1A4 is nice but needs some care, the large amount of wafer contacts need cleaning, and there's a lot of point-to-point wiring that can go bad. I even had a joint that was not soldered from the factory.
Also it contains rare dual JFETs, and the overall design is difficult to repair and easy to damage, there's 4 channels crammed into that plugin.
Maybe a nice 1S1.
But the days of trawling eBay for low price plugins were 10+ years ago. Prices are absurdly high now.
