A2Belectronic@wanadoo.fr

Regards,

Rob.

Resorob wrote:

I realise that this is a very old post, but you might want to take a look over here=>> http://www.valvediy.com/simplexpg1.html The article can be downloaded as PDF, the writer Ari Polisois developped a new kind of transformer called SC OPT "Self Compensating Out Put Transformer". This could be a unique transformer and  maybe it can handle the full range at full power. In any case I have never seen a similar transformer. The SC OPT has three windings, primary, secundary and tertiary the tertiary winding compensates for the dc current running through the transformer to the power tubes. Since this magnetism is compensated for, practically the whole core is available for the music signal, maybe Ari Polisois can better explain. Should you want it you can reach him at:

I did not see anything special about the out transformer, at lease in the papers that I read. Also, even if I did see it I’m not convinced that I would be qualified to assess the effectiveness if what Ari offers as it all should be heard.

Regarding Ari’s amp. I would do the input choke filters and beef up the power transformer in the output stage. I do not know how about the Ari’s driver stage. The tube he uses is fine tube but how 2 series halfs of this tube might sound? It should be tried and assessed. Unfortunately Ari does not writhe a lot about sound. It would be interesting if Ari try in there one Melquiades’ 5E5P. Also, Ari for whatever reasons chose to drive the 6C33c too hard. i do not know why but I presume he has his reasons…

Anyhow, the most important subject in the Simplex amplifier is the Direct-Coupling. This is quite competed question and it is not as simple as people usually fill. The logic that the best capacitors are not capacitors is not really applicable in this case, although it is true and the quality and type of the coupling capacitors are hugely important.

You see, there is something that I call: the “Tactical Sound”. The Tactical Sound is the separate inflictions of sounds the different caps inflict to Sound. Also, there is something that I call the “Strategic Sound”. The “Strategic Sound” is not depends from “the sounds” and more relates to the robustness and function of Sound in it’s entirety. The “Strategic Sound” very little depends from the coupling caps or from any other sounds polishing mechanisms but rather form the general topology of an amplifier. The coupling caps unquestionably affect sound negatively (and this why the Melquiades uses the Cubes 950) but the coupling caps (or any other DC blocking between the stages) does affect the “Strategic Sound” in very positive way.

I am not convinced in what I am proposing as I am sure that there are different direct-coupled implementations and I did nit heard all of them. A few years ago Vladimir Lamm published a quite interesting article in Russian magazine about his M1.1 amplifier where he mentioned about his research in the subject of direct coupling and his observations about the negative effect it had to Sound. That article made me to think about it further and to look very careful at my very certain reactions when I hear the two stages direct couple amps. Generally I would concur what Lamm proposed in his article but here is the problem: all my auditions were not “clean” experiments, methodologically speaking. I heard a few (perhaps 3-4 amps) but all of them were “built and closed” amps and there are a lot of other thing in those amps that might very much offset the auditable results. I never had an opportunity to have two stages and then, by building different PS supplies to compare the Tactical Sound and Strategic Sound of direct coupled, C- coupled and perhaps the transformer- coupled.

I know some people who do it and they shared their observations with me. I was not pleased with the level of those assessments as people told me the stories about the Sound but not about Sound. So, the main question in the Ari’s Simplex is: was the direct-coupling a good or bad thing. Unfortunately Ari did not provide any reference point in order to demonstrate the level of his assessments. All that he said was that the Simplex has an “Excellent sound” and it is defiantly too simple statement.

AnonymousUser wrote:

Fourth - What DCMB has achieved ?  a) simplicity  b) speed   c) no frequency discrimination  d) wider frequency range  e) suppression of the PSU noises ( I owe this claim to a Canadian friend who noticed it first), f) single point idle current adjustment and g) (under experiment) possibility of modifying the sound stage.

a) How whatever you/we “speed” relates with whatever we call “harmonic structure” and how realistic the harmonic pattern of your amplifier is

b) I do not know what “no frequency discrimination” is and I do not know at which power you took your frequency sweep. Whatever it was a regular SET, according to my believe, can not work properly full range and requires a DSET configuration

c) How naturalistic the bass and upper bass in your amp. Usually the direct-coupled designs (similar to OTLs) have some strangeness in there and produce overly open and “overly transparent” "melody range". In this case when I say overly transparent I did not mean “quality” but rather the “listener’s transparency”.

It is hard to explain what it the “listener’s transparency” in bass because the idiots who write for audio publications have crated a huge amount of buzz-words and bogus audio definitions but none of those that are important. By suggesting the listener’s transparency in the DC-coupling devises I mean very different concept then it might derive from the words. You see, when we listen music then music has some fulfilling effect. I mean the phrases, melodies, or juts the notes of this sequence is absorbed by out awareness and become our more or less permanent sensorial baggage. The question is if the audio processing topology coil affect the duration of that baggage. What I detected that when I listened the direct-coupled designs I got immediately impressed by the LF harmonic but at the same time I dot immediately “discharged” with my sensorial feeling as soon the music was over. I had very short accumulative memory of my experiences after I head the direct-coupled and the long-term musical fulfillment was very-very challenged. I call it the “listener’s transparency” as music become too transparent for a listener’s awareness and does not hold itself in a listener mind, as least in my mind. 

This why I am very withhold with the two stages, direct-coupled amplifiers…. As least they require a very careful listening assessment to make sure that they do not do their “easy come, easy go” sound…

Rgs,
Romy the Cat

Ari,

I do not think that we recognize the process of “audio designing” as the identical actively. It looks as you peruse to design an amplifier (for instance) as a conceptually well operating system where a set of deferential abstractly-measurable values would complies with some sort of notion that you have. I do not see the things this way. To me an amplifier is not a subject but a service, and this is how I approach to the process of an amplifier designing and an amplifier assessment. To me there is not such a thing as “speed” vs. “harmonics” and from the place where I stay the harmonic patters is measurable but quantifiably it is not interpretable parameter.

What I mean that “a result” might not be assessed with its contribution to the purpose and to the meaning of “the result”. A result is like a”tempo” in music. There is no absolute or predefined tempos, ever the reface to metronome is worthless because there was a number of the different metronome scales. The “correct” tempo is not something fixed but it is “moderated” by very many variables and in the end, result the human practice, tighten to the many not quantifiable reasons, set it to be “right”.

Well, this I sensed from what you have written and it might be a separate subject… If you wish we might continue it in other more appropriate forums of the site.

Meanwhile this specific forum is dedicated to help those crassly people who are wiling to build the Melquiades and we wonder off the subject. I think that your Simplex amp is in the Melquiades alley and it is great that people who might contemplate to build the two stages with 6C33C would have a change to see multiple options and multiple view valuable

PS: Nope, I am not familiar nether with your 3X6C33C amp nor with Duplex