"Holographic" presentation

As with most hifi subjectivity, the proof is in the listener's pudding so to speak. Also, many (many) other factors not including the use of mono amps (dual mono? most well made stereo anything?) can have a profound effect on what basically is great stereo imaging where the players seem to be sitting in front of you in a defined group, or simply soundstaging at its best. Sound engineers either strive for a realistic soundstage or they don't...I complain about the 17 foot wide jazz drummers sometimes, but often I'm not bothered by that if the music is great.

IMHO, a "more holographic" presentation has nothing to do with whether the amp is a monobloc or a stereo version.

Circuit Design, implementation and parts quality has way more to do with sound than if the amp(s) is/are a one piece or two piece design.

I've owned MANY of each kind and have found both to be either good or bad, but had nothing to do with them being a mono or stereo unit.

I should add that each mono amp does has it's own power supply and of course, they have less likelihood of any interaction between channels, since there is only one, but again, a poorly designed mono amp is just that, a poor design. Same holds true for stereo amps.

Plus you need to be aware that the amp/speaker interface plays a big part also.

The largest factor of holography is media itself and recording quality.
Carver made preamp with sonic holography effects, but they don't qualify for audiophile market due to 'purity' sacrifice.

Thanks for your informative responses. I've wondered about
this for some time.

TWo mono amps, or a stereo amp that consists of two highly isolated mono amps in a single box even, may well have better channel separation and less crosstalk, which could work in favor of a more "holographic" presentation, but whether or not this would be heard in comparison to something else or not would still depend.

Assuming quality gear designed well in all cases, using two mono amps is probably a good insurance policy that overall performance of each is fairly independently optimized which should always work in ones favor.

In a nutshell, more can be done better with a single self contained monoblock, with dedicated power supply, etc., than can be done for similar cost otherwise.

I think that speaker placement and room treatment are more important factors determining three dimensionality than whether the amp is of stereo or mono design.

I was comparing two different speakers - and there was a noticeable improvement in soundstage depth and width in one vs the other.

A speaker designer I know says there's a simple explanation for that - our perception of soundstage is determined by the slight differences we hear from the left and right speakers.

The speaker with a flat soundstage had a less rigid cabinet. As such, there is some vibration from the cabinet that is smearing the soundstage. The vibrations created tend to be "mono" like from both speakers and that masks the small differences that were in the original material.

As Mapman has stated, the use of mono blocks could reduce the amount of crosstalk (or mono information common to both channels) and I can see how a similar reasoning could explain why the soundstage could be improved with a mono block design.

Here's a question- what good are dual mono amps when you are using a stereo preamp?

My experience has been that as long as there is very good stereo separation, and the media contains the spatial cues necessary, you can get the holographic illusion. And it is an illusion because holographic suggests three dimensions, while our stereos are by definition 2 channel sources.

Mono amps may not make a night-and-day difference.
Much of the voodoo that we-do (vibration control, room treatment, power conditioning) doesn't fix everything.
Taken together, however, results in substantial improvement.

"Here's a question- what good are dual mono amps when you are using a stereo preamp?"

Two different things that work together. AN improvement anywhere is an improvement, and vice versa.

I suspect the reason monoblocks are fairly common yet stereo pre-amps are housed in the same box is that there is more potential for 1 circuit to interfere with another in a power amp due to its nature (ie high power, voltage, more current, high capacity power transformers, etc.).

Monobloc pre-amp is an interesting concept. Not sure I have ever seen that. Probably because benefits are not significant. Still, audiophiles like everything to be pure, so you'd think not having a good reason would not stop someone from selling the concept.

I have a pair of TAD Hibachi monoblocks. Each has continuously variable input sensitivity controls. Essentially, that is like having a built in pre-amp with volume control, so I suppose that's it. Nice amps! No multiple line level inputs and switch though.

Krell KRS-1 Mono Block preamp, where the control section and power supply are in their own chassis as well, resulting in 4 separate boxes.

A neighbor has one.

As far as whether monoblock configuration is more relavant in an amp, whi knows. Some might say that the very low level signal encountered in a preamp are more fragile, and when you add in a phono stage, well, the amount of gain in a preamp is going to be a lot more than in an amp.

Which get's back to what we should be satisfied with- if it sounds good, it is good.

This is what recording engineers do: Record things to their or the producer's or the artist's taste (mic selection, eq, possible compression, ambient information either natural or from devices), and pan each instrument to wherever they think it needs to go...little left, more middle, little right, lots of left, lots of right...that's it. Soundstage accomplished. Any decent stereo rig can reproduce this and if it's isolated (headphones or speakers stuck to your head) it can sound less "live" as in the actual world there is air and natural blending between speakers, as long as your ass sits between 'em. Tone, treble cues, bass nodes, yo mama, all differ.

I think there may be some confusion with terminology. The often-touted
advantages in soundstage presentation of mono-bloc amps have to do with
improvements in stereo separation and specificity; sometimes resulting in a
better defined soundstage and better defined images within that
soundstage, but not necessarily holographic. "Holographic" has
usually meant a presentation in which individual images are, not only well
defined in space with little image wander, but also dimensional with the
sense that there is air behind the images and not just to the sides and front;
IOW, 3D. As far as amplification goes, in my experience that trick is best
accomplished by good tube equipment; mono-bloc or not.

It is all in the quality of the implementation. I have had some excellent monoblocks through here, including Lamm M1.1s, Clayton M300s and M200s, and Acoustic Imagery Atsahs, and my current stereo amp is equal to the best of those and better than the others with regards to dimensionality and soundstage. From the amplifier, good channel separation is important as is low noise and the ability to provide detailed spacial cues. I suspect other, non amplifier related, factors play as big or greater a role such as room dimensions, speaker placement in the room including separation between speakers and distance from rear and side walls, listening position and ear height relative to the speakers, room treatment and other factors I haven't thought of. If the amp sounds good tonally and drives the speakers well, I would work on the room related issues first, to improve soundstage and dimensionality, before worrying about the difference between a stereo amp and monoblocks.

I owned an amp years ago that featured pornographic imaging. It was creepy so I sold it.

What brand was that? A buddy today just asked for an amp recommendation that did pornography well.

I seem to recall that Wolf mentioned that the brand was Conrad's Johnson.

Damn, I used to own a CJ 17LS2. I guess I should have read the manual.

There was that pass through feature I never tried, but I thought it was a home theater feature.

Gous....who said that.....if the mono amps and stereo amp has equal ability, they both are fine.

Yeah, Wolfie, I can't thank you enough for selling me your 'special' amp. I had to quit my job in order to dedicate appropriate time to all the serious comparison sessions I was compelled to hold... A/B, A/C, AD; B/C, B/D, B/E, etc. But this alphabet soup has been well worth it. Yessssss!