Zombie Chorus

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
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animalejo
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my favorite amplifier: Marshall JCM900
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Post by animalejo »

Here is a Zombie Chorus, i add a volume pot and the R.G. Keen anticlicking.

Have fun!!!
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mictester
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Post by mictester »

Nice layout. The volume control is unnecessary because the effect has unity gain - the same level comes out as goes in! There are a couple of small improvements that can be made - the 10k / 15k potential divider that biases the input op-amp and the MN3007 isn't quite optimum - it will vary slightly from sample to sample of the MN3007. I used a 10k preset with 10k to ground and 12k to +9V at each end of the track. This allowed me to finely adjust the bias for the MN3007 to give minimum distortion. I also like to add a little pre-emphasis to the input op-amp, to give more treble content, then roll it off again at the output - this reduces the background hiss inherently produced by the BBD. I usually use an LM358 for the modulation oscillator - this reduces the current consumption quite a lot. I add a multicolour (4 - lead) LED to the panel. With a little extra work, I have red for bypassed, green for chorus - pulsing to yellow at the LFO rate - and orange - also pulsing - for vibrato mode. It's easy to see at a glance how it's set! I also intended to add a second LED for the Clone / Leslie / Normal switch, though this is less important.

My additions to the circuit don't detract from the original concept of a "minimal" design. They're just small tweaks that increase the functionality of the basic effect. Interestingly, a couple of guitarists who've bought these from me have asked for the controls to be internal presets, so that they can "set and forget" the effect - it's either on or off and gives them their own characteristic chorus sound every time.

Now that BBDs are beginning to get scarce ( and therefore much more expensive ), I think it's time to explore the digital domain.....
"Why is it humming?" "Because it doesn't know the words!"

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animalejo
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Posts: 7
Joined: 29 Oct 2010, 02:00
my favorite amplifier: Marshall JCM900
Completed builds: http://www.pedalesanimal.cl
https://pcbdiylayouts.blogspot.com
Has thanked: 2 times
Been thanked: 12 times

Post by animalejo »

mictester wrote:Nice layout. The volume control is unnecessary because the effect has unity gain - the same level comes out as goes in! There are a couple of small improvements that can be made - the 10k / 15k potential divider that biases the input op-amp and the MN3007 isn't quite optimum - it will vary slightly from sample to sample of the MN3007. I used a 10k preset with 10k to ground and 12k to +9V at each end of the track. This allowed me to finely adjust the bias for the MN3007 to give minimum distortion. I also like to add a little pre-emphasis to the input op-amp, to give more treble content, then roll it off again at the output - this reduces the background hiss inherently produced by the BBD. I usually use an LM358 for the modulation oscillator - this reduces the current consumption quite a lot. I add a multicolour (4 - lead) LED to the panel. With a little extra work, I have red for bypassed, green for chorus - pulsing to yellow at the LFO rate - and orange - also pulsing - for vibrato mode. It's easy to see at a glance how it's set! I also intended to add a second LED for the Clone / Leslie / Normal switch, though this is less important.

My additions to the circuit don't detract from the original concept of a "minimal" design. They're just small tweaks that increase the functionality of the basic effect. Interestingly, a couple of guitarists who've bought these from me have asked for the controls to be internal presets, so that they can "set and forget" the effect - it's either on or off and gives them their own characteristic chorus sound every time.

Now that BBDs are beginning to get scarce ( and therefore much more expensive ), I think it's time to explore the digital domain.....
I needed a volume control, the level (in my case) is little more high than the normal, so is work perfect for me.
thanks for the tips !!
And last i love the analog stuff jjejeje, the digital world, in my opinion, is little artificial jejeje

Cheers from Chile !! [smilie=rlp_smilie_242.gif]

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