I want to report a bit on the subject of the rumor that ex-Neotek staff were involved in the design of at least elements of the AT-RMX64 signal path.
While still not confirmed first-hand from any bonafide source, I've had correspondence with multiple people in the past couple years or so that claim first-hand communication with either people who were involved with Neotek, or were professional technicians by trade and had relatively inside knowledge, who assert the AT-RMX64 signal path has Neotek design pedigree. Again, me sharing that here is essentially third-hand information with no verification, but I wanted to share it here as those conversations offer some support for the long-standing rumor.
The *other* thing I finally did was do some technical comparative analysis looking at schematic diagrams. One claim is the mic amp is Neotek designed. I see nothing in the AT-RMX64 mic amp design to suggest in any way it takes after anything in any Neotek console I looked at, which includes Series I, II and III consoles. In fact, the AT-RMX64 is a very weird asymmetric design where the positive going conductor of the mic input first hits a pair of FETs (2SK163) and then into one side of a 2043 opamp, and the negative going conductor of the mic input just goes straight into one side of another 2043. It's just..weird...and doesn't suggest it would make for a well-performing design. I wondered if there was anything about the 'weird" that made it special in some way so I reached out to a friend of mine that knows a LOT more than me...decades in electronics engineering, has been involved with mixer designs at Tapco and Mackie among many other things, and he basically said nope, its just weird. My conclusion and my friend's as well is the mic amp is *not* anything Neotek. The 2043 is a fine opamp, but the asymmetric design both with the FETs and the fact both sides of the mic input go to different opamps is not beneficial and is very odd, AND it looks like nothing in any Neotek design to which I compared. But the mic amp has never been what intrigues me or what I suspected may have Neotek influence...for me its the input EQ section.
The EQ on the AT-RMX64 input channels is, as I have stated previously, the coolest two-band EQ ever, and it sounds good...and there it is living in a cassette 4-track machine...push-pull pots on each band switching between peaking and shelving on the hi band and shelving or swept HPF on the lo band...literally the most powerful and usable two-band EQ I've ever encountered...I'd rather put my fingers on that EQ over any hi/lo shelving swept mid peaking EQ section any day. It is very similar to the hi and lo bands of the four-band EQ on the Neotek Series III console, which was introduced in the early 1980s, just a couple-three years ahead of the AT-RMX64. And you know what? When I compare the schematics between the AT-RMX64 EQ and the schematic for the hi and lo bands of the Neotek Series III EQ I find a pretty uncanny similarity...granted in the lo band, for instance, there are differences because the Series III push-pull function switches between peaking and swept HPF vs. shelving and swept HPF on the AT-RMX64, and the Series III couples mechanical and FET switching whereas the AT-RMX64 is all mechanical switching, but they are otherwise very similar, enough that I'm comfortable suggesting that, coupled with the long-standing rumor as well correspondence I've had with multiple second-hand-informed individuals, the AT-RMX64 EQ is derived from Neotek-designed EQ. Does that mean it's true? Nope...what do I know. But it sure looks like a derivation to me, and regardless it really does sound good and is *completely* unique among any all-in-one cassette multitrack mixer/recorder ever. I just wanted to share.
