Tony Ross
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Posts posted by Tony Ross
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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
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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
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Where is your GI wired? Is it on the incoming shore power prior to the changeover switch?
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
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I have absolutely no idea what that is. Perhaps someone else will know.
Tony
These are what I used to use.
Tony
Here's one from Farnell.
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
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125Hz is barely bass - more like mid/bass.
In my world below 50-60Hz is where the bass is.
Most people would be happy or simply not notice the loss in bass frequecies with an isolator.
Rather than call it an earth loop call it a ground loop.
It occurs whenever the source and the amp are connected to the same power source (and each other).
GL
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
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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
Is this the type of isolation transformer to consider? I'm always suspicious if something appears too cheap.
Tony
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I have spent quite some time with similar issues and despite my degree in electronics and many years working with audio electronics I still don't fully understand it.
Its most likely not the inverter thats to blame but all the switching that goes on within the mains power supply "brick". This is why its better on battery power
I often see similar issues when working with "real" mains electricity.
Its not a "classic" hum loop but is probably related and depends on a sort of capacitive rather than direct coupling.
Removing the earth from the connecting lead might work, or it might make things worse, or it might take all the low frequencies away.
The answer is the isolation transformer as many posts have suggested, but don't pay £38, have a look on eBay.
The HiFi purists don't like them but for a car radio on a boat it should be fine. My own measurements have not found the loss of low frequency that is often mentioned.
A 12v boat electric system can produce significant volt drops (or rises?) on the negative wire so an isolation transformer is also a good safety measure. I run my PC from a little car adaptor (12v to 19v) and managed to damage the radio due to the non isolated grounds when I connected the computer sound to the radio!!
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
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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
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To the OP - if the TV is being powered by the inverter and you have nothing connected to the input of your car stereo, but you have the car stereo volume at 'normal' level, do you still hear the buzz?
Tony
But are they wired as a ring, or just a daisy-chain?
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
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Is there a ring main from your inverter on 240V side? I seem to recall reading about strange effects on sound equipment under these circumstances?
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
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I am a recording studio engineer (or at least was, in a past life). I have also designed and built audio equipment. It sounds nothing like an earth loop to me.
Both your TV and Laptop will be double-insulated, meaning there will be no earth connection to them whether the mains is connected or not. Ergo it cannot be an earth loop.
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
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Proof positive that it's the inverter.
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.
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Sterling 1800w Quasi Sine Wave.
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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
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Hi All,
I posted a few weeks ago about adding an additional battery to an existing domestic bank of 2 x 120ah sealed "Leisure" batteries. I subsequently did this so I now have 3 batteries with a total stated capacity of 360ah. At the same time I added a Smartgauge, as I had become suspicious about the information the shunt based Power Management amp hour counter was giving. I set the Smartgauge to setting 1 as I was advised by the Marina who provided all of the batteries that they are Lead Acid.
I've just been out on a cruise for the last 8 days and had some interesting/surprising results. The batteries were all fully charged by the built in 4 stage charger before departing. After the first night, the amp hour counter was showing that only 47ah had been consumed yet interestingly the Smartgauge was showing battery capacity at 53%. I was cruising on average 8/9 hours a day so the there was plenty of time for charging and by the end of the 2nd day the Smartgauge was showing 100%. Interestingly enough though, the amp hour counter was showing that all of the power consumed had been replaced after about only 4hrs cruising! The second night showed only 19ah had been used but the Smartgauge was showing 75% capacity.
On the basis that the Smartguage doesn't lie, I think what I'm seeing is that my original 2 batteries were shagged before I added the 3rd! I base this on the notion that I expected to have approx 50% capacity available ie. 180ah yet by the looks of it, I've probably got 50ah! Am I correct or am I missing something?
Tony
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Hi All,
I've currently got just 2 x 120ah lead acid sealed batteries as my domestic bank with a further one as my engine starter, all of which were replaced about 3 years ago. The boat sadly hasn't had as much use as I'd have liked and as such despite being 3 years old, I suspect they are in good condition. The boat is permanently connected to a landline at my home mooring and the batteries are kept topped up using the fitted battery charger. I'm hoping to start using the boat more and have decided to add another 120ah battery to give a bit more capacity in reserve. Is there an issue about adding a new battery to a 3 year old bank?
I am also thinking of fitting a Smartguage as I've never been overly convinced by my Sterling Power M'ment panel but wondered whether the additional new battery would lead to Smartguage giving a false impression of the overall state of the batteries?
Any thoughts would be appreciated,
Tony
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Wait until the pump cuts out and then measure the air pressure in the accumulator. That will be the pump cut out pressure.
Hi Tony,
I know the cut out pressure, that's 30psi but it's the cut in pressure that i'm struggling with!
KR
Tony
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Thanks for all of the replies,
The pump model number i have is a Shurflo 3901-0213 as sold by midland chandlers. The frustrating part is I can't find a technical spec anywhere that tells me what the pump cut in pressure is as this seems to be the key. At 26psi (4 below cutout) this is obviously too high for the first Accumulator and far too low for the one at the hot water end of things. I'll have to call up Shurflo after this bank holiday weekend!
Thanks again,
Tony
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Hi Guys,
As part of my shower room refit, I've just had to fit a new fresh water pump (Shurflo 12v model running at 30psi) as the old one was putting more water into the bilges than down the freshwater pipes! I'm having a few issues getting the water pressure set up correctly so as to give my new shower constant pressure.
My system has 2 accumulator tanks, one just after the pump before where the pipework splits off for the cold taps and the hot tank and another, just before the hot water tank. The reason for the one by the hot tank was that originally, I was getting hot water syphon back up the pipe and coming out of the cold taps. It was suggested that i should put in a one way valve just before the hot tank to stop that happening and so as not to trigger the safety valve in the hot water tank, put in the second accumulator between the one way valve and the tank!! Seems convoluted but i've never had any problems in the past.
Any way, having put in the new pump (the original one was also a Shurflo but with less power) the water pressure seems all over the place. When i bought the accumulator that i fitted by the hot water tank, the instructions suggested that i set the pressure in the accumulator to about 4psi below the pump cut out pressure (so with the new Shurflo i've set them both to 26psi). When i turn on the pump, the pump pressurises both accumulators (seems to take forever). when the shower is turned on, initially there is great pressure then as the accumulators discharge the pressure drops to little better than a dribble, presumably because the pump is trying to pressurise the accumulators as well as sending water down the pipework.
What do I need to do to get a constant pressure? I would have thought that a 30psi pump ought to be able to provide that but am I missing something with the Accumulators? Are they still needed in this day and age?
Any suggestions gratefully appreciated,
Regards,
Tony
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FWIW i've got a Model 60 which has been a reliable engine over the time i've owned it (6 yrs). It is a 3 cylinder engine so prone to produce slightly more vibration than a 4 cylinder but mine has been well set up on it's engine mounts and is now lovely and quiet. Cheap to run as well!
Having put that in print it will now explode in my face time I fire her up!!!!
regards,
Tony
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I used http://www.cutsigns.co.uk/ a few years ago before I had a re-paint and i thought they were very good.
Hope that helps,
Tony
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Not sure if this is the best place to post this but no doubt i'll be pointed in the right direction if it's not!
I am looking at getting someone to do a partial refit on my 40' trad. The work would be re-modelling/re-designing the shower room and the rear bedroom. I could also do with a re-wire to bring the wiring up to more modern specs. To be fair, the current fit out is a reasonable quality self-fit but nowhere near up to some modern day standards and as such i'm looking for the quality of work to blend in rather than make the rest of the boat look too shabby. The boat is currently moored close to Braunston.
Can anyone let me have any names and numbers of people I could talk to who may be interested in this type of project?
regards,
Tony
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As a thought, rather than have a separate set of speakers for the laptop, why not have an integrated system that deals with all of your audio needs. I had a similar issue as i wanted a decent sound from my laptop and my TV. The solution i came up with was to replace the existing car stereo unit for one with an auxilliary input and a dedicated I-Pod connection. I then replaced the existing speakers with a pair of Gale mini monitors and built in a domestic sub-woofer (another small Gale unit that runs on 12vdc) under my L shaped sofa. The head unit i got was a Sony which came with a remote control and only cost about £90 but i know there are cheaper units available.
Now i can have my i-Pod permanently connected which also keeps it charged and i can use the separate Auxiliary input for either my laptop or the TV. The sound quality is excellent and i don't have any other speakers cluttering the place up.
Food for thought,
Tony
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A friend went to the Luton store and was told they weren't available until Thursday.
I just spoke to Lidl customer services to find out if this offer was being rolled out on different days. Apparently not, there was a distribution issue yesterday but all stores have now received their allocation and unless you are exceptionally lucky, they've sold out.
As someone else pointed out, had they asked another £10, i don't think many people would have batted an eyelid and they could have made a real killing!
Tony
Earth loop with TV and car Stereo
in Boat Equipment
Posted
And quite right you were too.
Many thanks,
Tony