european 230v power

[mcnach]

[quote name='Ed_S' timestamp='1388492572' post='2322557']
Well, it certainly [b]was[/b] correct when I bought and blew up the piece of equipment in question (September 2007 for the record - just looked at my order history). Understand I'm only talking about Tech21 gear; I agree that most items are fine, and Tech21 may even have altered their products since, but the screen shot of the voltage/fuse panel was taken from their website about 5 minutes before I posted.
[/quote]


to be fair, you don't know what caused your Tech21 to blow.

My first TC RH450 blew the third time I used it or so... sometimes it happens.

Given the harmonisation of voltages across the EU that has been going on for years, I doubt that the 230/240V was an issue. In fact, I am not entirely sure the power supplies will be any different... But I do not have authoritative information one way or the other, I admit.

[Ed_S]

[quote name='mcnach' timestamp='1388706703' post='2325260']
to be fair, you don't know what caused your Tech21 to blow.

My first TC RH450 blew the third time I used it or so... sometimes it happens.

Given the harmonisation of voltages across the EU that has been going on for years, I doubt that the 230/240V was an issue. In fact, I am not entirely sure the power supplies will be any different... But I do not have authoritative information one way or the other, I admit.
[/quote]

Ok, fair point - I don't know 100% that it was the voltage issue, but it worked for about 2 minutes and then blew, and when I picked it up to investigate why it'd gone off, the area round the power receptacle was extremely hot - far too hot to keep hold of. I took the fuse sled out and it had blown, so I let the unit cool down and replaced the fuse but the new fuse blew straight away when I re-powered it.

Aside from the serial number, the only visual difference between the unit I had and the unit I now own is what's written on the voltage panel. You're right, my first one might have just had a defective PSU, but if a manufacturer goes to the trouble of differently identifying two otherwise identical pieces of equipment and only selling one in a specific region, given past experience, it's enough to make me buy the 'right' one in future.

[flyfisher]

I would be very surprised if mains voltage was the problem in the above example, and if it was then its and example of poor design.

A '230v' device operating at ’240v' is only 4.3% above nominal voltage in the first place, which is less than half the +/- 10% tolerance of the mains voltage itself, so the '230v' device should be designed to work with any voltage from 207v to 253v.

The worst case scenario would be if the '240v' supply was actually +10% or 264v, which would be 11v above the maximum '230v' tolerance, or again 4.3%. I would be very surprised if a fuse would blow so quickly under such conditions as a standard fuse typically requires 2x its rated current to blow within 1 second.

Designing a piece of mains powered consumer equipment to such small tolerances is not what I would consider very good practice. It would be very interesting to know what the actual cause of failure was in this example.

Edited January 3, 2014 by flyfisher

[deepbass5]

I was going by the old P = V x I so if the voltage is down on the mains and the internal impedance (resistance) of your Amps power transformer cannot change the current it draws must rise.
Power = current squared x Resistance

But I have forgotten more than I learned 30 years ago so happy to stand corrected

[Dad3353]

[quote name='deepbass5' timestamp='1388782076' post='2326100']
I was going by the old P = V x I so if the voltage is down on the mains and the internal impedance (resistance) of your Amps power transformer cannot change the current it draws must rise.
Power = current squared x Resistance

But I have forgotten more than I learned 30 years ago so happy to stand corrected
[/quote]

Arithmetically, you're correct, but this would assume constant power. It's not so. Imagine a light bulb. Give it a certain voltage, it will light up. Reduce the voltage and the light dims. The power is less. It's much the same with (ordinary...) audio amps, with some variants mentioned above.