Tony Ross

And quite right you were too. Many thanks, Tony

Glad to see it's not just me having these issues with double skinned chimneys! I thought it was the seal between the liner and the flue pipe so thought of getting some asbestos rope wrapped around the outside of the liner so as to form a tight seal. Am struggling to visualise how the aluminium baking foil is working from the description given. Is the foil being made into some form of gasket or is the whole gap between the inner and outer skins being filled. Can anyone post a line drawing to explain? regards, Tony

Hi All, At last got back to the boat last weekend to look at this issue again. I think I can safely say it is the inverter and not an earth loop as I originally suspected as the buzzing is not present when connected to the 240v shorepower. Thanks for all of the suggestions but I now need to come up with a cunning plan. Am thinking of one of the Sterling 400w pure sinewave low noise inverters just to provide for the TV/Audio as this should hopefully be buzz free. regards, Tony

Tony, As someone who has a similar setup and has just wired a GI after the changeover switch but before the distribution panel as access was simpler, what is the problem you alude to? I haven't stuck my nose in the changeover switch but is there a common earth to both sides that I have overlooked which regardless of switch position allows the earth to use the the negative earth on the inverter case as a short cut bypassing the GI or have I missed something? regards, Tony

Hi Tony, Thanks for the links. The farnell one looks like it could be mounted in a box without having to put a pcb together. What would the circuit diagram look like as this would presumably need to go on the stereo "audio in" line between the source and the car stereo aux in? I've looked on their tech specs but that didn't seem to help. Tony

No disagreement about 125hz being "barely bass". The mini monitors roll off significantly below about 100hz and therefore the cut off options on the car stereo being 125hz and 70hz, 125hz was the better one to go with without causing a hole. Fortunately, being on the confines of a boat the lower frequencies aren't obviously directional and as such that figure works well. If an isolator proves to be an option, at what level should I expect so see the bass roll off at? Tony

Is this the type of isolation transformer to consider? I'm always suspicious if something appears too cheap. Tony My link

Will be interested to see what happens with the low frequencies as the main reason that I route the audio to the Car Stereo is because that uses a pair of domestic hi-fi (Gale) mini monitors and has an active sub which takes every thing below 125hz! The sound is great when watching movies from a battery powered source but frustratingly buzzy using "The mains". If there is a significant roll off, it somewhat defeats my original objective. Tony

Hi All, Thanks for the replies. Certainly provided a good debate! I'll start by making up a cable 3.5mm to 3.5mm and remove the earth shield from one end and then go from there. The existing cable was not a cheap one but as the jack plugs are sealed, I can't get into them to detatch the screen. I'll keep you posted with progress, Many thanks, Tony

Hi Tony, There is no buzz present on the Car Stereo when the TV is on and the Car stereo set to Aux input (nothing connected) at normal volume. Interestingly enough though, when the laptop is plugged into it's charger there is a buzzing on FM channels from the radio. I have blamed this on the switch mode adaptor that the laptop uses. Most other 240v adaptors that I have present no such symptoms, just the laptop charger and one for an ipod dock which is again Switch mode. The plugs are daisy chained Hope that helps, Tony

Yes, there is a run of 5 double sockets coming off the inverter although most of the time only the TV and the Satellite receiver are plugged in. Tony

Thanks for that Tony, I bow to your better judgement. So, on the basis that it is the inverter, why do the TV or the laptop not buzz on their own? Surely, the buzzing that is transmitted to the Car Stereo would come out of the internal speakers on the TV/Laptop as the audio output socket is just the signal that would normally go to the internal speakers had I not plugged in a 3.5mm jack to send it to the Car Stereo? Is there a way to put a choke on the Inverter or should I just accept the problem and run the TV off the 12v system as well? Tony

Or it could be that with the mains disconnected there is no earth loop! I accept that it could be the inverter but ask any recording studio engineer about earth loops and they will give you a very knowing look so I need to consider the options.

Sterling 1800w Quasi Sine Wave.

Hi Guys, I am getting what sounds like an earth loop buzzing when I try to output the sound from my TV (which is powered by 240v inverter) to the car stereo which is 12v. I do this as the sounds are significantly better than the built in speakers in the TV. The same happens when outputting sound from the laptop when on the mains charger but disappears when running on batteries. Is the correct way to deal with this to knock up a cable using 3.5mm stereo jackplugs and just omit to wire the sleeves, which if I'm not mistaken provide the earth? If not, any other suggestions other than just don't connect the two! As background, both 12v and 240v are negative earthed. Many thanks, Tony