[ TNT | Who we are | Ampli | Diffusori | Sorgenti | Tweakings | Inter.Views ]

Inter.View with G. Nember and the designers of Praecisa Acoustics

by Lucio Cadeddu

[Italian version]

LC >
Praecisa Acoustics is a lively Italian firm that is involved both on standard HiFi components manufacturing and in DIY kits.
May you tell us the history of this firm?

GN >
The name "PRAECISA acoustics" was created at the beginning of the 90s, but the passion and realization of the first apparatus for hi-fi kits goes back to the 60s.

In fact at that time, given the almost total lack of quality products of solid state on the Italian market, I (the writer of this article) made the first models of stereophone equipment, which were constructed completely by myself, except the record player (the DUAL and the THORENS) and eventually the recorder with coils.
This activity was done, given the limited means, along with my main job which gave me my so-called daily bread. It seems incredible, but the initiative was such a success, that I gave up my main job and some years later, I decided to start a small business with hi-fi equipment.

The passion for creating hi-fi equipment brought a certain success and became more developed, but always in a local area. At the beginning of the 70s this visceral passion, together with a great love for good music, led to a courageous adventure of construction: a studio for audio registration MULTI-TRACK.

That was a rarity in Italy at the time and unique for Brescia.
For this realization I used as a basis a 3/4 inch magnetic recorder for the computer, found at the fair of radiance and eletronics in Mantova, which after some patient work was transformed radically with regard to mechanics and electronics, and became an apparatus of 1 inch.
I then constructed the recorder audio with double track of 1/4 inch for the final stereo mixing, and the mixer board for multi-track registration.
For the loudspeakers, once again constructed by myself, I used some marvellous original loudspeakers from GOODMANS, without centring on the external cone and even the component for artificial reverberation was constructed by myself, after having seen and listened to a professional one of the EMT, at a registration studio in Milan.

Later on, also due to the fact that there did not exist any audio registration studios in Brescia, this work had developed up to a point where I had to leave it to others together with all the apparatuses which had been realized.
There followed some years where the activity continued almost exclusively in the commercial sector, and I had to abandon any work on projects, which made me suffer quite a bit.

Towards the end of the eighties I left all the commercial side to some very valid young people who are enthusiastic about this type of product and who continued extremely well and are still doing so.
For my part, after a short period of settling, I dedicated myself full time to the same passion as before: research in the field of audio.
During that period some projects of innovative loudspeakers were realized, which afterwards were handed over to the company which produces them in series still today for Italy and abroad (I do not want to give names for the reason of fairness).

Immediately afterwards I dedicated myself to the study and realization of some new projects both for kit and for finished products.
In fact the project "PRAECISA acoustics" was started (the name is of Latin origin and means: well defined, clear in the outlines, cut well), containing some kits to present in a new way.
The idea was to guarantee to the audiophile a good result by giving him the "know how" and the material for constructing by himself a real HI-END product in an easier way and with costs that are definitely lower than traditional HI-END products which are very expensive and almost always imported.

This is how the first electronic kits were born: the "pre NSP/1" and the power amplifiers "Mosfets 100 and 200" apart from some models for loudspeakers. The characteristic that all the electronic kits had in common was unusual, because they were given with the cards already assembled and tuned in our laboratory.
This choice was made after a detailed analysis of time, cost and image. The conclusion was that it was more convenient to act like this in every regard.

The cards which are assembled in our laboratory (strictly by hand) are most delicate and for this reason they are soldered with good quality alloy, for this we have expert workers and soldering irons with electronic control of temperature, a thing which rarely happens with do-it-yourself construction.

As it was the case then and still is today, after the assembly and soldering, the cards are undergoing a first testing and ageing test for 24 hours, under instrumental control and therefore, if the components have any faults or do not satisfy the specifications, we can notice these before they are delivered to the client.

The do-it-yourselfer has the valuable task of assembling safe components and it is left to his personal taste to eventually upgrade some connections.
In any case, the whole kit is planned for having best results already with the components given in the kit. Our clients told us that we were right, they were also satisfied with the more complex constructions and it was worth the money.
The historical part is finished here and we come to the present.

Recently the kit for loudspeakers F2 and the finished version F2/GOLD was designed, which incorporates a certain amount of innovations in the field.
The loudspeakers were in fact planned with regard to the needs of do-it-yourselfers in order to be personalized quickly, by giving the possibility to be completely disassembled in the kit version, by loosening only two screws.
Even though there is this unusual detail, once the system is assembled, it has a stability which is difficult to be found in the commercial products; the stability is due to the system "ALSON" which makes use of the technique of pretension of materials.

The finished products, which are made to be distributed in hi-quality shops, have been updated with regard to some small details in the circuit, in the cards of the "pre" and the power amps, without affecting the initial project.
At the present state of research we think that our solid-state electronics are in no way inferior to any products with valves, on the contrary, in contrast to what you might think, they have a sweet sound, clearly defined and very close to reality, without the problems characteristic of valves, and last but not least they can also drive loads which are "not easy" and have a module of impedance of 2 ohm.

Very recent and absolutely innovative with regard to sonic and aesthetic profile is the "NUOVO" loudspeaker with its beautiful form of a natural element (an egg, axctually).
Its planning and definitive realization took more than 1 year.

I would like to recall also our last complement apparatuses: "FASATORE", "BRIDGE" and the Valvolizer.
This shows our continuous effort in research and an enduring passion.

LC >
You seem to prefer solid state electronics to vaccum tube ones.
What do you think of this revival of old designs and old technologies?

GN >
For some years amplification with valves has been reintroduced and has had a positive effect for enthusiasts of HI-FI which was a rather quiet sector.

To tell the truth I am convinced about the good sound of the electronics with valves and I think that the relatively recent success of this revival is due to the fact that listening to the sound of the majority of solid-state products makes you forget that there is a delicious sound, decidedly airy and pleasant like that of electronics with valves of good quality.
This degradation was noticed in time by the ears of the not very young fans, while the younger ones, who had no previous elements for confronting, could choose as well as possible from what the market offered (mainly Japanese and Taiwanese).
The most disturbing element is that those choices were often guided by authoritative magazines of the sector.
In most cases in fact, apart from very rare exceptions, the electronic products made in big assembly lines in the Orient were characterized by a cold, dry and unnatural sound, typical for the poor selection in the quality of components and with highly negative reaction.
We have to keep in mind that the instrumental measuring of such apparatuses done in the lab gave comfort to those who did the tests by giving them flat diagrams and excellent frequency response.
But this is in fact the problem: the value of the instrumental tests was used as a basis and not as support for an opinion about musicality.

Then some years ago probably an enthusiastic opinion leader listened carefully to an old apparatus with amplification with valves and certainly noticed the sweetness and the musicality that had been forgotten in time.
If we combine this with the fact that someone had a nose for new business, then the game is made.
As an example I can give the enormous prices of some products on the market which I think are completely unjustified and the booming of the market of old products.
Please excuse us for this desecration which could annoy some people, but what we are going to say later on is part of our ideas and we think we must not be ashamed of them and must show them openly.
We from PRAECISA have always looked at the phenomenon with scepticism and we confess that we liked the idea of taking part in the game, and we have dedicated the necessary time to compare the sound of our apparatuses (the recent "EXFETS" both "pre" and "power amp") and some good products with valves.
Well, our opinion remains the same: our products are in no way inferior to the apparatuses with valves, but we had to use much more expensive products with valves to have a certain coherence in the comparison.

Talking about the period of reliability, there is no way of confronting the two systems. While the amplifier with valves deteriorates with time and has to be overhauled with not indifferent costs (a pair of valves KT88 chosen and tuned on the apparatus can cost up to 700.000 Liras (400 US $), and one of our clients had to change them after about one year), our electronics become better the more you use them, so that we recommend a running-in period which is above that which is already done in our laboratories.

The valves have a gradual and constant deterioration in time and the components around them suffer from the high temperatures, and as a consequence the parameters are unbalanced and, last but not least, one has to consider the poor possibilities of a power amp with valves to control difficult loads, to a point where the amplification tends to follow the modulus of impedance of the loudspeakers instead of controlling them.
There is a tendency to make the sound sweet and pleasant, but it cannot render the original event at its best.
Nevertheless, in our last cards for our "pre with EXFETS" we have taken some concepts from the amplifiers with valves: the high-tension supply and the monostadium exit of the type CATODE FOLLOWER for the pre.

LC >
It seems you pay a lot of attention to the mechanical construction of your designs, both amplifiers and loudspeakers.
I'd like to know which are the main ideas behind your designs relatively to this issue.

GN >
With mechanics I also mean the distribution and the rationalization of the wiring, of the whole lay-out of the equipment and of the electric panels, as well as the design and the materials for the cabinet of the loudspeakers.
I think that in a real HI-END product one has to take special care of these elements, and above all they have to be realized with materials of first quality, avoiding the waste of unnecessary material which serves only for the *looks*.
In particular in the electronic parts on the path of the signal there has to be the least possible number of solderings which should not be done not with the typical systems of assembly in series.
On the same path the switching contacts have to be reduced to the minimum.
In our "preamp" there is only one switching contact on the inputs and it was made with a custom made element, produced by a very valid Italian company and has gold contact surfaces, protected from oxidation and from dust and guaranteed with a resistence of only 0,01 ohm and for 100.000 switchings.
In our power amplifier I absolutely did not want to have output relays, even though this choice has forced me to elaborate the supply in a new and maybe unique way, but certainly with a high reliability in time and positive influence on the purity of sound.
Of highest importance to me is the control knob for the regulation of the volume which has to be of best quality in order not to jeopardize the purity and the focusing of the sonic image during the adjusting.
I do not like the electronic regulations of volume. The scheme of the electronics is the result of countless experiments on prototypes before reaching the definite version.
With regards to the external mechanics of the cabinets I think that a good mechanic stability can only be good for the general rendering of the sound, both as in/out shielding and to minimize the danger of phenomenon of microsound.
Our frames are made of special steel of increased thickness. Moreover we guarantee that every point is accessible or involves very little dismantling.
Special attention is paid to the disposition of the components in the inside of the cabinet, but this technique, which is the result of sometimes exasperating research, can not be explained in the limited space of an interview.

With regard to the loudspeakers I think they must be as solid as possible. It is important to have a great quantity of materials and solidity, together with techniques to reduce to the minimum the resonance in the cabinet, and also adequate components, in order to guarantee a pure sound possibly without undesired irregular waves.
From this point of view, the front panel of the loudspeaker is a very delicate part.
Just think of all the wholes that have to be made and the resulting weakening. Also the profile of the cabinet is of great importance and how the loudspeakers are fixed to it meccanically; the profile of the loudspeaker has to be connected to the panel and there should not be any edges near it.
In my opinion this problem is often ignored for economic reasons.
In the recent project called F2, this point has been improved so that the remaining elasticity which was already very low, has been reduced to almost zero due to the fixing system of the front panel with the back panel.
Then the front profile was created by one single fusion of special alloy called "ALSON" which guarantees the ranging of the components and an anti-diffraction profile.
Everybody can do a little test by simply knocking with the knuckles of your fingers on various points of the loudspeaker. If the solidity is good then you should hear a deaf sound as if it was a block of marble.
You should try this test for curiosity also on bookshelf loudspeakers made by big distributors (and small ones) and you will notice that very few respect this basic rule.

The loudspeakers of the "bookshelf" type (but the audiophiles know very well that the loudspeakers should never be positioned in that way), are greatly influenced by the height of the stand on which they are installed and also by the surrounding things.
To satisfy this important need the stand PD02 was created, which is unique in its way and can be ordered in the height set by the client.
The method used for the legs of this stand is also based on technology that reduces vibration in order to get a stability which has never been reached before.

LC >
During the last years audiophiles' attention has been caught by problems regarding power supplies, AC cords, power conditioners, mains filters and the like.
How your designs take these aspects into proper account?

GN >
My answer to this question is short not because I underrate the problem, on the contrary I think it is of great importance, but to say what the fans already know more or less, only that they often cannot control it in practical terms.
For a good project we have to take into consideration above all the transformation of alternating current from the network (which often has variations and considerable sudden peaks, irregular waves, radio waves etc.) into direct current, which has to be very clean for the supply of the circuit.
You have to keep in mind that this problem is more serious mainly in the first phases of amplification of the signal which is very weak and therefore more significant and also in the final stage where strong impulsive currents can also jeopardize the stability of supply of the previous stages.
In our pre "model two exf" we wanted to keep the supply separated from the pre. For its filter-system we use not only a number of cells of high capacity but also inductances planned especially for this and divided for every channel and also filters for irregular waves and radio waves.
In the moment when this supply arrives at the pre there is a continuous tension which could be compared to that of a battery of accumulators.

In our amps the supply is kept clearly separate and there are supply systems for the section of the services, the pre-stages, and the power amps; and in the dual version also the amps have a separate supply for each channel and filtered with condensers of high quality and capacity (very low ESR and total capacity of 160.000 uF in the maximum version).
Another detail, which you can find only rarely even in "noble" systems, is the way in which the supply for the amps works: it is a gradual supply with a rate time of about 15 seconds before reaching the maximum value. This was introduced to avoid the sudden stress which can damage the components.

Once it happened to me at the house of some people, who are excessively attached to foreign stereo systems which cost them as much as their flat, that the lights went down in the flat at the moment when the power amp was turned on and, what is even more alarming, the owner was proud of the phenomenon.

LC >
May you explain us the biggest problems in hi-end loudspeakers design?
What is the thing the can really make the difference (speakers, crossover, cabinet...)?
Are you planning to design a budget-conscious loudspeaker?

GN >
In our opinion you get into serious problems when you want to interface the loudspeakers with the furniture in which it is put and with both the active and passive filter.

We have to refuse the idea which the mass media have communicated during the past few years and which says that it is enough to put into the computer the data worked out on paper to get a loudspeaker that sounds good.
The computer programs work well (considering also that the data on paper have to correspond to the data of the loudspeaker in your hands), if you use it to make the first draft of the project, the rough outlines. The real work which often is exhausting consists in testing, modifying, listening and comparing until you get the final result.
We always do these preliminary tests in a room with the characteristics of a room where people live in. Usually we do these tests on prototypes and at this stage the ability of the expert counts enormously because he knows which elements have to be changed to get the result that he wants.
To avoid any sort of psychological influence we often listen to the prototype blindly without saying which one is being tested.
After this final stage the last corrections are made and we get to the realization of the first pair of finished loudspeakers and the results are compared again to the prototypes.
If all goes well we produce both kit and finished version.

With regard to the questions put to me, I think that the quality of the loudspeakers is an important factor.
These qualities have to be tested by confronting varous sets and with this procedure you sometimes have surprises, for example components which are not "noble" nor expensive do better than many other famous products.
There were also surprises by using inductances which we get made custom with decisively lower cost and far superior quality than those that are considered the "top".
But I know that you need to have at your disposal quite a big number of instruments and a storehouse of components in order to make these comparisons.
For the kit of loudspeakers there should not be missing at least one box of inductances and one of condensers and resistances.
For the condensers which we are using in the crossover filters we have found an Italian company which makes a product that can easily be compared to those made for HI-END at a cost that is up to twenty times higher.
The question about the importance of the components of a loudspeaker has been answered already, but I would like to add that the final result is very much connected with the various components that I dare say that every component is important and one of low quality is enough to jeopardize the final result.
In almost all my projects I take into consideration the experience of Eng. OLSON, and therefore I pay great attention to the shape of the cabinet.
The answer to the last part of the question is the following: I think that our kit F2, at a price of Lire 1,350,000 Liras (800 $) for a pair everything included except the cabinet, can satisfy this need if we talk about real HI-END.

LC >
Selling a quality DIY kit is one thing, having the audiophile assembling it the right way at home is a different story.
How do you think to minimize this problem?

GN >
It is true that kits are in a very good phase at the moment especially with regard to valves which are fashion now (see answer N°2), but we have also noticed that many fans were disappointed because they had quite an expensive apparatus and had spent a lot of time without getting the desired results in the end.
I think that our success is due to the fact that we have decided to give a kit which has been tested well and with the cards already assembled and tried out with clear indications for assembling and last but not least a "HOT LINE" for do-it-youselfers where they can speak at any moment to our Mr. Claudio, in charge of the tests.

LC >
May you unveil some of your next-to-come projects? Are you planning an integrated amplifier and/or a CD-player?

GN >
We have often considered the idea of constructing an integrated amplifier in our team, but have never been convinced about it.
We are working on CD-players at the moment, making some upgrades on commercial components.

Praecisa Acoustics:
Phone/fax: +39-30-9718071
Hot line DIY: +39-30-9718071

WWW site E-mail: giannemb@numerica.it

Courtesy Giancarlo Nember for TNT-audio.
Copyright © 1998 Lucio Cadeddu

[ TNT | Who we are | Ampli | Diffusori | Sorgenti | Tweakings | Inter.Views ]