Does running equipment at different hertz in AC power supplies affect the audio quality or performance of the unit?

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canidoit

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I was wondering whether hertz affect sound quality or the equipment's performance if for example a unit was designed to run at 18V AC at 60hz US and instead used in Australia at 18V AC 50hz?

I have an EQ that uses an 18v AC adaptor at 60hz at 110volts and I am changing it to 18V AC 50hz Australia running at 230volts.
 

Whoops

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I think normally you will only have problems with equipment that has motors in it, because changing the frequency will change the speed of the motor. I think in this case you are not incurring in any problems
 

Jon S

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Most older power supplies have a mains transformer and that has iron as the core allowing the transfer of energy from the primary winding, (mains side) to the secondary winding (low voltage side).
The more iron used the lower the frequency it will work efficiently at.
The range is usually quoted between 50 and 60 HZ and all transformers of this type work effectively at either frequency.
Most if not all newer power supplies have a switched mode power supply within them. These require DC to supply them and don't care what the mains frequency is.
The mains is fed through a rectifier, turned to rough DC, smoothed with a capacitor and then chopped up at a very high frequency to induce the required power through the windings.
That is why amplifiers and other equipment is much lighter to carry and the amount of iron used in the transformers is powdered and cintered, to form a Ferrite Core, which is still heavy but much less is required due to the high frequencies used.

Reference to motors is correct with synchronous motors, (electric clocks from years gone by and older record/tape players etc).
 

soapfoot

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Hammond organs also use synchronous motors, and there are special 50Hz models.

North American organs will run flat if shown 50Hz

also worth mentioning that, because 100Hz is a lower frequency than 120Hz, power supply ripple is slightly less-efficiently filtered. Most of the time this is academic, but it is technically a difference.
 

JohnRoberts

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I was wondering whether hertz affect sound quality or the equipment's performance if for example a unit was designed to run at 18V AC at 60hz US and instead used in Australia at 18V AC 50hz?
It can make a subtle difference as power supply reservoir capacitors will have 6/5 ths the ripple voltage.
I have an EQ that uses an 18v AC adaptor at 60hz at 110volts and I am changing it to 18V AC 50hz Australia running at 230volts.
presumably the 18v AC is delivered by both... Should be OK as long as the ripple voltage does not cause audible hum.

JR
 

Jon S

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Hammond organs also use synchronous motors, and there are special 50Hz models.

North American organs will run flat if shown 50Hz

also worth mentioning that, because 100Hz is a lower frequency than 120Hz, power supply ripple is slightly less-efficiently filtered. Most of the time this is academic, but it is technically a difference.
Fender produce amplifiers for the World wide customer base. They do not change the value of the main smoothing electrolytic, nor do other manufacturers. So I think it is such a small difference in ripple voltage, that it makes no real difference that can be detected.
For your 18volt supply, you will not notice any difference by using a different frequency of mains. Just be careful to select the correct voltage input. 110volt transformers don't like 240volts!
 

cyrano

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I think normally you will only have problems with equipment that has motors in it, because changing the frequency will change the speed of the motor. I think in this case you are not incurring in any problems

And possibly old digital clocks that use mains frequency as time reference. Haven't seen one of these in years, tho...
 

Matt Syson

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A slightly more subtle effect can be heard if overdriving valve guitar amps as the clipped audio will have either 120 or 100 Hz 'ripple' on it. thus a sustained overdriven note will have different 'distortion'.
transistor power amps probably do this too but then when clipped they sound rubbish anyway.
 

moamps

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I remember dbx graphics eqs from more than 20 years ago that were terribly buzzing connected at 220V/50Hz. They had some poorly designed saturated power EI transformers that we had to replace.
 

JohnRoberts

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I remember dbx graphics eqs from more than 20 years ago that were terribly buzzing connected at 220V/50Hz. They had some poorly designed saturated power EI transformers that we had to replace.
I feel bad about having to repeat this but I have designed SKUs for use all around the world.

50Hz mains transformers require more iron and copper due to only 5/6th as many charging pulses per second.

The real fun was designing SKUs for Japan that has some 100V mains, and iirc both 50hz and 60 hz circuits.

JR
 

Gold

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AC/DC brings a complete power system on tour with them. They always run the amps with the same mains voltage and frequency. The difference in sound between 50Hz and 60Hz is a big enough difference to them to be worth lugging a power system around.
 

JohnRoberts

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AC/DC brings a complete power system on tour with them. They always run the amps with the same mains voltage and frequency. The difference in sound between 50Hz and 60Hz is a big enough difference to them to be worth lugging a power system around.
cough?

A friend of mine (Steve Dove) was the "boffin" (techical nerd) on tour with ACDC when they played through Hartford CT back in the early 80s. I spent some time with them back stage and don't recall anything about a dedicated 50 Hz power system (the band is from Oz, but IIRC the sound company who supplied the rig was based out of the UK.). I still don't recall anything about 50Hz power.

Steve was pretty sharp even back then. ;)

And ACDC was too f'n loud. :rolleyes:

JR
 
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Whoops

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AC/DC brings a complete power system on tour with them. They always run the amps with the same mains voltage and frequency. The difference in sound between 50Hz and 60Hz is a big enough difference to them to be worth lugging a power system around.

They also do it because they can...
I'm not saying there's no difference, but if they were not multimillionaires, and if they couldn't do it they would more than happy with the guitar amp sound at 50hz or 60hz
 

Whoops

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in the early 80s. I spent some time with them back stage and don't recall anything about a dedicated 50 Hz power system

We are in 2022.
What Paul said it's correct but I think it only relates to Angus Young guitar amplifiers power supply, they run it at 60hz.

You can check it in this video starting at 9min24sec:


 
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soapfoot

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The larger point is good regardless: guitar amps will tend to have IM distortion products related to ripple when overdriven, and this can sound different if the ripple is at a different frequency
 

Script

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FWIW, Japan has an East-West 50Hz/60Hz divide.

No problem here for general audio gear or consumer appliances. Transfer via high-power landlines though is a huge problem -- impossible, well, technically possible but not feasible, I have been told. They have three converter stations, I think, but those can only handle 1GW in total.

History:
Two companies built the power grid in Japan. One used equipment by GE, the other by AEG (US versus EU standard). No problems for more than 120 years -- until wake of 3/11 earthquake.
 
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JohnRoberts

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FWIW, Japan has an East-West 50Hz/60Hz divide.

No problem here for general audio gear or consumer appliances. Transfer via high-power landlines though is a huge problem -- impossible, well, technically possible but not feasible, I have been told. They have three converter stations, I think, but those can only handle 1GW in total.

History:
Two companies built the power grid in Japan. One used equipment by GE, the other by AEG (US versus EU standard). No problems for more than 120 years -- until wake of 3/11 earthquake.
I recall hearing customer complaints about Peavey SKUs that hummed because 60 Hz transformers were unhappy plugged into 50 Hz mains. In general you can design the power transformer and size reservoir caps to work at 50Hz, 60Hz is easier. I believe there was also a 100VAC mains district thrown into that mix making our domestic 120VAC 60Hz transformers completely unusable. This further increased our cost to service that country.
We are in 2022.
What Paul said it's correct but it only relates to Angus Young guitar amplifiers power supply and they use 60hz not 50hz
A dedicated mains power rig for one or two guitar amps is certainly possible. We had a test bench in analog engineering rigged to deliver 220/240 VAC, 50 Hz mains power for testing export SKUs (we used a couple high power audio amps driving a special transformer).

As I recall AC/DC used many thousands of watts of power amplifiers for their PA system (used a UK sound company back then). The dummer had his own huge monitor (cave) system up on stage with thousands of watts for that alone. For less cost, the lads could have regulated the PS inside the guitar amp to eliminate mains frequency ripple modulation when clipped, but I suspect they weren't going for a clean sound, but a specific (familiar) dirty sound.

Hartford, CT power is 60 Hz so even if they had such a rig they wouldn't need to use it. Australia where the band was from back then has 50 Hz power.

JR
 

ccaudle

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Hartford, CT power is 60 Hz so even if they had such a rig they wouldn't need to use it.

I suspect it may have as much to do with having a very consistent voltage and trying to clean up any spikes or brownouts. You probably want to baby your equipment a little bit if you travel around the world with antique tube equipment.
 

Script

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In general you can design the power transformer and size reservoir caps to work at 50Hz, 60Hz is easier. I believe there was also a 100VAC mains district thrown into that mix making our domestic 120VAC 60Hz transformers completely unusable.
Maybe one reason (alongside Japan always having pushed their own stuff) why there isn't that much Peavey gear seen around here ??

Old J service manuals specify different transformers corresponding to country of export. But that was back in the 'golden' years.

Japan is 100V mains throughout. Plus/minus 10 percent. Usually minus. Old apartment in central Tokyo I once lived in had 94V.
 
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