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krca44

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Postovi objavljeno od krca44

    Odakle krenuti u svet vrteški?

    in Analogue

    Napisano

    Pre sat vremena, zerowaf reče

    Imam i jednu SPU A koja je, valjda originalno stanje. Zvuk joj je puno gušći od preostale tri, čak i gušći od stare GT/e.

    Te originalne tako sviraju jer imaju aluminijumski kantilever / konus-elipsa iglu 99% - cim stavis Boron kantilever i neku Fine Line odmah dobijes moderniji Hi-Fi zvuk.

    Treba to malo da ispitas, kako je izvedeno u originalu pa mozda trazis takav remont.

     

     

    Linkovi i Literatura

    in Data and tips

    Napisano

    Jel ima neko papire Mileta Nestorovica o cevnim pojacalima ?

    Na net-u ih vise nema a sa dropbox-om imam neke probleme - ako neko ima i voljan je da posalje na mail - ako staje ( gmail salje do 23 Mb ) - molim kontaktirajte me na pm za mail.

    Zahvaljujem unapred, Krca

    Kompenzator minor (Oprez! Sadržaj može prikazati Tannoy drivere!)

    in Zvučnici

    Napisano

    pre 10 minuta, zerowaf reče

    Zato nema jasnih relacija nigdje na svijetu koje mogu biti univerzalna pomoć

    Hvala - sve ovo sto si napisao mi donekle pomaze.

    Nisam nezadovoljan postojecim zicama ali povremeno mislim da bi mozda moglo biti sve malo kvalitetnije.

    Navikao sam na prezentaciju sa solid core zicama i relativno skoro ( 4.-ti/5.-ti put ) odvojio jedan dan da ponovo isprobam licnaste kablove koje posedujem, neki ofc 2-2,5mm2 i kombinaciju srebro/bakar 2,5mm2 - oba ova kabla su u odnosu na solid core unosila promenu u smislu naduvane zvucne slike sa nedovoljnim fokusom instrumenata i generalno jasno mutnijim "zvucnim oblakom".    Radi konteksta solid core daje jasnu i neposrednu prezentaciju. 

    Pa me je zato zanimao Duelund kao konstrukcijski nesto izmedju klasicne licne i solid core-a - i zato jer samo tu cujem jasnu razliku svaki put, na ostalim pozicijama mi nije tako bitno imati ne znam kakav kabl - radi sve kod mene dobro i sa "obicnim" kablovima ( kakva jeres :D ).

    Foliju mozda probam u neko buduce vreme s obzirom da stalno cujem price o tome kako su ljudi jako zadovoljni prelaskom na taj tip kabla....a i nekako mi se cini da je folija cenovno dostupnija sem manualnog rada da se izoluje i konektuje.

     

    Hvala ti jos jednom & izvini za off.

    Čime se zanimam... (ovih dana )

    in Project gallery/WIKI

    Napisano · Izmenjeno od krca44

    pre 7 minuta, NIXIE reče

    Druga nedelja januara je to.

    More nije nista hitno.   :D

    :cheers:

     

    pre 7 minuta, NIXIE reče

    Samo je bitno da kondenzatori budu dovoljno visokog napona za odgovarajući sekundar i to je to.

    1,000 Vdc imam a 10n ce biti 2,000 Vdc - to ima i odgovara mi.

    -------

    Nego to je za sekundar visokog napona - a za grejanje cevi .... hmmm nije visok napon ali ide 0A9 struje na svakom - pa da i tu uzmem bar X klasu mkp kondova ?

    Čime se zanimam... (ovih dana )

    in Project gallery/WIKI

    Napisano · Izmenjeno od krca44

    pre 38 minuta, NIXIE reče

    Samo da nađem još neki trafo da ovo probam

     

    Ako hoces dacu ti ja dva trafoa za probu....:bad_boys_20:

    taman mi pomognes da dobijem snubber vrednosti.... :D

     

    Uuups - izvini sad sam ukapirao kakav ti trafo treba, nazalost nemam ( imam trafo sa sekundarom od 21 Vac / 250 mA - ako ti igra mozes ga koristiti dok ne nadjes neki odgovarajuci, duze vreme ).

    Rupa na saksiji

    in Zvučnici

    Napisano

    Na temu CD drajvera bez horne videh slike Altec kutija na kojima je to probano, pre jedno 60-70 godina pa su izgleda odmah odustali ( neki komerc model ).

    Znam da su neki ljudi to radili relativno skoro ali iz onoga sto sam procitao / video to mi izgleda dosta nedoreceno - tipa sta su mane i slicno.

    Rupa na saksiji

    in Zvučnici

    Napisano

    Evo da ti citiram kako je radio kutiju i skretnicu drugog reda :

     

    "Going into more detail on the Altec Valencia and the Altec Model 19, the Valencia was a pre-Theile/Small vented speaker with a very basic 12 dB/octave crossover at a nominal 800 Hz. No horn EQ.

    The Model 19 came out ten years later as the successor to the Valencia. The bass cabinet is a T/S vented bass alignment in a 9 cubic foot enclosure, and the crossover was moved up to 1200 Hz, with adjustable mid and HF equalization. The bass driver and HF horn were essentially the same as before, while the compression driver was improved with the Tangerine phase plug.

    Another difference between the Valencia and the Model 19 was the Valencia was designed at the end of the tube era, and transistors had completely replaced tube amps when the Model 19 was designed.

    The new speaker is intended for use with triode amplifiers with damping factors of about 4 (Zout = 2 ohms), a closed box is a better choice, giving an overall system Qts between 0.9 and 1.0, not that different than the classic acoustic suspension speakers of the Fifties ... a moderate bass lift. Crossovers are similar, and the horn is a much flatter modern design."

     

    "It is standard practice to sum all resistances appearing at the terminals of the bass speaker ... output Z of the amplifier + cable resistance + DCR of the series inductor(s) of the lowpass section of the crossover. As mentioned above, this raises the system Qts if the box size is the same, but can be offset if the box size is increased.

    The overall goal is to have the Altec/GPA 416 Alnico-magnet driver in a loosely filled closed box, with source Z's between 1 and 2 ohms, and also accounting for "room lift" in the below-60 Hz region. An alternate approach is to use a vented box with about twice the volume, preferably in an alignment with favorable group delay characteristics.

    Both LF and HF sections use a passive crossover in the 640 to 800 Hz range, powered by a single amplifier in the 10 to 60-watt range. The expected attenuation in the HF section will be about 10 to 12 dB, with a shelf equalizer if the Yuichi A290 or ES290 type horn is used.

    It is a simple 2-way system optimized for vacuum tube amplifiers with zero to moderate feedback. If response down to 20 Hz is desired, that can be provided with a separately powered pair of subwoofers. In that application, Class AB or Class D amplifiers are the best choice, since they have the most power, are the most efficient, and there is limited impression of tonality below 40 Hz."

     

    "I want to thank Joseph (Troy) Crowe for his extensive measurements on the Altec/GPA 416 Alnico in a 100L sealed box enclosure. I suspect the very low IM distortion is the result of the underhung voice coil, which is very rare in modern drivers. I am also gratified to see the cumulative-decay (waterfall) curves are as good as they are.

    416 Measurements :
    https://josephcrowe.com/blogs/news/altec-416-8b-in-100l-sealed

    I also want to thank Gary Dahl for completing the Beyond the Ariel project with his sealed-box Great Plains Audio 416 Alnicos and the AH425 Azurahorn. He's chosen the extremely rare Yamaha 6688 compression driver, while I will be following Joseph Crowe's guidance on the SB Audience CDN-65T driver, which has remarkable performance for a large format compression driver.

    I will be contacting Joseph Crowe for guidance on getting the last mile of this project done: an optimal crossover, most probably using an 1.8 kHz notch filter for the 416, and a 3D-printed or NC-milled adaptor between the 1.4" circular exit of the CDN-65T driver and the 2.0" square entrance of the Athos Audio Yuichi A290 wood horn. Alternatively, using Crowe's own ES-290 wood horn, but I already have both AH425's and A290's horns sitting in the basement, awaiting use. I don't think I need three sets of horns to play with, but who knows?

    The measurements referenced above show a crossover in the 640 to 800 Hz region is well-suited to the 416, especially with a moderate notch filter tuned to 1.8 kHz. I still favor large format compression drivers, since they allow a crossover well below 1.2 kHz, in the 500 to 800 Hz region. An octave makes a big difference in this frequency region.

    The SB Audience driver is unusual because it extends smoothly to 17 kHz, while most drivers with 3 to 4-inch diameter Ti or Al diaphragms usually have their first resonance around 13 kHz. I don't know what SB has done, but that is exceptional performance, approaching carbon fiber or beryllium diaphragms, at one-third to one-tenth the price.

    As for other questions, I have no recommendations for transistor amplifiers, either Class AB or Class D, or bipolar transistor vs GaN FET. From what I heard at the Seattle show, Class D using GaN FETs has come a long way, and has surpassed linear Class AB transistor, but still isn't quite in DHT triode territory yet. But is getting close."

    Rupa na saksiji

    in Zvučnici

    Napisano · Izmenjeno od krca44

    pre 17 časa, chakija reče

    Poenta je korišćenje kompresionog BEZ horne... To već nisam radio

    Vidi ovde :

    https://www.diyaudio.com/community/threads/beyond-the-ariel.100392/page-767

    Par stranica pre toga Lynn objasnjava koncept - zatvorena kutija / kompresija + cd & Horna

     

    Smo probaj da gabaritno smanjis koncept.

     

    P.S. Izvini sad vidim da sam malo omasio al nema veze probao je on i RAAL kao visoki pa mozda odatle nesto uspes da izvuces.

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