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Mikorist

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Posts posted by Mikorist


  1. Evo lik na BIG DIY - prica o DX3 Pro - sta je dobio sa Sparkos (u izlazu) a sta sa OPA1612  - u zavisnosti sta se menja okolo ( bolji kondezatori i otpornici)

    dobijaju se razliciti rezultati

    Screenshot 2019-12-10 at 15.04.06.png

    https://www.diyaudio.com/forums/digital-line-level/333258-modding-topping-dx3-pro.html

    napominjem da je ovo DAC za slusalice

    .

     

    evo ga i ovde Zenon - nema gde njega nema - jos se samo ovde nije pojavio

    Screenshot 2019-12-10 at 15.12.12.png :smesna:

     

     

    Screenshot 2019-12-10 at 15.17.27.jpg

     

    :smesna:


  2. Sparkos bi trebao biti bolji od Bursona ima distorziju -120db (prema svom merenju na D10). Ja više ne ulazim u nabavku diskretnih opampova. Recimo TI OPA1612 ima performanse bolje od -140db (-140 je na 20hz - 165 je na 15khz ) . (Bolji je i od Sparkos i od Bursona V5 i V6 a jeftiniji) Po meni je pomalo blesavo (i lutrija) iscupati opamp i gurnuti drugi (sem ako je ocigledno fejk) , bez dodatnih intervencija na okolini. Da ne spominjem neku ozbiljniju analizu ili bar razmatranje kola analognog dela…


  3. 6 hours ago, Mikorist said:

    pa sve je bitno. ali ako vidis da pise BB unutra - a BB ne postoji od 2000 - nesto tu ne stima

     

    https://www.vintage-radio.net/forum/showthread.php?t=93127

    :jump:

     

    5 hours ago, Aleks said:

    Iako izašli iz TI fabrike, BB čipovi su do pre neku godinu i dalje imali BB logo na njima.

    Ne znam kako je sada, ali imaš brdo originalnih BB OPA2134 svud redom. Fejkovi su oni sa "običnim" BB slovima, a i njih je malo. Gde da fejkuješ čip od 5 dolara, ne ide...

     

    Meni pre 10ak godina direktno iz TI stigli PGA2311P samples, na njima uredno BB logo.

     

    Quote

     Fake ICs

    I have opened this thread as a companion to the "Fake Transistors" thread.

    Many of us buy integrated circuits (ICs) online (or from other uncertain sources) and it is up to us to determine if they are genuine. There is little monetary incentive for counterfeiters to fake low-price ICs. However, higher-priced ICs are commonly targeted, particularly if there is a demand. The fakes are sold through non-authorised distributors (particularly anonymous online sellers). Here is an example of some op amps that I examined to determine authenticity.

    The IC type was a high-performance Burr-Brown operational amplifier OPA2134, a dual amplifier in a plastic 8-pin DIP configuration. First the package was examined, then the electrical performance.

    Some samples of the op amps are shown in the photos. The logo and lot trace code (LTC) generally follow the manufacturer's rules and all LTCs were the same. There is no end notch in the package which is unusual for Burr-Brown amps of this type. The pin-1 designator is unlikely in terms of size and position. On the bottom side the die mark is wrong - it should state the country of manufacture. In addition, each op amp has a different die mark indicating the use of many dies - a high production part, but such a mix with the same LTC is unlikely. This corresponds with a wide variation in surface quality, as the photos show. The case molding finish is of poor quality. Overall the variability and poor quality of the case is incompatible with that of a major manufacturer.

    A genuine OPA2134 has a maximum offset of only 2mV! The measurement of this parameter therefore seemed an easy way to test the op amp's credentials. With the positive input of the amp grounded and unity feedback, the offsets were measured with a meter. The average offset was 4.0mV and the maximum 6.5mV! By placing a large resistor (10Mohm) in the feedback path any output variation shows that the input devices are BJTs rather than FETs. The input devices were found to be FETs, as they should be. Another simple test is to measure the supply current. This was found to be 4.0mA average rather than the expected 8mA average.

    Although no AC tests had been performed it was already certain that the op amps were counterfeit. (If one has an authentic IC sample available for comparison, simple tests with an analog ohmmeter could also have been revealing.) The test results were consistent with the op amps actually being inexpensive TL082 or similar types.

     

     

    Sto se toga tice TIP

    photo-0033.jpgovo je FEJK :sarcastic_hand:

    TB24RO9XGi5V1BjSspeXXcWPFXa_!!787128859.jpg

     

    Pravi  koristi postojanu belu tintu ... BB logotip je širi i ima masni font, proteže se od polovice O i širi se do polovice drugog A u OPA134PA. Odnosno, logotip bi trebao biti centriran.

    Ima REMARK znak . NA nekim nema - ali je BROJ 4 specificno napisan number-4-2.jpg

     

    E pa ono sto sam ja popio u D10 je ovo ispod :smesna:


  4. 1 hour ago, shonne said:

    Brate nista narocito ne dobijate ni sa DX7 , D50, D90 

    Sve je to ograniceno opampovima - da ne pominjem jos neki DAC - uvredice se neko.

    Sve to od 50 do 600 evra - sa opampovima relativno isto svira. Ma stavio neko Wima kondezatore u izlazu sa opampovima...

    DAC ce biti onoliko dobar - koliko su opampovi na izlazu dobri - da ne kazem originalni - nisu BB kopija :smesna::sarcastic_hand::D


  5. E da... Usviravanje. Imaces vise faza - prvo kad se zakaci zvuci hladno . Pa se onda menja sirina pozornice. Bass dobija jos na dubini. Pa zvuci hladnije u srednjim. Pa se visoki izjednace.

    Tek posle jedno mesec dana ceo spektar dobije - toplinu. Pre bi nazvao prirodnost nego toplina - zivost - sve izvire podjednako dobro - nema tvdocu -  razlika u mekoći i realnosti zvuka .

    Slusalice zakacene na cicnc pozadi ubrzavavaju proces. Brze se usvira nego preko preampa.


  6. 3 hours ago, Lemić said:

    Od sad, kad Mirko kaže u Dunav, ja skok. Šta je zvuk koji dobijamo iz naših sistema nego do modulisana električna energija, slušamo struju. Zakačio Gujićev injektor sa manjom "digitron" Omegom, kolko god znam iskustveno šta znači napajanje, ovo me ipak iznenadilo, toliko detalja i akustike nisam očekivao, a prostor, pa došla muzika isped stola. Slušam Boubacar-a, silne neke čegrtaljke, usna harmonika reže, a u pozadini talambas tutnji, doza agresivnosti koja mi je malo falila, bogato. 

    No, započesmo Guja i ja još onomad, vazda ja imam neke fantazije. Moraće da se uradi ispravljač i da se svi potrebni naponi privedu,  ovih 5v koji se tamo negde dižu na 8v je njesra, još kaže Gujić da je svičerskom metodom. Veli da je problem kutija, ma nije, skutija se to lako, nebitan gabarit koji uvek ograničava. Još jednom hvala što je bio ekspeditivno predusretljiv.

    Ja ti rekoh.

    :D

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