Absolute Radio 80s is returning to a stereo signal on Digital 1 after the station received complaints about dropping to a lower bit-rate.
The reduction in quality was to allow Absolute to trial their 90s station, Absolute Radio 90s, on the same platform.
In a blog post, the station says: "We would like to apologise for the time it has taken us to get back to you on this – this has been down to behind-the-scenes negotiations which we were unable to talk about until they were resolved.
"We are mindful of the opinions of our listeners and are pleased to say Absolute 80s will resume to stereo sound quality this week, and for the foreseeable future. We will update you as soon as we know exactly when this will happen."
The station also broadcasts, in full stereo, via a number of other platforms including Sky and mobile. An update on Absolute Radio 90s plans will be announced soon.