"...the best preamplifier ever made" says Mr. David Price, Hi-Fi- World

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That is not unusual, crows like shiny things and pick them up off the ground all the time. In the same way the psychology of television buying has the majority of people respond positively to the garish, over-saturated, overly contrasted image on the given TV in the shop. They buy that one, not realizing that after the 5 minute showroom romance is over that they now have to live permanently with this garish thing. Thankfully, these are merely settings that are programmed into the TV for the 'battle in the showroom'.

The same goes for the psychology of audiophiles.

Lets imagine that I make a cable that is obviously harsh and in it's mid-treble harshness is faking the detail out of self-noise and hiding real detail--this is quite easy to do. I remove the false detail and show the real detail that then appears in the noise floor or lowest levels -- and people complain that the cable is now dark.

The larger part of the audiophile crowd are relatively uneducated as to what real detail sounds like, as they've been raised in this faulted environment for so long (that for many of them) they have never heard a real and actual balance that is largely free of artifacts. A decent portion of this issue lies at the feet of loudspeakers due to their noise floor rarely eclipsing 20-25db, and the mis-education of audiophiles, due to the way they've had to learn to listen..and what they've been presented with by manufacturers. Audiophiles can have a large novice base (50%+) to their group (like any hobby group) and that novice crowd can be, usually is - and in this hobby is the group that has the most disposable cash.

So the novices create the worshipful caricatures (idolatry) out of specific manufacturers and their harsh and veiled products, in their mental and aural laziness that may or may not change over time, depending on the given novice individual.

So the bulk of the audio market is interested in noise masked as detail while true detail is lost in the dirtiness of the sound. Then they have the gall to ask you to fix it, somehow, as they finally report the thing that you ~KNOW~ they will eventually report. Listener fatigue! They are listening to transient related noise.

The cables I'm producing are, due to their method of conduction at the quantum level, largely free from molecular interaction noise, and can also self-shape the flow according to the load, in essence, they are self canceling of distortions at the exact molecular point of origin. Which is about as good as it is ever going to get. As well, I can take one (three singles, for this purpose) of the coaxial designs..and transmit a stunning analog 1080P component signal through them.
 
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If the winding are unterminated what kind of "mass bounce" you're talking about??
It must "bounce" even more in OPTS with higher currents. There are already too many "esoteric manufacturers" on the market ..

I've outlined the basic premise and execution above. A straightforward resistive execution for damping and control over the time domain of the given ring is likely the simplest and most effective path to a fix. Overdamping does damage too, so a small amount of damping with high resistance is likely the smart way to go. Basically, you are attempting to effect a simple and linear drain. Kinda like a constant flow (always open) pressure relief on an air shock. Akin to the original 'variovent' for loudspeakers.

Thorsten may have reasons for not revealing his particular 'fix', and there may be business related reasons for that stance.

The molecular transfer of energy, or electron transfer in latticed materials, has an inherent noise associated with it that is impossible to escape. The corollary to that is the quantum nature of inductance and it's mirror is skin effect. The two sides of that coin combine to create this transient emphasis in the broadband signal we call 'audio'. We get temporal skewing, and then stacked distortions, in the micro sense. If we fix the noise we will inherently loose signal to some minor degree. We fight with the noise vs signal balance all the time, when we buy and reject gear, or we try and design gear using various methods. But we cannot escape the coin and it's two sides - it is what we are working with, no other choice exists at this time.

Specifications and measurements do not suffice to show these issues. As an example of inherent molecular self noise due to design of the given device at the molecular level, we need look no further than sanyo os-con solid electrolyte capacitors. They have amazing specifications. They also sound like total carp.
 
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IMO, you don't want active(ish) circuits that take care of energies after the horse has escaped the barn, so to speak. You want to eliminate noise at the point if it's inception and you want to do it as passively as possible. The reason for that is the complex myriad dynamics of audio signals prevents a singular solution (best effective with steady state) from being entirely effective.

However, the saving grace is that the transformer has an equally specific resonance issue, for the larger part, so a solution of that nature might be effective -- but just for me, theoretically, it would not be my first choice. Practicality (a working solution) can make my my thinking and desires ineffective, though.
 
i'm with thorsten on this.

lightspeed sounds attractive in short A/B comparisons as subjectively sounds more detailed - hence the preference on the short demos. however it lacks subjective music qualities and simply loses in the room.

i believe i've heard all the known optocoupler volume schematics - they differ but the bottom line is they can't compete niether with AVCs nor TVCs in playing music.

the only LDR device i've heard sounding truly fantastic was paul haynes active (ECC88 i think) preamp with LDRs. (mind i haven't heard any of the stock products from yamaha, dartzeel, accuphase and others that claim to use a lightspeed concept)...

this leads me to wondering if there's more space for development of the basic concept. i think we haven't heard the LDRs in full power yet - at least not from a DIY product.
 
Hi george,



This is an interresting supposition. You are familiar with psycho-acoustics? And the fact that some times a distorted signal can sound subjectively better than an undistorted one?

Do a 60 HZ sound with 0% distortion is sound better than with distortion hum ? they still hum noise, music sound can only judge by listening, good volume control can make sound stage move closer or go away, not only turn louder.
regard Tony Ma
 
Hi,

Alright, I do have true MK1 units and would be interested to learn the trick with minimizing "bounce" if it is not a secret.

There is quite a bit variation in the MKI resonances and you must be empirical, plus you need a solid measurement setup.

First measure the frequency response at 0dB setting with your intended source and load impedance (include all parasitics you can account for).

Add small chokes or choke/resistor parallel combo's to the input and RC snubbers to the output (across transformer secondary) if needed, to attain a flat input impedance and a flat frequency response with a well controlled rolloff (uaully around 35K). Try to keep the capacitance values in the snubbers as low as possible and the resistor value as high as possible.

Then crosscheck the impulse response and if neccesary allow some peaking in the FR to get good steep slopes.

Depending on the exact pair of transformers you got and operating conditions you may find not a lot of need to correct the 0dB Attenuation FR/IR and may be able to correct using LR input circuits only.

Next switch to the range you normally use most.

Repeate the process above using a series RC circuit from the 0dB Tap to the wiper of the switch.

This snubber can be a bit more brutal, value-wise, but not too much, as you increase attenuation it will more and more load the transformer and source.

The optimum values for this vary sufficiently between units that if I gavce the values applied to the sample discussed they would likely be wrong for your application.

Ciao T
 
Hi,

Thorsten, what are your thoughts re autoformers vs transformers issue?

Well, strictly as a pure volume control there is little to choose, I am sure different devices from different manufacturers sound different and may be preferable to one or the other for a range of reasons.

What I find attractive with a true transformer as VC is that it can be employed in a wide range of "unorthodox" applications and that it can break earth/ground loops and so on.

An Autoformer simply can never do that and the performance gained with the unorthodox applications certainly convinces me.

Ciao T
 
Well, the comparison is not that simple. The TVC can actually work as stand alone preamp, offering 6dB gain, high input impedance and low output impedance, it can be wired for phase reversing and unbalanced to balanced (and opposite) conversion, all without any additional active circuitry.

Can your Lightspeed do all that?

Well said. And this isn't even the best quality of a TVC. With every signal there is power (watts), which is voltage times current. With a resistor type attenuator, the voltage drops, but the current does not proportionally increase, resulting in a loss of power. With a TVC, as the voltage drops, the current increases, maintaining the original power (less a small amount for the transformer windings).

ALSO, as the voltage drops, the impedance drops by a factor of squared. So, LOTS of punch and detail at low volumes.
More info about TVCs here:
FAQ for transformer volume contr

I have a Promitheus TVC, made in Malaysia (standard version, not reference).
Transformer Volume Control

I plugged it in at the home of the head of my audio club, who has a Jadis 4-chassis tube preamp, a truly high end machine (one of the channel power supplies was not working, so he didn't have a preamp at that time). My little Promitheus TVC was at least the equal of that incredibly expensive tube collection, according to the owner. And the Promitheus (basic) is only about $500US. Of course the better the core and the transformer, the better it will sound. And Promitheus offers their reference c-core transformers with the TVC, for a bit higher price of course.

And this is just one company. Check out Sowter:
SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL
They offer transformers with taps that you can use to build your own TVC.

Companies are coming out with TVC preamps claiming theirs is the best, but you can pay 1/20 of the price and get a damn fine preamp.

Gary
 
LDR passive pre better than TVC? I think so

OK it has been a while since I made that last post about transformer volume controls. In a weak moment I sold my Promitheous TVC to a friend of mine and then I got a Django TVC which I think may be a bit better. I used that for quite a while and was very happy with it, until I read about light dependent resistor (LDR) passive preamps. The best one I could find is the Tortuga LDR passive preamp and a year ago Christmas I took the plunge and bought one, partly because of the 30 day return policy. The way it works is that varying light from an internal diode shines on the light dependent resistor and this adjusts the LDR resistance for more or less resistance (volume). This allows you to have a remote volume control without that interfering with the signal path. All fine and good.

When I listened to it I could not believe the difference. With the Tortuga LDR passive pre, the sound was more clear and open, more detail with more punch and generally more “real“ sounding. I let it burn in for a few weeks and I know it got even better. Then I put the Django TVC back in and the Django actually sounded a bit muffled. Perhaps all that wire inside with the Transformers. I got the Django TVC used for about $600, and it is an older model. The Tortuga LDR passive preamp was about $1200, so I did put out some more coin for it. But I think the investment was well worth it. It is my go to preamp now and I really like it.

I also paid a bit more for the upgraded latest and greatest circuit board. That made it sound even a bit better.

By the way, Morten, the president of the company is very accessible and assisted me in a couple of problems I had with the preamp. No big deal, but he was very helpful and will not leave you twisting in the wind.

So why does a light dependent resistor in the path sound even better than a regular resistor or potentiometer? Dunno, and I don’t care why. All I care about is the liveliness of my music and how it makes me feel.

So there you have it. I know that the TVC listed above is supposed to be the best preamp ever, but I would question that now. Perhaps it is the best TVC passive preamp.
 
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