| dtm1962 |
I have built a Gainclone using the LM3875 chips, using basically
Joe R. circuit (tubeless) using a 10K pot.
Has anyone experience Switch- On Transients to the point where
a 3 Amp FastBlow fuse (temporary as I will use 2A Slo-blos) will blow on Turn-on.
I seemed to have DC offset on turn on (as the woofers will move in/out on start up), but my steady state DC offset is 1.6mV
& 2.4 mV for each channel.
I am using a single 300W Plitron 20+20V dual secondaries for the
Xformer and a total of 8000 uF for PS Capacitance.
There is no cap/resistor across the Power Switch at this time.
Is there anything I could add to prevent transient thumps etc on Power Up.
Any help would be appreciated.:nod:
Thanks in advance |
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| li_gangyi |
| that might be because on cap charges faster than another...leading to the offset and stuff...try no cap or a smaller cap...no cap for testing only~! |
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| carlosfm |
Toroids have big inrush currents at turn on.
Put a 10 Ohm 7~10 watts resistor in series with one of the primary wires. |
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| li_gangyi |
| Or you could use a NTC termistor... |
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