Constanten on Constanten

"I met Phil Lesh at UC Berkeley in the early '60s when he was 21 and I was 17. We shared musical interests and an apartment in Berkeley. Phil had been at the College of San Mateo playing trumpet in the jazz band, had written some jazz charts for them, and had also discovered some of the Stockhausen pieces I was into. We took a class together with Luciano Berio at Mills College in Oakland. Phil had also been hanging out with Jerry Garcia, who was staying in Palo Alto... Jerry played regularly at a place called the Tangent on University Avenue in Palo Alto."
"Jerry was one of a fistful of interesting people that Phil Lesh introduced me to when Phil and I shared an apartment a block off the UC Berkeley campus in the fall of 1961. Jerry was 19, and I was 17. We freely shared our musical enthusiasms, verbally and by playing for each other. Somehow my music impressed him enough for him to offer me a job a [few] years down the road... At the time we met, Jerry was an accomplished folksinger, drawing his material from the Carter Family, old Appalachian ballads and the British isles."

"In 1962 I went to study in Europe. Berio set up scholarships so I could study with him, Boulez, Stockhausen, and Pousseur in Europe, which lasted more than a year. When I got back to the States in 1964 I moved to the Bay Area."
"Phil and I had our first LSD from the same batch in early '64, when it still came on sugar cubes."
"I played with Phil, most notably at a 1964 concert, under the auspices of the San Francisco Mime Troupe, that featured Phil, Steve Reich, and me. Phil contributed a quasi-concerto for prepared piano called 6 7/8 for Bernardo Moreno, with me on piano. We gave four performances, each unique (although the third night was especially magical, in my memory)."

"Before I could approach rock [music], it had to evolve a little. I could appreciate the simplicity as a musician (easy chord changes = easy money), but as a listener it somehow didn’t do it for me... There were far too many interesting sounds around for me to want to diddle with I-IV-V.I’ve since come to appreciate the earlier blues and rock artists more than I did at the time. I remember at the Woodstock Festival, when Nicky Hopkins came to Pigpen’s and my hotel room (yes, we doubled up back then), they instantly had a lot to talk about - they’d bring up players going back decades, trading stories and impressions with a glowing zest for the music.It was the first time I’d heard some of the names... [And] I’d come to know Phil Lesh and Jerry Garcia in late 1961. Their tastes in music were as exacting as mine, and as they (and others) started to make things more interesting, it got my attention."
"What made '60s rock interesting to me is that the mind-stretching propensities of the experimental composers were brought to bear on the basic structure of rock & roll, so that it was sort of electrified conceptually..."

"I was unable to avoid the draft, so I got stuck in the Air Force for a couple of years."
"I had already received a draft notice, and it seemed like a natural thing that I'd rather program a computer in Las Vegas than an M-16 in Vietnam."
"They started to ship a lot of Air Force people to Vietnam, so I let it slip that I used to be a communist, which effectively killed any chance of my getting a security clearance..." (Unbeknownst to the military, he was also taking acid trips on his furloughs, and using the base's IBM computer to compose music!)
"When I was in the Air Force, I pretty much kept my head down and went along with the program. That, coupled with being reasonably competent at my job - I was a computer programmer - had its benefits. Among those were three day passes - extra time off from your job. By 1967 I had a fistful of these to cash in. It was during some of those breaks that I motored down from Las Vegas - Nellis AFB's locale - to Los Angeles to be at these recording sessions."

"It would have been better, in all sorts of ways, for me to be with the Dead from the start. I sure would have enjoyed it more. As it happened, I was spirited away, to put it malappropriately, into the U.S. Air Force. Still, stout fellows that they were, they held on and waited for me to get loose from Uncle Sam’s clutches."
"There were a couple of times I did get away, on leave or on a three-day pass, to record or perform with them. Other than the embarrassment from the shortness of my hair, I recall exciting times. It was during one of the Anthem of the Sun sessions that Jerry officially invited me to join the band."
"It was like a magic carpet that was there for me to step on, and I would have been a fool not to step on it. It was basically an invitation from Jerry. He said something like, 'I think we can use you.' It was at Columbus Recorders in San Francisco."

"On Anthem, I played prepared piano, did some electronic things, and the opening part of Alligator."
"The idea was that this chaos would come out of the Other One. The final part was an overlay of several live performances, whence it gets that incredible depth - it's a remarkable effect. So they wanted to take that up and swirl it into an explosion, and out of the ashes of that would stealthily enter the warm, misty waves of New Potato Caboose."
TC used a prepared piano: "You put things like screws, coins, or clothes pins inside the piano strings to make them sound different. I did one effect where I took a dime-store gyroscope, gave it a good spin, and put that up against the sounding board of the piano. It sounded like a chainsaw being taken to the piano. Producer Dave Hassinger cleared his seat by a foot and a half when he heard it being done."
"One of my other favorites was obtained by using coins... Then there's a sound like woodblocks that comes from combs stuck on the piano's higher strings. Another I liked was clothespins on the lowest strings, played either with the keys or on a string directly." (He also blended in parts of a tape he'd made of a ring modulator in 1962.)

On New Potato Caboose:
"If you listen to it on record, it was kind of produced with harpsichord and organ in a way that could only happen in a studio. There's one organ segment where Pigpen and I sat side by side to play it, because there were so many notes. As it turned out, it was too impractical to perform live."

"The Anthem album is sort of a bizarre document, a studio attempt to recreate what the band was doing in concert, where one tune would segue into another. Alligator into Caution was a sequence we could embark on and go sailing for 45 minutes at least. The first live album is also an example of that (Dark Star into St Stephen into Eleven), although by that time it was getting modular."
"At the time we were very aware of the gulf between the experience of our performances and our recordings. A live show was so much more fulfilling. We wondered what it was that kept the magic from getting to the grooves of vinyl. Anthem was a deliberate overcompensation, in the sense that we felt that if we raised our sights, maybe...we might have a better chance of hitting the target. And even if we didn’t, it’d be an improvement over the seemingly shrink-wrapped first album. It was like the producer felt he had to "dress us up" to make us presentable. We felt we knew who we were, and were in the best position to represent where we were really coming from."

TC was also able to play a couple shows with the Dead on his leaves - one in Las Vegas in September '67, and one in Sacramento on 3/11/68, opening for Cream.
http://lostlivedead.blogspot.com/2009/12/september-16-1967-convention.center.html

"I got discharged from the Air Force. It was like returning from exile, or getting out of jail."
He was discharged on Nov 22 '68, flew to Ohio the next day, and played with the Dead at Ohio University in Athens on Nov 23. (Which was actually an unscheduled free show. As deadlists says: "So many students from Ohio University came to the show in Columbus on 11/22/68 - a long drive, about 1 1/2 hours or so - that the band decided to go to Athens and put on a free show for them.")

"It was a case of being an Air Force sergeant one day and a rock & roll star the next."
"I'd heard the albums, I knew the changes, and knew I could land on my feet in improvisatory situations."
"Even though I didn’t come out of an authentic blues or rock background, everyone was supportive. The sixties ethic included being kind on general principle, and I was the beneficiary of that. Besides, the band members, each in his own way, encouraged me."

This was just a short time after Pigpen and Weir had been temporarily 'fired' - TC later thought he might have been "unwitting glue to divert attention to allow them to solidify their positions."
"It amazed everybody that anything happened, because there was so much sniping going on. There was always some sort of simmer."

Pigpen, the organ-player, was bumped to congas when TC arrived.
"On the tunes he did play on, he played more than I usually played. The band at that time had established themselves a lot more, and I was impressed with them and wanted to make sure I put in things that were workable, from the context I could work from."
"I don't think he felt that threatened by me. After all, they already had two guitarists and two drummers, and the interpersonal dynamics among the players were already strange enough... If anything, adding my keyboard stabilized it rather than disrupted it. I never felt any professional jealousy in that situation; it seemed much more like brotherhood and connection. If he did feel jealous he hid it well. Beyond that, it freed him up as a vocalist. He could stand up with a microphone, which he was really good at, and to judge from appearances, he liked. I think Jerry did some things to make Pigpen feel included, like featuring his songs and encouraging him... "
"There was one exquisite gig in Cincinnati where both Pigpen and I played keyboard. He had the B-3 and I had the Continental. The B-3 got repossessed because they didn't pay the guitar bill or something, so I had to play a Vox Super Continental. Our credit was not the very best back then. But I really felt the unfairness of it all, because the B-3 sounded so good and the Continental was so limited... I wasn't too pleased about having to play the Continental night after night, because it really had a hard time cutting through all those guitars and drums."

On the road, TC shared hotel rooms with Pigpen. "We also shared a house in Novato. We got to be as close as two heterosexual males could be. Bless him forever."

TC was soon back in the studio with the Dead.
"On Aoxomoxoa, I provided keyboard arrangements on all of the songs except Rosemary." (Garcia did Rosemary himself as a solo four-track. TC contributed electronic noises to What's Become of the Baby, and came up with keyboard arrangements for the other tracks.)
"I had a better chance to express myself than I sometimes did in concert, because, having my own track, I could ensure not getting mixed out."
"The harpsichord is especially prominent on [Mountains of the Moon]. Not unlike the organ on Dupree’s… It’s nice to be able to contribute something that fits into the mix."
"Everything was essentially subject to Jerry's approval, and he would make recommendations, or ideas would be presented to him and he'd sound it out. Sometimes things would be tried just to try them, so we weren't doing the same thing all the time."

"These were studio recordings. For the band, the situation could not have been more different from concert performance. In this instance, it worked to my advantage. For one thing, levels could be controlled, which meant I could hear both the band and myself on the headphones. Usually onstage I couldn't hear the organ at all. The technology of the times simply wouldn't allow a piano to join in live. But in the studio it was no problem, as can be heard on St. Stephen."
"St. Stephen and China Cat Sunflower were already staples of the live shows long before Aoxomoxoa came out. So the album had no effect on our public’s perception of the tunes, one way or the other, except perhaps to note the stiff, contrived nature of the versions on the album, due to the multitrack recording methods of the time. The live versions always flew, and went over well."

"It was simply a matter of grappling with a nascent technology. Those years marked the early stages of multitrack recording. Anthem was done on an eight-track system. Aoxomoxoa was done on sixteen... Multitrack recording invites you to separate the various parts of the textures and record them individually. Sometimes we’d overdub a single instrument at a time. This led to problems, though. For one thing, there wasn’t the "feel" of a live performance. It was more like building a house. First you pour the foundation - the rhythm section, then add the instruments, and then the vocals. And it was new to all of us. Imagine - you’ve got 14 tracks recorded. Funny how easy it was to think of two more things to add to round out the sixteen. That complicates the mixdown. The mixing sessions amounted to performances, themselves, what with three or more of us at a time with hands on knobs, faders, or whatever, listening for cues…"

Meanwhile, TC wasn't happy with his live sound.
"There were two organs, the Vox Super-Continental, and the Hammond B-3. Neither suited my purposes at all well, although the Hammond was a step up. For one thing, their sounds ranged from barely acceptable to cringeworthy. For another, I couldn't find a place for the sustained sound of an organ in a guitar band context - ahhh, for a piano! Furthermore, the action of an organ keyboard, electronic or not, was sufficiently different from that of a piano, which was all I'd known until then, to be an obstacle to my getting a feel for the music. Basically, I wasn't an organist. A Merl Saunders or a Melvin Seals could've stepped in...but they weren't there. As if that weren't enough, the amplification technology of the times was much kinder to guitars, with their direct pickups, than it was to pianos. All the electric keyboards available then, you might recall, represented some sort of cheesy compromise with the real thing..."
"I didn't like the sound the Continental put out at all. There was something about the Continental in that particular band that grated. The Dead's guitars were these strands of gold and filaments of light, but the Vox was like a hunk of chrome. I had terribly mixed emotions about everything I was playing because the sound didn't please me... I convinced them to let me play a Hammond B-3, which I was able to enjoy a bit more."
He could never use an acoustic piano live because "the guitar would come through the piano's contact mikes louder than the piano."

"I wanted to be able to say something and stay out of their way. You can have all kinds of musical activity side by side, as long as it's in certain prescribed areas of the audible spectrum."
"At the time, the songs were predominantly Jerry's, and the texture of it, with his amplification - I could never really wrest the lead away from him. Which is not to say I wanted to make it a competitive thing, but just that I never felt I had a secure platform to work from."
"The Grateful Dead, as freaky and far-out as they got, were Jerry Garcia's backup band to a large extent. So there wasn't any room... On top of that, there was the amplification problem. There was always a problem in balancing the keyboard volume. You get Jerry Garcia with four Twin Reverbs turned up to 10 - his mezzo-piano was louder than my forte. My major frustration was not being able to find enough turf to even set up a tent in the sonic texture, and scarcely having time when there was a break to make something happen. I'd get to solo sometimes when Jerry would break a string, but even then he'd go back and string his guitar as fast as he could."
"Weir and I got a chance to shine every time Jerry broke a string."

On the Live Dead album:
"It was a dilemma that we were constantly reminded of - how to capture the essence of the concert experience on tape. The first two albums didn't "get it," as far as we were concerned, and it sure didn't seem to be for lack of trying. So that weekend's concerts at the Carousel Ballroom in San Francisco represented the result of grappling with the problem of recording for quite some time."
"This was about the time we were finishing the work on the Aoxomoxoa project, and Warner Brothers was pointing out to us that they had sunk $100,000+ into it and hadn't seen a product yet. So someone had the idea that if we sent them a double live album, three discs for that price wouldn't be such a bad deal, and they went for it. So we started 16-track taping every show. That weekend when Live Dead was recorded was the first one where no one raised an objection to the performances. We were hoping that one of the [shows] along the line would be okay at least, and at the time, we figured they weren't objectionable - not that they were excellent. As I recall, shortly after that...with the pressure off, the band started to play even better."
"The weekend at the Carousel Ballroom was one of those few times that I had a relatively decent stage setup. That is, I could hear the organ in the monitors, and its sound didn’t make my skin crawl. As on other such occasions, however, it was such a surprise to me when it happened that it took some time to adjust to. And I never got that time, anyway. Thankfully, sound technology has progressed since then, but my other problem was timeless. Despite continued efforts, I’d been unable to get a keyboard to practice on at home. Hence, I was learning chord changes on the fly, if at all. And the opportunity to practice, such as I’ve had a taste of since, wasn’t even a dream."

On Dark Star:
"The thing that I liked about [Dark Star] is the proportion of how much it gives you in terms of places to explore, relative to the effort it takes to maintain. It is especially favorable to the performer."
"It's like Dark Star was always there. Like the Clouds of Illusion... It’s remarkably easy to fly. [In another number,] all the way through, you’re counting, preparing, concentrating. No time to enjoy the magic. Dark Star is the opposite. You can relax, even enjoy it from the listener’s point of view, cackle over what you’re planning to spring on them, listen, interact..."
"Certain motifs were integrated over time, almost like an 'aural tradition.' I viewed the piece not so much as something written out, but as a galaxy that would be entered at any of several places... Every performance would be unique... On the best Dark Stars there were a lot of one-of-a-kind moments that were completely spontaneous."
"They were exploratory ventures... It's not so much a set piece, that you know where you are in it and know where you're gonna go, as you're out on an ocean in a boat, and you can choose your landmarks and respond to things and move in certain directions as you wish - of course, always interacting... It's the opposite of what I call the Android Jukebox Syndrome, which you can do wearing a tie and a happy face and you need not be mentally present - which is exactly what we weren't interested in."

"We would play a long extended improvisational piece that went a lot of places. You find jazz players doing that. Sometimes it works and sometimes it doesn't. That's part of the chemical thing. But if you're there, you should try...anything could happen, not to mention segues."
"There were choices at any given point, and many of the choices were even made ad hoc on the stage... It was occasionally amusing to see when Weir would be taking the band into one tune and Jerry would be taking the band into another. You would have these tidal frictions of a thought or direction where the band wanted to go..."
"The band practiced all sorts of odd time signatures. [Besides the Eleven] there was also a ten Mickey brought in, and a fifteen that we tried - anything to break out of that square mold of threes or fours. Also, having more than one drummer, if gave them something to do that was more interesting."
"The Grateful Dead were able to rehearse it well enough so that they had a high percentage of things they discovered that worked. Although...some performances are better than others. That's a chance you have to take in courting serendipity - sometimes serendipity comes to grace your performances, and sometimes not. As far as some of the farther-out improvisations and directions, there were already tendencies in that direction among the band members, of which I was happy to be congruently in step with... Conversely, I think I might have had an influence on some of the more simple harmonic tunes the band got into shortly after I left."

Shows often ended with feedback: "[Like] bringing a plane in for a landing at the end of a huge jam. A guitar solo would naturally lead into feedback because you're pushing it for its last ounce of explosive power."

Bear mixed the live sound. "That was the pretext for traveling with the band. Healy would help with the knobs when people got fed up with the Bear. Pigpen described the system as one that worked 100% well, 20% of the time."

Other groups: "I remember a San Diego show where Santana sat in with us at San Diego State. Also, the New Orleans Pop Festival where the Jefferson Airplane sat in with us. There was also one time at a place on Sunset Boulevard called Thelma's...where Stephen Stills and David Crosby sat in with us."

The Fillmore: "Most any show at the Fillmore East was exceptional. The Fillmore East was a magical place to play - the crowd was very responsive. The band had a strong following in New York and it put an edge on the playing. I'd rather listen to any Dark Star from the Fillmore East. They were in a different class."

Playboy After Dark: "It was egregiously silly. Wish we could've done it more than once."

Woodstock: "I was the only one in the band that had a good time, and even that was mitigated because everyone else wasn't. The guitarists were getting shocked from their strings. Bob described his strings as being like barbed wire. The electricity wasn't grounded. We were supposed to spin on a circular stage...but our equipment was too heavy. It didn't work. The stage was swaying back and forth. Phil was visualizing the headlines the next day: 'Huge Rock and Roll Disaster - Thousands Maimed.'"

Drugs:
"The band found early on that too much of a good thing didn’t work. It took a while to find a happy functioning level."
"There were people who were always trying to dose us, and sometimes they succeeded... I remember one time when the band got rather heavily dosed and it seemed like the instruments were painted onto you." (He remembers one night at the Carousel when "four or five different people dosed the apple juice, unbeknownst to each other" - I wonder if this is the same night Phil talks about in his book...)
"During my entire tenure as keyboardist with the Grateful Dead, I made a sincere attempt to...'try and make it without any chemical corn.' I wouldn't even take an over-the-counter headache pill. This only applied to myself, however. What someone else wanted to do was their business. Besides, I'd already experienced LSD, peyote, and psilocybin in the early '60s, and found them all profoundly entertaining."
(This may have been one reason he shared rooms with Pigpen, who was also a non-drug user!)

Scientology:
"I got into Scientology through drugs, and got out of it the same way. With some of the more powerful psychedelics, there were places you could hope to remain...and, so Scientology portrayed it, by means of clearing out a lot of unnecessary garbage from your head, you could arrive at a state like that. What I found out, especially from the times I got dosed on the road, was that yes, Scientology really worked wonders with my head - I wouldn't have stayed as long with them, otherwise. Except it really enhanced the drug experience."
"It made me a non-participant in the chemical sacraments of the time, and that offended Owsley greatly... I tried not to proselytize, but I'm sure there's a certain amount you can't resist, and that I regret. It probably must have rubbed some people the wrong way."

(However, the Dead actually played a Scientology benefit concert - the "Bobby Ace and His Cards from the Bottom of the Deck" show on 6/11/69, where they played what seems to have been a mainly acoustic/country show with John Dawson and David Nelson - who were then about to form the New Riders - and possibly Peter Grant. Garcia may well have been on pedal-steel. One can only imagine what TC sounded like in that context!)

Hart: "He never fit in. He couldn't let go. He thought too much...everybody else was strange, but I knew their strangeness. I couldn't connect with him."
Weir: "He, like I, had to invent his own style - but he didn't. He had no roots in African American music." "He has apparently no innate, and certainly no cultured understanding of the idioms that are responsible for rock & roll. And so it occurred to us and him at the same time that he wasn't really a rock & roll musician; and the whole group when we were playing with him sounded more like an experimental group than a rock & roll band... We all, TC included, decided that it was best that he either learn to play rock & roll, or continue what he had been doing."

TC's last show as a member of the Dead was in New Orleans on 1/30/70. In a meeting that day, everyone decided it was time for TC to leave the band. He says it was a cordial parting - he had many reasons for wanting to move on. (For one, the Dead were about to go back into the studio to record their new country-rock songs.)
As it happened, that night the New Orleans police came prowling around. TC was rooming with Pigpen during the bust, and they weren't arrested: "If they'd come to our room first, there would've been no bust. I got to talking with one of the sergeants about the Air Force and we got along fine. We would've talked them out of it!"

TC went on to be composer & music director of Tarot, a music/theater project in New York - "I wanted to be a bigger fish in a smaller pond, and Tarot was more edifying." The rest of his activities are outside my scope here, but he also worked on an Incredible String Band album in 1970, and played a few shows that year with the Rubber Duck Company - on 7/14/70 they even opened for the Dead in San Rafael!
And TC did rejoin the Dead onstage for one show on 4/28/71:
"I was living in Brooklyn, doing the Tarot show, and was going to see Pigpen when the band came to town. We met at the hotel, the Essex House... So I wound up going to the show, too."
"I didn't even go to the Fillmore East with the idea of playing. I just went to visit Pigpen and the others. I was backstage at the Fillmore East, and the next thing I knew I was sitting down at the keyboard."

Around that time, Constanten was recording his Tarot album - some outtakes are available here:
http://www.archive.org/details/gd73-11-28.sbd-seastones.finney.968.sbefail.shnf
(Garcia and Lesh are said to contribute, but I find this unlikely.)

"Ironically, it’s only in the past couple of decades I’ve got the hang of the "jamband" idiom. But then, the keyboards are better now, too."
"A lot of this is in my book." (Between Rock and Hard Places, 1992)

Main Sources:
http://www.digitalinterviews.com/digitalinterviews/views/constanten.shtml
http://www.pooterland.com/index2/looking_glass/tom_constanten/tom_constanten.html
One More Saturday Night (Sandy Troy) interview
Golden Road (summer 1984 issue) interview

***

My comments -

It's true TC was no rock & roller! His forte was more weird, baroque-style, classical-influenced instrumentation - which was perfect for Anthem & Aoxomoxoa.
But by the end of '69 they were pretty much done with Aoxomoxoa songs, and they were doing simpler songs where he couldn't really add much. In Dec '69 they were also putting more rock & roll songs in the set like Not Fade Away & Dancing in the Streets. Since they'd already tended to play at volumes that drowned him out (if he couldn't hear himself, they probably weren't listening to him either!) - this didn't help his cause. And when he became a scientologist and stopped taking LSD, there wasn't a meeting of minds there! So they had an amicable parting in Jan '70.

In his early shows, he sounds much quieter on organ than Pigpen was - he's submerged in many of the mixes, which makes him a sort of spectral presence in the music. Sometimes barely audible, except when the others quiet down! He has more texture to add, though, seeping in between the lines, and by '69 he's stretching out and blending in. (It's surprising that he keeps playing Pigpen's infamous Dark Star riff well into summer '69, but apparently the band wanted to keep that little bit, like an appendix - and he just uses it as a brief stepping-stone into the jam.)
He can be rather subdued in early '69, which makes sense - to hear him tell it, he had no rehearsals, bad instruments, no sound monitoring, a "sink or swim" band attitude... (Which sounds rather antagonistic actually, but I think perhaps it was a vote of confidence - "here, we know you're up to this" - after all, the Dead had a daredevil mentality in those days, and a limited budget. They became more professional later on, since we have pretour "break in the new guy" rehearsals for both Keith and Brent.)
At the start, the musical environment was completely new for him - and as he says, Garcia was never willing to step aside for very long in a solo! TC does get better & bolder through '69. (Although, with all those shows, it would be more surprising if he hadn't!) Two later shows where you can hear him clearly on his own channel are 8/23/69 and 1/2/70.

It's hard to say how much influence he had on the changing jams. The Dead would have kept heading in their particular direction without him, but I'm pretty certain his playing had an effect on the guitarists and the way they handled the jams - there's a lot more space and subtlety going on in early '69 than there was in '68. A tune like Dark Star, which kept growing into more meditative, abstract spaces over time, was perfect for his swirling backdrops.
But the timing was poor. He wasn't with the band long before they started going country on him! If not for that pesky military service, he undoubtedly would have joined the Dead when they were recording Anthem, and our '68 shows would sound very different... But the time where Constanten had any influence on the Dead lasted only a short while, with Aoxomoxoa and Live/Dead (and a couple points on Anthem) the only albums where he left a mark. I think once they started getting Workingman's songs together in mid-'69, he was pretty much left to himself after that.
When he joined the Dead, he probably thought they'd carry on Anthem-type work - yet only six months later, they'd started adding heaps of covers and country songs to their set, and were losing interest even in their "new" Aoxomoxoa album. He must have felt the ground shifting under him... So it's telling that he left the band just a couple weeks before they recorded Workingman's Dead! (Also telling that they started playing acoustic sets immediately after he left.)

Few of the Dead's keyboardists managed to stick with them through a change in style. Pigpen was just fine in '66, but couldn't keep up by '68. Constanten was just right for the Live/Dead period, but the band moved out of that phase pretty quickly. Keith transformed the jams in '71 and the next few years, but he was doing nothing for them by '77/78.
Of all their keyboardists, TC may have added the least to the Dead simply because he came in 'too little, too late'... Even Pigpen, of the dubious organ prowess, had an immense influence over the Dead's shows which no one after him could match.
In comparison, Keith's influence on the jams starting immediately in Oct '71 is tremendous - unlike Constanten who stayed on the sides, Keith played all the songs like he owned them. It's hard to imagine what their '72-74 shows would have sounded like without him. (More like '71, presumably!) Whereas Constanten's departure in early '70 had about as little effect on the Dead-sound as Mickey Hart's exit in early '71.