Hi everyone, perhaps this idea has already been discussed. Here it is : As most of the energy of musical programs lies in the lower frequencies and is from almost to completely mono (as you can experiment if your speakers are reverse connected), a great improvement in power amplifiers PSU needs would be to invert the phase of one of the stereo channels (and reverse one of the speakers connection to restore the acoustic phase of course). As you can see on the shots (music program, phase / anti phase, same scale), the instant need for current is dramatically lowered in the "inverted" configuration. Channel blend, PSU regulation needs and instant symmetry of the current pulses in the transformer are improved as well. For stereo class A amplification, mono signals result in zero AC current. Plus for single ended amps : distorsion of mono signals is improved as the acoustic sum of the signals means anti-phase amplification as it is done in push-pull amps, where the sum of the signals is magnetically done in the output trans). Inverting the phase of one channel may be very easy (for instance for phono preamps, just invert the connection of one of the coils of the cartridge). Digital sources can be modified in the digital domain, analog sources will need an inverter. Not an issue anyway : transformers, tubes, transistors or opamps can do the job.
Could deserve a try as it is an easy mod.
M.
Could deserve a try as it is an easy mod.
M.
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What are we looking at here in the scope shots? Please give us a little more information.
Thanks!
Thanks!
I believe B&O did this many many years ago, reversing the phase of one channel to ease the PSU loading.
A similar idea could apply (if not already done loooooooooooooong ago ...) to passive biamplification. Both amplifiers could see a roll off far from the cutoff frequency (low pass for the bass amp - high pass for the med/high amp). Actually, I currently use this trick in a biamp SET EL34 - SET 2A3 - LA SCALA speakers setup with light filtering : a first order filter inserted in a DC coupled 6SN7 buffer.
M.
M.
I have seen this done in A/B switch mode powered car audio amps. It improves the load disrrtibution to both supply sides. Any bridged amp does it, by the way.
Sure it does, the idea was to improve the power management of any amp, whatever its design and without any mod.
When I worked in Japan, we sold class D chips to Sony for their boom boxes and they showed me and the apps guys the technique. We sat in their lab listening room with some of the finest hifi gear from all over the world around us listing to a Sony boombox on a table in the middle of the room at full volume. After the test, my ears ringing, they said the bass was a bit loose so we took it away and did some more work on it. They bought a few million chips a year from us for boom boxes that went to the Central and South American, African and some Asian country markets. Fun times!