P3A amp 100 watts Help

[jlester87]

Eto download link sis

[p®otocol]

share ko din sakin sis not yet tested though

[abeTIR]

Eto download link sis

Salamat na marami sis!



Protocol, nice work!

[Johannah Aleksandria]

share ko din sakin sis not yet tested though

Prang walang space for a heatsink sa driver sis.
P3A may be powered up to 50-0-50vac, so kung maari design it including the heatsink, just an option, using parallel outputs in force sharing sziklai arrangement.

[jlester87]

Salamat na marami sis!
Protocol, nice work!

Download mo nalang uli sir, ginawa kong vertical yung trimpot natatakpan kasi ng resistors...

[jlester87]

Ooops dapat pala nasa ilalim yung resistors, hindi pala kasya sa pagitan ng drivers/vbe yung mumurahing wirewound...

[p®otocol]

Prang walang space for a heatsink sa driver sis.
P3A may be powered up to 50-0-50vac, so kung maari design it including the heatsink, just an option, using parallel outputs in force sharing sziklai arrangement.

thanks sis johannah , for low power palang kasi na try ko, ill revised the design if i have time 

[abeTIR]

Ooops dapat pala nasa ilalim yung resistors, hindi pala kasya sa pagitan ng drivers/vbe yung mumurahing wirewound...

OK lang yun sis, yun nga ang nakikinita ko sa ilalim yung wirewounds "ala Baksa", yun namang ground tap ng zobel sa tingin ko rin me option na puede padaanin near sa input at dugtong direct sa power ground, ganun yung wire tap na ginawa ko direct sa power ground wire tap din...anyway maganda rin naman yang nagawa mo na, "ala Leach" separate din ang wire grounding ng zobel. Subukan ko rin itong gawin pero gagamit ako ng 1uf film cap sa VBE instead of electrolytics. Sa Leach, Apex at Giesbert HexFet, film cap ang gamit nila sa VBE. Perfect na sa tingin ko ang pagkakalapit ng miller caps sa pins ng trannies at yung spacing ng driver trannies (option to add heatsink) at pagkakalapit din ng mga ito sa outputs.

[jlester87]

Naka order narin ako sa rs Simulan ko na to...

Yung pinaka-unang layout na ginawa ko ayos din naman kaso sensitive siya sa wiring... konting changes lang nag iiba na tunog.

Sana stable tong latest layout

[abeTIR]

OK, fire it up sis!

[p®otocol]

Salamat na marami sis!



Protocol, nice work!

thanks sis

[abeTIR]

A little update dun sa P3A build ko, napaisip kase ako dun sa naging problema ni sis Jlester regarding dun sa high-frequency na napi-pick-up ng build niya, and while testing my other amp build binalikan ko yung P3A and I found a slight problem, without load sa DC-offset meron siyang AC signal measured at .010v (self-generated noise?) Hindi ko napansin ito nung una akong mag-test, anyway mababa naman ang reading para maging noticeable sa output.

But I found the culprit, yung input Bennic film cap (9uf) sinubukan ko palitan ng 1uf multi-layer ceramic at nag-zero ang AC reading, ganun din nung subukan ko gamitan ng 4.7uf electrolytic. Sensitive kaya ang input ng PCB lay-out o hindi match sa amp ang 9uf film sa input ?(dun sa DIYAudio may mga disagreement ata sa paggamit neto sa P3A) Anyway with regards sa sonic quality hindi ko rin alam kung may pagkakaiba perhaps by measurement malalaman natin...

[jlester87]

Parehas tayo ng ginamit na type ng input cap, siguro yung mahabang wire lead ng cap ang nag aact as antenna...
Mas ok siguro kung eto nalang ang gamitin natin sa p3a, diyan ko binase yung size ng input cap sa pcb

http://philippines.rs-online.com/web/p/plastic-film/1083034/

Anyway with regards sa sonic quality hindi ko rin alam kung may pagkakaiba perhaps by measurement malalaman natin...

Yung pinaka una kong config ng p3a ganda ng tunog eh., tapos nung iniba ko numipis yung tunog... try mo uli pakinggan ng wala nang hf noise

[01110011]

pwede yung gianmit ko na multilayer, ok naman po

[jlester87]

Mga masters pwede ba itong ginawa ko sa schem? Specifically yung nilagay kong R17 sa drivers. Ginaya ko yung aksa. lol
Mas maganda kasi ang voice quality nitong P3a kaysa sa BAKSA so ineffortan ko i-mod...

[tony]

180 <<< 0.47 ohms what did you wanted to achieve with this?

[jlester87]

Hindi pala pwede yung ganyang mod sa CFP... rerevert ko nalang

Eliminate Switching Transients – Implement charge suckout on the output stage drivers.
The output stage introduces switching non-linearities on the output as one output device hands over control of the speaker voice coil to the other.  Base junction charge suckout, identified by Self in his impressive 1993 series of articles, involves placing a small resistor and capacitor in parallel between the two driver emitters in a conventional darlington output stage.  This parallel RC network ensures that the drivers (and with them, the output devices) turn off more cleanly when speaker current flow passes to their opposite numbers at the crossover of the signal.  This greatly reduces switching distortion, the bane of all Class AB amplifiers, by removing the usual spray of high order switching spikes generated by the handover event.  It smoothes the transfer of the baton in the musical relay.  It is this phenomenon which is partly responsible for the splashy, grainy and often harsh top end of most solid state amplifiers, since the ear readily registers switching disjunctions at high frequency and the feedback loop lacks the necessary speed to correct it.
It is clear that many modern amplifiers deliver poor performance because of short term stability problems which manifest only in musical passages but rarely in steady tone testing favoured by contemporary testing regimes.

source

[tony]

^that is correct, but your application is wrong....those speedup networks are applied to the bases of the driver trannies where they matter....

and you already have C10 in there, that is what it is there for....it doesn't need to be 22ufd, 0.1 to 1 ufd is sufficient...

[jlester87]

^that is correct, but your application is wrong....those speedup networks are applied to the bases of the driver trannies where they matter....

and you already have C10 in there, that is what it is there for....it doesn't need to be 22ufd, 0.1 to 1 ufd is sufficient...

Iba pa po ata yung charge suckout na mod para sa mga drivers.

About sa 22uf electrolytic for VBE ganyan kasi yung gamit ni hugh dean, pag 1uf suggested niya film type na...

At dahil idol ko ang mods ni Hugh Dean inapply ko siya sa P3A hehehe.

Changes:
- changed input impendance, (para makatipid sa input capacitor, mas mura yung 1uf eh)
- added ground lifter
- added D4 and R18 (para madecouple ang output tranny sa vas at ltp)
- added C14 (again for LTP para may reserve power for transients)
- added C13 (phase lead cap), lowered value of C4
- added C10 and C12 (again, taken from aksa implementation)

[tony]

as long as you know the why's and the how's of it instead of just adopting them, then you are fine....

remember that Hugh's mods are done with listening tests extensively, unless yo have the exact same setup as his, i doubt you can appreciate his results....

for me what is important for a diy'er is to understand how the thing works....