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Przeróbka sprzętu audio B-Tech BT928 Headphone Pro Amp

PostNapisane: Cz 27 maja, 2010 19:31
przez Rych
Witam,

Miałem problem z wysterowaniem moich słuchawek (50 ohm) ze wzamcniacza słuchawkowego z odtwarzacza CD. Dokupiłem więc tani wzmacniacz słuchawkowy B-Tech BT928 Headphone Pro Amp, który co prawda daje rade w basie, ale reszta już jest dość słaba.

Kupiłem ten wzmacniacz, bo ponoć po wymianię bebechów za drobną kwotę nabiera nowego brzmienia.

Tutaj jest opis tuningu:
http://www.rock-grotto.co.uk/B-tech.htm
i poodobny po polsku:
http://www.techfanatyk.net/bt928-raj-dla-moddera/

Co do układu wzmancniacza nie wiem czy wybrać NE5532 czy może OPA2134PA, ale poczytam.

Interesuje mnie natomiast co oznaczają rezystory w wersji - Metal film? Czym one się różnią od zwykłych?

Na jakie kondestory mam wymienić stare? Coś nie moge się doczytać.

PostNapisane: Cz 27 maja, 2010 20:25
przez kazio79
co do rezystorow, to moze chodzi tu o rezystory metalizowane, maja mniejsza rezystancje i szybciej padaja (sa troche inaczej zbudowane)
co do kondensatorow, zerkne na to pozniej (weekend w pracy)

PostNapisane: Cz 27 maja, 2010 20:26
przez RysiekUK
Te metal film to pewnie rezystory metalizowane (chyba maja mniejsze szumy). Co do elektrolitow to zwykle wymienialo sie na tantalowe, ale sadzac ze zdjec wymienil na jakies inne.

Powodzenia

Rysiek

PostNapisane: Cz 27 maja, 2010 21:08
przez Rych
Doczytałem że "metal" mają mniejsze szumy niż "carbon" - kwestia jak zapytać w sklepie.
metal film resistors should be better (lower noise) than carbon film

chociaż
I could have used metalfilm resistors, that would have been alot cheaper, however I find the Kiwame and Riken carbonfilm resistors to be really good.


Kondenastory, muszę doczytać co Anglii znaczą FC czy ELNA - bo nie wiem jak zapytać w sklepie.
upgraded the capacitors to Panasonic FC and ELNA capacitors

I have already replaced the capacitors with ELNA Cerafines

Try using a (Ultra) low ESR cap like Panasonic FA, FC or FM instead of the 1000uF Cerafine. It should sound even better.

I replaced the 1000uf cap with a Panasonic FC type


p.s. Jak kupujecie części? W Maplinie czy przez net?

p.s.2 Znalazłem stronę dla prawdziwych maniaków tuningu, gdzie podmiana bebechów w choćby Marantz 5001 to zwykłe nic dla początkujących:
http://www.diyaudio.com/forums/

PostNapisane: Cz 27 maja, 2010 21:10
przez Rych
No i kwestia samego wzmacniacza. Widzę że w UK udziela się niejaki Majkel z Polski, guru majsterkowicz na polskich forach audio.

My favourite is AD825, it is single, stable starting from G=1, and 50mA capable. Great soundstage, no veil, very musical, impactful, no harshness, colorful but not colored sound. There is nothing better IMHO. I suggested one guy to use them, and he discarded from his amplifier 2x OPA627 for those AD825s. Another happy guy!
I heard all chips from balou's list except JRC4558 and LM4562. So...
NE5532 - the only good is from Signetics, all others suck
LM6172 - very nice, impactful, clean, dark, some people find it cold
OPA2107 - dark and laid back sound, very deep soundstage, not so broad
OPA2604 - a bit like a tube, rolled off on both ends, a bit boring and too rounded for me
OPA2227 - terribly laid back, bass heavy, veiled and slow. Completely not my type
OPA2132 - almost like OPA2134, maybe a bit smoother sound. Generally - tubby bass, mediocre soundstage, recessed subbands of the midrange and not very detailed treble. Nothing special.
NJM4556 - sounds... funny Nice sound but I don't know why it sounds funny to me. Smooth sounds with long decay, no harshness. I haven't listened to this one for prolonged time.
AD8066 - good soundstage, a bit narrow, big bass, veiled midrange, nice treble and overall caramel sound signature. I like it
AD823 - a bit harsh making it perceived as detailed, but it is not very detailed. Weak impact in sound, rather analytical. One of the noisiest I know. I don't remember all details well because I found better chips later soon.
AD843 - impactful and harsh, sometimes it's getting unpleasant. IMHO tangensoft overrated it saying it's around OPA637's class. It is not. Too unnatural.
AD744 - very natural in color and soundstage which might give impression as present everywhere. What I dislike is its relaxed and therefore "dead" sound. However some people may like it.
AD8620 - good impact with quick and punchy bass, very good soundstage, not spectacular though, slightly harsh and slightly veiled - kind of a nonsense tradeoff. Some people find its highs too aggressive, I don't.
Other tested...
OP275 - like V-shaped equalization curve, bass up, treble up, recessed mids, overally good and just nothing special, simply good, maybe very good.
OPA2228 - uncompensated alter ego of OPA2227 but totally different. deeper but not muddy like 2227's bass, actually very nice, lots of air in midrange and silky highs. Warm and natural. Just slightly laid back with delicate veil which pairs well with 2228's airy presentation. Electric guitars and female vocals sound nice and intimate. Very likable chip, but not for low gains. You can compensate its feedback loop with capacitors, but I don't like this method and find it degrading the sound a bit.
TLE2082 - many times my favourite but no longer. It's like unveiled, more metallic in treble and less harsh AD8620, better and clearer soundstage, punchy and filled up bass. This chip is more on the bright side.
TLE2142 - sounds dark, with well detailed highs, strong and precisely articulated bass but not as filled with mass as AD8066. You may find the midrange a bit loosing color, but soundstage and its deepness is ver good.
AD797 - is like more analytical version of AD825, less impactful and with some glaze over highs.
OPA637 - very natural and detailed in the whole spectrum, preserving all music singature besides life. For me this chip is uninvolving. It's good for analysing music, not listening for pleasure.
AD8397 it is power hungry and truly powerful. 310mA peak makes sense as a true amplifier. However you need efficient ground channel to keep AD8397's pace. It is a bit bright, very close soundstage, almost like being between performers. Short decay, overally gives impression of being transparent but it's a bit on the bright and smooth side. Comparing it to be more efficient than 2x BUF634 gives it overall high rating. You can use AD8397 as a dual buffer because it is unity gain stable.
I think, that's all... Is my liking non-standard?

PostNapisane: Cz 27 maja, 2010 21:15
przez RysiekUK
Ta ELNA to firma produkuja elektrolity do AUDIO http://www.thlaudio.com/elnaitme.htm

Wejdz na strone Maplina i poszukaj w katalogu co maja.

Rysiek

PostNapisane: Cz 27 maja, 2010 21:15
przez Rych
Co do rezystorów do sprzętu audio to już znalazłem:
Wirewound resistors are the quietest, having only thermal noise, followed by metal film, metal oxide, carbon film, and lastly, carbon composition

PostNapisane: Cz 27 maja, 2010 23:17
przez Rych
Ok, znalazłem stronkę dla grzebiących w sprzęcie audio. Tylko najlepsze komponenty najlepszych marek. Dla przykladu 0.5W rezystory Shinkoh to tylko 3 funty sztuka. 2W juz za 8 ::admin

http://www.hificollective.co.uk/

PostNapisane: Pt 28 maja, 2010 19:59
przez kazio79
zerknij tez tu
mozna on line lub na Team Valley osobiscie pobuszowac.

PostNapisane: Pt 28 maja, 2010 21:35
przez Rych
kazio79 napisał(a):zerknij tez tu
mozna on line lub na Team Valley osobiscie pobuszowac.


Thx Kazio!

Już co prawda zakupiłem większość ze stronki http://www.hificollective.co.uk/ , ale na przyszłość będe miał na uwadzę.

Przeglądam właśnie net w poszukiwaniu lepszego odpowiednika NE5532P, a w Maplinie zakupiłem dzisiaj lutownice i reszte sprzętu. ::piwo