- Brand: Ampex / Irish / Quantegy
- Type: 291, 292
- Reel: 5" (13cm), 7" (18cm)
- Lengths Available: 600' (180m), 900' (275m), 1200' (360m), 1800' (550m)
- Thickness: SP (1.5 mil), LP (1.0 mil)
- Tape Grade / Performance Level: 1-Standard
- Base Material: Acetate
- 2023 Advice:
- Where Produced: USA
- Mfg Years: Early 1970s, Late 1970s
- Sale Condition: Won't sell as used
The Ampex 291 / 292 AV tapes were a mystery until we realized all of the types we found were similar to the reject Shamrock / Concertape 031 / 041 tapes. The hold-down tabs so reflect the 291/292 formula code, but the wide range of formulations found point to a wide range of familiar Ampex formulations being used. We have identified many versions of this tape, and they are all unusable due to SSS. Hopefully this guide can help you determine which tapes you have, and whether you can play them (or need to bake them). One feature is that they were available in color coded reels. We know the Shamrock/Emerald/Concertapes were reject batches and were often spliced, we DO NOT know if the same holds true for the 291/292 – but we do know all of the formulas. We do know that no performance claim was ever made on the boxes (not sold as low noise or high output).
291 was the SP (standard play) version of the tape, while 292 was the long play version.
Here are the formulations we believe were sold as 291/292:
- Grey oxide tapes without back coating WITH sticky shed, we did not play or test these tapes but discovered them during our processing. Could be the same as #4 – the instrumentation tape without back coating.
- Grey oxide tapes with back coating, without sticky shed – these tapes have a slight brown tint. The quality is OK on these. As of this writing, we are still evaluating whether these can be sold as refurbished.
- Back coated master tapes with brown oxide, all have SSS.
- Back coated instrumentation tape. This has a shiny grey oxide, and the tape is thinner – you can identify this tape in that it looks like the reel is not filled with tape. This tape suffers from sticky shed. Also, it has a very low output and a strange bias characteristic that made it good for 3-3/4 ips and a noise reduction system at the time. This formulation was also commonly found in mid-1980s Concertape. Unfortunately none of this tape is usable today without baking.
- DO NOT PLAY OR WIND STICKY SHED TAPES BEFORE BAKING. Unless baked first, winding them can cause the oxide to be stripped from the polyester base material, essentially destroying them. In fact, many batches cannot even be WOUND without baking as the oxide can be stripped off and the tape permanently destroyed. We have encountered some tapes that are less sticky than others, but there is no way to tell as the sticky shed condition seems to be dependent on the humidity of the environment they were stored in…and it has been over 40 years. If there is any valuable program material, these tapes need to be baked first.
- Available Refurbished: These tapes are not sold as refurbished due to the SSS problems.