Aleks Napisano Oktobar 6, 2018 Share #199 Napisano Oktobar 6, 2018 Šta znači A B C D ? Mislim u zvučnom smislu? Čime poterati ovo? Jel može 6V6 (Salasov)? Msm, ne merem da pravim, a možda i da? čisto informativno. Pre svega treba $$$ za 200W disipacije, pa onda ostalo... Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 6, 2018 Share #200 Napisano Oktobar 6, 2018 malo razlike u gainu , malo razlike u Rout , malo razlike u THD , pa cak i THD spectra (odnos izmedju 2nd i 3rd) moze to da se svede i na 100-njak W disipacije , ne mora 200W , naravno uz manju snagu Aleks je reagovao/la na ovo 1 Link to comment Podeli na ovim sajtovima More sharing options...
vladd Napisano Oktobar 7, 2018 Share #201 Napisano Oktobar 7, 2018 Bolje bi cucnuo Iron, nego salasova igrarija. Ja nekako ne volem da miksujem koncepcije. Link to comment Podeli na ovim sajtovima More sharing options...
Aleks Napisano Oktobar 7, 2018 Share #202 Napisano Oktobar 7, 2018 10 hours ago, Zen Mod said: malo razlike u gainu , malo razlike u Rout , malo razlike u THD , pa cak i THD spectra (odnos izmedju 2nd i 3rd) moze to da se svede i na 100-njak W disipacije , ne mora 200W , naravno uz manju snagu Može ovako? Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 7, 2018 Share #203 Napisano Oktobar 7, 2018 aha samo drain od SIT-a oznaci voltazu kako bi trebalo , volt-dva manje od U/2 Link to comment Podeli na ovim sajtovima More sharing options...
Mikorist Napisano Oktobar 7, 2018 Share #204 Napisano Oktobar 7, 2018 16 hours ago, Zen Mod said: iteracija ampa koji je Nele skontao sa 2SK77B Da li se meni čini da i Nele prelazi na 2SK182 / THF51 Link to comment Podeli na ovim sajtovima More sharing options...
Mikorist Napisano Oktobar 7, 2018 Share #205 Napisano Oktobar 7, 2018 Ovo je deo iz Neletovog Manual za SIT3 Quote Introduction to and History of Static Induction Transistors In the mid 1970's a special variety of Jfet invented in Japan called a Static Induction Transistor (SIT) found its way into the “VFET” power amplifiers produced by Yamaha and Sony. These amplifiers were produced for several years and then discontinued, but are still highly regarded in the high end audio community. SIT devices have a unique characteristic which is of particular value for audio amplifiers. Quoting inventor Nishizawa's patent abstract, “(The) drain-current to drain-voltage characteristic simulates the anode-current to anode-voltage characteristic of the Triode vacuum tube very closely.” They have found use in radar and other exotic applications, but after Sony and Yamaha ceased production, versions suitable for audio power amplification have been highly prized and difficult to obtain. There has been renewed interest in SITs, partly because two companies have stepped up to the plate and spent the money required to fabricate new devices suitable for audio power amplifiers. The first of these is Digital Do Main in Japan, which has produced amplifiers based on newer versions of original Yamaha Silicon parts. The other is First Watt, which arranged for a production run of a new SIT device using a newer Silicon Carbide process by SemiSouth. It is that “Triode characteristic” which makes the SIT so special. Your ordinary power Jfet or Mosfet is a voltage variable current source with a set of curves which looks like a Pentode tube: By contrast, the SIT is a voltage variable resistor with a set of curves that look like a Triode: Audiophiles often go to great expense to achieve as little as 5 watts of power using Triodes because of their specific sonic character. Unfortunately Triode performance is limited partly by the need to transform the high voltage / low current operation of the Triode down to the low voltage / high current domain of loudspeakers. This means a power transformer and the distortion comes with it. Of course it would be nice if Triodes drove speakers without transformers. It has been a goal of some designers to get transistors to sound like Triodes, with very limited success. Fets can sound like Pentodes, but it takes a particular set of gyrations to make a Fet do the Triode trick.Then there are those who think that nothing less than a glowing bottle will satisfy tube aficionados. Perhaps that is true, but it isn't going to keep me from trying. There are two things we want out of a solid state device for this purpose. First,we want a “square law” input characteristic like that of tubes. Fortunately, Fets do that already – the current through the Fet is a good square law function of the Gate to Source voltage. Second, we want a low Drain resistance, equivalent to the Plate impedance of the Triode. This is where gain device can be regarded as a variable resistor instead of a variable current source. Why do we want this characteristic? Three reasons - first, it allows a single gain stage with both voltage and current gain, and having a high input impedance and low output impedance without a feedback loop or degeneration. Second, this character allows “working the load-line” - the particular description of the path of the gain device through the voltage/current region in the course of amplifying into the loudspeaker. By choosing this line wisely, you can achieve intrinsically lower distortion. Pentodes and Mosfets aren't as good at this. Third, like Triodes, SITs have a soft overload characteristic. When over-driven on peaks they present compressed, rounded waveforms instead of sharp clipping, the result being that they are more graceful under pressure. The entire effort revolves around simplicity and minimalism in circuit design. Certainly you can get good objective performance with multi-stage circuits and negative feedback. What we want is the sound that can be had from a single gain stage operated single-ended Class A without feedback or degeneration. We want it with a high input impedance and a low output impedance, and we want it with reasonably low and simple distortion. It is worth noting that the original efforts by Sony and Yamaha were not minimalist – they contained many parts in multiple gain stages and used a generous amount of feedback. Forty years later, the emphasis is on using the character of the SIT to achieve performance in a simple circuit. There are several reasons for the push toward minimalism. The first is simply aesthetic – there is much to admire about an amplifier which performs well with only one transistor. And of course there is an attractive challenge, which is “How good can you make such an amplifier?” There is another, more practical reason to explore simple circuits. It is generally agreed that if you are going to have distortion, you will want it in a low order harmonic form, kept to only second and third harmonic if possible. A singleended Class A device is going to generally give you the simplest version of this. Lots of audiophiles dislike the sound of negative feedback (or at least think they do). It is true that while negative feedback reduces the amount of distortion, it does tend to re-arrange it so that the character is more complex. Minimalism is the raison d'etre for SIT devices in audio. With them you can get good objective and subjective performance from a single SIT in a very simple circuit. Pametnom dosta . . . Aleks and Srecko je reagovao/la na ovo 1 1 Link to comment Podeli na ovim sajtovima More sharing options...
Mikorist Napisano Oktobar 7, 2018 Share #206 Napisano Oktobar 7, 2018 23 hours ago, Vix said: A i kondovi ogoljeni, negde procitah da tako bolje zvuce A ne videh ni osigurac Ko ne čuje razliku između ogoljenog i neogoljenog konda - ne može sebe nazivati audiofilom. Link to comment Podeli na ovim sajtovima More sharing options...
vladd Napisano Oktobar 8, 2018 Share #207 Napisano Oktobar 8, 2018 Ko ne pije vino iz Gaskonje, ne moz' da bude audiofil, ic... Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #208 Napisano Oktobar 8, 2018 kujgabe,uskoro ce pravim jedan, za napolje Dakle,opet razvoj.... Link to comment Podeli na ovim sajtovima More sharing options...
Impuls Napisano Oktobar 8, 2018 Share #209 Napisano Oktobar 8, 2018 On 10/6/2018 at 11:35 PM, Zen Mod said: ja mislim da ovo nece da radi. ili da preciziram, siguran sam da nece raditi Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #210 Napisano Oktobar 8, 2018 sto? Link to comment Podeli na ovim sajtovima More sharing options...
Impuls Napisano Oktobar 8, 2018 Share #211 Napisano Oktobar 8, 2018 zakucali ste ulaz na zenericu, nedostaje otpornik izmedju. A ovi 0.1 otpornici ce zavisiti od gornjeg feta da se ujednaci izlazna impedansa donje i gornje periode. mozda je nelson bas odabrao fet sa slicnom karakteristikom thf-u. treba snimiti harmonite pri razlicitim nivoima glasnoce da e vidi poklapanje gornje i donje periode Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #212 Napisano Oktobar 8, 2018 tesko da ce na gate da udje 18Vpp signal ikada ako udje , u problemu si Link to comment Podeli na ovim sajtovima More sharing options...
Impuls Napisano Oktobar 8, 2018 Share #213 Napisano Oktobar 8, 2018 zakucao si ulaz na 9v1. signal ce ici kroz zenericu a ne kroz thf. Ako si ulaz thf zakucao za 9,1V sta t vredi signal da dolazi kad je on uvek na 9v1. Bilo bi ispravno da ste napravili negativan referentni napon za gejt ali mora otpornikda bude prema tom naponu da postoji sving na gejtu. Ne interesuje me sta je nelson pricao na baf-u, kazem kako treba elektronicki Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #214 Napisano Oktobar 8, 2018 -B je prednapon za biasovanje SIT-a , za 3A je red velicine par volti 9V1 je zastita gate-a ........ SIT-ovi su osetljivi na preveliki negativni prednapon Link to comment Podeli na ovim sajtovima More sharing options...
Impuls Napisano Oktobar 8, 2018 Share #215 Napisano Oktobar 8, 2018 Hoces da kazes na semi nedostaje sklop za biasovanje sit-a? Zar nij jednostanije bilo iskoristiti vec tu zenericu samo dodati trimer za biasovanje sit-a? To znaci da ovaj sklop ne radi jer mu nedostaje jos sklopova za rad Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #216 Napisano Oktobar 8, 2018 pa vidi se iz aviona da ga nema .... mislim - luk i voda - otpornik i zenerica i kond i trimpot pogledaj linkovani snimak , pricao je 20 minuta o konceptu , kao i pokazao merenja napravljenog primerka Link to comment Podeli na ovim sajtovima More sharing options...
Impuls Napisano Oktobar 8, 2018 Share #217 Napisano Oktobar 8, 2018 ja sam banuo na semu koju ste stavili i sa takvom konfiguracijom vieo da ne moze raditi. nisam gledao video i nisam zakljucio iz date seme da je -b napon za biasovanje vec mi je izgledalo kao da je to negativan napon za polarisanje zenerice. U redu upao sam nepripremljen u temu pa cu je ubuduce preskociti jer me ne interesuje pojacalo za koje moram da vijam tranzistor a kad crkne da se oprostim od njega. Ako i budem poklonio paznju uradicu sa necim dostupnim a da se zadrzi pecat koji amp daje. Shvatam da je trenutni hajp za sit pojacavacima ali mislim da se moze uraditi i nesto drukcije a da radi posao isto ili mozda bolje sa drukcijim tranzistorima imozda bi trebalo malo tragati za nekim savremenijim koji bi zadovoljio buducnost na neko vreme. Ako je igbt mogao da zameni ulaz feta a izlaz bipolarca onda ce i neka kombinacija dva poluprovodnika da zameni sit adekvatno Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Oktobar 8, 2018 Share #218 Napisano Oktobar 8, 2018 pogledaj snimak ; po prakticno istoj semi ali sa dovitljivim trikovima je dao kako da napravis sa modernim i nabavljivim IXYS mosfetima ...... mozes da odradis i scale down i na kraju dobijes amp za tepsiju ribe uopste nije poenta u SIT-u kao jedinom resenju , nego je SIT odredjena referenca rezultata , razumevanje zasto je referenca i sta se moze nauciti iz toga hype ili moda naokolo, svejedno ...... ja se ovim ne bavim da bih uvek imao sledece najbolje , nego mi je prvenstveno zabavno s druge strane , zasto ne iskoristiti zabavu da svima bude bolje - em nesto naucim , nekome napravim nesto sto nikad ne bi mogao drugacije da ima , em se zaradi kinta za prsute i vina edit: kako mislis da crkne 400-500W tranzistor , jos narocito ako znas sta radis ? Link to comment Podeli na ovim sajtovima More sharing options...
vladd Napisano Oktobar 9, 2018 Share #219 Napisano Oktobar 9, 2018 7 hours ago, Impuls said: Ako je igbt mogao da zameni ulaz feta a izlaz bipolarca onda ce i neka kombinacija dva poluprovodnika da zameni sit adekvatno To je nesto kao dedukcija nevine domacice? Nece se to dogoditi, iz vise razloga, i ne moze da se dogodi, i nema potrebe, posto se oni "ozbiljni", koji razvijaju komponente, bave uveliko vrlo visokim frekvencijama. Audio je u velikom zapecku.. SIT je definitivno komponenta koja je tehnoloski ostala u svom prostoru i vremenu nastanka, i kao takva vrhunska za vec, vrlo opravdano izhajpovanu konfiguracije SE, ali znacajno bolje nego u varijanti triode. U svakom slucaju, SIT je obesmislio SETOTL, sa nekoliko desetina mocnih trioda(za nakapavanje nekih struja), nikada uparenih, u tehnickom smislu, u nekom raspojasavanju druge vrste ionako nema zdrave logike... Link to comment Podeli na ovim sajtovima More sharing options...
neskor Napisano Oktobar 9, 2018 Share #220 Napisano Oktobar 9, 2018 19 minutes ago, vladd said: SIT je definitivno komponenta koja je tehnoloski ostala u svom prostoru i vremenu nastanka, i kao takva vrhunska za vec, vrlo opravdano izhajpovanu konfiguracije SE, ali znacajno bolje nego u varijanti triode. zivi bili, pa videli Link to comment Podeli na ovim sajtovima More sharing options...
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