I read a post where someone replaced the 2SC871s with KSC1845s in the phono board and was unhappy with the sound quality. They put them back and the sound quality returned. This seemed a bit inexplicable to me, as the KSC1845s work fine in the tone control board. The measured response of the phono board leaves something to be desired so I put the circuit in LTSpice to see if it could be improved. Not done yet, but here are some things I've learned- 1) Important- they switch the eq in and out of the phono board and ALL signals pass through this stage, phono or not. A problem in the phono board can affect everything. 2) There is a peak of several dB right in the record warp area, and a general rise towards the bass. The whole response has a decided tilt. Call it rolled off highs or enhanced bass. In flat mode, non-RIAA, the response is better. 3) The bass response of the circuit is transistor dependent, particularly the peak. It's probably just the hfe of the transistor, which explains the sound quality difference. 4) The input capacitors (1.5 uF special Elna CS series) often get leaky. The phono response is a bit dependent on the value of these caps. 5) The 47 uF emitter bypass cap on on the second transistor appears to be wrong by a factor of ten or so, depending on what transistors are used. In any rebuild, the two input caps have to be replaced. Right now I'd suggest 2.2 uF low leakage types, but no higher than that. The low frequency peak can be controlled by increasing the 47 uF caps to 220 uF or even 470 uF. One could probably make the RIAA response flatter by messing with the eq components, but IMO the signature of the 2000x is a result of the values chosen and you might not be happy with a more clinical sound. More to follow as I implement and test this stuff.