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jet690 wrote: Worthy to note that it operates on 12v dc - centre POSITIVE connector.

This quote is from John Ashburn's message about his Blue Nebula in Guitars, Amps and Effects but I'm starting a new thread because he makes a very good point.
Suppose 12 volts centre positive has established itself as the standard, say, 40 years ago in the 1970s when low voltage transistorised gear was beginning to be common in households. Think of the saving today. Instead of houses being cluttered with umpteen out-of-date wall warts, 6v, 9v, 12v, 15v, many with centre negative, there would just be one standard, 12v centre positive. Cars have been 12v centre positive for many years. Once you'd bought one 12v transformer for the house it could be used for anything - a TV, a radio, a charger. Think of the saving in copper from those now-useless transformers that we have hanging around the house. We might even have a 12v centre positive ring main around the house - TVs, radios, chargers and all the rest wouldn't need to run from 13A plugs. Safer, too.

Sometimes one particular item creeps up to become a standard. The SD card is an example. At one time there were four or five different types of memory card. Now there is only the SD. All mobile phones now use the tiny USB socket for charging. What a shame that 12v centre positive didn't become a standard.

I am glad that this was not done!
To get the same amount of electric energy transported you would need a current that is roughly 20 times higher than what you have with 235 V. And the heating up of the wires is proportional to the current.
I.e. a water boiler in the kitchen for heating the water for tea etc. roughly draws 1000 W. With 235 V supply the current is 4.25 A, with 12V it would be well over 80 A.
Imagine the thickness of wires in your household, no saving of copper! If you have a look under the bonnet of your car and have a look at the thickness of the wires, especially for the starter engine, you get an impression.
No way! Sorry to disillusion this idea.

Ulrich

UlrichS wrote:I am glad that this was not done!
To get the same amount of electric energy transported you would need a current that is roughly 20 times higher than what you have with 235 V. And the heating up of the wires is proportional to the current.
I.e. a water boiler in the kitchen for heating the water for tea etc. roughly draws 1000 W. With 235 V supply the current is 4.25 A, with 12V it would be well over 80 A.
Imagine the thickness of wires in your household, no saving of copper! If you have a look under the bonnet of your car and have a look at the thickness of the wires, especially for the starter engine, you get an impression.
No way! Sorry to disillusion this idea

Ulrich

Surely this is to do with what I call peripherals and not homestead appliances. All households know how many various chargers they have for very similar items. In this global economy it is time a standard was reached and this also means Apple

You're both right!

As John Brown says, my idea of a '12v ring main' was only ever intended for low-current devices.

UK 13A sockets are now available with USB (5v) sockets incorporated (for phone charging). A similar concept.

Ray

Interesting point Ray. With 5v DC now universally available for phone chargers, is there any mileage in redesigning musical equipment to work on 5v?

Iain Purdon wrote:Interesting point Ray. With 5v DC now universally available for phone chargers, is there any mileage in redesigning musical equipment to work on 5v?

Generally a lower supply voltage will allow less headroom for the signal. Whilst most pedals are nominally specified as 9 volt many will operate better at a higher voltage (but don't test this theory if you're not sure!) and some may require AC if they have built in rectifiers or use some form of voltage multiplier inside.

RogerCook wrote:

Iain Purdon wrote:Interesting point Ray. With 5v DC now universally available for phone chargers, is there any mileage in redesigning musical equipment to work on 5v?

Generally a lower supply voltage will allow less headroom for the signal. Whilst most pedals are nominally specified as 9 volt many will operate better at a higher voltage (but don't test this theory if you're not sure!) and some may require AC if they have built in rectifiers or use some form of voltage multiplier inside.

Correct Roger. A 12V supply does indeed allow more signal headroom. A 5V supply would likely lead to unwanted distortion if the input signal from the guitar was high. This can happen on the transient at the start of a note when, for example a LP with humbucker pickup could hit over 1.2V peak-peak on the initial pluck of the string (Source Jack Orman http://www.muzique.com/lab/pick.htm). Even a small amount of gain in the input stage would cause it to 'hit the rails'.

With a 12V supply (internally regulated to 9V in the Blue Nebula) such problems are largely avoided. In fact the BN's Gain control allows it to cope with a wide range of pickups from low output single coils to hot humbuckers and still allow the specially designed preamp to create the triode valve like warmth that makes it sound so good.

Phil. (Blue Nebula Development Team Member)