I attach schematic for traditional hybrid amp that runs +-17vdc and has a series electro cap and resistor as a simple way to protect phones from electronic failure ... according to D. Self. I don't understand how this polarized cap survives polarity swings.
I tinkered with parallel opamps, as seen in the O2 amp, which worked great even with 62 ohm AKGs. Now I want to try hybrid discrete circuits but I am wary of mistakes.
2. Can feedback be taken from the load side of this circuit.
I tinkered with parallel opamps, as seen in the O2 amp, which worked great even with 62 ohm AKGs. Now I want to try hybrid discrete circuits but I am wary of mistakes.
2. Can feedback be taken from the load side of this circuit.
Attachments
Certainly not ideal, yes. A reverse biased cap is not going to short right away and you should turn off a failed amp before it does. As far as AC with ~zero DC is concerned, it is not great either but feedback decouplers live that way for a long time. Back-to-Back "AC" electrolytics are much the same. But most of the protection is the resistor, at the expense of half the potential signal level. A resistor and wasted voltage are simpler than current sensors/limiters. Using a single supply eliminates the problem but you have to live with on-off thumps. I would just use a common single ~19V laptop supply. It's not hard to make better small amp but it takes more parts. Feedback at the load is a low impedance out, may be better, maybe not, and increases the effective gain.
Attached is an improved version. Note the single supply, could be 19V. Ground DC voltage is set by the amplifier and if it fails, ground DC follows.
Attached is an improved version. Note the single supply, could be 19V. Ground DC voltage is set by the amplifier and if it fails, ground DC follows.
Attachments
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