230V AC Stabiliser

jaymenon

I'm thinking - for US amps that are set to 230V AC (that we wish to use in the UK, where our 240V is sometimes too high).

Some amps don't have mains transformers that can be set to 240V

I understand that some resistors can be changed to optimise the voltage to the various tubes.

How about a 230V mains stabiliser designed to stabilise voltage at 230V...? Surely would feed 230V to the amp - and so do the job without needing to tinker about inside the amplifier...?

Expert opinions deeply appreciated.

Kind regards
Jay

uncledick

FWIW, I've never measured UK mains at more than 236V.  

DJH83004

You could always try one of these, they can be preset to provide a 230v output
https://www.criticalpowersupplies.co.uk/le1200i

SunDevil

I’ve seen 246v from the wall at home before now, so your mileage may vary...

I’ve looked into (and tried) voltage stabilisers before and unless you spend a lot, you’re not getting a lot more than a step down as a percentage of wall voltage.

Our local tech experts may beg to differ, but generally +\- 10% is likely good enough 

jaymenon

Thanks guys for your insightful replies.  Interestingly just like SunDevil my voltage at home is 246V too...that's 7% above the 230V at which my amp is designed to run, which seems sort of okay.

I don't know if the voltage fluctuates though...if it goes into the 250's are we talking significantly higher voltages?

DJH83004

The nominal UK mains voltage is 230v  +10 / -6% so the extremes are 216 to 253v. It can fluctuate to due load at peak times, but generally due to the LV distribution network it tends to stay around the nominal voltage in your area, so if yours is say 245v it will swing several volts either way but not down to say 216v (which in theory it could and still be in tolerance), it that makes sense     

jaymenon

Thanks DJH, from what I understand the EU stipulated 230V with a wide tolerance so that both the UK (which remained at 240v) and Europe (which remained at 220v) could both be ‘compliant’ without changing a thing...

Mesa Boogie for instance make 240v models for the UK and 220V models for Europe (unless I’m mistaken)

martinw

Not necessary. Valves (not tubes please!) are very tolerant.

Yes, I change the voltage setting on Fenders to 240 instead of the 230 the come set at, because it's obviously better to have them running at nearer optimum. However, all of the amps that I do that to have been running fine, some of them for many years, without any noticeable issues. Maybe the valves have worn out a bit faster, but it's not clear cut.

Anything within the amp that needs a fixed voltage (e.g. ic's for switching) will have some kind of regulation in the voltage supply, although there are notable exceptions to this and they do cause problems on a few amps that were designed to run at 230, in areas where the wall voltage is 240 or higher.

My wall voltages were often in the 245 area when I was in Derbyshire.

Gadget

I use a Furman AR-2330 voltage regulator. It's expensive but good.

I once had a chat with Pete Cornish where he recommended using a true-online UPS.

Cabicular

Brian mays guitar tech swears by them (but he is travelling a lot)
he says it’s the only way to make AC30s running at full tilt semi reliable