| Hybrid fourdoor |
Just wondering if you need to connect the mute pin on the lm3886 in order for the amp to work. Its the only thing I can think of, mine is unconnected right now. The amp doesn't have any output.
Also, when I turn my amp on and measure the V+ and V-, I get +40V and -14V. Is this normal at idle? I also accidently hooked the transformer up backwards and got +1.4V and -54V the first time, which may have fried my amp, but i heard these things are pretty resiliant to overloads and stuff.
Heres the schematic from national. |
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| ddog |
Yes, you have to connect it with resistor between Mute pin and -V, value calculated so 0,5mA or greater can be drawn from Mute pin.
+V = 40V and -V= -14V doesn't seem normal to me. Are supply electrolyts connected correctly? |
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| soundNERD |
How did you make your power supply? Did you just use 2 caps, a transformer, and a rectifier? Do you have the schematic you used? Remove the power supply leads from the amp and test them with a multimedia. See what you get.
I think that the low - voltage is because you skipped connecting the mute pin and it is shorting the amp, though. did you skip any resistors/caps either? If so, which ones? |
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| Pan2 |
Reversing the V+/- has probably fried your chip, happened to my friend when he mixed up the lines.
/Peter |
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| macboy |
| quote: | | Reversing the V+/- has probably fried your chip, happened to my friend when he mixed up the lines. |
I agree. These things are pretty resilient when it comes to overheating, difficult loads, etc., but like virtually any semiconductor, reversing the voltage is a very bad thing. |
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