NVA, Diego nardi e gli Audioti

Richard Dunn ha scritto:First, I apologise for writing in English, as I am afraid I do not speak Italian.

I have to rely on Google translation, which is not very accurate, especially when some of you write in slang Italian.

There is much misinformation and insult that has been published here and in that article from what I can see, plus that article is libellous and I have not yet decided if I can be be bothered to sue, but here I have the right of reply, for which I thank you.

There has been so much false information published that it is difficult to know where to start, so what I would ask is that forum members either repeat statements made or ask question regarding our design and construction and I will reply. There is one I will address here as it seems fundamental and a classic example of the ignorance and misinformation published in this thread. I am told that we mount the output transistors with some sort of cement and that it is unnatural and against safety regulations and bad design, well I will draw your attention to a product called Loctite 315 output adhesive, which has been designed specifically for this job and is generally available worldwide. So if you members of this forum, or the so called expert who wrote the article, have not heard of it then I am afraid it is your ignorance.

The other thing that concerns me is the lack of knowledge as to CE marking and safety regulation. Again I am afraid this is ignorance, as one of you member said CE is a self certification process either with the help of a testing company or using your own documentation. It is up to other to prove that CE is not complied with. But CE is a very loosely help regulation otherwise there would be *no* valve amplifiers made, as valves cannot fit in the rules of CE regulation. Also you should note that this amplifier has different regulation as opposed to most other amplifiers, it is a different electronic product class. Almost all hi-fi products fall under Class 1 regulation, we use Class 2 regulations (double insulated) that means we have to do things differently to the way you are used to. Any true electronics engineer would recognise this if they had any knowledge. If you wish to read about it then go to http://en.wikipedia.org/wiki/Appliance_classes

Anyway I am here to answer any comments or questions, but I will not enter into fights with rude idiots! I will ignore them.

Richard

Mr. Dunn, ask to who inform you about this discussion, to buy the last number of the specialistic magazine Costruire HiFi and to ship it to you. It costs just 5 euro.

Here there's just a report about the article published on that magazine about your product. Also, the author of that article is a well know guy here in italy, and not just a journalist.

Before to continue to use "ignorance", "idiots" and any other negative term, read the article, do not make a good impression to be rude...

Richard Dunn ha scritto:First, I apologise for writing in English, as I am afraid I do not speak Italian.

I have to rely on Google translation, which is not very accurate, especially when some of you write in slang Italian.

There is much misinformation and insult that has been published here and in that article from what I can see, plus that article is libellous and I have not yet decided if I can be be bothered to sue, but here I have the right of reply, for which I thank you.

There has been so much false information published that it is difficult to know where to start, so what I would ask is that forum members either repeat statements made or ask question regarding our design and construction and I will reply. There is one I will address here as it seems fundamental and a classic example of the ignorance and misinformation published in this thread. I am told that we mount the output transistors with some sort of cement and that it is unnatural and against safety regulations and bad design, well I will draw your attention to a product called Loctite 315 output adhesive, which has been designed specifically for this job and is generally available worldwide. So if you members of this forum, or the so called expert who wrote the article, have not heard of it then I am afraid it is your ignorance.

The other thing that concerns me is the lack of knowledge as to CE marking and safety regulation. Again I am afraid this is ignorance, as one of you member said CE is a self certification process either with the help of a testing company or using your own documentation. It is up to other to prove that CE is not complied with. But CE is a very loosely help regulation otherwise there would be *no* valve amplifiers made, as valves cannot fit in the rules of CE regulation. Also you should note that this amplifier has different regulation as opposed to most other amplifiers, it is a different electronic product class. Almost all hi-fi products fall under Class 1 regulation, we use Class 2 regulations (double insulated) that means we have to do things differently to the way you are used to. Any true electronics engineer would recognise this if they had any knowledge. If you wish to read about it then go to http://en.wikipedia.org/wiki/Appliance_classes

Anyway I am here to answer any comments or questions, but I will not enter into fights with rude idiots! I will ignore them.

Richard

Hi Richard and thank you for being here!
First of all, please forgive my english, but I really slept the most part of my english lessons at school and here's the result!
A lot of us readed about NVA products and many of us want to listen to them working very much, believe me, but can you answer me some questions about some doubts we had seeing them open in their cabinets?
For example:
why the choice of using glued pieces of wood instead of bits?
why so many not insulated wires?
I want to let you know that I'm asking these questions only for knowing something more about audio diy and not for anything else!
Thank you very much again!

The amplifier that was repaired (or not!) is 15 years old, we do things differently now. It has been an on going process of removing resonant and field interfering parts from the construction. Back then we still used aluminium in the case for top and bottom covers and back panel, with front panel made of acrylic and side cheeks of wood. All the metal plates were anodised and the panels are glued together so had no electrical connection, so still Class 2. But it was open to question as we still used metal in the outside case, so we have now changed to a full acrylic case as DNM use as well. The wood was used as a stand off for the board as it was convenient at that time, we no longer use it as the pcb can be laid close to the new case as it is entirely acrylic and we now use rubber pads as stand off.

The uninsulated wires are used because we feel the insulation creates resonance, and anyway air is the best insulator. The cable is 16swg tinned plated copper bar, so it doesn't move, so it cannot come in contact with anything. It only carries signal or voltage rail or 0v so there is no danger, and anyway we have a sealed case, with instruction not to open so everything is safe and within regulation

Richard

Richard Dunn ha scritto:The amplifier that was repaired (or not!) is 15 years old, we do things differently now. It has been an on going process of removing resonant and field interfering parts from the construction. Back then we still used aluminium in the case for top and bottom covers and back panel, with front panel made of acrylic and side cheeks of wood. All the metal plates were anodised and the panels are glued together so had no electrical connection, so still Class 2. But it was open to question as we still used metal in the outside case, so we have now changed to a full acrylic case as DNM use as well. The wood was used as a stand off for the board as it was convenient at that time, we no longer use it as the pcb can be laid close to the new case as it is entirely acrylic and we now use rubber pads as stand off.

The uninsulated wires are used because we feel the insulation creates resonance, and anyway air is the best insulator. The cable is 16swg tinned plated copper bar, so it doesn't move, so it cannot come in contact with anything. It only carries signal or voltage rail or 0v so there is no danger, and anyway we have a sealed case, with instruction not to open so everything is safe and within regulation

Richard

Thank you so much for your answer, Richard!
Your explanation is really interesting! But can I ask you something else?
Why do you think that metal (iron or steel) bits or spacers can interfer more than aluminium casings and heatsinks? Is it because of the non-magnetic properties of aluminium?
Thank you again!

quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

Diglielo in inglese, no?
E probabilmente intendeva che l'aria è il miglior dielettrico, cosa, peraltro, assolutamente vera, no?

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

ma quel filo volante, non alimenta il led sul frontale? Mi sbaglio? Pure quello crea risonanze?

Ma io un po' di guaina la vedo, a sinistra... li non ce n'é risonanze?

piero7 ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

ma quel filo volante, non alimenta il led sul frontale? Mi sbaglio? Pure quello crea risonanze?

Ma io un po' di guaina la vedo, a sinistra... li non ce n'é risonanze?

Vi dà fastidio dirglielo direttamente?

non glie lo so dire in inglese, se usa google translator credo che non abbia difficolta' a fare la traduzione.

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

Aristide ma davvero credi a questa cosa??

poluca ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

Aristide ma davvero credi a questa cosa??

naaaa

"the insulation creates resonance"
"air is the best insulator"
and then
air creates resonance

aris69 ha scritto:

poluca ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

Aristide ma davvero credi a questa cosa??

naaaa

....pensavo!!

porfido ha scritto:

piero7 ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!
Stiamo imparando molte cose, grazie Mr. Richard Dunn.

ma quel filo volante, non alimenta il led sul frontale? Mi sbaglio? Pure quello crea risonanze?

Ma io un po' di guaina la vedo, a sinistra... li non ce n'é risonanze?

Vi dà fastidio dirglielo direttamente?

A me no, ma infatti, non mi interessa dirglielo. Quando uno si presenta come s'è presentato lui, dando dell'ignorante e del cretino a destra e a manca, e che giustifica con "risonanza" il perché non ha isolato un filo che sembra che vada ad un led, mi suona tanto di nullologia, ed intavolare una discussione facendo uso di google translator perché l'interlocutore non ti comprende mi pare, francamente, tempo perso. Questo mi suona come un certo grundista che venne qui e che... ricordi?

A parte il fatto che da un genio mi sarei aspettato risposte ben diverse da un paio di "ignorante", di "cretino" e di "risonanza". Ma magari i geni so fatti così e magari pure fanno tutti così... boh! E non ho nessun interesse a tirare in mezzo nardi in questa discussione. Io, a differenza di altri, ho di meglio da fare che fare il ruffiano per conto terzi.

P.S. avevo pensato di prendere qualche foto di qualche apparecchio progettato da un vero maestro di qualche prodotto di fama mondiale indiscussa. Ma servirebbe a qualche cosa? Matteo tfan cable maglio del genio, e a prescindere dalle risonanze (vere o presunte e che a me lasciano basito) in tanti anni di passione audiofila da semplice hobbista, un prodotto commerciale fatto a quella maniera non l'ho MAI visto, ne' in foto che dal vivo. E di foto di aggeggi ne abbiamo viste davvero tante...

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!

L'aria e' il miglior dielettrico.

piero7 ha scritto:
A me no, ma infatti, non mi interessa dirglielo.

Poi non te la prendere quando ti si da del "rude" - il modo in cui hai scritto certi post in questo thread era decisamente poco educato.

For Richard, to avoid silly google translation:
Then dont feel hit when they call you "rude" - the way in which you wrote certain posts in this theread was definitely unpolite.

Telstar ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!

L'aria e' il miglior dielettrico.

ok, grazie per la precisazione, avevo interpretato male.

Telstar ha scritto:

piero7 ha scritto:
A me no, ma infatti, non mi interessa dirglielo.

Poi non te la prendere quando ti si da del "rude" - il modo in cui hai scritto certi post in questo thread era decisamente poco educato.

Questo post è nato come semplice reportage di un articolo, non è il primo che apro su articoli di CHF. E' iniziato così: su CHF i questo mese c'è un articolo su... etc etc e suggerivo di comprare la rivista e leggerlo. Stop!

La mia presunta rudezza viene dal solito king of polemica che l'ha buttata in vacca, e non contento, è andato pure ruffianeggiare, dimenticando che l'autore dell'articolo è Diego Nardi, non io. Son convinto che se ne avessi parlato tu, non avrebbe fatto le pagine che ha fatto sto post. Se poi aggiungiamo che di "costrutto" non c'è niente, ma son solo post di bla bla bla, e abbiamo detto tutto. E bisognerebbe pure sapre cosa è stato riferito a dunn, perché è arrivato qui a testa bassa...

Telstar ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!

L'aria e' il miglior dielettrico.

Il migliore è il vuoto spinto ....

Telstar ha scritto:

aris69 ha scritto:quindi niente guaina termorestringente sui cavi perche' crea risonanza, l'aria e' il miglior isolante!!!

L'aria e' il miglior dielettrico.

Si, ma ha una costante dielettrica variante con l'umidità!
Ciao Mauro

......no è l'aria fritta....ma de che stamo a parlà,........eddai!!

poluca ha scritto:......no è l'aria fritta....ma de che stamo a parlà,........eddai!!

Non so'... forse dei vecchi e bellissimi condensatori variabili lamellari in aria delle radio valvolari!
Ciao Mauro

Eeeeeh, ridete, ridete, cari miei....

Sorry for late reply as I have been Christmas shopping to Oxford Street and then some nice BBQ duck in Chinatown, just got back.

Anyway there seems to be a fascination in the LED dropper resistor. I presume some of you understand what happens to a voltage dropper resistor. The power that is being dropped most go somewhere, and it goes to heat. So if you put heatshrink over the resistor firstly it will stop the resistor dissipating that heat and will likely burn, and secondly if placed over the wires again you lose heat dissipation from the wire. Plus it seems no one here seems to understand class 2 construction, it means double insulation not triple as that is unnecessary. The anodising on the heatsink is one insulation and the acrylic case is second insulation. Also the resistor is in the air above the heatsink and will stay there as the wires holding it are rigid, so there is another insulator which is air.

Regarding metal, every manufacturer has his ideas and foibles, they may be right and they may be wrong, but there is an English expression "that the proof of a pudding is in the eating", so it is very easy to see if you agree with my design choices, and that is buy an amplifier, and if you don't like my choices send it back for a refund. Anyway there is lots of metal in the amplifier, as every component has metal leads, every wire is made of metal, PCB tracks are metal, even solder is metal, heatsink has to be metal, all of those are unavoidable and good. All I object to is ferrous cases that contain the field generated by circuits and transformers. If a field is blocked it doesn't dissipate it reflects and mixes with new field and creates harmonic patterns that interfere with the music. It is much better to let the field out to dissipate naturally. This makes the unit more susceptible to field getting in, but this is only a problem with a phono amplifier.

I think the root of your lack of understanding is down to two things 1/ I strive to keep things simple as anything in the signal path gets in the way of the music 2/ I use class 2 IEC electronic regulations, which none of you seem to understand. For instance with class 2 I have to use a fixed mains lead.

Someone commented I think that the circuit is complicated and uses a lot of transistors, again little understanding. A large number of those transistors are in the current mirror, which means the voltage rails track each other automatically so there is no bias set-up or circuit voltage drift over time and temperature. So they are not in the signal path, so the gain circuit is still simple. Think of them as a form of regulation. You also have to take into account that the circuit is designed to be used with a passive pre-amp, so there is more voltage gain than usual in the power amp.

I think that covers everything so far, but I am obviously open to more questions.

Hello Mr. Dunn and welcome in the T-Forum!!!
Many of forum's peoples are DIY and homemade amplifiers and other audio electronics: We do non comment about the very hight quality sound of your amplifiers, we have same perplexity for the assemby methods looking internal photos of your amplifiers.
Why You do not use isolating copper wires? why flying wires?
we like to see more electrical security in commercial electronics around transformers and power supply.
Thank's Mr. Dunn and excuse for my bad english