The 406/407 are part of the series of tapes made famous for sticky shed syndrome, especially since for a long time they were the undisputed sales leader for professional studio analog recordings in the 1970s and 1980s. These tapes offered generally excellent performance when compared with competing brands at the time.  There were a number of generations of this tape, and all of them are now virtually unusable. The 406/407  was a type 4 (+3) tape with slightly lower performance than the 456/457 Series. UPDATE 9/2023: When baked, these tapes are usable for at least a year after baking, which is enough for most recording projects. We now sell baked 406/407s in our store (if available) with the callout.  Notes:

• You can identify this formulation by its brown oxide and back coating.
• The 406 Series represents the SP (Standard Play) version and the 407 is the LP (Long Play) version with the same oxide coating. No DP or TP versions of this formulations were made to our knowledge.
• These tapes were excellent in every measurable way when new, which is why they were so often used for professional studio recording and mastering.
• Unfortunately like many tapes of this period, the back coated versions suffer from Sticky Shed and cannot be played without baking. DO NOT PLAY OR WIND THESE 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.
• Ampex was spun off to form Quantegy in 1995. According to anecdotal evidence the tape binder was reformulated to eliminate the sticky shed syndrome, so Quantegy branded tapes *should* perform properly. Update 2023: SAD NEWS: We have confirmed that the Quantegy versions of 456/457 and 499 ALSO require baking as they are starting to go sticky.
• IMPORTANT NOTE (9/2023):  Too many people trashed these tapes thinking they were total junk. This is not the case. They can still be used after baking.  It’s easy with a cheap food dehydrator, they are $60. Anyone into the hobby should get one to make the sticky tapes playable again. They are usable for at least a year after baking, maybe longer. I have baked hundreds if not thousands of tapes. THERE IS NO REASON TO TRASH THEM WHEN THE FIX IS SO CHEAP.
• Available Refurbished: No we do not sell refurbished reels of 406 or 407 but some *might* be available used (sold without a guarantee) in our store that are available for collectors or research purposes. UPDATE: Baked 406/407s might be available in the store. They can be used for at least a year after baking (research is ongoing). Quantegy branded tapes will also be baked.