The Mytek manual claims 128 dB of dynamic range, which is better than the 120 dB of many mid-price modern recorders but still only a tad more than 21 bits as I count.
Ah, so THIS explains the confusion over "full use of 24/32-bit dynamic range" conundrums some here seem to be facing.
The 6 dB-per-bit "rule" is NOT actually a rule. Rather it's a
general trend that holds true for bit depths well below 24 bits (really ~6 to ~18 bits is where this rule holds true), based on a theoretical limit. Really, it's a carryover simplification from back in the day, when going past 16 bits seemed like an impossibility at the time.
The absolute BEST 24-bit converters are capable of producing ~132 dB of dynamic range, and the top-of-the-line-super-expensive 32-bit float converters can stretch that to ~140 dB. Obviously this is mostly in highly-controlled rack mount gear, and it all costs an arm and a leg plus sometimes your firstborn.
Edit: I also want to mention, it
is worthwhile to discuss to what level of detail we can distinguish between 16 or 24 (and beyond) bits of dynamic range. At the end of the day, I could understand an argument that we wouldn't take full advantage of 24 bits, and that 16 bits is for the most part "good enough" to pull a solid tape especially when taping live rock music. However, my counterargument to that argument lies with people who do post work; having a larger bit depth will assist in lower errors particularly when using equalizers. As a studio guy, I fully support higher bit depths, with this reason being a strong one.