Boss CE-1The Boss CE-1 is a classic chorus effect that first appeared in June 1976 and is based around the chorus circuit used in the Roland JC-120 Jazz Chorus amplifier. The CE-1 is one of the earliest pedal style chorus to employ the BBD (Bucket Brigade Driver) chips. Despite its input stage being better suited for organs, electric pianos, and other line level devices; the CE-1 has become extremely popular for guitar and bass players. Several companies (notably Analog.man Effects) offer mods to make it more guitar friendly. In addition, many pedal manufactures have tried to clone this venerable classic pedal.
The sound of the Boss-CE1 can be described as dark, full, throby. It has a tendency to really change the character of the sound. It is not as subtle as many other choruses. The CE-1 decreases the highs (3db/octave roll off at ~1k) and boosts the low mids a bit. Its input is very sensitive and clips very easily. This non-optimal SNR also make for a noisy pedal. Clones like my RetroSonic CE-1 do a good job of preserving the character without all the noise.
The Boss CE-1 is a 2 voice chorus. This means it has a dry signal that is combined with a delayed signal that is modulated. The modulation of the delayed signal causes an oscillation of the pitch of the signal causing a warbling sound. The wider the range of the delay time min/max (often times called depth or intensity), the larger the pitch shift. When not mixed with a dry signal, this is known as a vibrato effect. When the signal is mix with the dry signal you get a doubling effect like 2 or more instruments playing the same thing (hence the name chorus).
Generally chorus effects will have delay times between 20-30ms. The Boss CE-1 is a notable exception. Its delay time is more akin to a flanger with a delay time on my unit ranging from 3-5 seconds. This makes for a very unique sound.
There a two modes on Boss CE-1. First is the Chorus mode. Chorus mode only offers one control, this is intensity. The only noticeable effect I saw with intensity (which is normally thought of a depth control) is the rate of modulation. It maybe that it also slight reduces the mix of dry and wet. I saw no difference in delay times though. In chorus mode the rate went from 1Hz to 3Hz. With the knob at 50% the rate was about 1.75Hz.
The other mode of the CE-1 is Vibrato mode. There are 2 controls in Vibrato mode (rate, and depth). Vibrato mode in the CE-1 is a bit of a misnomer. Typically vibrato does not mix the wet and dry signals. This means all warble, no dry. However, in the CE-1 the vibrato mode the mix is still approximately an equal amount of wet and dry. The difference is the rate starts faster the chorus mode ends and gets really fast from there. This range from 3.2 to 11.6Hz. In addition, the depth knob controls the width of the delay min/max. The width of the delay is from 3-5 (min) to 3-7 ms(max).
The CE-1 uses two different waveforms for each mode. For Chorus mode it use a triangle wave form; while in Vibrato mode it uses a roughly sine wave.
The final feature of the Boss CE-1 chorus is its stereo mode. The stereo mode simple outputs a dry signal from one output and the modulated signal from another.
That in the nutshell is the Boss CE-1
Here is a comparison of the Axe-fx and Boss CE-1. I added the background noise of the Boss CE-1 to the Axe-fx to make them harder to guess.
This is the chorus mode with Intensity set at noon. A tone match block was added for added authenticity, but can easily be removed for efficiently.
Axe-Change - Download Preset - Boss CE1 - by javajunkie