Hi All,
(This is my first thread so go easy if possible)
Have Superscope BLA-530 Amp by Marantz that is distorting in a strange way. I cannot find much on it at all on the net so diagnosing from a schematic is out at the moment. Normal 1khz 400mv sine wave on either channel input will produce output as you would expect until about 1/3 volume then turing up after that it starts distorting. On the Cro you can see the output signal undergoing what looks like almost 180 degrees phase lag but with some clipping as well. Really got me scratching my head!
Signal looks fine after input section (without schematic its hard for me to tell wether its the diff amp or some kind of buffer input) but then after that the distortion is present right through the amp.
Any ideas? If it helps I can post ome pics of the Cro with distorted wave forms?
Cheers
Bunyip
(This is my first thread so go easy if possible)
Have Superscope BLA-530 Amp by Marantz that is distorting in a strange way. I cannot find much on it at all on the net so diagnosing from a schematic is out at the moment. Normal 1khz 400mv sine wave on either channel input will produce output as you would expect until about 1/3 volume then turing up after that it starts distorting. On the Cro you can see the output signal undergoing what looks like almost 180 degrees phase lag but with some clipping as well. Really got me scratching my head!
Signal looks fine after input section (without schematic its hard for me to tell wether its the diff amp or some kind of buffer input) but then after that the distortion is present right through the amp.
Any ideas? If it helps I can post ome pics of the Cro with distorted wave forms?
Cheers
Bunyip
read this ....http://www.diyaudio.com/forums/solid-state/136261-vintage-amplifier-repair-upgrade-manual.html
if you can follow procedure and have basic skills you r going to have an ok amplifier after that in your hands
the specific amp doesnt get any better even if you invest 1000 usd on it ....so stay with the basic replace only what need to be replaced only dont go any extreme since this will get you nowhere ...
also is this a radio amp or just an amp ???? cause if you have a tuner section there you need to be very carefull with it since replacing the elcrolytics ( all of them ) will bring the tuner back to life but in any case the only thing that you dont do is start to play arround with trimers
regards sakis
if you can follow procedure and have basic skills you r going to have an ok amplifier after that in your hands
the specific amp doesnt get any better even if you invest 1000 usd on it ....so stay with the basic replace only what need to be replaced only dont go any extreme since this will get you nowhere ...
also is this a radio amp or just an amp ???? cause if you have a tuner section there you need to be very carefull with it since replacing the elcrolytics ( all of them ) will bring the tuner back to life but in any case the only thing that you dont do is start to play arround with trimers
regards sakis
Hi Sakis thanks for the reply. This is not a receiver (no radio) just a pre amp/power amp unit.
You have lots of good ideas in your tutorial. I think the most likely culprit in this case will be the electrolytics somewhere. I have seen old faulty electrolytics cause some strange distortion effects in other amps before but for some reason I did not think of it this time!
I will check them again.....as you say in your tute:
RECHECK EVERYTHING!!!
You have lots of good ideas in your tutorial. I think the most likely culprit in this case will be the electrolytics somewhere. I have seen old faulty electrolytics cause some strange distortion effects in other amps before but for some reason I did not think of it this time!
I will check them again.....as you say in your tute:
RECHECK EVERYTHING!!!
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