Audio Technica AT-RMX64 Overview & Under-The-Hood Look! 

Yeah thanks…the AT has been a curiosity of mine for a good many a year.

Yeah the mixing section is really uniquely interesting…definitely stands alone amidst any other all-in-one cassette multitrack machine. It really sounds great. I love the simple but pragmatically useful eq section, and I’m consistently learning how useful some of the other distinct are…like the fact the input channel PAN controls only sweep between SUB 1 and SUB 2…SUB 3 and SUB 4 are direct with no sweep between them. At first I thought this was unfortunate, not having the PAN functionality, but what it actually does is enable some greater flexibility for how to use the SUB busses because you can then use SUB 1 and SUB 2 as your stereo mix buss, but then you can also setup additional post fade mixes on 3 & 4 to feed whatever. The mixing section is definitely small format, but, again, has some surprising and useful features you don’t see at first glance. And, again, it just simply sounds good. Thanks for the comment.

Thanks! About the empty space, lots and lots of mixing consoles have unpopulated control surface area. I know what you mean, but bear in mind there is circuitry underneath that vacant space, so it’s not completely void.

I thought about calling the guy…but I just don’t know if that’s worth the effort. But that’s what you have to do if you want answers with this kind of stuff. Forget emailing…the reality is if the guy was actually involved he probably has no interest in talking about something from nearly 40 years ago that he may very well consider inferior at this point, or he’s been bugged about it before and doesn’t have or doesn’t want to make the time. So I’m resting in the fact I was pleasantly shocked at how the signal path sounds. And that’s good enough for me, since we *really* don’t know if there is *any* truth to the Neotek rumor. It is moot in light of how it sounds.

@@SweetbeatsTechStop Most guys I've met in the industry love to talk about this stuff. Maybe you're right and it was such an insignificant thing that he doesn't really remember or care that much. I was talking to someone in the MuffWiggler group who also said that he reached out to someone at NeoTek and didn't get a reply either so I thought I would take a chance. BTW, I know you from Homerecording Analog thread. Haven't been there in a while but my username is Levelanything. Been a memeber since 2015. Thanks for sharing and for all your hard work my friend!

Oh hey yeah of course I recognize that handle from homerecording.com! Yeah I just think it’s a dead-end, unfortunately (regarding the Neotek rumor), but whether or not there’s any truth to it, it doesn’t change that it’s a cool signal path that really sounds nice.

Well I think the AT-RMX64 is their only multitrack recorder. But, yes…it seems its existence is far less widely known than many other similar devices from that era. But it was next-level compared to those competitive offerings, from the transport to the signal path and design/construction…uncommon circuitry for exceptional local noise filtration, robust power supply, signal path using what were, at the time, cutting-edge opamps, and I have been able to validate rumors the signal path design, namely the EQ, had involvement from ex-Neotek staff. And it does sound good.

Where was the ad posted in terms of cities? Out of curiosity.

@@Vade700 Minneapolis

Or near there

Hi there. I monitor comments on all my videos. Congrats on the find. I’m looking for schematics, not the block diagram. I have the original sales brochure and both manuals, but not a service manual. I’m looking for the electronic schematic diagrams with detail as to the circuits.

Yeah it’s really a shame the service manual and schematics are so unobtanium, but they exist. There was an auction on eBay about two and a half years ago I just missed of an OEM service manual and large size schematics. Somebody has them. I’ll probably have to start reverse engineering…but the way the sections are grouped helps. I mean, you have a bias amp card, reproduce and record amp cards, the capstan servo is mounted to the back of the capstan motor…keyboard PCB and control PCB…like, compared to every other cassette-based multitrack “Portastudio” I’ve worked on, which is about a dozen different models, the AT-RMX64 is the most well set up for service. The ribbon cables aren’t that bad. What’s a pain is the thin stock phenolic resin PCBs and the mini Molex card edge connectors. In your situation with the machine you’re working on did you reflow the solder joints on all the plug-in cards AND the motherboards for all the card edge connectors? I think just doing that alone on any AT-RMX64 with signal issues will take care of 90% or more of the problems. Would have been lovely if they used glass fiber, but it is what it is…the design concept is great as far as this format of machine goes, and much of the engineering design is far superior. And the EQ section is the best of any cassette-based multitrack all-in-one period. The signal path sounds great. [EDIT] Also applying DeoxIT D5 to all the card edge connectors and carefully/gently exercising them.

@@SweetbeatsTechStop Great thoughts here and thanks for your reply. The only issue I’m chasing at this point is a channel that won’t play back, I’ve traced it to confirm that it’s somewhere on the repro amp card. I went as far as to make break out cables to probe that card… it seemed that everything checked out… I wonder if those film caps you pointed out are in the path…

So you did or did not ascertain that the issue resides on the repro amp PCB assembly? It seems like that’s what you are saying, but then are also wondering about components on the motherboard. I take you’ve exercised the card edge connections for the PCB and applied DeoxIT or the like? I know if I keep my AT-RMX64 long-term, at some point I’ll be doing some reverse engineering, starting with at least determining the pinout on the card edge connectors on the input PCBs. I’ve got mine substantially opened up right now…it really is, overall, a well-engineered, designed and built machine…nice to work on…evidence of over-engineering compared to the period competition…you see the heat sink on the headphone amp opamp?? I haven’t pulled that off yet to see what’s under there, but they weren’t messing around. And while the input channels use the TL072 and 4560, the playback amp, which is a critical stage, uses the 5220 which, for the day, was pretty new I believe…not very common.

@@SweetbeatsTechStop Thanks for your response. I agree, you'll be hard pressed to find a better C.M.T. in terms of component quality and so on, I was so impressed when I opened it up! The previous owner of the unit included a tape he had recorded on when the unit was working…it sounded incredible. The first thing I did was what you mentioned, treating the headers for those cards… solder reflow, Deoxit into all connections, and then continuity testing the traces into and down the bus board… sadly that didn't make my channel 2 recording re-appear. So… at this point, I know I'm getting to and through the cue, record amp, and head(s) for my channel that won't play back (#2). I can hear playback when I audio probe the re-pro card (which I painstakingly created extender cables for).. Play back is where the signal drops off… somewhere. I swapped in known working op-amps on the repro card, tested transistors, checked for bad solder joints… nothing. I'm pretty stubborn when it comes to giving up, but I had to due to the lack of any road map (schematics)… does the signal go elsewhere after the repro-card and before it makes it back through the mixer? Thats where the troubleshooting gets a little hairy for me. I'm wondering about those stand-off looking film caps… man we need that service manual!! It would seem that so much can go wrong with the best cassette multi track unit ever made… I've seen that service manual you mentioned and I've gone to some pretty desperate attempts to try and get it.. contacting people who've sold the RMX64 on Reverb, reached out to Audio Technica. Ugh.

@@SweetbeatsTechStop got one of these and it certainly needs service. no one i know will touch it lol. it seems tracks 1, 3 and 4 record but the rest won't. buddy opened it up and cleaned up and res-soldered some of the connectors. know of anyone in the southern california area willing and skilled to service this?

It’s a relatively rare machine, yes, and completely unique in the quality and design of the audio path compared to any other “Portastudio” type multitrack cassette machine. It’s a genuinely nice sounding device.

Hey so what’s the deal with the ribbon cables?

@@SweetbeatsTechStop before I owned it someone had done some repairs in there and must have had to redo all the solder connections for the cables. They're barely long enough to get the cover plate with transport controls put of the way. And the through holes and traces will lift off the board if you look at them funny. Hopefully yours isn't like that.

Oh…man…I see…that’s pretty terrible. No mine is all factory, plenty of slack in any of the hard-wired cables. If it was me I’d probably get some replacement cabling and re-do the wiring. And the traces lifting…that’s part of what I talk about that’s unfortunate in the video, that the boards aren’t glass fiber, but phenolic resin instead…not as strong for insertion/extraction, or as far as the motherboard having boards inserted/extracted, but also you have to have better soldering skills and it’s more critical to the right equipment…you have to be able to get in and get out quick when soldering to avoid traces hearing and de-laminating like that. What a pain for you. Sorry somebody did that. All fixable though, and the phenolic resin boards *work*, one just has to take greater care when handling them or working on them.

Hey thanks for the feedback. I appreciate it! Glad the content is considered helpful and/or interesting. That’s the whole point after all. :) 1. It may not surprise you I’ve done a lot of thinking about that. Anything is possible, it just depends on how much effort one is willing to put into it, and sometimes one’s capacity for creativity and compromise. The problems with transplanting the AT-RMX64 EQ circuit into the 244: first challenge is, of course, the AT-RMX64 EQ circuit has to be reverse-engineered since technical documentation is essentially unavailable. Once you draw up a schematic for the circuit you can then work through how, electronically, the circuit transplants into the 244 signal path. Once that’s all worked out, along with any revisions to the EQ block input and output design (which likely there wouldn’t be any), you can then move on to the next steps. Which is the harder part of the process…how to physically and topologically transplant the circuit from one to the other. There are some particular challenges with this case: though the two models’ input PCBs have similar density, the AT-RMX64 boards have about 30-40% greater area, and it’s EQ circuit is significantly more complex. So you’re not going to install the circuit on the 244 boards…it won’t fit. So you have to design a PCB or do point-to-point wiring on proto board or something, basically build up a daughter board. And then the pots…it’s one thing to find push-pull pots in common varieties for guitars, but the pots in the AT-RMX64 EQ section have very different and harder to find value and taper combinations, and because of the switching function the are tall…at least the lo band is particularly tall. Like, I’d have to measure if there is even enough clearance for that pot assembly between the underside of the input PCB sub-chassis and the back of the dbx PCB that goes under the input PCBs in the 244. Maybe a different pot with the same values and functionality can be found that’s shorter, but I’m extremely doubtful. I can’t even find replacements for the ones that are installed from the factory in the AT-RMX64. So then it means ripping them off the AT-RMX64 boards to Frankenstein into the 244, and you’d have to have an AT-RMX64 you’re willing to sacrifice. Oh and all the 244 pot shafts are spline-type and the AT-RMX64’s are ‘D’ type. So if you want the knobs on the 244 to match the other ones you have to find some Tascam ‘D’ type from that era, and they exist, but the bodies are all light brown instead of dark brown. You could get away with that. But the AT-RMX64 pots are all clocked 90 degrees counter-clockwise relative to the Tascam knobs, so the pot terminals will all have to point toward the back of the machine so there will be a whole bunch of straight point-to-point wiring to do there since your daughter boards won’t be oriented left-to-right, they’ll have to be front-to-back. As you might realize by now I’ve done a bit of thinking about this. Again, sure it’s possible. I arrived at “mmmmm that’s not worth it.” 2. Regarding the 424 series generally but specifically the mkII, what I like about the 424mkII over the 244 is some slightly greater flexibility with track assignment, a little more flexible monitoring including the tape cue with the two aux busses, and the balanced mic inputs…just saves the need for the adapter. And it’s lighter. You also have the simple onboard auto-locator and auto-punch/rehearse functions. That last one I never really used but for a LOT of people it’s important. But what I *don’t* like about *any* of those next generation Portastudios (and I kind of consider the 1st generation as the 144, 244 & 246) is the shift toward more plastic in the chassis, monolithic PCBs and cheaper components. All the pots and faders are horizontally board mounted to that monolithic PCB. It’s just a lot more fragile, and the pots are smaller so the same amount of dirt is going to cause exponentially more problems…the source select switches are these small slide switches that do oxidize with age and they’re much harder or not even worth servicing…they’re just not built to be serviced or to last like the earlier generation units. They won’t take the age, abuse or servicing like the older stuff. I had a 424mkII and 244 sitting side-by-side for awhile and I wanted to tear them both open and do a comparison video of the design and construction and I just didn’t have the motivation at the time. But it’s night and day. Whenever I’m taking a 424, 488, 644 or 688 apart to service it (and this would also include the 464, but I’ve never had one) there’s always this careful fear to handle things gently. They’re just not robust inside. So, things I like about the 244 comparatively is obviously the more robust design and components, I’m really a fan of the nice big analog VU meters, the inputs, though they’re not balanced, are a far less garden-variety discrete design with some good potential for an upgrade though I think they’re fine stock, and overall the sound. I think because of the circuit design and better components the 244 has a better sounding mixing section. And on either the 244 or 424 series you have to go through that mixing section to get to tape. So I like that the 244 sounds less limiting to me, and the signal path is relatively simple with lots of opportunity to eke a little improvement out of it using modern and more expensive components than what the factory used. Not that what Teac used was bad. They were clearly selective and strategic about what they used to avoid compromising sound, but still honoring the market target. Anyway, I’ve mentioned this elsewhere, I have a comprehensive and complete upgrade kit I put together for the entire signal path and power supply for the 244. Someday I hope to have time to try it out…to be able to do some scaled side-by-side comparison of individual section upgrades and full system upgrades. I think the 244, already a good sounding Portastudio, can have significantly lower noise, distortion, better clarity across the frequency spectrum and also as a result have a wider soundstage. So the 244 is my favorite. I like it better than the 246 because of the size. I mean, the 244 is relatively heavy. But the footprint is relatively compact. If I need something with more complexity it’s going to be an open reel machine and outboard mixing console and other gear, not a more complicated heavier bigger 4-track. That may be different for others depending on their needs/desires. The AT-RMX64 is an exception here because it’s not necessarily more complex…the EQ is but it’s the most practical and usable 2-band EQ I’ve ever found on a mixing console, integrated or otherwise…but it’s a nice simple control surface, there just happen to be 6 full-featured input channels, which is powerful…but it’s a very practical control surface, and the most robust, and best sounding…the easiest to service too. So it doesn’t matter as much that it’s the heaviest and has the biggest footprint. That’s the price of admission for the unique design and feature set.

@@SweetbeatsTechStop Wow, I don’t think I could have asked for a better/more comprehensive response. Thank you! So I have the 246, 244, 144, 424mkI, 414mkII, PortaTwo, Yamaha MT3X, Sansui MR6/MX12 and am borrowing a friend’s 424mkIII (not terribly impressed w it beyond the transport controls). Yes, I have a bit of a problem, perhaps…. But there’s a purpose beyond collecting! I am seeking out that unit that is both robust and sonically capable of approaching the sound of R2R. Currently the 246 is my main unit, but its mixer’s sound is a bit lackluster compared with the 244 (which I’m told shares the same channel design). As someone who primarily plays acoustic guitar, both units’ Achilles’ heel is the limited frequency response in the higher frequencies. I am guessing that no upgrades one could assign the 244 could compensate for this, as that is head replacement, correct? That said, I am completely serious when I say I’d like to be considered as a client/candidate for this upgrade kit you’re talking about, regardless of frequency response. I, like you, am fond of the large VU’s and build quality of the first gen portas’. It is simply disappointing that the improvements to higher/wider frequency response came simultaneously with inferior components in plastic chassis. Anyway, if that’s something you are seriously considering, let me know where I can get in touch with you to discuss further 🙏🏻

That’s a substantial collection. When you say you are seeking a “unit” that is both robust and capable of approaching the sound of open-reel, are you talking about a “Portastudio” type unit? Integrated mixer and recorder/reproducer? And specifically 4-track? If so I think the limits of the format, at least what was available technologically before the format died out, in the range of +/-3dB, is about 40Hz~15kHz or 16kHz tops. But those numbers on spec sheets are all so dubious because there are no specific standards around how the data is derived, and manufacturers disclose those details to varying degrees, right up to putting the response range as 20Hz~18kHz but then not telling you that range is far outside +/-3dB. What would be nice is to see the graphs. And sometimes manufacturers are conservative. Case in point with the AT-RMX64. The documented frequency response for record/reproduce tops out at 15kHz, but the May/June 1986 edition of dB magazine did a comprehensive review with lab testing that revealed the -3dB point at about 21kHz with noise reduction off, and 16.5~17kHz with Dolby B and C switched in: worldradiohistory.com/Archive-All-Audio/Archive-DB-Magazine/80s/DB-1986-05-06.pdf But we don’t get that nicety of lab testing and graphs from the manufacturer. And there are other factors like what reference level was employed for the test, because there’s diminished response at higher amplitudes as you approach saturation and distortion. I’m pretty sure the 234, 244 and 246 use the same R/P head. One of those manuals indicates response testing at 160nWb/m. I believe that’s chrome cassette standard operating level. So, and I’m not positive about this, but that may mean the test conditions were more challenging for those early generation machines; sustained tones at the standard operating level. Or the head technology improved and that’s why later machines spec a marginal improvement in HF response. Do you know if that’s the case? If it is, then yes that would be the only way you could improve the on-paper performance of the 244…swap in a later generation head, but you’d have to find somebody with the tools and experience to do that…it’s no trifle process to mechanically align a multitrack cassette head. And even then there might be modifications needed to the record and playback circuitry to actually take advantage of the replacement head’s improved performance potential. I wouldn’t do it. Have you done any response testing in your various machines and if so what were the results? I’m just curious if your experience related to the limited high frequency response is based on a machine that’s performing to spec or if it’s time for service. It’s always valuable to measure. I think more than anything at this point there might be gains in recapping the older machines. New and more modern caps have better HF performance and that might help the overall performance of the recording, but it’s also important to recognize there are simple limits to the format. Yes the 244 and 246 have almost the same input channel signal path. Interestingly there’s a coupling cap that’s present just before the EQ block on the 244 that’s not present on the 246. That would be an improvement on the 246, not that you could actually hear a difference. I’ll have to measure the DC offset at the output of the relevant opamp on the 244. If it’s nil then maybe that’s a simple mod for the 244, is to just bypass that cap with a jumper. Obviously I’m still working through issues with my AT-RMX64, but I think it will probably end up garnering my opinion as the most robust best-sounding integrated mixer/4-track cassette multitracker. It’s already the most robust. That I know. Even though there are care and handling considerations with the phenolic resin PCBs, the serviceability and integrity of the design is second to none, and the transport itself is my favorite of any I’ve worked on, which a fair number of them. And I already know I like the sound of the signal path and the EQ. I just have yet to do much with actual record/reproduce because of the issue I’m having with tracks 1 & 2 not recording. But I’ll tackle that. And what I’ve heard like from Eugene Pugachov and his RU-vid living room jazz recording sessions he tracked on an AT-RMX64, I’m impressed.

@@SweetbeatsTechStop You’ve touched on a number of key points in your response, so I wanted to wait until I had a moment to focus to respond. To start, no I haven’t actually plugged my units into my DAW, for instance, to see EQ rolloff points with any of my units. About half of them have been properly serviced and calibrated, the other half not yet. So at the moment I can only use my ears. And you are absolutely right about dubious claims of frequency response; a number of times I’ve had a raised eyebrow when considering the printed response numbers in the manual vs. what my ears tell me. For instance, the 246 (which I love, seems to be a smaller RMX64 in certain ways) has a disappointing frequency response beyond 13-14khz in my opinion from what I can hear. And that’s with DBX both on and off. Yet it claims to have a maximum record response of 20hz-18khz (no way). The Yamaha MT3X claims to have that desirable response of 40hz-18khz, but somehow seems to lack the more substantial overall soundstage and low end of the 246. As an acoustic guitar player, higher frequencies really make or break the experience of listening to playback. Yet it’s hard to argue there’s some dimensionality in the sound of the 246 that is not reflected in the spec sheet. My understanding of the history of tape heads at that point was that they had indeed made a number of advances in shaping the head, which is why most of the 90’s four-track models could hit 16khz. However, as you spoke about here in the video, the frustrating dark side of that advancement is the loss of build quality, especially by the 424mkIII days. You’ve certainly convinced me to seriously consider the RMX64. I still do feel it takes up so much space for what’s ultimately just four track recording. That being said if I have the chance and space for one, I could see myself owning one. It’s ironic I came by one via happenstance nearly 24 years ago. I actually find the 244 to be sonically superior to the 246. There’s certainly no doubt the 246’s features out place nearly every other four tracker Tascam made. But the sonic limitations are frustrating. The 464 is one I do not own I’d consider trying. I know that increased impedance because of the increased functionality components in any unit will affect the overall output/ sound. But I still wish the 246 could be at that same level as the 244. I’d still be interested to speak with you further when the time is right to consider an upgrade kit for the 244 (or 246), so when that day comes it would be great to get in touch with you. Cheers and congrats on getting the unit mostly working! I saw the recent video - well done 👍🏻

“…no I haven’t actually plugged my units into my DAW, for instance, to see EQ rolloff points with any of my units. About half of them have been properly serviced and calibrated, the other half not yet. So at the moment I can only use my ears. And you are absolutely right about dubious claims of frequency response; a number of times I’ve had a raised eyebrow when considering the printed response numbers in the manual vs. what my ears tell me.” Yeah I’m not discounting using your ears at all. I think generally there’s been a shift over the decades in audio production toward using visuals and tools instead of our ears to mix. I remember early in my experience wanting meters on both the tape deck and console for monitoring of multiple points…I was looking at a multitrack open reel machine that lacked onboard metering…a long-time engineer asked me “Why? Can’t you hear when it starts to break up?” I still like the ability to monitor levels at multiple points, but I always remember what he said and try to keep those tools philosophically as verification for what my ears hear, rather than telling me what my ears should hear. But outside of that, quantification of a device’s performance requires measurement…that’s different than mixing. And we’re talking about comparative HF response across multiple devices and it would be valuable to measure what’s happening. Otherwise any decisions made about what’s “good” or “bad” or what you want to do to rectify perceived deficits is all done blind. “…the 246 (which I love, seems to be a smaller RMX64 in certain ways) has a disappointing frequency response beyond 13-14khz in my opinion from what I can hear. And that’s with DBX both on and off. Yet it claims to have a maximum record response of 20hz-18khz (no way).” The meaningful documented frequency response of the 246’s tape section in high speed mode is 40Hz~14kHz, +/-3dB. That’s the meaningful response spec because it gives you the -3dB parameters. Frequency response specs with no roll-off parameters, like at what point the signal starts to dive are meaningless IMO…still interesting, but not useful. 20Hz at what? -18dB? 18kHz at what? -23dB? So ignore the 20Hz~18kHz response spec. The marketing department required them to print that on the spec page. The engineers were throwing up in their mouths. This is why I say specs need to be considered with a degree of discernment. So your experience of a “disappointing frequency response beyond 13-14kHz” is what the spec sheet tells you you should expect. A recap and some bias tuning might help that, but that’s about what you’re going to get, according to the spec sheet. But that’s another reason why it can be valuable to actually measure, because sometimes, and this is the exception, manufacturers publish specs that are conservative. It’s really dependent on the company and it’s culture. I think Teac’s specs at least on this analog era stuff is pretty reasonable. But the AT-RMX64? As I mentioned in an earlier reply, spec sheet says +/-3dB 40Hz~15kHz. Seems reasonable. But, again, that dB magazine review of the AT-RMX64, the May/June 1986 edition I linked in a previous reply, included comparative lab testing. Sorry to repost this info, but it’s relevant here…They measured the -3dB HF frequency response at better than 16.5kHz with Dolby B or C engaged. So…doing your own measurements have value for at least a couple reasons. As to your comment about the 246 being a smaller AT-RMX64 in certain ways, I kind of agree with that, just in terms of a high level comparison of the feature set…but I actually think of the 246 as a baby 388…compare the controls and control layout…and I also think of it that way because, unfortunately, the 246 and 388 share some of the same design philosophy with how power is distributed through the unit and the interrelation of the different PCB assemblies…it makes it more complicated to work on than other models. The 246 does have better monitoring faculties than the AT-RMX64, but the AT-RMX64 has a far better mixer both in features and sonics…I/O…EQ…and of course is a much more robust design and easier to service. Also no belts on the AT-RMX64, and it has better specs on paper than the 246…better headroom throughout the signal path with the +/-15V audio power rails…phantom power…balanced mic and line inputs…but yes the 246 is lighter with a marginally smaller footprint, and has some greater monitoring flexibility with the 4 x 2 onboard monitor mixer. But I think overall the AT-RMX64 tromps every other integrated analog cassette 4-track multitrack/mixer device ever made in just about every way, depending on your individual needs and vantage point. But that’s my vantage point. The 644 has more bells and whistles for sure, and the MIDI sync capabilities. But that’s not of interest to me, and sonically the AT-RMX64 is better I think. The big Achilles heel of the AT-RMX64 at this point remains, of course, the lack of technical documentation and knowledgeable user community support…but I’m making gains on some of that…and we know the transport is Sankyo and similar to the one in a Nakamichi BX-150…we know you can get an excellent drop in upgrade replacement pinch roller from Athan, and a new reel table drive tire is readily available just by searching “BX-150 tire.” This takes care of just about any transport issue. And most of the signal continuity issues are solved by exercising all the plug-in module/card connections and flushing/treating with a quality contact cleaner like DeoxIT D5. You noted at the end of your last message a congratulations to me for getting my AT-RMX64 “mostly working”…maybe I wasn’t clear in my last video or you weren’t referencing my very latest video…my AT-RMX64 is 100% functional now…wasn’t too painful. I still want to figure out all of the calibration trimmers so I can fully service it, but that’s not preventing it from fully operating. My spare AT-RMX64 needs a transport overhaul, card edge connector exercising/treatment, and doesn’t record or erase on any tracks, but honestly I think I’ve learned enough about them at this point I’m confident I’ll be able to fix it. So at least for me the biggest Achilles heel of the AT-RMX64 is not so big anymore. And I’m building up the user community support with my experiences and sharing that through RU-vid and other online collaboratives.

I’ve seen on occasion an AT-RMX64 with wood-grained side panels, but that’s not from the factory. I’ve seen somebody that made replacement side panels out of solid hardwood, as well as added a faux wood laminate over the top of the factory grey vinyl laminate. I’m not sure how I can have an opinion about the likelihood of you finding your old AT-RMX64.

Hi. I’m not sure I understand. The TAPE OUT jacks source the tape tracks. Are you saying you recorded to the tape tracks using external microphone preamps through the input channels and SUB channels, but when monitoring playback via the TAPE OUT jacks, EQ adjustments you made on the input channels at the time you recorded don’t seem to be printed to tape? There is no way to monitor inputs directly at the TAPE OUT jacks. Again, the TAPE OUT jacks source the tape tracks. If you want to apply EQ to the tape tracks you need to set the source of each applicable input channel to TAPE, adjust the EQ to taste, and sum using the SUB channels.

@@SweetbeatsTechStop hey, thanks for the reply. I was looking at the manual and it said the Direct Ins on the channels bypass the EQ, so If I’m using this like a tape machine in real time going out the Tape Outs into my DAW, would that mean EQ moves would not be present on the tape?

Right. The insert points (DIRECT OUT and DIRECT IN) are pre-EQ. If you want to use the EQ in between the tape and the DAW, instead of using the TAPE OUT jacks, set channels 1~4 source to TAPE, assign each channel to a distinct SUB buss and connect your DAW inputs to the SUB OUT jacks.

The DIRECT IN jacks are pre-EQ, so if the outputs of your external ores are connected to the DIRECT IN jacks in order to bypass the onboard preamps, then EQ should be applied to tape.

@@SweetbeatsTechStop EQ in real time off the tape outs, or the EQ will be present in the SUB outs only? I guess what I’m getting at, is if I want to track through the mixer into my Daw in real time (and still hit the tape) can I get 4 channels live post eq + tape while using external pres? I’m kind of confused if EQ is applied to the tape when recording…

Hi. So I’m probably not any more interested in sharing my personal email address with the world than you are. I frequent the forums at homerecording.com. You can, if not already registered there, register and send me a private message; handle is “sweetbeats”…-OR-…just post your question here. It may help others. I have yet to come across a tech support question that is personal and requires 1:1 correspondence.