Hallo all,
I got this amp to check out. It had lots of dry joints. I see that the transformer has no secondary output, so no symmetrical amp. I suspect it has a cap on the output using single rails. Does anybody have any info and perhaps a circuit diagram. I have not tested it yet.
Much appreciated.
I got this amp to check out. It had lots of dry joints. I see that the transformer has no secondary output, so no symmetrical amp. I suspect it has a cap on the output using single rails. Does anybody have any info and perhaps a circuit diagram. I have not tested it yet.
Much appreciated.
Attachments
It is very unlike that such "pro" amp has the output coupled through caps, it is more probably it is a "bridge" amp which also uses single rail power supply.
You can check if the output terminal marked as "-" is grounded or not.
You can check if the output terminal marked as "-" is grounded or not.
Could be an old-style pseudo-ground, similar to vintage QSC. Separate windings for each channel, no center taps. But TWO identical reservoir caps per channel, which effectively couple the speaker output. Those amp designs were often copied, with varied levels of success. When they do that, the “designer” often does not have a good understanding of it and flaws will creep in.
If it is one of these, the center connection between the caps is hard wired to the hot (red) speaker terminal, and the collectors of the power transistors directly connect to chassis ground.
If it is one of these, the center connection between the caps is hard wired to the hot (red) speaker terminal, and the collectors of the power transistors directly connect to chassis ground.