You have to purchase the Expansion Packs as In-App Purchases in BIAS Amp app on your iPad/iPhone, and download the amps individually. The amp models are listed as below:
Glassy
’65 American Lux: 65 Fender Deluxe Reverb
’66 Bass: 66 Fender Bassman
Vibro Queen: Fender vibro king
Gret 6156: Gretch 6156
’66 AC Boost: Vox AC 30
’76 Jazz: Roland JC 120
Crunch
British Lead 900: Marshall JCM 900
British OR 30: Orange AD 30
’65 Plexi: Marshall Plexi
Standard 18: VHT The Standard 18
Grid Crunch : by Positive Grid
GA-18: 1959 Gibson GA18 Explorer Tube Amp
Insane
RB Uber: Randall RB-125
Thrasher: Randall Thrasher
GH50: Laney GH50
Invader: Engl Invader 150W Guitar Amp
Herbert: Diezel Herbert
Grid Metal: by Positive Grid
Please note that these amps will need to be downloaded manually from the store page. To do so, go back to the store page and tap on them individually to download them.
