Crude Chorus Implemented

I implemented a single tap chours. The chorus is driven by a 1Hz sine wave. The delay offset is 30ms and chorus depth is 10 or 20 ms. No interpolation between the samples.

I have 2 configurations:

1- Left channel dry, right channel is left channel with chorus: The chorus sounds like somebody is changing the pitch @ 1 Hz. No atrifacts are present. This is a surprise since no interpolation takes place.

2- Both channels are left with chorus: There are clicks and artifacts just as expected as the result of non-interpolation.

I can't explain why the 2 configurations sound different. In theory they should be the same. I will investigate further.