Spatial Inc preamp

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amolas

Member
Joined 2005
In the past, my father owned a Spatial inc preamp, which sounded very well !

I know that it uses a technology called T-FET Valves...

But I was not able to get more information about it. So now, I'd like to build such a preamp.

Does anyone have any information about this preamp ?

PS : I don't know if it's the good place to ask... but I hope you will able to help me !

Have a nice day

Antoine
 
lineup

lineup

Member
Joined 2005
Looks like Richard Knapp may have been the constructor of this preamplifier.
But found almost nothing about this amp, besides at his own website,
where he tells how good he is:

Audio Science & Engineering

Audio Engineering: invented numerous audio and sound technologies, including: coherent pre, mic, line, and power amplifiers [TFET]; multi-band noise reduction, compression, expansion, and exciter systems; non/powered loudspeaker systems; true-3D stereo recording system.

Audiophile Electronics: designed the Spatial Coherence Preamplifier and Power Amplifier, audiophile amplifiers that received world-wide acclaim as "by far the best sound."

Semiconductor Physics: invented the TFET-Valve Coherent Amplification Technology [2 patents] implemented in the Spatial, Inc. audiophile electronics, using an original discovery of electron-velocity modulation to linearize the transconductance functional.

Audio Phenomenology: solved the issue of auditory differences among amplifier technologies, a problem debated for decades, using coherent information theory as it applies to semiconductor physics.
Click to expand...

http://www.msoracle.com/rktech.htm
 
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lineup

Member
Joined 2005
amolas said:
Thank you for answering to my post ;)

I 've read this website, I will try to contact him, because it seems that his job is no more linked with audio...
Perhaps he will give me some details...

Any other informations ?
Click to expand...

Yeah, contact him.
I am sure he will be glad to talk about his unique amp.
If so, maybe you will find others that wants to build this, too.
:)
 
Nixie

Nixie

Banned
Joined 2006
I just read it, and the core idea is in the latter patent's summary:
In accordance with the method, the nominal operating point for a Field Effect Device is chosen so that the electric field in the drain depletion region is biased in the carrier partial velocity saturation regime. With this biasing, the transconductance and output conductance of the field effect device have the same current dependence so that the rario of these two parameters is independent of current. Thus the gain of the device is independent of bias source noise, so that the bias source noise does not modulate the input signal. In addition, if a device is biased in accordance with the present invention, the drain noise modulation of the edge of the drain depletion zone emulates that created by a gate input, so that the depletion zone noise may be considered as a gate input noise, andd the transconductance is not intermodulated by that noise. Accordingly, the output of the device is substantially free of noise intermodulation components and has maximum coherence with an equivalent gate input so as to both minimize the noise output by the field effect device and allow maximum reduction of the noise when using feedback.
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Removing modulation with power supply noise is not interesting because one can just have a very well filtered power supply. What is, however, interesting is his claim that his biasing method ameliorates the effects of modulation with the device's intrinsic noise. Is it BS or is there something to it? Hopefully someone here will answer this for us.
 
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lineup

Member
Joined 2005
In accordance with the method, the nominal operating point for a Field Effect Device is chosen so that the electric field in the drain depletion region is biased in the carrier partial velocity saturation regime. With this biasing, the transconductance and output conductance of the field effect device have the same current dependence so that the rario of these two parameters is independent of current. Thus the gain of the device is independent of bias source noise, so that the bias source noise does not modulate the input signal. In addition, if a device is biased in accordance with the present invention, the drain noise modulation of the edge of the drain depletion zone emulates that created by a gate input, so that the depletion zone noise may be considered as a gate input noise, andd the transconductance is not intermodulated by that noise. Accordingly, the output of the device is substantially free of noise intermodulation components and has maximum coherence with an equivalent gate input so as to both minimize the noise output by the field effect device and allow maximum reduction of the noise when using feedback.

That is a good one.

I wouldn't give myself trouble to search for a patent for this,
when I can't show any useful products or practical results of it.
Why should I?

I can say just about the same in this way:
I have set up, using fet transistors, a circuit
that is pretty much without noise.
It works good.
And I would present a simplified circuit topology along with this.
Not necessarily with all component values shown.
:)

lineup
 
Nixie

Nixie

Banned
Joined 2006
Well, I though he had commercial products where this was implemented.

I got more interesting replies when I posted this on the prodigy-pro forums:

I think what he's saying is that he has a way of making the drain noise modulation emulate gate noise... always assuming that drain noise is significantly higher than gate noise, and if this is the case, then removal of modulation by that noise could possibly be beneficial
Click to expand...

What he seems to have done is drawn attention to the "triode" region of a FET operating point. This is not, typically, the operating point for miniumum noise. But since in that region, incrementally, the transconductance has the same dependence on channel current as does the output conductance, when driving a high-Z load, and with high-Z biasing, for small signals the distortion should be low.
Click to expand...

What I really can't figure out is why people on diyaudio instantly condemn or praise something and expect their reasoning to be apparent without further elaboration in 90% of the posts.

Your replies are useless to me if you don't give any reasoning behind your conclusions.
 
anatech

anatech

Administrator
Joined 2004
Paid Member
Hi Nixie,
1. Read his web site.
2. No commercial examples of this preamp exist.
3. Total noise is often referred to an equivalent input terminal noise.

I deal with some low noise, high performance audio circuits (although older examples). His work would definitely be utilized by more companies or at least copied by some if it was useful.

There will be posts based on opinion. Mine are and I am not going to set up some test situations for this. It just doesn't sound right to me.

Now, take the diamond buffer. That circuit configuration is enjoying a resurgence of popularity. So is error correction. Those have use.

Anyway, noise is completely random in nature. If it could be eliminated, op amp engineers would have done so. Same for LNB designers right down to the lowly phono cartridge designer.

-Chris
 
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lineup

Member
Joined 2005
Nixie said:

What I really can't figure out is
why people on diyaudio instantly condemn or praise something
and expect their reasoning to be apparent
without further elaboration in 90% of the posts.

Your replies are useless to me if you don't give any reasoning behind your conclusions.
Click to expand...

Why don't you post some more details, Nixie
if you even have such details .....
Like a practical circuit - using what you think is model of this.

How can you you get good answers from us
... you can't expect us to search the web or even go to another website
just to GIVE YOU basic facts and details.
If yo want good answers, please Bring discusson stuff HERE.

Otherwise, I'm afraid, you will get nothing more
then random shooting in the blind.

We are trigger happy, VERY - when people talk here about something
that is of no use for most DIY builders.
Because diy audio projects and constructions
.. is what this website is mainly about.
It NOT, mainly,
- a discussion club for intellectuals and higher educated electronics besser-wissers
- with meter after meter with interesting papers in their bookshelfs
- where not one useful audio devices or circuit has come out of it

- seems like some can go on discussing audio topic for months
- that are close at atom physics level
.... but does this ever produce anything useful
.... what i have seen : NO! NO!

========================================

for example:
I have seen highly educated, Engineers and University peoples here
seriously discussing loudspeaker cable models and effects
endlessly, for a long period
---- all that were way above my head ----
...
If putting so much energy and time and effort into a thing
by guys that are way more clever and knowing than little lineup

.. wouldn't you expect at least ONE Useful Loudspeaker Project
with one prototype and details and schmematic
so we can build the best cable
:D

lineup :cool: Can make a good loudspeaker cable - WITHOUT SCHEMATIC
 
M

mariogert

Member
Joined 2006
dekunstvlieg.nl
D

DORENLOT

Member
Joined 2012
Hi, this message is for Tichu. I don't know if you have find some pictures of the inside of an original Spatial Coherence preamp. If you already need some, I can send you all you wanted. I am an owner of this preamp (n°571) for 30 years and as it's broken down on one channel it's open !!! If you have some information to repair it Iam taker !!! Thank's.
Eric
 
J

jmgilmore3

Member
Joined 2006
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