Help with weird AC problem anyone?

[Paul C]

Its not that complicated: nothing should trip a working (ie not faulty) RCD. I think you need to commit to getting it tested properly, eg by ideally checking the stereo out a mains power supply other than that your inverter is supplying; or you could at least look at all the connections and replace the RCD with another. (but this isn't conclusive in itself).

 

Yes there's the option to not use an RCD, or to "hide" everything for the BSS test then reinstate it after....but its not the best way to approach the issue. I know an RCD doesn't 100% guarantee electrical safety but it goes a long way to helping.

 

I'm surprised its not possible to test it by another mains supply....all you'd need is a boat moored alongside and an extension lead.

[Loafer]

May be it does. I will have to go back and start reading the thread from the beginning, but from my conversation with a BSS inspector if you dont have a "Shore Supply" then for BSS you don't have to have a RCD. but I am not sure this is 100% correct.

Do you have a second RCD on the shore supply to the battery charger?

 

We don't have a shore supply at all (CC), but on the rare occasion we use one, it goes straight to the battery charger. That's also where I plug the little honda generator supply regularly. No RCD there yet, but I have one ready to be installed. I just need a round tuit.

Its not that complicated: nothing should trip a working (ie not faulty) RCD. I think you need to commit to getting it tested properly, eg by ideally checking the stereo out a mains power supply other than that your inverter is supplying; or you could at least look at all the connections and replace the RCD with another. (but this isn't conclusive in itself). Agreed but we DID check the stereo with another supply - my last Victron combo! All was fine for years, until we got this one. I am going to try a replacement RCD tomorrow. I'll report back!

 

Yes there's the option to not use an RCD, or to "hide" everything for the BSS test then reinstate it after....but its not the best way to approach the issue. I know an RCD doesn't 100% guarantee electrical safety but it goes a long way to helping.

 

I'm surprised its not possible to test it by another mains supply....all you'd need is a boat moored alongside and an extension lead. An interesting point. Trouble is, I have no friends. Can't easily arrange that but I have logged the idea!

 

 

ETA: PS: I appreciate the wisdom tips. I don't plan to remain cavalier about all this - I just don't quite know where to go with it. But the end result will be safe, once I have absorbed enough good sense.

 

Keep sending good sense, guys, I'm grateful.

Edited November 16, 2015 by Loafer

[ditchcrawler]

 

We don't have a shore supply at all (CC), but on the rare occasion we use one, it goes straight to the battery charger. That's also where I plug the little honda generator supply regularly. No RCD there yet, but I have one ready to be installed. I just need a round tuit.

Sorry I go along with Chris Paul from a safety point of view, From a BSS point of view I would suggest if you have a fixed inlet where you plug your genny or a shore supply into and a fixed battery charger they would consider that a shore supply that required a RCD on it.

 

Edit

 

Sorry Paul not Chris

Edited November 16, 2015 by ditchcrawler

[Paul C]

Does it still trip if you run the stereo off the generator? I assume you're putting the generator's output through the RCD too.....??

[Loafer]

Sorry I go along with Chris from a safety point of view, From a BSS point of view I would suggest if you have a fixed inlet where you plug your genny or a shore supply into and a fixed battery charger they would consider that a shore supply that required a RCD on it.

 

You don't have to apologise dc - I'm with you on safety issues. Our 'fixed inlet' isn't visible to a casual observer, it's inside a cupboard and the cupboard door has to be open in order to plug a supply cable in there. I could have put it there myself.

 

By the time my next BSC is due, I will have a safe operational DC hifi and return all the AC stuff to how it was. Complete with RCD which no longer trips!

[Loafer]

Does it still trip if you run the stereo off the generator? I assume you're putting the generator's output through the RCD too.....??

 

I'd have to plug the stereo directly into the generator to do that. No RCD there. I will dig out my extension lead though and give it a try.

 

My generator output doesn't go through an RCD yet (and only supplies my 40A Sterling charger), but it will do when i've sorted out my final requirements!

 

Not very helpful, I know. Thank you Paul for remaining interested!

[Paul C]

No worries, have a look at the BSS regulations (they're online) - you won't fail for no RCD since bizarrely, they are not compulsory. But you can still die from the electric shock of even a small inverter, its the voltage which shocks you and there's enough current to kill even with a tiny one.

[Loafer]

Just as a general question re the original thread title, who can tell me how this can happen?

 

Why have we only started seeing the tripping problem since we replace our inverter?

 

Why is a centre-tapped earth so prevalent in inverters, if it can so easily cause a problem on what was a perfectly operational AC system?

 

If my stereo amp always had a fault, how come it used to work so well, and still does now that I've removed the RCD?

 

OK I admit that was FOUR questions. Sorry.

[ditchcrawler]

One point is we have not CONFIRMED that your inverter is centre earthed, we just strongly suspect that's the case.

[ditchcrawler]

Just as a general question re the original thread title, who can tell me how this can happen?

 

Why have we only started seeing the tripping problem since we replace our inverter?

 

Why is a centre-tapped earth so prevalent in inverters, if it can so easily cause a problem on what was a perfectly operational AC system?

 

If my stereo amp always had a fault, how come it used to work so well, and still does now that I've removed the RCD?

 

OK I admit that was FOUR questions. Sorry.

If the output from your inverter was strapped neutral to earth and all the wiring in good condition would be very unlikely to trip the RCD if you have any leakage between neutral and earth .

Sound equipment grounds lots of bits to stop hum etc. using capacitors which conduct AC electricity. Parts that pick up radio signals are bonded to earth, so IF your electrical earth is not at the same potential as the neutral then you only need 30ma to flow between the two to cause the trip to operate.

[Loafer]

One point is we have not CONFIRMED that your inverter is centre earthed, we just strongly suspect that's the case.

 

It appears to be. I connected a 15W 230V filament bulb across L-E and N-E. Lamp lit strongly on both connections. I am led to believe that this inverter will go BNAG if I connect the earth to the neutral.

[GUMPY]

 

But they are still better than any car stereo set-ups I've heard, and the CD storage would be an issue. Maybe I haven't heard enough 'good' car stereos, but I haven't liked what I've seen so far. More research, I guess!

I have worked with live sound most of my life and even at the age of 63 and with reduced frequency response im my hearing I can clearly hear whether its over Bluetooth or not, using it is just not something an "audiophile" would consider.

If CD storage is a problem then there are lossless methods of storage. (FLAK) available if you have a big enough hard drive.

 

It appears to be. I connected a 15W 230V filament bulb across L-E and N-E. Lamp lit strongly on both connections. I am led to believe that this inverter will go BNAG if I connect the earth to the neutral.

Yes the smoke will escape if you do that.

[Loafer]

I have worked with live sound most of my life and even at the age of 63 and with reduced frequency response im my hearing I can clearly hear whether its over Bluetooth or not, using it is just not something an "audiophile" would consider.

If CD storage is a problem then there are lossless methods of storage. (FLAK) available if you have a big enough hard drive.

 

Yes the smoke will escape if you do that.

 

I'm onto FLAC now but my old stuff is still 380(?) MP3 and it has become acceptable over the last few years. Digital storage is no longer an issue for anyone really, certainly no problem here.

 

I too can discern occasional lapses in quality, but much better with my own system than others I have heard.

 

If you have a mediocre source, it's still better to have a good means of playing it, IMHO.

 

crap source plus crap delivery =

 

crap source plus good delivery=

 

 

ETA: I agree with ALL audiophile opinions on here. I know the limitations of my best attempts. The only bit I can control, with my whole life's music (and my wife's) in MP3 format, is the delivery system. All our later additions to our library seem to be either FLAC or AAC, both seem ok so far.

Edited November 16, 2015 by Loafer

[ditchcrawler]

 

It appears to be. I connected a 15W 230V filament bulb across L-E and N-E. Lamp lit strongly on both connections. I am led to believe that this inverter will go BNAG if I connect the earth to the neutral.

Well at least that means you have a maximum of 120 volts to earth which is considered safer that 240 volts With that you need to ensure that the RCD is double pole so that it breaks both live and neutral when it trips.

[Loafer]

Well at least that means you have a maximum of 120 volts to earth which is considered safer that 240 volts With that you need to ensure that the RCD is double pole so that it breaks both live and neutral when it trips.

 

This one does - I thought they all did!

[GUMPY]

If you have a mediocre source a decent delivery system will show just how bad it is........

 

This one does - I thought they all did!

Not only should it be double pole it should have current sensing on both poles. Most don't.

[Loafer]

But chaps - this is all very well, but we're now talking about sound quality, not weird AC snags!

 

I will happily engage anyone on sound reproduction, but I just want to fix a weird AC snag, AND replace a 240V stereo with a good 12V DC one, with minimal disturbance to the sources already in place!

 

Any great ideas remaining anywhere?

Loddon:

 

I DO appreciate the crap in=crap out thing. BUT BUT BUT - I still loved the sounds from my system. You get used to that, to such an extent that even a really rubbish system can sound good after a while. Until you go to your mate's and hear HIS good system, then you go back to thinking yours is crap.

 

I may well be happy with the sounds from a dashboard car stereo if it's a good one, but I still would wish for something that didn't look like one!

[GUMPY]

You could do what I did which was to have a small 12v audio preamp driving a Blaupunkt 100w per channel power amp. Good clean low distortion system. Think I may still have the amp somewhere.

[Loafer]

You could do what I did which was to have a small 12v audio preamp driving a Blaupunkt 100w per channel power amp. Good clean low distortion system. Think I may still have the amp somewhere.

 

Tell me more, Mr Loddon. That sounds like it could be the sort of thing I'm after. If you can give me a linky, I'll look it up myself.

 

Can you give me any idea of power drain, perhaps, while not driving hard? Background music levels, say?

 

Would my TV & DVD headphone output need the audio preamp at all, or could it go straight to the Blaupunkt? Same question for other 'Aux' sources, like RCA output from Logitech Bluetooth doodad.

[cuthound]

I have worked with live sound most of my life and even at the age of 63 and with reduced frequency response im my hearing I can clearly hear whether its over Bluetooth or not, using it is just not something an "audiophile" would consider.

If CD storage is a problem then there are lossless methods of storage. (FLAK) available if you have a big enough hard drive.

 

Yes the smoke will escape if you do that.

I converted my CD collection to FLAC (Free Lossless Audio Code) and stream it to my home hi fi. Typical bit rate is 800-1000 Mbps, compared to 128-256 Mbps for MP3. Sound quality is good but not quite as good as the original CDs, but with circa 750 CDs I am more than happy to trade the last bit of sound quality for the convenience of being able to find a track or CD in seconds.

 

On the boat I play MP3s coded at 320 mbps over the marine car type speakers fitted to DQ, as the speakers cannot reproduce higher quality sound. If I want better quality I used headphones.

[GUMPY]

No link I'm afraid for the amp its long out of production

Behringer make reasonably priced mixing desks between 4 and 24 channels often powered by a brick psu so can be run on 12v.

If you google Tripath amp you will find some efficient class T amps.

 

On the barge I ran a Quad 34 with a Quad 405 amplifier with near field studio monitors and a sub :0

But the room was 4x3metres.

 

Will have a look to see if I can find the amp.

[Loafer]

No link I'm afraid for the amp its long out of production

Behringer make reasonably priced mixing desks between 4 and 24 channels often powered by a brick psu so can be run on 12v.

If you google Tripath amp you will find some efficient class T amps.

 

On the barge I ran a Quad 34 with a Quad 405 amplifier with near field studio monitors and a sub :0

But the room was 4x3metres.

 

Will have a look to see if I can find the amp.

 

Blimey that will test the old grey cells. I can remember vaguely about Class A and Class B amps, quiescent current draw and that, but haven't heard of a class T amp.

 

Best I rush back to skool then!

 

ETA: I used to love the Quad gear. Great stuff.

Edited November 16, 2015 by Loafer

[GUMPY]

Class T is a trademark its really a switching amplifier (class d)

I love the 405 as its a class A amp and therfore very pure, mine needs a service and new capacitors, well it is nearly 40 years old.

[Loafer]

If anyone's still awake, the original problem of our stereo tripping our RCD, has gone away!

 

I changed the RCD and it doesn't trip any more. How queer...

[Paul C]

Faulty RCD then!