There are very limited selections of 2-track 7.5 IPS pre-recorded tapes out there. Most pre-recorded tapes found on the bay are 4-track, and IMO not worth the trouble if you're looking for the ultimate sound.
A few years ago, I modified a 7.5 IPS Revox B77 to highspeed 15 IPS using an article written by Arian Jansen of Sonorus Audio, The instructions were really clear and it involves replacing some caps and resistors on the PCB. This mod allows you to play all the new pre-recorded 15 IPS tapes currently available from:
https://store.acousticsounds.com/c/397/Reel_to_Reel
https://tapeproject.com/catalog/
https://elusivedisc.com/music/reel-to-reel-tape/
Another option is to sell the B77 (reel to reel go for a premium these days on the bay) and get yourself an Otari MX-5050 B2, it plays 2-track and 4-track tapes, has 15 IPS high speed, and is an overall a better deck.
A few years ago, I modified a 7.5 IPS Revox B77 to highspeed 15 IPS using an article written by Arian Jansen of Sonorus Audio, The instructions were really clear and it involves replacing some caps and resistors on the PCB. This mod allows you to play all the new pre-recorded 15 IPS tapes currently available from:
https://store.acousticsounds.com/c/397/Reel_to_Reel
https://tapeproject.com/catalog/
https://elusivedisc.com/music/reel-to-reel-tape/
Another option is to sell the B77 (reel to reel go for a premium these days on the bay) and get yourself an Otari MX-5050 B2, it plays 2-track and 4-track tapes, has 15 IPS high speed, and is an overall a better deck.