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previous: CJ Landry Re: Technology of Phasers and Flangers -- 10/20/2000 4:41 PM View Thread

Chips and ring modulation

10/20/2000 8:35 PM
Mark Hammer
Chips and ring modulation
1) The NE571 is pin for pin replaceable with the NE570, and has slightly worse noise specs (like anyone would notice in an analog delay!). So, if you find a local distributor with 571's but no 570's, you are at liberty to sub.  
2) ANY...I repeat....ANY modulated effect whose LFO speed can be brought up to, or currently can oscillate in, the audio range, can produce vaguely "ring modulation" type timbres. It won't be *exactly* the same as a true ring mod, but it will have enough of that rubber band kind of tone to suit most tastes. In most cases (and LFO circuits), the range of possible LFO rates is set by a single capacitor. Reduce that capacitor value, and the range of oscillation will be increased by a proportionate amount. So, if your LFO is spec'd to range between .1 and 10hz (100:1 is common), simply cut the cap value by 10 and it will now sweep from 10-100hz. Since the lowest rate of sweep will likely be unsatisfactory, one would ideally want to be able to switch between cap values. Some modulated pedals already have this feature, but usually it involves switching to a cap value that permit super slow modulation (e.g., with units that offer chorus and flanging).  
Those Small Stones that seem to possess this capability probably have rate-setting caps that are a bit on the low side of their rated value, yielding higher possible sweep rates (e.g., as high as 20hz). I have an old MXR rackmount Digital Delay, and it has a pull-switch function to increase the LFO rate by either 10 or 100 (forget which), giving ring-mod type sounds. Of course the nice thing about being able to do it with a 4-knob modulated effect is that you often have control of the balance of modulated vs straight signal, so you can mix the "boing" to taste.  
Once again, this will work for vibrato, tremolo, phase shifters, flangers, chorusses automatically swept filters and anything else where the sound goes back and forth at some predetermined rate.

Rob I tried replacing the pot and it di... -- 10/22/2000 6:45 PM