7

Overload matters

There are no gain controls on RIAA inputs, so the overload margin, or headroom, is of considerable importance. The issue can get a bit involved, as the frequency-dependant gain is further complicated by a heavy frequency-dependant load in the shape of the feedback network. This heavy loading was a major cause of distortion and headroom-limitation in conventional RIAA stages that had emitter-follower outputs with highly asymmetrical drive capabilities, and for some reason it took the industry a very long time to wake up to this. Once more the 5532 op-amp solved that problem.

There are also interesting limitations to the levels which stylusin-vinyl technology can generate. This chapter tries to sort out the issues involved in maximising ...

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