This does NOT include live versions, or the re-recordings from the 20th Anniversary Album.
Koji Mikuma, Amy Michaels
Prior to the introduction of 8-track and better in 1968, the sessions were generally recorded on 4-track machines, which severely limited the stereo potential of the final mixdown. Generally, the final mixdown required that the vocals would take up at least one track (two if double-tracked), later guitar and/or strings taking up at least one track, and the remaining rhythm tracks (bass, drums, piano, backing guitar, etc.) limited to whatever space was left. The result was a very limiting session tape, and the general result was to split the instruments to one side and the vocals to the other. In rare instances where no overdubs were recorded, there was the possibility of giving one or two instruments a dedicated track, but this seldom happened. It appears that most of the songs recorded by Gerry for release up to and including the How Do You Like It LP were recorded to twintrack--instruments on one track, vocals on the other! With I understand that The Beatles' "I Want To Hold Your Hand" was one of the first songs to be recorded on Abbey Road's 4-track machine. (I beleive the first Beatles 8-track recording at Abbey Road was "While My Guitar Gently Weeps".)
As a result, stereo mixes prior to 1968 or so tend to be very weak, forcing drums and bass to be split off to the side - a process that modern recording engineers absolutely cringe at. Levels usually had to be altered, and generally reduced in the stereo version, to allow for an acceptable master. Indeed, it seems that stereo was regarded by many within the recording industry as little more than a sales gimmick, and a way of getting another dollar or two out of unsuspecting fans. (I suspect it was with this in mind that EMI decided not to release the first four Beatles LPs in stereo when the catalogue was put on CD. Pity...they should have extended this practice up to about Rubber Soul, if you ask me!) It was only with The Beatles Sgt. Pepper and The Who Sell Out that stereo became a form of enhancing the recording. Of course, then came Hendrix, and it became absolutely mind-blowing...
In general, I have found the stereo versions of the old Pacemaker masters lack the clarity and power of their mono equivalent, especially due to their problems with frequency cancellation, and a completely unnatural stereo spectrum.
It would be nice if EMI would give the old 4-tracks a listen and see if they are perhaps candidates for remixing using modern mixing practices, i.e. centre the bass and drums, and play with the stereo separation using the other tracks. The two recent re-releases of the Pacemakers' British albums were remastered, and were either remixed staying faithful to the old methods, or were just taken from the original mixdown tapes. I suspect the latter.