C-Audio schematic?
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From: Eeyore on 2 Jul 2008 14:41 Gareth Magennis wrote: > Anyway, don't MOSFETS, which C Audio mostly used as their output devices, > suffer from real RF if the PCB etc is not carefully designed? That's one way to make them oscillate ! LOL ! They were fun to tame when they came out. Good point though. Check the value of the series gate resistors. Expect anything between 100 and 1000 ohms. Quite possibly ~ 330. Graham
From: Gareth Magennis on 2 Jul 2008 14:51 "Eeyore" <rabbitsfriendsandrelations(a)hotmail.com> wrote in message news:486BCABD.879CC7C4(a)hotmail.com... > > > Gareth Magennis wrote: > >> "Joe Kotroczo" wrote >> >"Eeyore" wrote: >> > >> >>>>> And: does anybody happen to have a schematic for a C-Audio ST600 >> >>>>> amplifier? >> >> >> >> Well I did once. God only knows where it is now after 3 company moves. >> >> >> >>>> 2u job ? With one puny fan at the back blowing blistering hot air >> >>>> over >> >>>> the reservoir caps at the front ? >> >>>> >> >>>> If it's the model I think it is, I could tell you a thing or two >> >>>> about >> >>>> that. >> >>> >> >>> It's a 2U job, with a single fan in the back, but the front half only >> >>> contains a big transformer. >> >>> >> >>> It's this one: http://www.gbaudio.co.uk/data/st600.htm >> >> >> >> That's the one ! I'll save the story of shame for later. >> > >> > I've put the pictures here: >> > http://homepage.mac.com/kotroczo/PhotoAlbum62.html >> > >> > Am I right in assuming that the left side should be the same as the >> > right >> > side? Same value resistors? It looks like that, but I'd rather be safe >> > than sorry. >> >> Those 3 power resistors that look burnt are possibly part of the Zobel >> network. If you simply replace them they may just go again until you >> find >> why they burnt, which may be RF oscillations. > > Agree 100%. Or inadvertent 'RF' on the input. > > >> Check also the capacitor(s) >> in this network, or better still just replace it as well. And the one on >> the other side for good measure. > > Not quite sure why you suggest that, unless they're physically burnt. I seem to remember coming across a faulty one in a C Audio, and ever since have just replaced them along with the resistors as they are so cheap. If the resistors have burnt, then the caps may well have taken a beating too, or may even have caused the problem, and I don't have to worry about them any more. Gareth.
From: gwatts on 2 Jul 2008 16:34 Phil Allison a/k/a ALLISON, PHILIP MARTIN of 7/19 Prospect Rd Summer Hill NSW 2130 Ph: +61 02 9799 8242 ABN: 88 719 310 180 wrote: > "gwatts" == who ??? > > ** This trolling, psycho fuckwit is one: > " Galen K. Watts " of Arbovale, WV... etc etc. Ya been gone a while, Phil. I missed ya, but my aim is improving! Gee Phil, wrong about 'supersonic' AND off your meds again. Tsk tsk. Oh, by the way: BANG! Har har har! Almost got ya!
From: Denny Strauser on 2 Jul 2008 16:45 gwatts wrote: > Ya been gone a while, Phil. I missed ya, but my aim is improving! > Gee Phil, wrong about 'supersonic' AND off your meds again. > Tsk tsk. > Oh, by the way: BANG! > Har har har! Almost got ya! Thanks for your insight ... just what we need. Someone to encourage & participate in the pissing contest. Not that I don't appreciate the entertainment. But.......... -Denny
From: Gareth Magennis on 2 Jul 2008 17:02
"Eeyore" <rabbitsfriendsandrelations(a)hotmail.com> wrote in message news:486BCBCE.36986872(a)hotmail.com... > > > Gareth Magennis wrote: > >> Anyway, don't MOSFETS, which C Audio mostly used as their output devices, >> suffer from real RF if the PCB etc is not carefully designed? > > That's one way to make them oscillate ! LOL ! They were fun to tame when > they > came out. > > Good point though. Check the value of the series gate resistors. Expect > anything > between 100 and 1000 ohms. Quite possibly ~ 330. > > Graham > What kind of frequencies are we talking when they oscillate like this? Gareth. |