The problem with Baxandall’s circuit is the overload margin at HF is poor. There are many Stereophile reviews of solid state RIAA EQ amps proudly flying their passive EQ flags with 9 dB overload margins. That is just not enough to cater for ’hot’ cartridges, hot recordings and the overall dynamic range of recorded material to say nothing of surface noise clicks and pops that may be overlaid on that. Use passive in tube circuits where you have high supply rails and plenty of swing, and use all active a la Lipshtiz for low voltage (ie =-15V rails) opamp or discrete designs.
Shure did a lot of work on this in the 1970’s and the recommended OL margin is 26 db. Consider the requirements made up as follows: 12-14 db for music dynamic range + 9 dB to cover hot carts and hot recordings. That’s 20 dB to which a further safety margin of 6 dB is added to cover clicks and pops etc.
Shure did a lot of work on this in the 1970’s and the recommended OL margin is 26 db. Consider the requirements made up as follows: 12-14 db for music dynamic range + 9 dB to cover hot carts and hot recordings. That’s 20 dB to which a further safety margin of 6 dB is added to cover clicks and pops etc.
Back in the 1980's when such things still mattered, I was asked to build a phono preamp. It was two inverting stages using a quad op-amp. I make no claims to it being exceptional, but it worked very well with no high frequency overload problem and imuned to ESD. I was also asked to repair an audiophile discrete phono preamp, that frankly was junk and way overpriced.