50hz vz 60hz

[Jerrold Tiers]

A transformer good for 50 Hz should have NO problems at 60 hz. The change in frequency is not enough to cause problems (400 Hz would probably be an issue).

As has been said, the big issue is with a 60 hz transformer used on 50 hz.

For 50 Hz, the transformer needs more "magnetizing inductance" so that the idle current is low, and the transformer does not "saturate the core". Increasing the size of the "stack" (the total thickness of steel "laminations") increases the inductance per turn, and it may not be necessary to increase turns. That is a design choice made by the transformer engineer.

Some words to the transformer purposes.
......................................................
Stupid question:
Transformer power differs depending line frequency. 50Hz amps (EU models) and 60Hz amps (US models) very often used the same transformer. But output power of the amp differs as well by nearly appro 8-10%.
I'm wondering that manufacturers output power ratings where always just the same for US and export EU models.

Who says the power output changes?

The power supply ripple voltage will change, it is larger at 50 Hz. But if designed with sufficient capacitance, a transformer type, or SMPS type will have no problem at either frequency. There is no reason the power output should change.

Perhaps you are thinking of motors. There IS a slight change with motors, although even there the design can easily be such as to avoid any problems.

But - Their FAQ is specific enough that you'd better get it in writing from Markbass if you ever have a warranty problem:


Can the voltage be changed if I move to another country?

Unfortunately, due to homologation issues, the voltage may not be changed without having the amp reapproved for electrical safety. If you're just traveling internationally with your amp, we recommend using power transformers, which are generally available from backline companies and can also be purchased inexpensively.

Can I use my Markbass amp in countries with different voltages?

No! Your amp/combo was manufactured to be sold and used in the country of purchase, and is factory preset to that country's voltage. If you use it in a country with a different voltage without using a power converter, it will not work and may be seriously damaged.

Homologation is translatable as "certification". So they have certification issues.

This appears to mean that the Markbass design is certified only in the country it is sent to, i.e. only UL, or C-tick, CE, CCC, etc, and that they certify a separate version for each country......

It also appears to mean that the power supply is not readily changed from one voltage to another. This seems very silly, since the rest of us have the very same unit "certified" all over the world, simply changing the voltage tap and the fuse (or circuit breaker) for different voltages. With a universal IEC power connector, any suitable cord can be used.

 

[iiipopes]

But Ampeg did it always.

Yes, but have you seen the size of an Ampeg SVT power transformer? Sheez!

 

[iiipopes]

Perhaps you are thinking of motors. There IS a slight change with motors, although even there the design can easily be such as to avoid any problems.

Especially synchronous motors, like those which drive a Hammond tone generator, which need changing for 50 Hz, and my electric razor runs slower in the UK.

 

[agedhorse]

Especially synchronous motors, like those which drive a Hammond tone generator, which need changing for 50 Hz, and my electric razor runs slower in the UK.

Synchronous motors will lock to the syncronous speed based on line frequency depending on the design of the motor. Under normal operation there is no slip. A 4 pole motor will turn at 1800 rpm when operated at 60 hz but will turn at 1500 rpm at 50hz

Now within a limited range, a syncronous motor can be made variable speed by driving it with a high voltage amplifier and a Sine wave signal. This is what was done to make variable speed large format tape machines and film projectors. Add a tach., a stable frequency reference, some feedback and you now have a stable variable speed machine that can be regulated and stabilized with set points! Early servo baby

Transformers are different of course.

 

[cliff78]

A transformer good for 50 Hz should have NO problems at 60 hz. The change in frequency is not enough to cause problems (400 Hz would probably be an issue).

As has been said, the big issue is with a 60 hz transformer used on 50 hz.

For 50 Hz, the transformer needs more "magnetizing inductance" so that the idle current is low, and the transformer does not "saturate the core". Increasing the size of the "stack" (the total thickness of steel "laminations") increases the inductance per turn, and it may not be necessary to increase turns. That is a design choice made by the transformer engineer.





Who says the power output changes?

The power supply ripple voltage will change, it is larger at 50 Hz. But if designed with sufficient capacitance, a transformer type, or SMPS type will have no problem at either frequency. There is no reason the power output should change.

Perhaps you are thinking of motors. There IS a slight change with motors, although even there the design can easily be such as to avoid any problems.





Homologation is translatable as "certification". So they have certification issues.

This appears to mean that the Markbass design is certified only in the country it is sent to, i.e. only UL, or C-tick, CE, CCC, etc, and that they certify a separate version for each country......

It also appears to mean that the power supply is not readily changed from one voltage to another. This seems very silly, since the rest of us have the very same unit "certified" all over the world, simply changing the voltage tap and the fuse (or circuit breaker) for different voltages. With a universal IEC power connector, any suitable cord can be used.

so you mean it is safe for me to use it on a a 60hz power supply?

 

[agedhorse]

so you mean it is safe for me to use it on a a 60hz power supply?

I would say that generally this is true, but if there is any syncronization to the line frequency for any aspect of the amp (I can't think of any application that would require this BUT there's always possible there's something that we overlook), the difference may be large enough to prevent lock-up.

Just thinking of some of the schemes used in UPS's, which are essentially a cross between a class D amp and an SMPS, frequency plays a role in sync. I'm not that familiar with other company's products, but maybe Jerrold, Bobby, JR or Bob might have additional insight.

 

[Jerrold Tiers]

so you mean it is safe for me to use it on a a 60hz power supply?

Well, I have never seen their schematic..... Consequently I can guarantee nothing about their unit. I can very strongly suspect, highly doubt, etc, etc.

Ampeg units would never have had any problem with such a change, SMPS, regular transformer, whatever.

I am with Agedhorse, I can't think of any common or even uncommon scheme that would actually be upset by the change. You are changing ONLY the frequency, and not the voltage (220/230/240 are essentially all same-same as far as the power supply, many units make no distinction between them, the net change is about 10%).

What's more, you are apparently changing UP in frequency, which is the "easy direction".

The folks at Markbass should know, and they seem to be saying that the main, or perhaps only issues are that the unit is not agency approved unless specifically made for the destination country and voltage/frequency.

There was some mention of damage, but I suspect that referred to using the wrong voltage, not the one the unit is set for.

I would bet it would plug in and work fine. However, you should remember it is cheap for me to make that bet, since I have nothing at stake!

 

[ThisBass]

Who says the power output changes?

direct current

 

[ThisBass]

But I did a mistake, some more words I'll give tomorrow.

 

[B-string]

direct current

I realize the translations are a labor. But DC rails are designed to be the same with either mains input voltage.

 

[agedhorse]

I realize the translations are a labor. But DC rails are designed to be the same with either mains input voltage.

The only possibility here, and I don't know if it's what ThisBass means due to translation challenges, but in many SMPS designs, the output voltage drop and/or power drop when operated at 230V will be less than when operated at 115V because at 115V many designs use a voltage doubler circuit on the input to step up the HVDC bus that is less efficient delivering the high voltage DC under load than when the HVDC bus is fed directly with 230V.

 

[B-string]

Thanks agedhorse, always enjoy reading yours and Jerrold's posts as well as other prominent engineer's here. Great resources. I left design a few years before SMPS and infancy of Class D. Did not not know about the use of voltage doublers in some SMPS.

 

[Jerrold Tiers]

The major issue with a doubler is that it typically has a bit more ripple voltage than a straight rectifier, and it may change the "sag" of voltage under load.

But unless the unit is a rather "squeaky" design, there should be enough margin to make rated power regardless. The best combination of voltage, frequency, etc, may produce MORE power, but the minimum should always be the printed specification power, plus some margin at the discretion of the engineering folks.

EVERY amplifier produces more power under some circumstances vs other conditions. But that generally isn't a significant change...... a few percent at most, amounting to an non-audible difference.

However, in this case, the change seems to be from 220/230 50 Hz to 220/230 60 Hz. My call is that it is unlikely to be an issue, and if anything, the 60Hz will allow more power, etc than 50 Hz.

 

[cliff78]

Thanks Jerold and to everytone who replied to my post. Do we have any Markbass techs in the forum that can put their insights into this?