c-audio sr606 amp
Hello to all of you out there,
As a repair tech in a music shop I see all different amp's on the bench day in day out and these range from valve types to bipolar/mosfet amps. some are stright forward and some can drive you nutt's!!!
Any way before I plug a amp in under service I always cold check first just to see what's burnt and shorted out. nine times out of ten it's the o/p componets that have been roasted to death
or the inrush limiting resistor fried (soft start). common fault list's are weak signal, filler caps that have split/blown apart, distorted o/p, zobel rc net work burnt....
all the best for now
Hello to all of you out there,
As a repair tech in a music shop I see all different amp's on the bench day in day out and these range from valve types to bipolar/mosfet amps. some are stright forward and some can drive you nutt's!!!
Any way before I plug a amp in under service I always cold check first just to see what's burnt and shorted out. nine times out of ten it's the o/p componets that have been roasted to death
or the inrush limiting resistor fried (soft start). common fault list's are weak signal, filler caps that have split/blown apart, distorted o/p, zobel rc net work burnt.... all the best for now
This is a fairly old thread but since amptech resurected it to add some advice, thought I might too!
When testing C-Audio amps, the normal lightbulb in the mains doesn't work because it will just cause the soft start to oscillate (relay cuts in, current draw increases, bulb lights up, voltage drops, relay cuts out, current draw drops, voltage rises, relay cuts in and so on...).
What I do which works well is I have another lightbulb on a flying lead which I solder across the soft start fuseholder instead of fitting a fuse. The bulb, along with the soft start resistor will limit the inrush current. If there are no faults the soft start relay will short both out and the amp will run as normal but in the case of a fault the bulb will continue to limit the current draw to a safe level at which measurements can be made to determine the source of the problem.
When testing C-Audio amps, the normal lightbulb in the mains doesn't work because it will just cause the soft start to oscillate (relay cuts in, current draw increases, bulb lights up, voltage drops, relay cuts out, current draw drops, voltage rises, relay cuts in and so on...).
What I do which works well is I have another lightbulb on a flying lead which I solder across the soft start fuseholder instead of fitting a fuse. The bulb, along with the soft start resistor will limit the inrush current. If there are no faults the soft start relay will short both out and the amp will run as normal but in the case of a fault the bulb will continue to limit the current draw to a safe level at which measurements can be made to determine the source of the problem.
Hi Chris
I've never got round to buying a variac so I use the lightbulb trick all the time. One of the most useful pieces of test equipment on my bench! Wired up with a bypass switch of course and I have a plug-in energy monitor inline so I can actually measure the supply voltage, current and even power factor!
Completely off topic but given that we're both Chris's talking about C-Audio amps, I seem to mainly repair amps beginning with C! Crest, C-Audio, Carver, Chevin, Crown.
Chris
I've never got round to buying a variac so I use the lightbulb trick all the time. One of the most useful pieces of test equipment on my bench! Wired up with a bypass switch of course and I have a plug-in energy monitor inline so I can actually measure the supply voltage, current and even power factor!
Completely off topic but given that we're both Chris's talking about C-Audio amps, I seem to mainly repair amps beginning with C! Crest, C-Audio, Carver, Chevin, Crown.
Chris
a belated update but my amp is working again. Replaced a few components but still no improvment so I cleaned the relay contacts on one channel and at least got something from both channels then.. then got a friend to have a look. For some reason both the input ICs were blown! plugged in new ones and she's away!
xr3801 repair
Hi, ! have 2 c-audio xr3801 amps and they have both died in similar circumstances. The latest one was last night, plugged in a mic with phantom power on and made a big bang. Blew fuse inside amp next to large ceramic resistor, changed fuse and said resistor blew up...sound familiar... The first amp totally confused my local repair guy who has given up on it, I'm in the Agen area of SW France. my question is does anyone know of someone who will fix them for me? I tried to mail Lee Basham but don't have enough privileges yet. I'm pretty desperate as I need at least one of them working for upcoming gigs in september.
Hi, ! have 2 c-audio xr3801 amps and they have both died in similar circumstances. The latest one was last night, plugged in a mic with phantom power on and made a big bang. Blew fuse inside amp next to large ceramic resistor, changed fuse and said resistor blew up...sound familiar... The first amp totally confused my local repair guy who has given up on it, I'm in the Agen area of SW France. my question is does anyone know of someone who will fix them for me? I tried to mail Lee Basham but don't have enough privileges yet. I'm pretty desperate as I need at least one of them working for upcoming gigs in september.
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