Using power conditioners with Guitar amps?

[random_name]

I've seen quite a lot of online discussion about whether or not running your mains through a power conditioner will improve the tone of your Guitar amp....opinion seems to be pretty divided - a lot of people seem to think it's Snake Oil...anyway, it occured to me that one aspect of it might be measurable/testable - anyone who has an FFT-capable Oscilloscope would be able to examine the spectrum of the mains voltage (with and without the power conditioner)...they could also look for noise etc on the secondaries of the power transformer, the output of the rectifier etc.

Has anyone here ever tried anything like this, or have any thoughts about it?...

[Chuck H]

Why would noise on the power transformer secondary affect the sound of the amp?

[tedmich]

why not just do a +/- test and earball it?

Might help reject line hash from SMPS or fluorescent lights, but it would be on a case by case basis, not global.

[random_name]

Why would noise on the power transformer secondary affect the sound of the amp?

Well I realise it's going to be rectified and then filtered before it gets to the valves, but I was thinking maybe some of that noise could get through and affect the signal, I doubt if noise on the heater supply matters though.

why not just do a +/- test and earball it?

Might help reject line hash from SMPS or fluorescent lights, but it would be on a case by case basis, not global.

Well I'm trying to find out a bit more before I decide whether it's worth buying one.

[Chuck H]

Ah. Then take your amp and guitar to the store that sells them and tell the sales person that you want a demonstration of why you should buy a power conditioner from them. After all, their job is to sell one to you. This presumes that the product is notably useful to you and the sales person should be able to demonstrate this.

[Jazz P Bass]

[QUOTE=random_name;247791]I've seen quite a lot of online discussion about whether or not running your mains through a power conditioner will improve the tone of your Guitar amp...QUOTE]

What are you after?
I find this concept intriguing.
Can you expand the statement about "better tone"?
More treble, less bass.
More this, less that.
What?

[R.G.]

The advertising phrase "You'll get much better tone out of your [whatever] if you buy this here widget." can be loosely translated as:

"If you are suggestible enough to believe this, I think I deserve to have some of your money."

Power line "conditioners" can be made. As far as I've been able to tell, almost none of them do what they imply they will. An amp power supply is a fairly brutal mixmaster blender as far as the power line is concerned. A properly working amp power supply sucks a little blip of high current out of the AC power line right at the peak of the AC waveform, and then turns off, not 'eating' another blip til the next peak. These little blips are amperes to tens of amperes big, and can cause RF problems in their own right. The blips of current run into a filter capacitor which was designed to look as much like an AC short circuit as the amp maker could afford.

One consequence of this process is that anything that happens on the AC power line between cap charging blips can't get into the amp at all. The power supply rectifier diodes are off, and holding the AC power line out. It's only any wiggles that happen right when the diodes connect the power line to the nearly-AC-short filter caps that the line can get through at all.

It is possible that high frequency hash and grack could be coupled through the power transformer under some circumstances, and possible that the power supply filter caps are old enough and high-frequency-feeble enough that you could hear some of this grack, but there are other ways to fix this.

It is possible that Big Transients on the AC supply can get through. This is often because the power line also powers welders, electric motors, HVAC compressors, and such. Often these are dangerous to the amp, poking holes in the power transformer insulation instead of being audible nastiness.

What all of these issues share is that they are either not there or are clearly related to the power line frequency, not a subtle subtraction of "tone", assuming anyone could ever define some way to measure "tone".

As I type this, I notice that power line issues are only subtractive. That is, you can never do better than a clean, quiet 60 (or 50) Hertz sine wave. You can't "polish" the power line. You can only keep it from degrading what you already have, and when it can no longer make the sound worse, no amount of polishing or using unobtainum parts will make the sound better.

There is a slam-dunk, iron-clad way to make sure the AC power line is not causing any issues with your amp. It's not a popular one with the sales people, as it involves something heavy and fairly expensive. But it's good. If you want to do this, get a harmonic-neutralized ferroresonant transformer (also called 'constant voltage' transformers) with a big enough power rating to run your amp. This thing transforms AC power line at a variable voltage with junk and interference on it into a pretty-well constant output that's almost entirely a sine wave. It does this by maintaining a BIG resonant filter to reduce whatever comes in to just a sine wave going out. It's an admirable solution, but as I noted, is heavy and expensive. It's much better for business to sell guys a little box with several MOVs, inductors and capacitors in it and convince them it sounds better.

There is a modern, dark-horse alternative to the constant voltage transformer. That's a sine wave inverter. This thing takes the AC power line, does its own internal slicing and dicing to make DC out of it, then runs a high frequency, high voltage switching power supply to make that high voltage, high power DC into a stepped approximation of the sine wave you'd like to have. So far, so good, but the original caveats apply. This thing is only supplying power into your amp on the peaks of the AC wave, just like the original AC power line, so your amp is presenting it a fairly brutal load too. And it's doing high power, high frequency switching so it can radiate switching hash into your amp through the air if not carefully designed. And it's complex, high power electronics that can fail all on its own.

[soundguruman]

I've seen quite a lot of online discussion about whether or not running your mains through a power conditioner will improve the tone of your Guitar amp

Well no, it does not claim to improve the tone, only condition the power

....opinion seems to be pretty divided - a lot of people seem to think it's Snake Oil.

Well yes, overall it's a waste of money.
You already have an isolation transformer in the amp, and all the caps and MOVs, etc...that the amp manufacturer installed...so installing the conditioner is redundant redundant.
2. what a bunch of people don't understand is that the components used in most power conditioners don't clamp the line voltage until it's WAY over voltage. By that time, the components in the amp could be already fried.

A lot of people are blaming the noise on the electricity, but principally, it's the guitar pickup, normally single coil, that is contributing most of the noise. And then the noise that the amp, effects pedals, itself adds + to that.

..anyway, it occured to me that one aspect of it might be measurable/testable - anyone who has an FFT-capable Oscilloscope would be able to examine the spectrum of the mains voltage (with and without the power conditioner)...they could also look for noise etc on the secondaries of the power transformer, the output of the rectifier etc.

Has anyone here ever tried anything like this, or have any thoughts about it?...

Well yes, any guitar pickup will absorb 60 cycle fields in the vicinity and the amplifier will faithfully do it's job. So you will hear 60 cycle in the final product. Does the power conditioner stop that? No.
Does the power conditioner stop the guitar pickup from absorbing 60 cycle via fluorescent lights? no.
we approach most noise reduction with humbucking pickups, then consider what could be done to reduce noise in the circuitry of the amp also.
But is the noise you are trying to get rid of really coming from the electricity? I mean really.

[Chuck H]

See post #5.

Just see if you can hear a difference. Just see what the sales person has to say about what they can hear or what is actually happening compared to your own experience. We can prattle on about all manor of obscurities and it won't change the fact that the subject matter is obscure to anyone without technical knowledge of the question. That's why companies can sell these things. So...

Go and see for yourself and make your own evaluation.

[Gingertube]

I have a guitar teacher friend who always ran his teaching amp through a power conditioner.
He complained that the power conditioner rattled and obviously had a loose part in it and brought it to me to look at. Sure enough, a cap had broken loose inside and so I cable tied it back down.
While I had it open I did a full check - it had a blown fuse on the control board and had been defaulting to power straight through rather than being conditioned. This was indicted by a red fault lamp on the outside. When I asked him about that he told me it had always been that way.
So the power conditioner he swore by was doing absolutely nothing and apparantly had been for the 2 years or so that he'd been using it.
When I sent it back fully functional - he told me he could'nt tell any difference.
I'm accordingly a bit sus about claims that a power conditioner can make a big difference.
Cheers,
Ian

[soundguruman]

I have a guitar teacher friend who always ran his teaching amp through a power conditioner.
He complained that the power conditioner rattled and obviously had a loose part in it and brought it to me to look at. Sure enough, a cap had broken loose inside and so I cable tied it back down.
While I had it open I did a full check - it had a blown fuse on the control board and had been defaulting to power straight through rather than being conditioned. This was indicted by a red fault lamp on the outside. When I asked him about that he told me it had always been that way.
So the power conditioner he swore by was doing absolutely nothing and apparantly had been for the 2 years or so that he'd been using it.
When I sent it back fully functional - he told me he could'nt tell any difference.
I'm accordingly a bit sus about claims that a power conditioner can make a big difference.
Cheers,
Ian

It's another gimmick like monster cable. They want to convince us that we need another useless thing.

[Alan0354]

It's another gimmick like monster cable. They want to convince us that we need another useless thing.

Big speaker cable do make a difference. You don't need monster cable, you do need big cable with fine strang.

Back to power conditioner, I don't buy any of that. You pick up more noise from the guitar than anywhere else...........Well maybe Eric Johnson can tell the difference as he claimed he can tell what 9V battery being used.

[soundguruman]

[QUOTE=Alan0354;247948]Big speaker cable do make a difference. You don't need monster cable, you do need big cable with fine strang.

I will replace your big fine strand speaker cable with 18 GA lamp cord from radio shack. And you will never know the difference.
I will replace it with coat hanger wire, and you will never know the difference.

[Steve Conner]

The "Furman power conditioner" was a standard accessory in racks of the metal era. Some people also claim that this era was an all-time low in guitar tone.

Therefore, the evidence suggests that power conditioners actually make your tone worse. They may also be implicated in big hair and Spandex.

We have dreadful noise on the mains in our lab, from some rogue switchmode power supply somewhere in the building. I measured something like 10V peak of switching spikes at 160kHz. They get into everything. I've seen them on the outputs of audio circuits that I've been playing with in my spare time, where they ruin distortion measurements.

Whether noise like this would degrade the sound quality of audio equipment, and whether a consumer-grade power conditioner would help, are two other questions. Rather than spring for a Furman, I bought a bigass 20 amp filter on Ebay, originally meant for a variable speed motor drive, and wired it in the mains feed to my lab bench.

Modern equipment is required to pass radiated and conducted immunity tests to earn its FCC or CE approval. It gets bombarded with radio waves in a test chamber, and RF crud is fed up the power cord and signal cables. However, when guitar amps get EMC tested, I somehow doubt they have a golden ears on hand to check for tonal degradation. The amp is probably allowed to make dreadful noises, as long as it doesn't suffer any permanent damage. Maybe RG knows more about this than I do.

[soundguruman]

Really, the only ones that do work are the big assed LC filters, or regenerating the power entirely.
It was power harmonics that burned down the MGM Grand Hotel, but I don't think a Furman could have saved it.