Limiter For Guitars

EE JULY/AUGUST 1987 by W Teder The basic dynamic character- istic of a chord can be analysed as a fast rising, needle-shaped pulse with a virtually exponen- tial decay-see Fig. 1. This typical amplitude characteristic can only be faithfully reproduc- ed by an amplifier if this is oper- ated well below its overload margin, and that, many guitar players know, generally results in too low an average sound level. Also, when it is desired to use a high volume setting, the distortion soon rises to an unac- ceptable level. Although the above difficulty is widely remedied by means of a tightly set compressor or limiter, the sound may then lack the required agressiveness. This circuit is expected to give bet- ter results than most other limiters, because it is only active in the upper range of the dynamic characteristic. The gain of the preamplifier set up around IC, is asjustable with Pl. The inverting input of the opamp is grounded via the drain-source junction of n- channel FET Ti, wh...