has all of the ICs with a width of 0.3" instead of 0.4". I'm building using 4ms' CBCB method so it was fairly easy to drill all the holes on one side of each chip 0.1" further over but if you etch a board it will be more awkward.

I should be finished it by early this week but probably won't get a chance to post a review until late in the week (working out of town).

There has been an update to that layout... There were no major changes, apart from the IC spacing. I think....long time since I did it.

I am actually working on a complete redraft of the clone theory just now. It will be around the size of the small clone board on tonepad, will also incorporate MAX1044 for the +15v and maybe pads for stereo mod.

[nelson]

I jsut remembered if you are using the version of the cloen theory layout I am thinking of, the area around the CD4047 is all wrong. I drew it like it was a 16pin IC......

Check how many pins the cd4047 has on the layout....

email me if you want most up to date layout.

[RickL]

The version I'm using has the 4049 as a 14 pin chip. All I have left to do is the jumpers and the off-board wiring. I'll know by Monday night if it works or not (I tend to work on pedals in hotel rooms when I travel) but I won't be able to post until I get home.

[Mark Hammer]

Just about ANY chorus, commercial or DIY, can be made more pleasingly subtle by doing two things: shaving off the bass from the wet signal, and trimming back the blend of wet signal.

Let's start with the most mom and apple pie chorus I can think of, the Boss CE-2 (not all that different from many others out there).  A schem for one of the issues can be seen here: http://home.hetnet.nl/~chrisdus/download/ce2.gif

Look in the upper right hand corner of the schem.  You will note an FET, labelled Q8, which is used for switching the wet signal in and out (most chorus and phaser pedals that use FET switching ONLY cut the wet signal in and out and do not bypass the rest of the circuit).  To its left you will see R22 (47k) and C14.  R22 is the same value as R21, and is intended to provide a 50/50 blend of wet and dry at the mixing node (pin 2 of IC1) when the FET is "on".  If R22 is greater than R21, then dry becomes more obvious that wet, making the chorus effect subtler.  If one replaced R22 with a 39k fixed resistor, in series with a 250k pot, the user could a) find the *perfect* 50/50 blend and the sweet spot (remember, just because it says 47k doesn't mean it is exactly 47k) and b) trim back the wet signal so that it was just a whisper of delay in there.

C13 is intended to block DC and provide as much bandwidth as possible on the delay/wet path.  In tandem with R20, C14 forms a highpass filter rolling off at just under 5hz.  Keep in mind that the "wobble" of a chorus arises from the pitch changing, or more importantly, the fundamental of the note.  Pitch shift in the harmonics provides more of a shimmer or animation.  If a person trimmed back on the low end of the wet signal, you get less obvious wobble without losing the shimmer.  In the case of the CE-2, you'd want to drop the value of C14 to probably something like 470pf or at most .001uf. 

Note that since the largest amplitude portion of almost any guitar signal (and especially when it is as heavily lowpass filtered as delay signals are) is going to be in the 500hz and under zone, chopping the low end is a sort of two-fer-one because it also ends up dropping wet-signal amplitude noticeably.  That's one of the reasons why I recommend using a fixed resistor LESS than the original along with the wet-volume pot - to compensate for the volume drop when bass is cut.  In fact, if you were going to implement both bass-cut and wet-level cut in the CE-2, you could probably go as low as 33k when replacing R22 because of that.

make sense?

[birt]

jups it does make sense.
now i have to find those spots in the small clone schem (because that's the one i'm going to build) so i can do every mod there is on it and make it as versatile as possible.

[lowstar]

in the ce-2b, the bass version of the ce-2, the value of c14 is 0.012 µ, and the resistor r 22 is replaced by a 250 k poti with 47k in series to control the amount of wet signal added to the mix.

mark, it is always a pleasure to read your posts and learn something new or understand something better !

cheers,
lowstar

[Mark Hammer]

Thanks for the compliment.  If it's a Small Clone we're talking about, then the cap and resistor in question can be found once again at the far right of the schematic ( http://www.tonepad.com/getFile.asp?id=97 ).  The cap is 1uf in this instance, and the fixed resistor is 20k.  Drop the cap down to, say .01-.022uf, make the fixed resistor 15k and the added pot 100k, and you're in business.

As a sidenote, I've done this to my Zombie Chorus.  I buddy in my language class plays guitar.  I ased him if he had or had used a chorus pedal.  He replied that he had but found them too annoying because they were too obvious and in-your-face.  I asked if he would be interested in trying something capable of more subtlety, and when he finally returned it to me he said it was probably the first time he actually enjoyed using a chorus.

Once again, I will flog the idea that just because it's good for audio reproduction doesn't mean its good for music production.  Normally, full audio bandwidth (especially at the low end) is a good thing.  In this particular instance (chorus pedals), maintaining full or maximum feasible bandwidth gets in the way of decent sound because the most distracting parts of the audio spectrum are allowed to "bully" the rest of the effect.  Sometimes you have to stop and ask the question "Is there some part of the signal that has too much impact here?"

Incidentally, in the CE-2b, more bass is rolled off than in the CE-2, and there is a means to trim back the wet level.  Why?  Because the "wobble" (pitch shift) is more distracting on bass than on many other instruments.

[birt]

so that extra pot lets you make the effect more subtle but you can still get the original sound if you turn it up right?

[Mark Hammer]

Yes.  No reason why you couldn't wire up a toggle to enable/disable the bass-cut like I did on my Zombie.  It's ALL reversible, so you can get very obvious chorus as well as subtle..

[birt]

I'll second the Small Clone. Lots of good mods to make it produce a much wider range of effects, too.
http://www.moosapotamus.com/wavy/wavy.htm

~ Charlie

you didn't use the extra pcb for the stereo mod as described in the tonepad pdf but just an spst switch right? with output 2 connected right before the circuit cut?

[birt]

Yes.  No reason why you couldn't wire up a toggle to enable/disable the bass-cut like I did on my Zombie.  It's ALL reversible, so you can get very obvious chorus as well as subtle..

i can't really find where to make the bass cut in the small clone schematic. the little piece of the circuit before Q1 is identical to the ce-2 but then wher the ce-2 has that cap it's completely different.

[birt]

can i use the mn3008/tda2108 instead of the mn3007 wich i can't find?

[A.S.P.]

The version I'm using has the 4049 as a 14 pin chip...

where do you guys find 4049 in a DIP14