need help I have a Nikko Alpha 230 power amp one channel is not outputting base only trebble? I have a schematic.
No bass in a power amplifier only? After first swapping channel input leads and checking upstream, I would start by looking at the faulty power amplifier's output stage by testing for failed semis - i.e. output and driver transistors. Next and more obvious problem area is the coupling and DC blocking capacitors capacitors - the smaller electrolytics.
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This is quite an unusual amplifier having a variable bias circuit. There is a DC/AC coupling switch located right on the inputs that switches a 2.2uF cap in circuit. Apart from that and its DC coupled all the way.
Definitely do the basic checks that Ian describes. Also check your speaker... a DC fault could have burned the woofer out leaving just mid and HF drivers intact. Unlikely perhaps but don't discount it.
Two basic checks in the power amp are measuring DC offset voltage (should be zero) and checking the bias current (idle current adjustment).
Definitely do the basic checks that Ian describes. Also check your speaker... a DC fault could have burned the woofer out leaving just mid and HF drivers intact. Unlikely perhaps but don't discount it.
Two basic checks in the power amp are measuring DC offset voltage (should be zero) and checking the bias current (idle current adjustment).
thanks for your reply's, it was 1 of my speakers. Soundfield DBX 1A, there is a circuit board on the bottom inside the speaker. Will see if I can find a circuit diagram.
Used to have lots of Nikko stuff. Its a nice amp. Well built.
DC on the output would not clicked speaker relay.
DC on the output would not clicked speaker relay.
after switching parts with the good speaker found the problem was 2 of the 4 woofers had less than 1 ohm resistance, so will replace them.
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