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Audio and Video Talk
Valves / Vacuum Tubes
4,8,16 Ohm OPT taps question (leak amp)
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<blockquote data-quote="Mars" data-source="post: 252226" data-attributes="member: 817"><p>Power = Voltage^2 / Load</p><p></p><p>Voltage = ^/(power * load)</p><p></p><p>Thus V = 580V </p><p></p><p>In a push pull amp, the power supply voltage swings to double value on the tube anodes and inside the OPT. This is irrespective of the load the output tubes see. So voltages exceeding 1160volts DC are present in the circuit.</p><p></p><p>If you were to put a 8 ohm speaker on the 4 ohm tap, theoretically the tubes are seeing a 11200 ohm load. Here I run out of formula's :Ooooooh: but flashing 1160v peaks at a 11k ohm transformer does look a bit risky . You need very good speaker connectors and a slow start up when you switch on to avoid arcing in the sockets etc. If the 8 ohm speaker sounds very good on the 4 ohm tap in your setup, I would find a way of dropping the anode voltage down to about 420V and run the amp at about 20watts power.</p><p></p><p>Thus: I would rather keep the 8 ohm speaker on the 8 ohm tap.</p></blockquote><p></p>
[QUOTE="Mars, post: 252226, member: 817"] Power = Voltage^2 / Load Voltage = ^/(power * load) Thus V = 580V In a push pull amp, the power supply voltage swings to double value on the tube anodes and inside the OPT. This is irrespective of the load the output tubes see. So voltages exceeding 1160volts DC are present in the circuit. If you were to put a 8 ohm speaker on the 4 ohm tap, theoretically the tubes are seeing a 11200 ohm load. Here I run out of formula's :Ooooooh: but flashing 1160v peaks at a 11k ohm transformer does look a bit risky . You need very good speaker connectors and a slow start up when you switch on to avoid arcing in the sockets etc. If the 8 ohm speaker sounds very good on the 4 ohm tap in your setup, I would find a way of dropping the anode voltage down to about 420V and run the amp at about 20watts power. Thus: I would rather keep the 8 ohm speaker on the 8 ohm tap. [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
4,8,16 Ohm OPT taps question (leak amp)
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