Depending on your scale this can look pretty scary but you may only be down 3 to 6 dB at both ends which would not be out of the realm of normal.
I wasn’t thinking about it being a logarithmic scale, so it’s not as dramatic as I thought.. The change was close to double in amplitude, so approaching 6 dB. But, I thought typical frequency responses were flat within about 1 dB for cartridges.
At what exact frequency? Is your scope calibrated? Are you accounting for the RIAA effect on frequencies below 500Hz?
Unfortunately, I haven’t had time to go and measure the exact frequencies at which this occurred. That would require me to actually do some work :), as they don’t state the frequencies on the record. It is however midrange/upper base, and not low bass frequencies that are elevated. I’m going from memory of the waveforms on the scope that it was probably around 250-500 Hz where it was elevated. It does roll off after the low bass as well.
I am measuring after the phono stage, in the tape outputs, so shouldn’t the RIAA effects already have been compensated for?