[1918] Little Angel Chorus – NYE v2

Date: December 11th, 2015 | Comments : [3] | Categories: DIY.

Little Angel chorus prototype

A couple of years ago I posted an article about a revised version of the Little Angel Chorus, which uses the PT2399 delay chip. I finally got around to doing a few mods on it to see if I could further improve the sound.

I disassembled the pedal and had it modded in short order. I changed the series resistor to the pin 2 modulation input to 10k, as was suggested in the original article.

Next, I replaced the voltage regulator with one that outputs 6 volts instead of 5 volts. I had found that the internal clock of the PT2399 runs faster at the higher voltage, which is needed to make a more convincing chorus effect with that chip.

Little Angel chorus gut shot

The faster clock speed on the PT2399 makes a shorter delay time and I find that the chorus sounds better on the higher voltage. The chip does not run hot with the increased power and so far it is working without problems, but it is a risk to run the chip near its maximum rated voltage, so be aware of that.

The improvement is not as dramatic as I had hoped but it is an improvement.

Read the original article about the NYE version of the chorus.

Little Angel, New Year’s Edition Schematic v2



3 Responses to “Little Angel Chorus – NYE v2”

[767478] Adam Says: 6:49 am, January 1st, 2016

Hello, I just assemblied this beast 🙂
Had some issues with noise so I added 100 Ohm resistor in series before 5 V regulator with 47uF in between 🙂

But what I found is that input / output resistors are in some strange configuration.
It actually miss 2 caps in schema:
the appliation note uses 2nd order LPF filter on input and output but your schema miss the ones that go to the ground. (see :http://sim.okawa-denshi.jp/en/OPtazyuLowkeisan.htm ,I mean you miss C1 from that schema). For 10kHz bandwidth it should be 2n2 ,with no change to other compoments.

I am gonna to try out preemphasis/deemphasis as in BOSS/IBANEZ stompboxes as next attempt 🙂
Best redards


[771001] Kristin S.Martinez Says: 4:43 pm, August 6th, 2016

Thank man.
It should be easy to build the circuit on the previous perfboard layouts with only a simple mod or two to the layout (See: http://musicalstudy.com/). The jfet startup is optional and the bipolar version can certainly be used. The two mods to the LFO are the most important and helped my pedal out the most (bias and reduced resistor on pin 2).

[781225] Mono211 Says: 1:18 pm, December 2nd, 2017

Hey ho!

I build one of these but I have some strange noises. If I activate my pedal a clicking noise starts – sounds like an infinitely echo. Sometime I get some chorus effect on my guitar input. Is it possible that my pt2399 chip is damaged?
By the way: Do you have the voltages of each pin?

Thank you!


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