Citaat:
The 4558 dual amp is linked with the history of the guitar pedals development. Many designers included this part in some of the most successful effects like the Orange Squeezer, DOD YJM 30, Boss OD1, Tube Screamer or Peavey equipment.
This IC was undoubtedly chosen in the beginning by Japanese design engineers because it was one of the cheapest dual opamps on the market with acceptable audio performance. As such, it was used in huge volumes of Japanese audio equipment. Despite its questionable audio performance, it seems to be well suited to duty in overdrive circuits.
Dat is dus de reden dat die chip overal in zit, niet de klankmatige eigenschappen want dat is grotendeels lood om oud ijzer. Het ontwerp / de componenten er omheen zal meer klankbepalend zijn dan het op-ampje.