Author Topic: ilan po ba signal ng portable music players (like mp3 players,ipod, etc) (Read 4104 times)

rdpzycho · « **Reply #20 on:** March 05, 2009, 11:56:29 AM »

1V rms ang line level sa consumer products. 'yung 1mV, IIRC, reference ng mga headphone manufacturer kung anong SPL output at 1mV rms.

Philippine Electronics Forum · « **Reply #20 on:** March 05, 2009, 11:56:29 AM »

mr.Electro · « **Reply #21 on:** March 05, 2009, 07:49:38 PM »

sir pasensya talaga di ko maintindihan..kasi first audio amp project ko po palang to...uhhmmm ano ba ibig sabihin ng iirc at spl?? ...so if i have this circuit...i will treat my input signal (yung music source) as 1 Vrms???

Philippine Electronics Forum · « **Reply #21 on:** March 05, 2009, 07:49:38 PM »

mr.Electro · « **Reply #22 on:** March 05, 2009, 09:11:08 PM »

ito po

yan po gagawin namin...three stage amplifier... first stage pre-amp ay classA for current and voltage gain
second stage ay classA for another current and voltage gain... tapos power amplifier for driving the speaker output.. sa rating nang speaker namin ay nasa 5W- to 10W ang power rating nya at decided namin na utilize lang namin 7W with the input signal (Vin) given... and by this 7W power we will use, we can already calculate the voltage peak to peak (depende sa dc supply namin) or rms of our output voltage Vout (or of the speaker), ...ang problema po kasi ilan gagamitin namin or anung value ng input signal or Vin (rms) or pk to pk nang audio source (mp3 players or compact audio players) para malaman namin ilan gain dapat gagamitin namin sa bawat stage ng amplifer...

Philippine Electronics Forum · « **Reply #22 on:** March 05, 2009, 09:11:08 PM »

rdpzycho · « **Reply #23 on:** March 05, 2009, 11:09:59 PM »

actually, karamihan ng amplifier merong specified gain na lang like 22 dB (overall gain). main reason, hindi pare-parehas ng output levels ang connected devices.

isa pang reason nito, pwede mo kasing gamitin 'yung speaker at (example 7W) sa peak power niya. so kung designed lang sa 7W 'yung sagad nung line level, 7W na lagi ang peak power mo.

kayo na ang bahalang mag-set ng gain niyan. lalagyan niyo na lang ng volume control.

hindi rin kasi pare-parehas 'yang mga portable player. though line level is 1V rms max (supposedly).

Philippine Electronics Forum · « **Reply #23 on:** March 05, 2009, 11:09:59 PM »

mr.Electro · « **Reply #24 on:** March 06, 2009, 04:59:00 PM »

diba kung naka set na gain mo sa amp mo ay yan na talaga yan....so gagamitin namin dito for computation ay ung Vin = 1Vrms??? pero pag ang input signal ko ay naging mas lower na sa 1Vrms (example 100mVrms) then hihina ang max power na magagamit sa speaker?? diba po ba?? but anyway thanks talaga..laki natulong mo saken..insights...

Philippine Electronics Forum · « **Reply #24 on:** March 06, 2009, 04:59:00 PM »

Woots29 · « **Reply #25 on:** March 06, 2009, 05:05:32 PM »

kaya kelangan mong gumawa ng preamp para jan. pwede mong taasan ng gain ung amplifer pero hindi na standard at pwedeng unstable ito. so i must recommend desgn a 1V input to max power amplifer then make a pre-amp na pwedeng adjustable ang gain

HINT:
most amplifiers' sound quality rely on well desngd pre-amps.

rdpzycho · « **Reply #26 on:** March 06, 2009, 05:10:14 PM »

yup hihina siya. typically kasi ang music hindi naman aabot ng 1V rms. dynamic kasi ang music. so kung ise-set mo ang max power mo sa 1V rms, makukuha mo lang 'yung max volume mo kung ang music mo ay clipped (distorted), o madalas umabot sa 1V ang peaks. typical 'to sa mga nag-eedit na pinupuno ng bass 'yung music para sa subs. kapag tinignan ang waveform nito, driven to clipping talaga.

isa 'tong typical audio waveform, given na max power ay maabot mo lang at 1V, sa areas nung half nun, mahina ang output mo. marami kasing speaker, na pwede mong i-stretch 'yung peak power niya.

safe 'yung design niyo kung 1V equals max power, pero tandaan niyo kung ang ico-connect niyo ay portable player, pwede pa rin 'tong mag-vary from 1V rms to 2V rms output.

mr.Electro · « **Reply #27 on:** March 06, 2009, 08:13:12 PM »

ahh nagets ko nah...so design kami sa Vin = 1Vrms para sa output max power...tapos lagyan nlang ng potentio sa pre-amp para machange ang gain at therefore volume kung ibahin ang input (pag i-lower)... thanks...

mr.Electro · « **Reply #28 on:** March 10, 2009, 10:03:50 PM »

guys patulong naman...ito may values na ako for my two stage.. isolating the power amplifier i can get a total of 54 for voltage gain from input...but when i connect my power amplifier (class ab) ay biglang lumiit yung ouptut voltage at lumiit sobra yung voltage gain...baket ba to?? gamit ko pala complementary transistors for class ab ay 2sa671 at 2sc1061 ..at ano po dapat diode ko gamitin to match the transistors characteristics?? by d way vcc = 30 V to accomodate the Vout peak to peak of 24Vpp for a power of 8W...tnx talaga sa lahat

rdpzycho · « **Reply #29 on:** March 10, 2009, 10:16:59 PM »

'yung diodes mas maganda kung hand-picked mo. 1N4148 pwede na, pero i-tester mo kung ano ang matched doon sa transistor. ok lang na mas mataas, huwag lang mas mababa sa Vbe nung transistor.

mr.Electro · « **Reply #30 on:** March 10, 2009, 10:22:22 PM »

ok tnx boss rd...pero panu ba toh?? na pag connect ko yung class ab ko sa total ckt. ay biglang bumaba ang voltage gain or ang final voltage output... when i isolate naman class ab and only use the first stage and second stage au makakuha nman ako ng malaking voltage gain... ano ba dapat values ko for biasing resistors...

Google · « **Reply #31 on:** March 10, 2009, 10:26:02 PM »

ganyan din nangyari sa amin nuung gumawa kami ng gnyan... imbes na lumaki yung output, lumiit pa

mr.Electro · « **Reply #32 on:** March 10, 2009, 10:29:07 PM »

yah..di na ako natulog para mag design ng amplifier tapos naging attenuator na di na ampliifier..hehehe... ;Dhehe pano ba toh.... sa analysis ko ay yung papasok na signal sa class ab ko ay mas maliit keysa sa mapunta sa secondstage kasi mas more resistance yung sa secondstage ko keysa sa class ab... para loaded effect...pero panu ba toh?? anu gawin ko...

Google · « **Reply #33 on:** March 10, 2009, 10:40:52 PM »

hindi naman kasi accurate yung mga computations na ginawa pag dating sa practical applications. Hindi porke't na lumabas ay kunwari 20 dB yung gain eh yun na mismo ang magiging gain pag ginawa na. At saka hindi lang sa computation binabase dapat kasama yung characteristic curve ng mga transistors. Baka di mo alam na wala na cya sa active region.

rdpzycho · « **Reply #34 on:** March 10, 2009, 10:48:35 PM »

i-check mo ang output niya per stage para malaman mo kung saan ang problem.

Google · « **Reply #35 on:** March 10, 2009, 10:50:35 PM »

baka duun sa gitnan or sa huling stage nag antennuate

Woots29 · « **Reply #36 on:** March 11, 2009, 08:46:42 AM »

30 volts ung supply tapus ganyan ang desgn? owwss.

~JahBoy~ · « **Reply #37 on:** March 16, 2009, 06:50:12 PM »

pwede po yan ...nasubukan ko rin yan dati, 25V and vcc... in order to utilize a high power, u have to have a greater vcc... but just make sure na gamit mo transistors ay power trans like tip, 2n60xx ,or mjexxx etc etc.... at bantayan mo rin na gamitin mo resistor ay di 0.25W but 0.5W or 1W depende sa design...

but wth discete design, dont expect to get a good sound production..

Woots29 · « **Reply #38 on:** March 16, 2009, 08:33:22 PM »

pero mas maganda kung mjo complex desgn para mas maganda outcome at mas mlakas ang output.

~JahBoy~ · « **Reply #39 on:** March 20, 2009, 07:26:06 PM »

btw... y not use op-amps..si-simple talaga buhay mo with op-amps tapos mas maganda pa ang desired output nito at mas makasave ka pa sa gastosin...

Philippine Electronics Forum · « **Reply #39 on:** March 20, 2009, 07:26:06 PM »

Author Topic: ilan po ba signal ng portable music players (like mp3 players,ipod, etc) (Read 4104 times)

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