Do I need BOTH amp and pre to be sonic holography?

I have Carver TFM 35 amp and C6 pre. I was considering replacing Carver pre with McIntosh C35 pre. Would I still have the sonic holography with just the Carver amp, and any thoughts as to whether this might be a worthwhile change/upgrade? (I'm not concerned with a tuner at this point.)
No. The sonic holography is built into the preamp. Not the amp. The other option, if you really like that feature, is to pick up a stand alone Sonic Holography unit. They were the Carver C9. I see them pop up from time to time. I actually still have one sitting in the closet. You should be able to get one pretty cheap.
Can you please define what you mean by "sonic holography". I may be able to give some useful input, but I want to be clear about what we are talking about.
Isn't sonic holography something from Star Trek?
Sonic Holography was one of Bob's ploy's to get people to purchase his products. These names really meant nothing.
get yourself a good tube amp.
sonic holography is just another phrase for sound stage
back in the 80's i owned a carver preamp w/that sonic holography feature built in & used it all the time. i had the m4.0t amp at the time which emulated a tube amp supposedly. for it's time i thought it sounded great. carver used to sell an individual holography component (small black box that Zydo mentions above) that was installed inline somewhere - like a tube buffer i'm guessing? seek out that box if you can find it or just buy zydo's. just for grins i'd love to hear that setup again:)
Carver's system, otherwise known as the 'Sonic Holocaust' was a way to clean up the stereo image.
When recording say....just for example.....a singer and band with a pair of microphones, each mic will get information....somewhat time delayed, perhaps, from the opposite side.
Sonic Hologram will subtract right side information from the LEFT and left side information from the RIGHT. This eliminates the 'crosstalk', if that's the right word.

Polk did the same with speakers a few years later, by having a pair of midrange drivers about 6" apart horizontially. The distance was decided by the space between ears.
They fed signals between speakers to accomplish the same 'subtraction' and used the distance between drivers to account for the time delay.

I never heard the system. I'd like to hear it with headphones.
Magfan Pehara and Zydo have it right. The Sonic Holography circuitry took a band limited (mostly midrange) signal from each channel, delayed it slightly, and injected it in reverse phase in the opposite channel. Carver built the circuit into their preamps, and also offered it in several stand alone configurations. The C9 was a dedicated Sonic Hologram processor, and the ECS-U included Holography along with several other speaker control functions for the Amazing series speakers. Both units went between pre and power amp, or in the tape loop.

In my early years of audio (the 80's) I loved the Hologram generator. It required careful setup of speakers, room and listening position, but the effect was quite startling on most material. Images extended well beyond the speakers and often wrapped 180 degrees around the listener. You could often hear the acoustic space if the recording was live. Occasionally sounds would appear to come from behind.

As I grew in the hobby I realized how gritty and transitory both the C9 and ECS-U sounded and I weaned myself off them. They were built with crappy parts and cheap power supplies. Sometimes I wonder what a high quality implementation of the concept would sound like.

Crosstalk cancellation would be a natural for digital processor implementation, and a vaguely recall the some Meridian processor offered it as a side function.

As Magfan mentioned, Polk offered a series of speakers in the 80's that atured an extra midrange driver in each speaker that was fed a reverse phase signal from the opposite channel. Spacing provided the necessary acoustic delay to make the effect work.

Bottom line: The Carver gear was never great sounding, and updrading the pre would be a good place to start.
The phrase was something like 'Interaural Crosstalk Delay'.......

In my (now ancient) messing with backchannel phased speakers (no delay) I was able to get great results by using a 2nd amp and wiring a pair of speakers IN SERIES between positive poles. Live recordings were LIVE.
In those days the system was a pair of JBL4311s in front w/ an SAE power amp and a pair of RSL3600 Studio Monitors and a Kenwood KA7100.

I STOLE the idea from the then popular DynaQuad circuits I saw.
Get a c-9, but get the manual for speaker set up. If you like the sound, you won't want to go back.
Wow. The depth of knowledge, and generous willingness to share it, is stunning and very much appreciated. Obviously I am a neophyte to this hobby, but learning as I go along with limited finances at this point, from research, trail and error, and in no small way from quite helpful people such as yourselves.
Sorry, I did realize I needed the pre for holography, but was interested in the value of the concept. Thank you Ghost, I shall start search for upgrading preamp first, as affordably as I can. Perhaps the Mc C35 I mentioned.
I know I sound like a stuck record, but nothing can replace auditioning equipment at a "high end emporium". No amount of reading post's written by some of the smartest people I have ever encountered will tell you what true "high end" sounds like.

You have to make that trip to a "high end emporium". Once the sound get's stamped on your brain, you'll know when you're getting it right.
to tmsorosk:

It's really incorrect to say the name meant nothing. The sonic holography circuit is first patented, which means it has to do something. What it actually does is send a little of the left channel signal to the right channel, but 180 degrees out of phase. It also adds a little of the right channel to the left channel but 180 degrees out of phase. In this way, it helps to couple the left speaker to the left ear, the right speaker to the right ear, and the out of phase signals make that happen. Impressive on the right recordings, awful on gimmicky recordings. The C-6 preamp will work with any amplifier.
Sonic holography is patented, there is a patented circuit which intentionally manipulates phase to couple the left channel to the left ear and the right channel to the right ear. Sound stage is wonderful on tubes but a totally different thing than Sonic Holography. Do a patent search and you will find Robert H. Carver holds the patent
Sorry, Robert W Carver.
There is someone on ebay selling C-9 upgrade kits, also sometimes C-9's with the upgrade installed.

This unit below seems to me much the same thing, but modern implementation, seems you adjust the settings with a computer via USB..
Phase Linear 4000, was the first time Carver used that circuit. While it was quite interesting when compared to "Mid Fi", it doesn't hold a candle to a "high end" sound stage, and not only that; but the parts were cheap.
The delay that Carver's holography unit developed was not just to somewhat counteract the signal from the opposite speaker, it also accounted for diffraction caused by the listener's head. When sound from the left speaker hits the listener's head, the head itself causes the soundwave to travel around the head from the left side to the rigt side, again on a delayed basis. The Carver circuit compensates for this as someone described above (delayed, inverse phase signal sent to the right speaker).

I have (somewhere in a closet) a holography generator. It does create, with most recordings, an extremely wide soundstage, with some images sounding like they are completely to the side and quite close to the listener's head. The sound is quite phasey and not entirely realistic (though fascinating).

There are recordings that were made with these compensating signals built into the recording in order to throw images way outside the speaker. Roger Water's "Amused to Death" is an example. A less extreme (more subtle) use can be found on a Nouvelle Vague "Nouvelle Vague" recording (French girl group doing terrific covers on Brit pop/rock). If you want a rough idea of what the Carver circuit can do, get the Roger Water recording.
yes, the head causes additional time delay.
It also causes the 'downstream' side to get fewer high frequency part of the sound. That's the reason for the 6" speaker seperation on some Polk models seeking to mimic this circuit.

In nature, the time delay, spectrum difference, loudness and several other things are all 'cues' to location and direction and distance.
VITAL to survival.
The reason for the delay is that you want the out-of-phase right channel signal injected into the left channel to arrive at the left ear at the same time as the (in phase) acoustic right channel signal arrives at the left ear, resulting in cancellation of the right channel at the left ear. Similar logic applies to the out-of-phase left channel signal injected into the right channel. In other words we want the left ear to hear only the left speaker and the right ear to hear only the right speaker.

There are always side effects. Mixing the delayed out-of-phase signals cross channel results in some comb filtering, which explains the phasey sound noted by some listeners.

The effect is record-able, and the c9 had a sticker on the back warning the user that it was illegal under the Sonic Hologram license to use the device to make recordings.

That Ambiophonic device looks interesting.
"Sonic Holography was one of Bob's ploy's to get people to purchase his products. These names really meant nothing."

Well, the name is descriptive of the effect and the effect does in fact work with the right gear set up properly for it.

Its merits versus other approaches or whether one likes it or not is a different discussion.
Left + right and left - right. It does work very well with the C-1 preamp and/or the outboard C-9 unit. It cancells interaural crosstalk and the sound is really good, but you must set up the speakers correctly. It's not a ploy of any sort. If you get the McIntosh pre just add a C-9 to it.
The only downside I heard with the Carver sonic holography when I used it was a noticeable loss of dynamics, mostly in the low end. It did however work as advertised if set up properly as instructed and listening smack in the sweet spot. Away from the sweet spot, the effect was detrimental.

No snake oil there. It worked exactly as advertised.

ALso I found that it worked best with more directional conventional box speakers (with a smaller sweet spot) that had coherent integration of drivers to start with, most monitors and some floorstanders. It worked with Maggie planars also but proper setup was hard.

I found it did not add anything with my OHM Walsh speakers which are essentially omnidirectional. Apparently, Carver sonic holography works best with more directional speaker designs and the effect is less noticeable with wider dispersion or omni designs.
It most certainly worked as claimed, and sonic holography is a good description of the effect-images appeared to be placed around the whole front hemisphere, and some images seemed to be startlingly close up (VERY three dimensional).

But, the effects seemed artificial and exaggerated. There was also a phasey quality to the sound. I also did not like the tonal changes--upper bass seemed to be overly prominent.