i remember j.l. hood had different voltages for the output stage on some of his amps, so my question is, if i run a tda2030 and bd907/908 as per the data sheet with +36v, can i add bigger output trannys at higher, 50v, to up output? if so how? bearing in mind that this is +v / earth, not +v 0 -v?cheers for ideas and help, see you soon, steve.. ..
I don't know what kind of circuit you are constructing, but you have to have enough voltage to cover the peak to peak AC voltage swing, without driving the signal transistors into saturation. Whether this is done with a +/0V/- supply or just +/0V you have to have room to fit the peak of the signal within the rails, less the unsaturated Vce of transistor. With a single sided power supply, the peak to peak must fit within. With bipolar power supply, just the peak AC has to fit, the other peak for the other side. The power output is a fuction of the maximum AC signal voltage across a load impeadence. P=VI This is of course determained by the output device charactoristics.
Hi, normally the voltage amp stage runs off the same Vrails as the current amp stage as the thread implies. Some run the VAS off regulated low current rails usually just above the high current rails.
If you want to run VAS off low voltage rails then the current amp stage must have a voltage amp at its front end to bring the peak voltage from VAS upto the required volts to drive the current stage to full power.
e.g. VAS off +-22v rails then the pk to pk approx. 40v.
followed by a times 2 voltage amp gives pk to pk 80v.
After a suitable current stage this will drive 8r to about 100watts.
Adjust the values to suit your design.
regards
Andrew T.
If you want to run VAS off low voltage rails then the current amp stage must have a voltage amp at its front end to bring the peak voltage from VAS upto the required volts to drive the current stage to full power.
e.g. VAS off +-22v rails then the pk to pk approx. 40v.
followed by a times 2 voltage amp gives pk to pk 80v.
After a suitable current stage this will drive 8r to about 100watts.
Adjust the values to suit your design.
regards
Andrew T.
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