First category of most desirable pre-recorded reels:
'70s-era, 7 1/2IPS Rock near the end of the format's consumer popularity: ESPECIALLY THE TITLES "MAGTEC/STEREOTAPE" DUPLICATED FOR WARNER BROS./REPRISE/ATLANTIC AS WELL AS FOR RCA (ex: Led Zeppelin up through "Houses of the Holy", Fleetwood Mac's "Rumours", Neil Young, Doobie Brothers, Stones up through "It's Only Rock and Roll", Bowie, Elvis, Lou Reed, Nilsson) AND: THE AMPEX 7 1/2 Capitol Beatles albums plus, THE QUADRAPHONIC MIXED MOODY BLUES ALBUMS.
Second category:
1956-1960 RCA/MERCURY/CAPITOL/and COLUMBIA TWO-TRACK Classical and Jazz titles.
AVOID OVERPAYING for:
Either really late era ('77-'84) tapes from Columbia Record Club (catalogged as "CRC"; even if the Rock titles seem unique to the format: THEY ARE ALL HISSY 3 3/4IPS GARBAGE dubbed, most likely by then, from the same masters wrongly eq'ed for cassette and copied at 120IPS)
or....
Pre-1968, 3 3/4IPS, Rock made by Ampex or Capitol on brittle ACETATE-base tape. THAT was how 3 3/4IPS tapes were often as much as $2 CHEAPER ($6.95 vs. $8.95 for a 7 1/2 title during the '60s). Only after 1968 did they change to polyester base across the board. However, for example: the first issue Capitol 3 3/4 Sgt. Pepper on brittle red acetate IS JUST NOT WORTH somebody wanting $200 for it (vs. the 7 1/2IPS 1970 Ampex reissue Ken Kessler swears by AND, better yet: the 1969 Japan Toshiba 7 1/2 copy I swear by).
'70s-era, 7 1/2IPS Rock near the end of the format's consumer popularity: ESPECIALLY THE TITLES "MAGTEC/STEREOTAPE" DUPLICATED FOR WARNER BROS./REPRISE/ATLANTIC AS WELL AS FOR RCA (ex: Led Zeppelin up through "Houses of the Holy", Fleetwood Mac's "Rumours", Neil Young, Doobie Brothers, Stones up through "It's Only Rock and Roll", Bowie, Elvis, Lou Reed, Nilsson) AND: THE AMPEX 7 1/2 Capitol Beatles albums plus, THE QUADRAPHONIC MIXED MOODY BLUES ALBUMS.
Second category:
1956-1960 RCA/MERCURY/CAPITOL/and COLUMBIA TWO-TRACK Classical and Jazz titles.
AVOID OVERPAYING for:
Either really late era ('77-'84) tapes from Columbia Record Club (catalogged as "CRC"; even if the Rock titles seem unique to the format: THEY ARE ALL HISSY 3 3/4IPS GARBAGE dubbed, most likely by then, from the same masters wrongly eq'ed for cassette and copied at 120IPS)
or....
Pre-1968, 3 3/4IPS, Rock made by Ampex or Capitol on brittle ACETATE-base tape. THAT was how 3 3/4IPS tapes were often as much as $2 CHEAPER ($6.95 vs. $8.95 for a 7 1/2 title during the '60s). Only after 1968 did they change to polyester base across the board. However, for example: the first issue Capitol 3 3/4 Sgt. Pepper on brittle red acetate IS JUST NOT WORTH somebody wanting $200 for it (vs. the 7 1/2IPS 1970 Ampex reissue Ken Kessler swears by AND, better yet: the 1969 Japan Toshiba 7 1/2 copy I swear by).