Searching for information on the differences between the SL-1210 MK7 and SL-1210 MK2, I found this forum post and linked article (in greek).

Here's a summary of the post with the key differences and similarities between the two models.

Rotation Quality

• Mk7: Excellent rotation quality (0.036% IEC, 0.036% NAB).
• Mk2: Close but varied (0.297% IEC, 0.032% NAB) due to arm suspension tolerances.

Rotation Accuracy

• Mk7: High accuracy with modern direct driving but less precision than a micrometer setting.
• Mk2: Similar high level with a slight difference (0.137%).

Wow & Flutter

• Both Models: Similar W&F variations over time, staying within [-2, +2] seconds.
• Average W&F: Mk7 at 0.072%, Mk2 at 0.079%.
• Peak-to-Peak W&F: Both at 5%.

Frequency Analysis

• Low Frequencies: Both show very low coordination levels at -60dB.
• Higher Frequencies: Mk7 around/below -100dB, Mk2 slightly different but similarly low.

Rumble

• Mk7: Very low rumble with minor tuning spikes.
• Mk2: Similar low rumble with minor frequency differences.

Signal Reproduction

• Harmonics: Both models show the second harmonic at -40dB, with Mk2 having lower noise levels up to 2kHz.
• Higher Harmonics: Mk2 changes slightly above +6dB.

Frequency Response

• Low Frequencies: Focuses on 20-30Hz range.
• Higher Frequencies: Minimal differences above 100Hz.
• Acoustic Feedback: Mk7 has improved isolation, particularly in the 50-80Hz range, due to changes in materials and support points.

Percussion Response

• Both Models: Good compatibility with Denon's head, with Mk2 showing slight instability due to tolerances.

Conclusion

• Both models are similar with small measurable differences.
• The Mk7 maintains high quality and performance, despite cost reductions, while nearly matching the older Mk2 model's performance.