Mains Hum through Amp/Guitars Help required

ToneControl

ecc83 said:

I STRONGLY suggest you get a sparks in ASAP. You may have lost an earth (or a neutral). You might have an appliance with a serious earth leak, yes, if you have a consumer unit with an RCD it should trip but ***t'appen.

Do you own a multimeter? If so check everything involved including amps for earth pin to chassis continuity. I know a DMM is not the proper tool for such low resistances but view anything over 2 Ohms with deep suspicion.

Dave.

I was having similar worries

Anyway, a typical domestic fusebox does not always have RCD on all circuits, so having an RCD fusebox does not eliminate the possibility of a wiring fault

I'd get the kitchen wiring fixed, not add a new circuit to the office

Also, washing machines are famous for tripping RCDs, so if it's not tripping but causing that noise, I'd wonder if there was an RCD for the kitchen

have you got on of those standalone RCDs sold for use with garden power tools? try one of them with the washing machine

Mr_Bluesman

yeah I am, my bros a spark and wired my extension but this was there before that anyway. My unit does have RCD
It's not the washing machine on it's own because I've removed every kitchen appliance from the circuit and it's still there without them connected.
I'm gonna get him to have a look on the off chance

spark240

Try the test button on the rcd to make sure it works....

Mr_Bluesman

yeah it works no issues, trying to pin my bro down to come and take a look. He thinks I need some ground rods installing

ecc83

Mr_Bluesman said:

yeah it works no issues, trying to pin my bro down to come and take a look. He thinks I need some ground rods installing

I am starting to get a bit worried about Bro! If he has heard that hum and has even the REMOTEST concern about the earthing in your place he should be round there YESTERDAY! (does he perchance hold a big life insurance on you?).

I really recommend that you get a top electrician in ASAP.

Dave.

Mr_Bluesman

Hey man I appreciate your concern but there is nothing severely wrong to that degree. My house is grounded etc, just a problem with studio equipment picking up mains hum amplified by appliances, guitar amp etc with transformers in them. My brother is a top spark which is why he's so busy all over the country, not just domestically but commercial and industrial work too. He wired my extension and if we'd known we have done an extra unit at the time. He's gonna sort it for me one way or the other. thanks though

Gadget

A power conditioner or regulator like a Furman may work, but I doubt it'll deal with that much 'noise'.

Another option (recommended to me by Pete Cornish) is to use a true online double conversion UPS, such as those made by Liebert. You can pick them up on eBay for reasonable money (certainly less than a Furman regulator), or maybe see if you can borrow one from an IT tech friend? It must be the TRUE ONLINE DOUBLE CONVERSION type though, not just any old UPS - An uninterruptible power supply using true online double conversion technology provides the highest level of power protection available. The UPS converts the 230V input AC mains supply to DC power which is then used to charge the battery. The DC current flow is then fed through an inverter stage which reconstructs the 230V AC mains output. Because the AC output is completely regenerated, it will be completely free from any mains-borne interference such as spikes and voltage variations.

ToneControl

Gadget said:

A power conditioner or regulator like a Furman may work, but I doubt it'll deal with that much 'noise'.

Another option (recommended to me by Pete Cornish) is to use a true online double conversion UPS, such as those made by Liebert. You can pick them up on eBay for reasonable money (certainly less than a Furman regulator), or maybe see if you can borrow one from an IT tech friend? It must be the TRUE ONLINE DOUBLE CONVERSION type though, not just any old UPS - An uninterruptible power supply using true online double conversion technology provides the highest level of power protection available. The UPS converts the 230V input AC mains supply to DC power which is then used to charge the battery. The DC current flow is then fed through an inverter stage which reconstructs the 230V AC mains output. Because the AC output is completely regenerated, it will be completely free from any mains-borne interference such as spikes and voltage variations.

for home use, I had one of these:

http://cpc.farnell.com/ups-uninterruptible-power-supplies/prl/results

it packed up after 3 years or so though,but quite cheap

As I say though, given that it's your own home I'd try to fix the underlying problem first

Mr_Bluesman

Yeah it didn't work. Narrowed down a bit more to all guitar pickups picking up interferance from the kitchen cicuit (no hum if guitar not plugged in)  even with nothing plugged in like washing machine etc. But is amplified if say washing machine is on.  Goes away if kitchen cicuit is turned off on the board.
Brother (spark) is gonna look a couple of ways of maybe extra grounding on the kitchen circuit

ToneControl

sounds like screening is what you need

Mr_Bluesman

Yep gonna try that too,
The problem developed but I think for the good.
My bro came round we went through the whole consumer unit, tighting all earths to make sure no arcing etc. He gonna try more stuff on my electrics as hum is gone if kitchen circuit is turned off. Although technically it's fine and not dangerous etc.
The hum is still there but now it goes away when touching metal perts on guitars (mainly 3 PLs I've tested so far) which inciates the guitars are grounded correctly and the noise is transmitting through me.
Bought some shielding tape and will try on one guitar to start with

Mr_Bluesman

Ended up shielding a guitar as a test, helped a tiny bit, then got an ISP decimator II G String to replace MXR Smart gate, which gate both the front and loop of amp. Works a treat, with a very tiny tone suck which I can live with, dead silent now

ToneControl

hang on, are you saying that your strings are not grounded?

Mr_Bluesman

No, they are grounded