Power Conditioners...Do They Make A Difference And Why?

I have found the triplet LCR2400 Voltage regulator has made a small difference here in KC In Galveston I wouldn't do anything without one!
The question should be two part do I need a condition ,and what do I need to solve my problems?

NO. 99% of the time the mains is clean. A good power supply will handle small fluctuations even 1/2 good one's will be fine.
However if you have dirty power welding pant next door or similar for example you may need to do something about it BUT. The only way to stop large spike's is to convert the AC to DC (battery bank) then back to AC for your gear. I use to be an electrician in an ICU where people's live depended on uninterrupted clean power this is how we did it. The backup generator kicking in could cause a spike the battery bank prevented it getting to the sensitive equipment. For audio a power conditioner will generally do nothing.

Lemme say a few things and then people can decide for themselves.

A power conditioner is typically comprised of two things:

Transient/surge voltage suppression (TVS, gas arresters, MOVs, etc)
Low pass filtering (caps/inductors, etc)

The purpose is to add some protection from surges and transients (same as the common power strip) and then filter out any higher order harmonic noise and/or EMI/RFI from the AC line.

A balanced power isolator is typically comprised of one thing:

A large matching (1:1) toroid transformer.

The intended purpose is to transform single phase AC into differential AC.  I'm not sure where "balanced" came from, but it's not balanced, it's now differential.  There is a BIG difference.



So now let me explain each a little better.

The power conditioner doesn't change the fundamental AC signal (50/60hz sinewave), but forms a low pass filter just above the fundamental frequency so that any noise above it will be filtered out.

While I believe this is a good thing, most modern electronics have plenty of filtering designed into the product.  If the unit has a SMPS (switch mode power supply, AKA a switcher) then the additional filtering from the power conditioner means nothing.  A SMPS rectifies and then switches the AC into a much higher voltage square wave before cycling the duty cycle to reduce the RMS power to the transformer secondary, before rectification, decoupling and possibly linear regulation.

If the design has a linear supply, the input power transformer forms a lossy LC filter, before the transformed AC is rectified and filtered.  Better designs will have an EMI/RFI filter built into the AC input like this:



Which already incorporates the AC LC filters.

HOWEVER..  And here's the kicker..  A majority of noise in a system comes from poor grounding and increased AC line filtering doesn't help as much as it should.


Ok, so now for "balanced power"..

In the USA, standard wall outlet voltage is 120V/60Hz single phase.  ONLY the "hot" (black conductor) is intentionally powered.  The "neutral" (or the current return as it truly is) is essentially at "ground" potential and is tied to ground in the fuse box/circuit breaker installed in your house.  The "ground" conductor is not for carrying current UNLESS there is an issue with the device plugged into the outlet.  It is for safety ONLY.  This is why devices that have ground loops are exhibiting a failure, and should be repaired or modified, not jerry-rigged, but I digress for now.

So in a device that has a SMPS, differential power means NOTHING again.  Same as the filtered AC above, the modification of the AC signal is so extreme that any noise on the input AC is swamped by SMPS switching noise and is then filtered out with the switching hash on the output of the supply.

In a linear supply, the input transformer typically does a single-ended to differential conversion between 120VAC and +/-XX VAC  on the secondaries.

The step down ratio also applies to any signal present on the AC input, so lets say that it's a 12VAC secondary which gives a roughly 10:1 ratio.  If AC noise on the power input is 300mV, then it's now 30mV, etc.  The input transformer also forms a LPF due to the series inductance of the windings and the shunting parasitic C of the coils/core.  It's not going to override nasty hash from a refrigerator, but then again, that's a lot of noise and a PROPER fix would be to use a different circuit altogether.

Anyway, you also have rectification and filtering on the linear supply output.  If it's properly designed, then you shouldn't have any issues that require external devices.

So back to the differential power conditioner..  It's nothing more than a single ended to differential transformation like your power input transformer already does, and works just like your audio signal transformers.  Some units also incorporate the same filtering as the generic power conditioners, and this is what I believe does the majority of the AC signal improvement.  Any improvement of the AC signal from the matching toroid is done by parasitic filtering and not by the "differential" nature of the output.

It looks to have a circuit breaker, and probably at the very least has some MOV devices to catch lightning surges and things like that. Since it's sold as a power conditioner, it probably has some filtering, but how much filtering it has is unknown.

You can always add another inline AC filter to the box though.

It's kind of a debate when you consider the facts. There are two things that I always wrestle with, with this.
1. Near elimination of RF interference
2. Increased transformer loads in the studio that create a buzz my telecasters just LOVE to eat like candy... when I track in the control room (most of the time).

1. RF interference always has an ingress point.  A lot of what folks call RF interference is actually intermodulation where a fundamental frequency and a nonlinearity (diodes..) act as RF mixers and downmix into the audio spectrum..  Tubes do this a lot, as do cables with bad grounds or open ends (similar to antenna designs..).  Not because the cable allows the RF in, but because the cable wavelength and the nonlinearity form a receiver.. 

2. I've found this a couple times, and typically if you turn 45/90 degrees you'll find a null in the field.  Otherwise, you have some kind of issue with shielding on something, or in the guitar, and the wavelength/nonlinearity forms another receiver.  

Isn't electronics great?

I think it's probably the same for all types of input power transformers.  I've used all kinds of transformers for both hobby and paying work and they each have their quirks.  Even those of the same type from different manufacturers can act differently in similar situations.

Once, I actually did find that using a large E-core matching transformer worked to get rid of a lot of noise from a gas generator.  most generators output a "modified" sine wave which is essentially a square wave at 120V P-P.  The lossy E-core smoothed the edges of the square enough to stop overheating the transformers in all the equipment that was being powered by the generator.  Power transformers do not like square waves!

As for non-toroid matching transformers, I'd stay away from them for audio purposes.  They can have high leakage currents and large EMI fields.  Toroid or bust!

I'd also say that if you have a situation that calls for large instantaneous currents, linear transformers are not the way to go.  They are pretty slow at current propagation delays.  Large and fast currents should either be dealt with at the DC stage with large capacitors and low impedance traces, or very fast Point-of-load regulators.  These days, I'm dealing with 10A at 0.9V in some digital supplies for FPGAs I'm designing into products.  Some of the peaks during synchronous switching can be very high, into the 30A range for very short periods.  I'm using POL regulators and 2x 1uF 0402 caps per power pin..  One design has about 200 decoupling capacitors on the FPGA alone, along with 8 power supplies of various voltage and currents.

Anyway, brownouts are probably best dealt with a UPS if they are expected to be any length of time.  Very short drops could be handled at the DC level with large banks of bulk cap, but that's probably not feasible to add to a lot of designs.  A very large external matching transformer might deal with brownouts or surges if they fairly fast.  A very large core will hold a lot of flux and could probably smooth out the brownout/surge fairly well, but it would certainly be up to the current demands of the devices plugged into it and so on.

I auditioned several power conditioners at my old shop in Van Nuys. All of them reduced audio quality. Some cost as much as $5000 and had analog and seperate digital device AC outputs.

What they did was reduce available current and that showed with reduced low end energy.

A quality high current isolation transformer does work. I've installed these in studios. They are large and placed in a box/room far away from any audio gear. You take 120 V off the mains and run these as a center tapped output. This feeds + - 60 volts to hot and neutral. The centertap is your technical ground run with a 8 awg copper cable to a 1/2" 8 foot long copper rod driven into the ground.

This creates 'balanced power'. Since hum fields are now common mode cancelled electric guitars run quietly. The acoustic hum level from the individual power transformers in each audio piece are also reduced. These large 80 to 100 amp isolation transformers cost a couple thousand dollars but the results are stunning.

The biggest audio improvements I've ever heard came from:

1. plugging all audio gear into a single duplex outlet.

2. Tightening up the screws in that outlet and every single connection back to the service entrance of the building. In a great many cases those connections have never been touched for 50 years or more.

Same thing happens to me here, Ward.  I have to turn away from the monitor to get rid of the audible RF.

I have been advised to add a "hospital grade" circuit - a 15 or 20A line, in conduit, run all the way from my service box to my family room, where all the action takes place. I was also advised to "re-ground" my box with a fatter, longer grounding rod. But I wonder if this would eliminate the rather bad hum picked up by anything single-coil when a refrigerator and air conditioner(s) are running off the same municipal power source. It seems that my entire house would have to be on an isolation transformer, which doesn't seem practical, or affordable.

One widely-known thing I can confirm: lighting dimmers are bad bad bad for AC line hum. Insanely bad. And of course all of my overhead lights are dimmed. We work in low light these days because of it.