H-CAT™ Doppler-Free playback includes the world's first Wavefront Timing Control.
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New breakthrough "Super Resolution" - X8 Doppler Control System
UPGRADE available to P-12B owners!
H-CAT™ is Doppler-free with remote control and HT Bypass
(Remote features: Volume +/- , WTC +/- , Input Select +/- , Mute On/Off and Display intensity.)
P-12R (X8)
Inputs: 4 pair RCA unbalanced with input Z of 500K
Outputs:
2 Pair of RCA unbalanced out with Z of 50 Ohms
1 Pair of XLR True Balanced out with Z of 50 Ohms
Straight talk about H-CAT™
from Roger Paul
This is an attempt to make the H-CAT™ amplifier method more understandable to the average audiophile reader and to clear up any misconceptions about the nature of H-CAT™. It has been difficult thus far to introduce a product so radically different in its operation to the audio industry. All I ask is that you be open-minded when it comes to learning about H-CAT™ and how it deals with amplification.
It has come to my attention that many audiophiles visiting my web site believe that H-CAT™ is using special circuitry to manipulate the audio signal and somehow generate the illusion of 3D imaging. This could not be farther from the truth. In fact it is just the opposite.
Several “holographic” products come to mind - all of which rely on the introduction of signals added to the original stereo channels to produce a phenomenon of dimension to the listener.
Here is text taken directly from literature on such a product…
“This is accomplished by sending a complex crosstalk signal from the left and right speakers in addition to the normal program. These extra signals are virtually identical to the unwanted second sound arrivals but they are out-of-phase with them and they cancel each other out. The result is a more three dimensional and wider soundstage, where the positioning clues are restored.”
This was a clever circuit arrangement that was designed to “overcome a problem in obtaining accurate sound reproduction”
Here are the facts as plain as possible:
H-CAT™ does not operate this way nor does it involve the use of opposite channel information or phase inversion or crosstalk or anything even remotely close to this.
H-CAT™ does not take any portion of the left channel information and introduced it into the right channel
H-CAT™ does not take any portion of the right channel information and introduced it into the left channel
H-CAT™ does not use any phase shift to create the illusion of dimension or space. Zero.
H-CAT™ does not use negative feed back (NFB) to remove distortion.
H-CAT™ channels are totally isolated from each other and are completely independent.
H-CAT™ uses common controls for volume settings (but still independent)
H-CAT™ is 100% pure analog and has no sampling or digitizing or processing of any kind.
Up to this point there does not seem to be anything special or unique about a simple 2 channel amplifier circuit. Except for one thing – the H-CAT™ method of amplification – the circuit itself - is virtually distortion free and does not rely on conventional NFB to suppress harmonic distortion. Everyone knows that doesn’t work.
Defining the problem
Electrical amplifier circuits whether solid state or tube design have imperfections in the way they handle the simple task of taking an input signal and delivering a larger (amplified) version at the output end of the circuit. It is essential to first grasp the concept of how a signal “travels” through a circuit. The idea that a signal enters the input terminal and leaves at the output terminal is just not true. The output signal is merely a suggested rendering of the input signal – not the same signal.
The output signal is typically a voltage potential that is changed by applying a corresponding change to the input (potential). It can be seen therefore that the signal itself does not travel through the stage but rather the influence of the input changes are passed along (from device to device) until the output is taken from the final device in the stage.
This is true even under the simplest of circuits like a single triode. The input signal voltage is applied to the grid (resistor), which in turn varies (influences) the plate current causing the plate voltage to vary in a larger fashion thus producing voltage gain. The output signal does not share the same current as the input signal but represents an isolated bigger “copy” of the input signal. In this case it is also phase inverted.
The final signal contains a degree of distortion (errors) that is based on the instantaneous efficiency of the “influential” part of the circuit. In short, it is how the circuit behaves when asked to “move”.
Take the case where a given circuit has 6db of gain and is non-inverting. This would mean that a 1V peak-to-peak input signal would provide a 2V peak-to-peak output signal or a 2:1 ratio. Let us for the moment assume it is perfect in performance and has no distortion.You should be able to take a snapshot in time of the output voltage – then divide it by 2 and know the exact input voltage. For example, at a frozen moment in time you measure +1.40V out (divide by 2) and you expect the input voltage to be exactly +0.70V and so on.
In the real world there will be times when the output divided by the input will not equal (in this case) exactly 2. If you apply exactly 1V in and you measure 1.999V out – then your instantaneous gain is 1.999 (not 2) therefore it has less than 6db of gain AT THAT MOMENT when the ability of the input to influence the output has become weaker. This is an indication that the apparent speed or velocity of the “traveling” signal has slowed down since the output has fallen short of the theoretical potential of 2.0. This in turn changes the shape of the output slightly altering its “pitch”. Yes, with no moving parts – it is possible to alter the speed and therefore the “pitch” of the traveling signal. This minor deviation from the true shape has caused the original signal to alias itself as a different frequency – at least for the short period of time when THAT segment of the signal did not comply with the ideal 2:1 ratio. This is a form of velocity induced "shape shifting" that produces harmonics. It can also pass through a region where the gain is slightly higher than 6db thus causing a slight acceleration in velocity. As these minor fluctuations in speed occur, the listener is exposed to a sonic effect impressed upon each sound object that is essentially out of focus and "wobbling". This is Doppler. This is what happens in virtually ALL playback systems.
Defining the solution
H-CAT™ is the only amplifying method that can monitor and maintain constant velocity. It is accomplished by special built-in detectors. Unlike NFB which does a crude comparison of input and output signals, these “Doppler” detectors are placed in strategic areas of the circuit to validate the exact velocity of the circuit and ensure that it does not vary. In other words if you expect a gain of 6db or an amplification factor of 2 - the Doppler detector coupled with an exact velocity countermeasure will maintain an ampification factor of exactly 2 at all points along the swinging output voltage. In other words through 360 degrees of operation. This Doppler Control System is not only extremely sensitive but reacts in real time. The solution or “correction” is applied by way of either red shift (de-acceleration) or blue shift (acceleration) circuits that are linked directly to the Doppler detectors. Therefore, since the correction happens internally, prior to the signal appearing at the output terminal - you never experience distorted output even for a brief moment. With the use of a proprietary control technique found only in H-CAT™, the gain can be maintained at exactly 2.0 with a tolerance better than +/- 0.000000001
This gives you the mathematical stability of a digital domain but in the pure analog world. The output of H-CAT™ is metered at a constant velocity and finite changes in pitch are omitted. Everything is in focus, with unlimited depth of field.
There is only one other place in nature where this caliber of accuracy occurs - and that is when sound waves travel through air at constant speed of Mach One. Your brain recognizes the Doppler free property and is convinced it is air - not electronics. If you can cause your hi fi system to also have a fixed gain with the tolerance you see above - then your electronic segment of the entire chain takes on the property of air and your electronics are “cloaked”. The electronics will appear to have nothing to do with the music in front of you. The recording venue is exposed as original air space and is coupled to the air space in your listening room. Sound from voices and instruments appear to be coming directly from the object to you through a medium of nothing but air.
Developing the Wavefront Timing Control
Earlier versions of H-CAT™ like the P-12A did not have a means to adjust the wavefront. It meant that if you were lucky and your system synergy was such that H-CAT was a good “match” then you would be able to hear the benefits of its Doppler free nature. If it did not mate well with your power amp or CD player / phono stage then unfortunately you would experience a strange phenomenon. It would sound totally “electric” and irritating. This is due to the left over Doppler that is caused by the sum of your other components. This is why early feed back from the field has been mixed. Some audiophiles loved it and some hated it depending on their system.
As a result I decide to create a scientific “tool” for myself to enable the microscopic trim of the final velocity so I could set it once and for all at the factory and seal the adjustment. I figured this would give me an average degree of compatibility with most systems. The control itself is actually making ultra tiny changes (in parts per billion) to the Doppler detectors internal reference. Thus “fooling” the detector into thinking it has discovered velocity errors in either the lead or lag direction. What happened next was a surprise to me. I found that I could get the velocity trimmed “perfect” in MY reference system. Then when I switched source material to a different CD - it sounded great but I was curious to know if my “trim” was still dead on. After making a slight adjustment (3 digits) - it caused the new material to “pop out” as a natural acoustic Doppler free display. Of course as a designer I had to go back to the original reference CD and verify if it is a different setting or did the velocity trim somehow drift. I did have to return it to the original setting to restore the “magic” I heard in that first recording. The result was both a disappointment and a delight. I was disappointed that I could not simply set it and forget it. But I was delighted to realize that if I were to provide this tool directly to the end user, it would virtually guarantee that it would match any system. So that’s what I did. As you may know the P-12B was designed to include a manual front panel control allowing users to trim the velocity. This gave H-CAT™ a far better track record for acceptance because more audiophiles were able to recognize the benefits of this design and understand why other audiophiles were so happy with their units. They could duplicate the results in their own system. It soon became obvious that not only is there a different setting for different record labels (due to the electronic path using different brands of mic preamps, mixers etc.) but when you switch from your CD player to your phono stage - the final trim can be quite different due to the analog stages in the DAC.
Even more interesting was the eventual verification that indeed everyone’s system was different. H-CAT™ owners would call each other and compare notes about what they found to be the “true” WTC setting in their system. These are custom settings and rarely did they match.
The Remote Control
Complaints about having no remote finally got to me and I realized I would have to develop a remote volume control circuit that would maintain the caliber of purity realized by the main line stages. The solution was a new stage containing a digitally controlled resistor ladder with taps that are fed into its own H-CAT™ “wrapper” complete with its own Doppler detectors to ensure consistent velocity management as the volume is adjusted. The result is pure analog signal path.
However, the real beauty of having a remote control was not for the volume but for the Wavefront Timing Control. Now you can sit back in your listening position and adjust the WTC on the fly for perfect trim. Having the extra control electronics on board also allowed me to store the learned “best” setting for that source in a memory slot tied to that input selection. So if your CD player sounds best at -6 and you switch to your phono input and trim it to +4, when you return to CD it will automatically reset your WTC to -6.
Home Theater Bypass + Wavefront Timing Control
The home theater bypass (HTB) is technically not a bypass since the audio feed from your video system still passes through the H-CAT™ line stage. However, in this case the volume setting as well as the WTC setting are both stored in a memory slot. Once you dedicate an input to the HTB, upon selecting that input, H-CAT™ will reset the volume to a preset level. The advantage of this is that the Wavefront Timing Control is still fully engaged in this mode. This allows you to trim the velocity of the soundtracks of your favorite movies. When switching to this mode - the letters “VOL” on the display will switch to “HTB” to remind you that the volume setting is independent for this input and is stored in memory.
Making the most of H-CAT™
It is important to note that two conditions can give you very undesirable results. One condition would be the misalignment of the Wavefront Timing Control. If the compressed and rarified images are not registered (time aligned) then you will hear a bloated and out of focus final image. The second and more common condition is the incorrect grounding of the overall system. This is one of the most difficult issues to deal with in today’s hi fi systems. Audiophiles have spent a small fortune obtaining isolation transformers, filter boxes with special power outlets for digital and separate outlets for analog and so on. Some have dedicated lines for each component in their system. Some have converted part of their system to balanced power. All of these newly added devices may help but it also makes the equation for ideal grounding more complex. The bottom line is that there should not be ANY ground loops in the system when you’re done. If a loop exists it will surely interfere with the operation of H-CAT and make it nearly impossible to use the WTC effectively. Even if you have no “noise” in your system when you (pause) the source material - this does not guarantee that you do not have ground loop(s). The manual recommends a "star" ground where the preamplifier alone is grounded to a wall outlet and everthing else is ungrounded. This is the only way to assure you have no ground loops. Please take the time to get it right - the results are worth it.
Some comments from owners...
The following comments are from a new customer that took the 30-day money back trial from (Mike) at VSO marketing - after 2 days in his system…
Mike,
No refunds, please. The price of admission is more than worth it! Wow - where do I begin. Basics - cymbals - beautiful tinkling, sizzling, punctuating, individual instruments all by themselves; Snare drums - snappy & distinctive; Kick drums - they actually have tone; Basses - big and spacious, you can hear the timbre very clearly, meaning you can hear the higher frequencies of the strings; guitars - acoustics are sensational, you can hear very clearly the attack of the player with the strings vibrating or not against the frets, you can feel the thump of a hand on the sound board and recognize when the player has moved off the mic a bit; pianos - boy do they sound nice filling here and there - a chord, a line, left and right hands; vocals exactly how raspy is Clapton’s voice compared to Allman’s?. Effects - the delicacy of reverb reveals itself, which brings me to the Sound Stage - the delicacy of that reverb is now revealed across a stage that is as wide as the speakers are apart (somewhat wider actually), previously you could hear instruments, of course, across that stage, but the reverb is real surprise; not only is there width, but depth. You can really get a feel for where the instrument is on the stage. You can hear the individual voices making up the back up vocals; Space - its as if you can sense the air in the music because there is space between the instruments, I can hear the two different drummers in the Allmans Bros. Band - the ride of the right hand drummer’s and the splash of the left hand’s, you can tell how far apart the instruments are from each other - Transparency - it all just sits there and shimmers in front of you, volume doesn’t slam you any longer, it’s just this pleasant wash of sound. You were right, it’s like old times when you sit and listen to the music for music. All these exquisite timbres working together to form a whole, moving together, moving separately, coming together again. I can’t wait to hear it all. It took a while to find the sweet spot and at first I thought I was nuts because 0 sounded better than + numbers. But then, I started going in the negative direction and it all started to pop out. I’m still settling in, but boy it’s like an old shoe already. And I read that once it’s broken in it’s even better? Is that true?
Thank you very, very much...
Aloha,
Dave [B.]
Some excerpts from Audiogon postings...
The H-Cat just keeps getting better and better…I have never heard a more realistic sounding preamp than the H-Cat. I own a pair of Duntech Sovereigns which I have had for 26 years. I also have owned preamps which were considered top-rank in their time (Audio Research, Spectral, Placette passive. Threshold) and I am here to tell you that I had never heard how really, really great the Sovereigns are until I purchased the H-Cat. It is an unbelievable piece of engineering and the sound that comes through it is amazingly "alive". Get you hands on an H-Cat preamp and see how really great your [speakers] can sound. I've been an Audiophile for 50 years and love it more than ever. Trust me.
“Soundlock” (Audiogon)
I've been an H-Cat dealer for a couple of years now. I've owned & listened to the last 3 versions of this preamplifier. The Doppler detection & correction technology that Roger has developed has been evolving for a quite a while now. Based on what I hear at home with the P12R he has finally managed to exploit this technology. I've had my P12R for about 10 days so far so and it has been running in 24/7. I promise, I will try not to start babbling on and on about the sound. I've been doing that that all week :) But I will try to explain a characteristic this preamp brings to the system. It really sounds like this preamp is bringing the system to a state of "absolute phase", if there is such a thing. Individual sounds, voices, images, etc. are portrayed with such a direct - phase correct, extremely transparent manner, it's a rather unsettling experience. Overall I find it difficult to explain the sound of this piece, because it has so little self sound. I just sounds like you are listening to "the" recording for the first time. If the music is textured rich and lush sounding that is all you will get. If the recording is very fast paced and dynamic, it will sound blindingly fast and amazingly powerful. I can hardly imagine what this thing will do when it's finshed breaking in. I would strongly encourage you to seek out an audition of this P12R preamp for yourself.
“Tony007” (Audiogon)
This from "Joeperfi" who has owned a P-12, P-12A and now the P-12R (x7) remote -
Yes, it was Norm's suggestion to give this equipment a try and I am now an H-CAT convert. The first time I heard it was at Rogers in a system that also had his power amp. I won't give the details about the other equipment; let's just say that it was very ordinary. I found Anna Logg's review in TAS to be right on. Cheap CD's were very enjoyable, the audiophile stuff sounded magnitudes better as it should. The remarkable thing was that I was able to almost see the performers, their (stereo) position and focus was just so precise. I had only heard this perhaps once or twice in my audio experience and both times at audio salons in systems that were almost six figures. I'll give you an example. On Shawn Colvin's Cover Girl she does a live version of "Killing the Blues". She's sitting in a chair and you can hear it squeak and rock as she performs but the exact position of the chair has always been vague. In this system with H-CAT I knew exactly where the chair was located (just to right of center and a bit lower, closer to the floor). I was amazed. And this was the same for all types of music. There was no effort involved with finding and locating performers across the wall of sound. With regard to tonal balance, it doesn't seem to have a sound of its own just that of what else is in the system. (I know this sounds so much like magazine reviewer "speak" and I'm kinda cringing as I write this, but I can't come up with any other way to convey my experiences) In my own system, the unit is dead quite and responds to any and all changes you make. (Norm has much more experience with ancillaries) I have not done much experimenting yet because I'm awaiting the arrival of the power amp. I'll be able to comment again when I complete my system (all H-CAT) and experiment with cables, cords etc. ... you really need to hear this equipment.
I sold my 14k JRDG Coherence II and have not looked back.
--Joe
"Joeperfi" (Audiogon)
From AudioAsylum - reviews by Norm...
In July of 2002 in a review on AudioAsylum, Norm said of the then P-12 H-Cat line stage -
What will most impress you is the sound staging. Performers are narrower as their location is more specific; this is one of the design goals of H-Cat. No more yard wide mouths! This all contributes to a more plausible sound stage and realism. Applause on live recordings is real. The timbre of instruments and vocalists without the smear of normal electronics is truly exceptional and real. Volume settings are a real problem with this preamp. Because there is no smearing around the sounds, you are likely to turn up the volume to get to what you previously liked. This works fine until there is a crescendo when you may clip your amps! I cannot believe that I much prefer a solid state preamp! I have heard some exceptional tube preamps and have never been able to stand even the best transistor preamps. I cannot believe that I am now considering buying the SS amps from H-Cat. Listen to these units at your own peril. You will buy them.
In February, 2008 he updated this review, saying -
I would say that were I able to compare the first P-12 I had (which received TAS's Golden Ear award) I would think it broken. What sets the H-Cat P-12R x7 apart is the realism of the sound stage and the trueness of tones, with both being the result of the Doppler correction. On most recordings, either vinyl or digital, I get an uncanny realism that really does impress you of being at the recording venue. I toured the last CES and THE Show with a copy of the FIM K2 Sampler playing cuts 2 and 16 in most sites I visited. There were enormous differences in what I heard in different suites. Some were excellent reproducers and others caused me to leave quickly. There was no H-Cat at CES, but on returning home, my sound quickly bested the best of the best at CES. No doubt the inferior sound at CES was a combination of poor rooms, unbroken in equipment, and manufacturers sharing the expense of the rooms and as a result using equipment that often held down good speakers from sounding like it in rooms.
H-CAT™ Vacuum Fluorescent Display shows all settings at a glance.
The P-12R has built-in memory for re-setting the WTC when selecting a different source
Pricing
Holographic - Cloning Amplifier Technology (Made in U.S.A.)
(DF-100.2 Power Amp) 100 watts per channel / X8 Doppler Control Sysytm / $7995.00
(P-12R Preamp with X8/WTC Full Rem) 2 Ch, 4 input Line Stage / $4995.00 (Extended with no price increase)
(PH-300 Phono Preamp) Moving Magnet / Moving Coil / now with X7 DCS / $3495.00
See the original Golden Ear Award in the Dec/Jan issue (139) of The Absolute Sound
Where to audition H-CAT™...
This web site is currently being updated including our dealer listings.
In the meantime, to locate a dealer near you contact us at mydealer
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