[Sideband]

I can confirm as suggested above it is a Philips N2506 (it has DNL...Dynamic Noise Limiter) fitted. They were reasonably well regarded in their day but could hardly be regarded as true hi fi since their top response was around 12khz. They did sound good however and the DNL made a huge reduction of tape noise. Note that DNL only operates on playback.

Repaired a good many of those when I was at Philips....not because they were unreliable, far from it, but because there were so many of them about.