"Little Angel" - Super Simple PT2399 Mini Chorus

[cpm]

Yes, but slacker's Echo Base does modulated delay better, and with multiple repeats and a host of other useful functions. But with Little Angel I think having any more than the absolute minimum resistance between pin 6 and ground is missing the point. Little Angel is a chorus, so it's desirable to keep the delay time as short as possible.

and... what about feedback,
maybe a small, frequency controlled feedback may add interesting effects

[markeebee]

Then, if we're adding an extra opamp for the LFO, why not add a second dual (or a single quad) and use the spare as an output buffer? This moves away a little from the (desirable) simplicity of the original concept.

Just make two layouts:

* Little Angel
* Medium Angel

Or maybe Little Angel and Little Devil?  Then Rick could retrospectively enter the 666 competition (as he made the rules up as he went along anyway) and win himself a Murder One!

Oh hang on....from the 666 comp thread.....

Thanks rick. The overall prize aside, can we expect any "work" from you???

Nothing demonic sorry. I'm working on angelic!

*****CLANG****  The penny drops.


I love the sound of the clips, Rick.  Not usually a fan of chorus but I really like the organic-ness of this.  I take your point about Echo Base doing modulated delay better , but I think I'd like a variable R at pin 6 so that I get a really really nice sounding chorus (primarily) with the added bonus of mod delay (secondary).

Good work, sailor.  As always.

[frequencycentral]

*****CLANG****  The penny drops.

Hahahaha - well spotted sir!

I think this project will continue on two seperate paths:

• I'm determined to keep the super simple version as close to the original schematic as possible, there should be an entry level chorus build available. I am avoiding 'feature creep' like the plague. I've just completed the layout for this version, including the most basic of Tomas's mods.
• The 'elite' version could have wet/dy mix, bright cut, feedback, variable delay time, improved LFO, differential output buffer.........anything else? But it's going to take a while to get there.

[~arph]

I'd increase the max available depth of the effect. What you have now I'd say is in the middle of what I'd want.

[frequencycentral]

I'd increase the max available depth of the effect. What you have now I'd say is in the middle of what I'd want.

That woud just require the 100k at pin 2 to be reduced to say 47k.

[~arph]

Yes, I know, but I'd include that in the minimal version so it's a bit more versatile without increasing circuit complexity 

[DougH]

Not bad. About what you would expect...
http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632

WTF?!? 

that's for 460 pcs

Oh my goodness, you're right. 

I didn't see that... I just checked the "quantity" at the top. My bad.

And sorry for the thread derail.  Carry on...

[Renegadrian]

Yes, I know, but I'd include that in the minimal version so it's a bit more versatile without increasing circuit complexity 

A switch a one more res. should keep it simple yet

[frequencycentral]

Fresh from the breadboard:

• Tomas's suggested 1uF cap to ground from pin 2 stops the modulation!
• The minimum useable value for the resistor at pin 2 is 33k.
• Just for giggles, I implemented a feedback loop and got a very metallic sounding pseudo reverb.

[p_wats]

I'm with Rick on this one: keep it as simple as possible for now, as this could definitely be the easiest chorus build around.

...but once that's verified then let the feature tweaks commence to see how far we can take this thing!

Rick, would you say your initial schematic is ripe for people like myself to perf to our hearts content (you had suggested waiting earlier)? Thanks again!

[frequencycentral]

Rick, would you say your initial schematic is ripe for people like myself to perf to our hearts content (you had suggested waiting earlier)? Thanks again!

I just updated the schematic and reloaded it into photobucket, it should show up in post #1 of this thread if you refresh. It says version 2 on it. At this very moment a friend of mine in NJ is populating a PCB made from my layout. Once he verifies it I will post it.

[Renegadrian]

no version 2 even on refresh...

[frequencycentral]

no version 2 even on refresh...

Yeah I noticed that. I deleted the original and loaded the new one under the same name, so it should be showing up. Probably an issue with photobucket. If it doesn't refresh in a few hours I'll upload it under an new name and repost it. I just didn't want to confuse the thread with many different schematics.

[p_wats]

If it doesn't refresh in a few hours I'll upload it under an new name and repost it. I just didn't want to confuse the thread with many different schematics.

Nice! Works for me now. This will have to go to the top of my list...

[frequencycentral]

Hmm, still not refreshing for me...

[soggybag]

Very inspiring, great work. I love this chip. Pin 2 is still sort of a mystery to me. What exactly does this do?

[doug deeper]

awesome!
add a blend pot and a square/triangle option and a delay time pot and you pretty much have the pitch pirate.
does this mean i can modulate pin 2 on my next pedal?
 

[culturejam]

This mutha is a verified, working beast of a chorus.  

With the depth control very low, the effect is quite subtle at lower LFO speeds. With the Speed slow and the depth cranked, you get classy shimmery (ever so slightly metallic) chorus tones. But still kinda unique. And with the Depth and Speed both high, the overall effect is more like a vibey chorus. There is a bit of a pulse and throb at that setting.

Very versatile and highly recommended. I simply cannot believe something this simplistic (parts-wise) can sound this big and great.

Super kudos to Rick.  

This is the simple version, as built by me earlier today and verified just now. I'll play around some more with the settings and see if there are any dead spots, but my initial tweaking yielded only positive results.

[frequencycentral]

Verified schematic and layout:

[culturejam]

One important note that might save people some time:

The orientation of the voltage regulator on the layout is correct for the 78L05 version.