Dirty power

gpw5150

Anyone else played a pub/dive with dirty 240v power that creates a loud hum through your amp?

Played a place last night and the 240v power noise was quite loud.  The amp works fine at home and on other power sources and is generally quiet.

any solutions for filthy power…?

Kittyfrisk

Fairly affordable solutions available, eg,  https://www.richersounds.com/tacima-cs947-6way-mains-socket.html

breadfan

Would dirty power cause ghost notes?

I’m hearing very prominent ghosting when playing above the twelfth fret through my two NMV Marshall style amps.

I hadn’t noticed it until I moved to a new house but I’m definitely running the amps more open lately.

Apologies for jumping in on your thread @gpw5150 - I’d been meaning to ask for a while & your thread just reminded me.

Danny1969

The 240V coming into the amp is rectified, then stored in  reservoir caps and smoothed with filters, so amps are fairly tolerant in terms of fluctuating power coming in. They can run from generators and 12V inverters outdoors with no major drawbacks normally. 

You can get switching noise through the mains, especially if something is switching highish currents like TRIAC's but generally the biggest cause of noise is because the band is using sockets where there's a difference in earth potential and multiple paths to ground. Sometimes you can room area / stage  with 10 sockets or so across but one lot might be ringed or spurred of the lounge circuit and one might be on some other ring circuit. 
When that's the case try putting the whole band on the sockets that are on the same ring and in some cases on the same socket. Just remember the first 4 way plugged into the socket will take the whole load so make sure it's not a little 3 or 5 amp job. 

ICBM

Danny1969 said:

When that's the case try putting the whole band on the sockets that are on the same ring and in some cases on the same socket. Just remember the first 4 way plugged into the socket will take the whole load so make sure it's not a little 3 or 5 amp job. 

Contrary to what you will sometimes read, this is also the safest because everything now shares a common earth, so you can’t get a shock from something with a live fault to something earthed on a different circuit. Less of a risk now with modern electrics though.

As long as the extensions are correctly rated there’s no risk of overloading them. It’s best to use a ‘tree branch’ arrangement rather than a ‘daisy chain’ - ie a couple of heavy-duty 13A 4-ways plugged into the same double wall socket, then four more (possibly lighter rated) ones into each of those, which gives up to 32 available sockets, probably enough for most bands.

gatheredinsong

Useful advice @Danny1969 and @ICBM , didn't know that. Thanks.

newi123

Danny1969 said:

The 240V coming into the amp is rectified, then stored in  reservoir caps and smoothed with filters, so amps are fairly tolerant in terms of fluctuating power coming in. They can run from generators and 12V inverters outdoors with no major drawbacks normally. 

You can get switching noise through the mains, especially if something is switching highish currents like TRIAC's but generally the biggest cause of noise is because the band is using sockets where there's a difference in earth potential and multiple paths to ground. Sometimes you can room area / stage  with 10 sockets or so across but one lot might be ringed or spurred of the lounge circuit and one might be on some other ring circuit. 
When that's the case try putting the whole band on the sockets that are on the same ring and in some cases on the same socket. Just remember the first 4 way plugged into the socket will take the whole load so make sure it's not a little 3 or 5 amp job. 

ICBM said:

Danny1969 said:

When that's the case try putting the whole band on the sockets that are on the same ring and in some cases on the same socket. Just remember the first 4 way plugged into the socket will take the whole load so make sure it's not a little 3 or 5 amp job. 

Contrary to what you will sometimes read, this is also the safest because everything now shares a common earth, so you can’t get a shock from something with a live fault to something earthed on a different circuit. Less of a risk now with modern electrics though.

As long as the extensions are correctly rated there’s no risk of overloading them. It’s best to use a ‘tree branch’ arrangement rather than a ‘daisy chain’ - ie a couple of heavy-duty 13A 4-ways plugged into the same double wall socket, then four more (possibly lighter rated) ones into each of those, which gives up to 32 available sockets, probably enough for most bands.

That`s interesting and very useful - thanks guys. 

We kind of do this anyway, but should prob pay more attention to the ratings of the extension sockets.