How is One Chips Chorus Compared to Little Angel Chorus?

[nguitar12]

Anyone built both circuit and tell me the different between two?
One Chips Chorus look very simple but will it sound anything close to the real Chorus?

[canman]

I built a One Chip Chorus a while back...it sounds cool for sure, almost like a vibe-y seasick kind of thing, but I had a hard time getting classic chorus sounds out of it.  Though, I had PT2399 lockup problems with mine so I may not have been able to really test and see what kind of chorus sounds I could get.

If you're after a lush, classic chorus sound, I'd bite the bullet and build something with the MN3007 chip.

[Govmnt_Lacky]

There are varying opinions on this but...

The Little Angel should not be classified as a chorus IMHO. There is barely any effect to it and is more of a sound "Colorer" than anything else. To me it sounded like an Electric Mistress stuck in Matrix mode without any adjustment to it. Even when the Rate pot was maxed it got nowhere near what I would consider a chorus.

[Cozybuilder]

Sam Hay designed a very nice sounding PT2399-based chorus, the "Cherub".

If you are looking for a classic chorus sound though, look closer at the BBD designs. For example, the Zombie Chorus is very nice if you incorporate the recommended mods.

[Mark Hammer]

That would suggest that both are "slightly incomplete" circuits, in the way that the Zombie Chorus was a good idea but a bit too minimalist and incomplete for pleasant use (though, as Cozy notes, a coupla mods and it's a keeper).  I've made a few One-Chip Choruses, and I've never gotten any of them to work decently.

As ideas or experiments, plenty of minimalist circuits can be brilliant  Tim Escobedo has plenty of them.  But that doesn't mean they're the sort of thing you can box up, and be glad you spent the money on the chassis and knobs.

[samhay]

The Little Angel uses a very neat trick to modulate the delayed signal - hats off to Rick - but, like others, I found the overall effect to be somewhat lacking.

I designed the 'Cherub' to work in a more conventional way. The thread is here: http://www.diystompboxes.com/smfforum/index.php?topic=106854.0
There are a few audio clips scattered throughout.

As I see it, the problem with using the PT2399 for a chorus is somewhat twofold, and neither of these are complete show-stoppers. The minimum delay at ~30 ms is too long for a chorus, so it is all too easy to modulate the delay so much that the wet signal gets excessively sharp/flat and un-musical. That said, you can get pretty close to a BBD-based chorus sound, and the chips are still fairly cheap, easy to find and probably easier to work with than BBDs.

[anchovie]

I came up with the One Chip Chorus as a personal challenge, really - to produce the LFO without any additional active components. Of course, if I wanted something more elegant and less lo-fi, I'd aim for proper input impedance, stability, better control - but then it wouldn't be a One Chip Chorus!

[anchovie]

(By the way, it sounded OK on the amp I had at the time but it's garbage with the one I have now!)

[nguitar12]

Thanks all I am going to build both and explore it myself.

[mattoverse]

Wouldn't describe it as a classic chorus sound, but I get plenty of effected sound with my take on the Little Angel NYE Chorus. 

[FUZZZZzzzz]

Sounds right up my alley. Thanks for this!

I built a One Chip Chorus a while back...it sounds cool for sure, almost like a vibe-y seasick kind of thing, but I had a hard time getting classic chorus sounds out of it. 

[anotherjim]

I think, you can (technically) have chorus with a longer delay than the classic bbd type. It's just a variable delay signal mixed with the original right? The trouble is, the longer delay of the PT2399 introduces a slap-back echo especially noticeable from pick attack. You have to keep modulation depth level low - it could really do with automatic depth reduction as LFO rate increases. Having some feedback can smear it (and the double picking) out a bit. Might be better to call it a double tracking effect.

Some time back I built a PT2399 chorus to simulate the dual LFO rate type used in string synths (a la ARP-Solina). When I played a sample of a string synth with it's own chorus switched out through it, it sounded bang on to me, and the original synth chorus used TCA350 BBD with only (IIRC) 288 stages. This though, is a completely a different situation to guitar - the synth has a slow attack, no picking transient and a consistent waveform, so it's really no different sound wise using a longer basic delay than the BBD chorus. Guitar tone is rapidly changing after initial pick, so chorus needs to act very early on and sooner than our brains can register an echo.

[WhiskeyMadeMeDoIt]

Has anyone tried running the PT2399 at 6 volts? I know it can't handle much voltage but I have a suspicion it will increase the clock speed and shorten the minimum delay.
Another stupid thought. Run the signal into two PT2399 and set for a very short delay but just enough difference between the two to get under the 30ms limit and mix the delayed signals back together. If maybe you had a 20ms difference in the delay between then you could get a nice chorus .Would this be feasible or is this off.

[anotherjim]

If I ever get time, I'll try with a bit more than 5volt on the PT2399.
I do have doubts, because I suspect the chips VCO control resistor versus clock rate varies from chip to chip, batch to batch, phase of the moon...
Anyway, it's easy to jack up your existing 5v reg with a diode.

...here the reg is being raised by a diode drop to compensate for the transistor VBE drop - but ignore the transistor and take the normal regulator output raised at 5.6v. With a 78L05, the diode could be a 1N914 or 4148. This is an old trick that you don't see often. It's commonly used to get a 7808 nearer to 9v (who or what uses 8volt?)

I don't see why parallel PT2399's can't achieve what's suggested - but you're increasing cost/complexity. While BBD's are still available, they probably beat it.

[~arph]

Yes, I have seen someone (merlinb? I seem to recall) doing the voltage experiment and measuring minimum delay times. Higher voltage does indeed increase the clock and lowers the minimum delay time, but at a risk.

[samhay]

Another stupid thought. Run the signal into two PT2399 and set for a very short delay but just enough difference between the two to get under the 30ms limit and mix the delayed signals back together. If maybe you had a 20ms difference in the delay between then you could get a nice chorus .Would this be feasible or is this off.

Not a stupid thought. That's how the 'Dimension P' works.
http://www.diystompboxes.com/smfforum/index.php?topic=94435.0

[WhiskeyMadeMeDoIt]

Jim that is one of the thing I intend to try out. I have heard of the diode trick before. I may take this little angel that i built and abuse it to see what happens. i was never really happy with the sound anyway. I'll try the diode and then if all else fails rip out that 5 volt reg and pop in a 6volt reg that i have laying about.

Arph thanks for the confirmation.

Samhay I will have to look into that circuit in depth when i get home from work. It doesn't look that complex. I know the BBD's are still around but at a premium price. it would be nice to have an alternative... and an excuse to fiddle. 

[anotherjim]

Yeh, I just looked and I can still get PT2399 reasonable cost from a "normal" retailer. Mind you, my attempts at the one-chip fried 3 of them. I'd been experimenting with the LFO coupling caps to the reference pin (while power-off of course) - too big seems dangerous. Op-amps still work, reference pin is 2.5v, but no delay left in them.
I have 5 left from the 10 I bought. Thinking of a 5 chip delay with the signal paths connecting all points of a pentagram. Should break through the space-time continuum and play what I was going to play before I play it.