[2] He started out in the Solingen prog rock band Pythagoras in the 1970s[3] but is best known as the former bassist of the heavy metal group Accept, having played bass guitar on their first 15 albums.

[4] After 42 years as a member, Baltes announced his departure from Accept in November 2018;[5] the band later replaced him with former Uli Jon Roth sideman Martin Motnik.

[2] Outside of Accept, Baltes has sung background vocals on the Scorpions' Savage Amusement album and has played bass on John Norum's albums Face the Truth, Worlds Away, and more.

[4] Baltes played bass on all but two tracks on Dokken's debut album, Breaking The Chains, after regular bassist Juan Croucier "missed the deadline to get to Germany" for recording.

[8] Baltes later performed bass and background vocals on Don Dokken's solo effort Up from the Ashes.