idairyou
500+ Head-Fier
There are a lot of them out there some more well known than others.Ah! that's very good to know, and yes I think I will invest on a supercharger at some point. Just to make sure that the amp quality is always stable.
https://orangeamps.com/product/op-amp/ Is this the one you're talking about? I'm actually interested in Opamps rolling. So any guide would be very helpful.
Burson (of course)
Orange
Stakkato or is it Staccato (I'm not sure witch)
SparkOS Labs
Hairball Audio
Iron Age Audioworks
There are also DYI kits you can buy.
Do a google search on discrete op-amps, and you will have a lot of choices. So many out there to buy on EBay or AlliExpress.