OOPS

Records-Double the pleasure at zero cost

I remembered coming across an article in an audio magazine sometime ago detailing a novel design for a stereo amplifier.I cannot remember the name of the writer or magazine. However I could still remember the gist of the article. It laid out an interesting twist to maximise the efficiency of the power supply of a stereo amplifier. The writer called this system "OOPS" or out of phase system. This entails introducing a circuit to reverse the phase of one channel of a stereo amplifier that shares a common power supply. Of course if this amplifier was driving a pair  of speakers in the normal way, the output would be out of phase at the speakers end. For this this system to work the speakers cable is reversed on one channel and the music is back in phase again. This system seems to be on the surface an unnecessary complication. But according to the writer this system has a major advantage. This is with regard to the more efficient use of the shared power supply.

In a standard amplifier with a common power supply , the handling of large signal peaks is often far from ideal as the strong , simultaneous demand from both channels strain and drain the power supply. However if the signal peaks on both channel do not occur at the same time as when the two channels are out of phase then the power supply will be able to work better to meet the demand. If the amplifier was a duo mono design or monoblocs where each channel has its own independent power supply then the above mentioned problem do not arise. As far as I know this idea was never used in a commercially made amplifier. However the idea can be used by the audiophile to improve on his analog playback system easily and at no cost whatsoever. The idea may appear to be radical at first but rest assured that it is perfectly safe and if the audiophile do not like the result the process is easily reversible.This is what needs to be done to effect the idea. Reversed the cartridge leads on one channel on the headshell. Taking as an example we reversed the lead for the right channel which has the colour coding of red and green. In the standard hookup, the red wire goes to the red pin and the green wire goes to the green pin on the cartridge. In certain cases the cartridge pins are not colour coded but are instead marked as "R,L,+ and -" In this case the right positive is red and the green wire goes here. The right negative is green and the red wire goes here. If this is confusing some of you perhaps the diagrams below will be of some help.

 

Standard connection for Cartridge.                OOPS connection for cartridge.                OOPS connection for cartridge

 

Cartridge Tonearms Leads                                Cartridge Tonearm Leads

           Red      Red                                                                Red         Green

Right    Green    Green                                               Right      Green     Red

Left      White    White                                               Left        White      White

            Blue       Blue                                                              Blue         Blue

 

 

Of course after having done that , the playback resulting from this would caused your system to be out of phase. To get it back in phase again (which should be the proper way to play your system) reversed the speakers cable on the right channel on the speaker end. That is connecting the ground of the amplifier (usually mark as black) to the positive input of the speaker (usually marked as red). The positive output of the amplifier is then connected to the negative input of the speaker. This will bring your system back in phase and hopefully sounding much better. Again the diagrams below will make the configuration clearer.

 

 

 

Standard connection for amp to speaker           OOPS connection for amp to speaker. Standard connection for amp to speaker           OOPS connection for amp to speaker. OOPS connection for amp to speaker. Standard connection for amp to speaker           OOPS connection for amp to speaker. OOPS connection for amp to speaker. Standard connection for amp to speaker           OOPS connection for amp to speaker. OOPS connection for amp to speaker.

 

Amplifier Speakers                                              Amplifier Speakers

            Red       Red                                                    Red         Red

Right   Black      Black                                       Right    Black      Black

Left      Red        Red                                        Left       Red        Red

            Black      Black                                                 Black       Black

 

Superficially there should not be any difference since this is similar to a man looking at a lovely landscrape who is then asked to turn 180 degrees twice which would cause him to be looking at the same view again. However in practice there is a very marked difference in the sound produced by a turntable based system when connected in the OOPS configuration. The sound is distinctively airier and more open sounding. Bass is better defined with clearer separation between images and the system seems to be able to play much louder than before. The most important difference lies in the observation that the surface noise of the LP appears to be at a much lower level. Overall it is hard to go back to playing LPs in the standard manner once you get used to the sonic capability of an analog system configured in this manner.

Technically there is a possible explanation as to the why and how of this system. When a cartridge is connected with one of the channels leads reversed, the music signals of the two channels are out of phase. However noise that is usually associated with LPs such as scratches and surface noise would be picked up in the two channels as in phase.If this state of affair is allowed to proceed through the amplifier to the speakers the result would be that that the music would be out of phase and appearing to be coming from outside the boundary of the speakers and the normal record noise would form a nice soundstage in between the speakers where the music should have been . But if we were to reversed the speaker leads on one channel the music would now be in phase and the noise would be out of phase and banished to the edges of the musical soundstage. We can just sit back and enjoy analog heaven without the noise and the best thing is it does'nt cost you a cent. Surely a value for money mod.

Of course this "out of phase system" do not give you perfection in a medium that has never claimed perfection {unlike another medium I know of.).It does make the analog medium less imperfect allowing the listener to enjoy the music without being distracted by the clicks and pops that many vinyl lovers have endured ,ignored or caused them to simply give it up.

For those planning to try this out on their system there are a few finer points to note before jumping into it. The first is this . If you also run a CD player in your system , everytime you change your listening source from LP to CD or vice versa you will have to reverse the speaker leads. This is a bit of an inconvenience. If you don' play CD at all, than this article may be just what you need.If you play CD only, than unfortunately this information may not be so useful to you. However it is possible to effect this OOPS configuration if you have two DAC with a phase invert switch. Perhaps this can be the subject of another article.

Secondly to maintain correct absolute phase always ensure that when you reversed the cartridge leads on the left channel,you also reversed the leads on the left speakers. Thirdly ,the mono switch cannot be used any more.Hit that switch and you have the left and right channel cancelling each other out. Finally this system do not aimto allow the vinyl user to get away with playing a dirty record. The dirty record will still sound dirty but this system will make a clean record sound even cleaner. Often users of this system may mistakenly think that they are playing CDs due to the lack of surface noise. But there is no mistakening the natural tone of a well set up LP records playback system.