Ok, so my son wants a power supply for his various Guitar Pedals. Here are the specs that are supposedly needed. I guess that they want a Linear, not Switching supply, but do they want individual transformers for each individual output? Galvanically isolated??????


AMAZING TONE STARTS WITH PEDAL POWER!
Pedal Power 2 PLUS is the most dependable and widely used guitar effects power supply in the industry, delivering legendary performance to a wide variety of devices from sensitive vintage battery-powered stomp boxes to modern DSP effects. The 2 PLUS is equipped with eight galvanically isolated 9V outputs, including six outputs switchable to 12V, two 250mA outs for more power-hungry effects, and two outputs featuring a SAG function that simulates the output of a low battery. 18V and 24V operation is also available by combining outputs with available special cabling. A handy onboard 200-watt courtesy outlet is included for powering an additional device such as an AC-powered effect, wireless system, or another power supply. Pedal Power 2 PLUS is ideal for small to medium pedalboards or as a supplemental power supply in a larger rig.
ELEMENTS OF A GREAT POWER SUPPLY
Isolation
Ground loops cause hum and the solution is to break the unwanted ground path. Isolation is the best way to do it. Unlike many power supplies, Pedal Power isolates every output. This eliminates tone-robbing interaction between other effects. Pedal Power powers everything from vintage overdrives to modern digital marvels in a way other power supplies simply can’t.
Proprietary Balanced Transformer
Typical transformers, like those used in a wall wart, create large magnetic fields that cause hum in any audio path near it. Pedal Power uses custom-designed, ultra-low noise toroidal transformers with separate balanced windings for every output allowing even the most sensitive pedals to be dead quiet.
Linear Power
What’s good for charging a cell phone is NOT good for your pedals. While digital switching power supplies are small and inexpensive, they also generate noise. Pedal Power uses an audiophile quality linear supply for consistently stable, clean, pure power.

 

but do they want individual transformers for each individual output?

No. This is what they said:

Pedal Power uses custom-designed, ultra-low noise toroidal transformers with separate balanced windings for every output

A separate winding (not separate transformer) for every output.

 

Because you'll only get a toroid with 6 secondaries if you have it custom made, separate transformers is the best route.
But most off-the-shelf transformers have two secondaries, so you'd get away with three transformers for 6 outputs. If you put them in a steel box, you could get away with EI-laminated transformers instead of toroids.
If only guitarists had a little common sense and had adopted balanced line. . .
(and balanced line did pre-date electric guitars, if only by 6 months)

 

I believe that in a Classic Rock electric guitar environment, powerline hum is not really considered a problem, but a sonic feature.

I know, lame attempt at humor.

 

If only guitarists had a little common sense and had adopted balanced line. . .

Funny, I was just thinking of this today: why don't electric guitars have an XLR jack?

 

Funny, I was just thinking of this today: why don't electric guitars have an XLR jack?

I could say that it was because balanced line was a British invention (Blumlein, 1931) and Electric guitars were an American invention (Richenbacher et al, 1932), but it is most likely due to what amplification was available. The electric guitar connected to a public address amplifier intended for a high impedance microphone on a short cable, because that design required fewer valves. Blumlein was more concerned with getting microphone signals over several miles of cable, rather than from guitar to combo at the guitarist's feet, so he was prepared to spend more money on mu-metal screened transformers and larger numbers of valves, so, for the guitarist, the short co-ax cable didn't matter at the time, and the effects pedal hadn't been invented, which is where all the earth loop problems started.
If the effects pedal had arrived earlier, then the guitar amplifiers would have been provided with an effects loop to deal with them, instead of having to attenuate the signal to guitar level every time and re-amplify it.

 

The problem gets worse, from my limited experience with fixing just three effects pedals: Some of the pedals tie positive to the common shield side, others tie thenegative to thecommon side. ALL of them tend to operate from a single 9 volt battery. So any external power supply will need EVERY output to be isolated!!!

AND, they dont use an XLR because it costs a lot more, it is bigger, and it is impossible to repair when your gig is already set up in a bar and the show starts in ten minutes!!
A screw terminal phone plug connection CAN be be repaired in that time!!

 

The “centre-live, outer=earth” is correct for germanium pedals which use positive earth. Everything more modern still uses the same Voltages on the pins, but the earth is now negative i.e. the centre pin.

(I‘d venture that an XLR would be less likely to be broken than a ¼” jack)

 

The “centre-live, outer=earth” is correct for germanium pedals which use positive earth. Everything more modern still uses the same Voltages on the pins, but the earth is now negative i.e. the centre pin.

(I‘d venture that an XLR would be less likely to be broken than a ¼” jack)

The polarity of a power input connector should have no relationship to the technology of the circuit within the enclosure!!
Nor should it have any effect on which polarity is common to the enclosure. Why would anybody think that it should??? Consider that the typical coaxial power connector may tie the outside sleeve to the pedal enclosure, why should the polarity of the common on the PCB matter?? Positive as a common in the circuit just requires a bit more wisdom in the mechanical assembly process.


The only broken 1/4 inch plugs would be the ones with the "Breakalite " plastic shells. The 1/4 inch plugs of any quality use a less fragile shell material.

 

Funny, I was just thinking of this today: why don't electric guitars have an XLR jack?

What ...are you insane!!!

 

Look in a catalog and compare the prices!! THEN, consider that there were electric guitars perhaps 20 years before the first XLR connector was ever made.
THEN, look at the 3 connections in an XLR and try to guess which one gets the shield!! AFTER THAT, try to repair a broken connection to an XLT with only a pocket screwdriver!! In poor light!!
After THAT, try to unplug an XLR connector in a hurry!!
There are probably other reasons, but those are the ones that pop up in my mind, instantly.

 

What ...are you insane!!!

No. Just not a musician.

 

Funny, I was just thinking of this today: why don't electric guitars have an XLR jack?

Because it would look ugly..

Probably because guitar pickups are high impedence devices, their designs are "sacred" to get certain "tones", and 1/4 jacks/plugs remain compatible with older amplifiers, and....

 

Because it would look ugly..

Probably because guitar pickups are high impedence devices, their designs are "sacred" to get certain "tones", and 1/4 jacks/plugs remain compatible with older amplifiers, and....

Vocalists prefer the tones of certain microphones, Shure SM58, for instance, and they don't have a problem with XLR connectors and balanced line.

 

Vocalists prefer the tones of certain microphones, Shure SM58, for instance, and they don't have a problem with XLR connectors and balanced line.

That's obvious, but not the same if used for a guitar.

 

That's obvious, but not the same if used for a guitar.

With guitarists, common sense won't win the argument.