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Topic: The ultimate buffer #2...?

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Posted by Romy the Cat on 11-23-2006

If you remember it was the way how it started:    HELP: I’m a line-level looser.

Then there was this one: The ultimate buffer – light in the end of a tunnel

and course then it lead to the following: Reviewing preamps by imbeciles.

it is really insulting that it is so damn difficult to have an absolutely transparent buffer. The Guy Hammel buffer is absolutely transparent but it is “bitey”. Guy kindly agreed to supply his buffer in order to incorporate tem into “projects” but with $2K it is little but painful. For instance for the FM Time Delay that Dima was contemplating it would be necessary 4 buffers… So, I was bitching about a lock of absolutely transparent buffers and Dima said why you worry? Let me to built one.

Well, a couple days ago I received from Dima a prototype of his buffer. It has no gain – just an active SS follower with output impedance. Dima used in there his “signature Newton Bias” the similar that he uses in his Zarathustra hybrid amp. I hardly know what it is and I successfully resist all his attempts to make me to understand it. I decided that I will learn about it if the buffer will sound absolutely transparent.BR>

I built for it a PS and put it yesterday in use. It works. It is not transparent and has at this point some sonic imperfections and some musical blemishes. Most likely I will spend some efforts to get the best out of this buffer and will see if this design will be useable. I will be posting about the progress.

The caT

Posted by Romy the Cat on 11-24-2006

Interesting that a notion of an Absolutely Transparent Stage is kind of bizarre. Let presume that we do have an Absolutely Transparent, musically and sonically, stage. The stage might be transparent only with own enclosed scope. If a stage modifies transparency in regards to any other reasonable external conditions then we would probably call it “Transparent”. Right?  Still, we have lot highly non-transparent stages in allegedly “Transparent” playback. For instance the driving stage in Melquiades is very non-transparent by itself. If you remember when in past I made an attempt to use juts Melquiades’ driving stage in a stand-alone application (ether with transformer or capacitor coupling) then that idea failed die to it was quite a pour sounding and very non-transparent sounding preamp. However, in context of whole amps, the driving stage combines with Melquiades output stage for whatever reasons demonstrates more transparency then juts just any of the amp’s single stages. Interesting! We nave a two-stage, no global feedback amplifier where each stage is not necessarily “transparent” but the entire amplifiers is relatively transparent… isn’t it strange?

In my assessment of Transparency I more frequently use term Eventlessness instead of Transparency. The buffer’ input is Realty and the buffer’ output is Realty. The buffer itself is a Realty Exchange Mechanism that does whatever it does but while doing it injects into the Output Realty own events. There are different events. There are transparent events. A division or multiplication by “1” is a transparent event in mathematics. If the values of numbers could be determined ONLY but the fact that they even numbers then a multiplication by 2 is also an absolutely transparent event. In many instance in audio, but not always(!), a pace of wire could be considered as absolutely transparent mechanism that do not impose any “event”…

Interesting that although most of the “Audio Events” are negative but sometime  the Audio Events, although they have own methodologically negative value but they still are not affect musically and sonically quality of the Output Realty. In fact sometimes the pure Audio Events not only do not violate Output Realty but embrace and stimulate it… Here is where the “Beach Effect” perhaps kicks in….

Romy the Cat

Posted by Romy the Cat on 11-27-2006

.... of “the buffer transparent” and it does not look as transparent at all. The buffer adds some very minor dynamic compression, very-very minor transient’s corruption, some overlaying sense of grayness and generally if has more fatter sound then a “just wire”. It feels like someone injected smog into music. The smog is very minor and it does not affect sound itself but rather inform me that some alien form took peace in sound. I was wondering how MUCH was placebo in what I feel but regardless of the placebo, so far, I do detect some quite audible lack of transparency with this buffer. Perhaps something should be tweaked in implementation. Perhaps the topology might be different… I do not know… Generally what the buffer does is not different then any other preamp that I’ve heard; in fact, it is much better then most preamps out there. Still it is not absolutely transparent buffer yet….


Posted by morricab on 12-05-2006
Hi Romy,
I too have for quite some time been on a quest for a truly transparent preamp.  To this end I have tried some that were indeed very good such as the Silvaweld SWC 1000 that I now own and especially the Vacuumstate RTP-3d from Allen Wright, which is the closest to invisible I have yet heard.  My own Sivaweld, while being very good indeed, is not completely neutral tonally.  Dynamically it seems to be just about right but I can hear some coloration in the lower mids.

None of the so called "passive" solutions I have heard did the job; be they transformers or resistor based...until very recently.  All of the ones I heard before lost information in tone and especially dynamics.  However; I have now heard one that appears not to lose anything nor does it add anything (the transformer based "passives" all add something as well as losing something).  It is from a company in Germany called Purist, which is a pretentious sounding name, but it appears to lose nothing in dynamics and nothing in tone.  It is resistor based using very expensive Vishay resistors but apparently it has been impedance optimized for audio signals (the designer is a high frequency engineer by training) so it appears not to have the losses normally heard with "passive" solutions.  I will be trying this out in more detail in the future but my initial impressions were very positive and revealed to me quite clearly the coloration from my current preamp.  So far it is the closest to truly invisible I have yet found from a preamp.

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