London, I hear you. Consumption meter it is then!
If you read his message, he actually says "We are at 227v and 50hz here. If your's is much higher we may need to trim back the CCS current".
In other words, he's saying he'll take it back.
He's just telling me the technical stuff because the company is based in Hong Kong and if I was a DIYer, I might just be saved the bother of returning it by making a simple adjustment. So, I do not see anything untoward about his email- like I said, the company's business is supplying kits to competent DIYers. The phono stage only arrived yesterday from Hong Kong.
I'm not sure the mains in this house is very good, as I have had some hum from the transformer of another, completely different preamp. The company must send quite a bit of stuff to the UK so I'm sure my phono stage was set up properly.
I'll get that consumption meter!
......
UK used to be 240 volts AC 50Hz. European voltage was mostly 220. When we all got together and set the standards at 230 I don't think anyone actually changed anything, they just said its 230 and made the allowable error larger to accommodate 220 and 240 !
Even a good, well wired mains supply will vary with local load and time of day. I expect you will see 240ish most of the time. Here in Monaco which comes from the French grid and is very densely populated I see mostly 230ish.
Just to give you an example, here is 30 minutes worth of my UPS log from my house in Spain.
Nobody was in this house during this time and nothing of any consequence was switched on. The house is newly wired and is served by a newly installed substation, so its about as good a supply as you will get in Spain.
01/06/2007 07:30:00 224 49
01/06/2007 07:31:00 224 49
01/06/2007 07:32:00 225 49
01/06/2007 07:33:00 224 49
01/06/2007 07:34:00 224 49
01/06/2007 07:35:00 223 49
01/06/2007 07:36:00 224 49
01/06/2007 07:37:00 224 49
01/06/2007 07:38:00 224 49
01/06/2007 07:39:00 224 49
01/06/2007 07:40:00 224 49
01/06/2007 07:41:00 223 49
01/06/2007 07:42:00 223 49
01/06/2007 07:43:00 223 49
01/06/2007 07:44:00 223 49
01/06/2007 07:45:00 223 49
01/06/2007 07:46:00 223 49
01/06/2007 07:47:00 223 49
01/06/2007 07:48:00 225 49
01/06/2007 07:49:00 225 49
01/06/2007 07:50:00 225 49
01/06/2007 07:51:00 224 49
01/06/2007 07:52:00 224 49
01/06/2007 07:53:00 224 49
01/06/2007 07:54:01 224 49
01/06/2007 07:55:00 225 49
01/06/2007 07:56:00 228 49
01/06/2007 07:57:00 228 50
01/06/2007 07:58:00 229 50
01/06/2007 07:59:00 228 49
01/06/2007 08:00:00 229 49
01/06/2007 08:01:00 230 50
01/06/2007 08:02:00 231 50
I don't know much (anything) about valve amps but it seems a strange design that the mains effects the CCS current so much as to cause buzzing.
Good luck.