Power regulator

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Recently I acquired a cheap chinese make tube amp.

The power transformer is rated for 220Vac, but in the UK we use 240Vac (my house is on 240Vac anyway).

This will overstress the amp (the tubes, its components, the transformer itself, etc). To prevent my amp from breaking down prematurely I want to use a unit/device/object, that will output 220Vac constantly (fluctuations may occur ofcourse). SO effectively I am lookig for a device that steps down the maisn power from 240Vac to 220Vac.

Before anyone suggest making some sort of contraption that does this, I do not have the knowledge, facilities, or skills to do so.

Any suggestions?

 

[Anonymous]

Have a look Here

Maybe this is what you are looking for.

 

[Anonymous]

You do not have to do anything.

The valves, resistors and transformer are quite capable of handling the variations.

The only voltage rated components really are the capacitors and unless the manufacturer has been stupid with the component selection all the items should be rated at least 10% - 20% above the maximum design levels.

Even if your voltage runs to the maximum ( over 24 hours mine runs at an average 232v with max 241v ) it should be well within the design and component tolerances.

 

[RCduck7]

Stumpy21:

You do not have to do anything.

The valves, resistors and transformer are quite capable of handling the variations.

The only voltage rated components really are the capacitors and unless the manufacturer has been stupid with the component selection all the items should be rated at least 10% - 20% above the maximum design levels.

Even if your voltage runs to the maximum ( over 24 hours mine runs at an average 232v with max 241v ) it should be well within the design and component tolerances.

I will back that up. And i just read about it yesterday, it shouldn't do harm.

 

[Anonymous]

RCduck7:

I will back that up. And i just read about it yesterday, it shouldn't do harm.

I would like to read more, could you provide a link....

 

[proffski]

In theory you should be ok, but if they have skimped on the materials used in the transformer then even if the components are ok there is the possibility of Core Saturation of the transformer, unlikely but still a chance. Check how hot the mains transformer is running. Chinese gear made for retail in the UK via distributors generaly is fine, not always so if bought on ePrey... I have seen one example where the screening cans for the output transformers were simply hiding much smaller transformers underneath (explained the poor bass). Even seen a tube rectifier wired so that the filament glowed but in the chasis a solid sate silicon rectifier was doing all the work. The anode of the valve was not even connected!

 

[RCduck7]

raym87:RCduck7:

I will back that up. And i just read about it yesterday, it shouldn't do harm.

I would like to read more, could you provide a link....

It was shared by some on a forum that have the experience and bascially there is a 10% tolerance in volts. The link is in dutch.

EDITED BY MODS - House Rules

 

[Anonymous]

RCduck7:raym87:RCduck7:

I will back that up. And i just read about it yesterday, it shouldn't do harm.

I would like to read more, could you provide a link....

It was shared by some on a forum that have the experience and bascially there is a 10% tolerance in volts. The link is in dutch.

Mmmm....the link is not a lot of use to me I'm afraid.

A 10% tolerance is supposed to be standard across the EU. It used to be +10% -6% but has been opened out to +/-10%. The UK, for reasons best known to themselves, still centre their mains around 240V. The official EU voltage rating is 230V but the tolerance allows up to 253V. I have been doing some checks recently (at different times) and my supply has been up as high as 248V. Still within tolerance but only just.

 

[Anonymous]

proffski:In theory you should be ok, but if they have skimped on the materials used in the transformer then even if the components are ok there is the possibility of Core Saturation of the transformer, unlikely but still a chance. Check how hot the mains transformer is running. !

Agreed. If the transformer core is of poor design and without the proper air gap, then overheating could arise.

But that could happen at 220v if the transformer is that bad!

 

[Anonymous]

Thanks for all the input guys. However, when you go to DIYaudio.com, you will find that the opinion is 180 degrees from what is being said here. Running transformers on a voltage that is above what they are specified for (I suspect the chinese use 220V transformers, and label them 230 so that when used in Europe they get warm, but should still spit out acceptable voltages for the tubes), will make them pretty hot. This could result into damage to the transformer and a burned down house as a result. However, this being a small risk as one would be there when listening to music, I am more concerned about the sonic impact this has and the life span on the tubes. When tubes are driven at 10% higher voltages than their designed rating (6p1's are rated at max 300V, and 12.6 for heaters I believe), not only will this have a sonic impact (reduced sound quality, observed by those that already lowered the voltage as a test), but should also increase lifespan of the tubes. As for the other components I am not worried. It's like said earlier, these should not be affected by a 10% increase in voltage.

I got myself an APC line R 1200 voltage regulator that has a selectable voltage. I can set it to 220 and the 240 would be regulated down to 220. The benefit is that I can actually use it all over the world (except 110-120V countries of course), bring the voltage to 220Vac, AND the supply would be smoothed/regulated. So double whammy!