ahh tats a very simple and cheap way indeed.. thx for the tips!

Just wanna ask you guys something. I have one of those PAV2V headphone amp I bought not too long ago. Is there anywhere/anyone in Malaysia that repair these kind of stuff. I wanna make sure first before sending it all the way back to Canada. Thanks

Not that I'm aware of..
Whats wrong with it?
(I bought 2 x PA2V2)

hi all sifu.. i hav a problem again..

so i have construct my class A mosfet according to this schematic..



im using 2 IRF510pbf mosfet and LMC7660 as the voltage regulator..

my problem now is it produce a tweeting/hissing sound... very noticeable unless i turn the volume up which could hurt my ear.. how to decrease the annoying tweeting/hissing sound? could it be the wiring problem? i did minimize the usage of wire ald though..

thx in advance!

edited
ok i think i jz burned my capacitor... this is the 2nd time ald.. smoke coming out and pooff.. strange thing is i can still turn it on after awhile, functioning.. so izzit the burned capacitor that cause the twitting sound???
will error in polarity cause capacitor to burn? there's a possibility that im having tat kinda of error..

This post has been edited by gu~wak_zhai: Apr 13 2010, 10:15 PM

polarity mistakes and overvoltage usually means kaboom.

why are you using a noisy LMC7660?



This post has been edited by LittleGhost: Apr 13 2010, 10:46 PM

oh? so the culprit is the 7660? if i redesign my voltage regulator, the noise will disappear? thx alot!

You still have to solve the issue of caps blowing up don't you?

Also, I don't think the LMC7660 counts as a regulator. It's more like a buck boost isnt it?

hmm im not too good wif the terms.. sry if i confused u.. got the idea of the schematic from here and its datasheet..

will try to solve the capacitor 1st.. thx!

finally after few days of troubleshooting.. i solve the buzzing problem!

still using the lmc7660, before it was like this..


the buzzing sound gone completely after i connect the capacitor to the pin 7...


got the idea after looking at the datasheet.. there's a thing called oscillating capacitance (C osc).. which is the 1 i jz add in..

i did try it with smaller value of capacitance.. eg 0.1uf and 220uf... the difference is huge! it improves drastically as the capacitance increases!

when i was using 0.1uf.. there's still buzzing sound.. but it it buzz rather slowly..

then 220uf.. the buzzing sound is even slower..

finally 470uf... the buzzing sound gone completely...

from the datasheet
It is possible to dramatically reduce the quiescent operating current of the LMC7660 by lowering the oscillator frequency.
The oscillator frequency can be lowered from a nominal 10 kHz to several hundred hertz, by adding a slow-down capacitor Cosc.

conclusion
the LMC7660 is not tat noisy after all..!

my F5 is ready to go!

This post has been edited by chchyong89: Apr 18 2010, 12:59 AM

wow nice 1 bro!

here's mine.. so miniature compare to urs LOL..


CMOY amp


Class A MOSFET amp



This post has been edited by gu~wak_zhai: Apr 18 2010, 01:05 AM


Attached thumbnail(s)

bro gu wak chai, still hanging around MMU?

Let's hang out EDIT AT CHCHYONG89's PLACE.

I have a few good things you can try.

This post has been edited by LittleGhost: Apr 18 2010, 09:23 AM

come come, if you don't mind my place is dirty la

wow... it'll be great.. but now i still need to rush assignment lar.. mayb nex week or sumthing? i hav alot to ask sifu oso haha...

anything just ask little ghost, he know everything

we have tons of shit to do too Next week is nice.

yeaa.. almost the end of the sem d.. assignment due and finals.. sienz..
will let u guys know by then!

my 5532 was on fire yesterday! the stupid transformer wire is loose and went down under the pcb


Attached thumbnail(s)

Sorry to hear that chchyong...
salvageable?

lucky i got one spare

i just get one channel of the F5 working. Omg, it's so transparent, ~
And it's connected to only PC's onboard soundcard to drive it now.