Coherent RTZ GROUNDING BOX

[Bigman80]

I had Alan visit today with the Coherent RTZ grounding box. I must say straight off the bat that I didn't know what to expect. I use a BMU for all parts except the amplifier (Krell KSA 100 MK2) which is plugged directly into the wall.

The Source was Vinyl via my SP10 MK2/Kontrapunkt B/PMAT1010

Phonostage was the Bigbottle into the DCB1 preamp.

We started off with a track I know very well:

Paul Simon - Under African Skies

We did an acclimatization of the system without the RTZ in the system before we got going.

We put the box in and started the track again. Instantly I could hear that the box was having an effect.

At the end of the track, Alan and I discussed what we each heard. Alan felt the bass got tighter but I didn't feel it was "tighter" I actually felt the bass had hardened and wasn't quite as descriptive.

We decided to play the track again.

After the second, more intent listen, I had more concerns. The transients had been lost and the (artificially reproduced) room acoustics on the recording were missing. I suspected this in the first evaluation but was sidetracked by focusing on the effect it had on the bass.

Again we discussed what we heard.

I was absolutely convinced that the normally cavernous soundstage had gone, the chest cavity was no longer audible and everything sounded a little flat.

We then took the RTZ grounding box out.

As I suspected, the sounstage returned to its huge size, transients returned and to be honest, it was just better all round.

The ambience and detail was completely sucked out by the RTZ and I am totally perplexed by it.

We then tried: David Bowie - Stoned Love

I picked this track because of the hand claps at the start, and the large amount of reverb on the track.

Again, with the RTZ in circuit, it was flat. The reverb didn't decay, it just didn't happen and in the end Alan told me to turn it off. It just sounded shit. We tried it again without the box and again, without it we were listening to a great track, full of layers and depth. It was not subtle. I'm very serious about that.

Obviously, there will be claims of "in a balanced system" and all that jazz, but this system IS balanced. It IS high quality. It is a superb tool at revealing the qualities of anything you plug into it. Nothing is able to hide in the chain. I compiled it to be exactly that. Revealing.

I can only surmise that the suspicions I had before it came here, that if you properly sort the mains out, either by a BMU or some megastructure in your garden, it's unlikely to have such a large effect.

In Alan's system, the result is totally the opposite. It helps his system to perform better but here it killed everything. Alan's had better space in the soundstage and definitely appeared more revealing. I think I now need to revisit Alan's system and do the same tracks there.

What I can now say, CONCLUSIVELY, is that it does do something. It just may not be entirely desirable.

[walpurgis]

Perhaps you'll now receive suggestions that your system was not suitably matched (to it?). Or that the box was not used correctly. Or that the mains supply in your area has adverse effects. Or that the nasty Hi-Fi demons have cursed you! :eek:

[Barry]

I have read somewhere that it is not a good idea to mix gear running off a balanced mains supply with gear fed by unbalanced (conventional) mains in the same system. Something to do with a potential safety issue - but I can't think at the moment what that might be.

[Bigman80]

I have read somewhere that it is not a good idea to mix gear running off a balanced mains supply with gear fed by unbalanced (conventional) mains in the same system. Something to do with a potential safety issue - but I can't think at the moment what that might be.Not sure what could be an issue but Its universally accepted and recommended to plug a power amp into the wall.

I'm sure someone will provide info.

[Bigman80]

Perhaps you'll now receive suggestions that your system was not suitably matched (to it?). Or that the box was not used correctly. Or that the mains supply in your area has adverse effects. Or that the nasty Hi-Fi demons have cursed you! :eek:I don't know what folk will say mate. All I can say is what I heard and it's a shame it didn't work here. I'm happy to add anything that will improve the system.

[Ali Tait]

It’s not recommended because theoretically, under the right fault conditions a potential difference could exist between the chassis of balanced connected gear to that of unbanced connected gear, certainly enough to cause harm. It’s unlikely but possible.

Good article here-

https://www.google.co.uk/amp/s/www.soundonsound.com/sound-advice/crosstalk-readers-writes%3famp

[doodoos]

Interesting. We’ll see if these boxes survive the test of time or whether it will become another bubble that eventually bursts.

[Firebottle]

I can confirm that the effects in the two systems are polar opposites.

It is very baffling that what I have heard in my system, and others in their systems, is an opening of the soundstage, with more space, air and realism.
In Oli's system the RTZ removed the air and space that was already there making the soundstage flat and dull.

The conclusion can only be that it is system dependent.

I do reiterate that I am more than happy that I have put one into my system as it has been a very worthwhile upgrade.

[Firebottle]

Interesting. We’ll see if these boxes survive the test of time or whether it will become another bubble that eventually bursts.

It is interesting but I certainly don't see it as a bubble that will burst as you put it.

[Barry]

Thanks for that link Al. In fact I hoped you would respond, knowing you both use a BMU in your system and work in the electrical distribution business.

Actually I had seen that item before, but could not remember where. I have now bookmarked it.

Clearly, any competently designed BMU needs to have a circuit breaker fitted to both legs of the secondary winding, and for the two breakers to be mechanically linked, so if one trips the other is also disconnected.

[Bigman80]

Thanks for that link Al. In fact I hoped you would respond, knowing you both use a BMU in your system and work in the electrical distribution business.

Actually I had seen that item before, but could not remember where. I have now bookmarked it.

Clearly, any competently designed BMU needs to have a circuit breaker fitted to both legs of the secondary winding, and for the two breakers to be mechanically linked, so if one trips the other is also disconnected.

Mine is a DIY BMU and has MCBs in both legs. It's also substantially earthed and complies fully with the latest regs.

With two small kids in the house, it's a must that everything is safe.

[blackmetalboon]

Mine is a DIY BMU and has MCBs in both legs. It's also substantially earthed and complies fully with the latest regs.

With two small kids in the house, it's a must that everything is safe.

Are you sure the part I have highlighted is correct? For optimum safety it should be a double pole RCD on the secondary supply of the BMU.

[Bigman80]

Are you sure the part I have highlighted is correct? For optimum safety it should be a double pole RCD on the secondary supply of the BMU.

Yes it's a double pole RCD on the secondary.


Actually, I can't remember if it's a MCB or RCD.

I'll have to have a look

[hifinutt]

I don't have a balanced mains unit and wouldn't mind seeing how this unit sounds with the fb monoblocks sometime

[Bigman80]

I don't have a balanced mains unit and wouldn't mind seeing how this unit sounds with the fb monoblocks sometimeMatey, if you come and get me and drop me off home after, I'm more than happy to bring it. That said, the conventional wisdom is not to plug a power amp into them.

No idea why. It could also be Bullshit

[Marco]

Interesting review on the grounding box, Oliver.

For me, your findings aren't surprising, because by the very nature of how these things are claimed to work, they're likely to be system dependent, due to how the partnering equipment itself is designed (in reference to grounding) and the operating environment where the box is being tested - and if significant differences occur there, then you're liable to get quite different results, from system to system, as was the case in yours and Alan's.

It's a warning though, that these boxes, much like anything else in hi-fi (BMUs, too) can *never* automatically be seen as a 'magic bullet'!:nono:

Marco.

[Joe]

It is interesting but I certainly don't see it as a bubble that will burst as you put it.

I guess it depends on whether it injects air or removes it.

[Ali Tait]

Thanks for that link Al. In fact I hoped you would respond, knowing you both use a BMU in your system and work in the electrical distribution business.

Actually I had seen that item before, but could not remember where. I have now bookmarked it.

Clearly, any competently designed BMU needs to have a circuit breaker fitted to both legs of the secondary winding, and for the two breakers to be mechanically linked, so if one trips the other is also disconnected.

Yes indeed, I built mine with a double pole RCBO on the secondary and double pole MCB on the primary.

[Bigman80]

Yes indeed, I built mine with a double pole RCBO on the secondary and double pole MCB on the primary.Ah! This rings a bell. I'll look into this tomorrow.

[Bigman80]

Interesting review on the grounding box, Oliver.

For me, your findings aren't surprising, because by the very nature of how these things are claimed to work, they're likely to be system dependent, due to how the partnering equipment itself is designed (in reference to grounding) and the operating environment where the box is being tested - and if significant differences occur there, then you're liable to get quite different results, from system to system, as was the case in yours and Alan's.

It's a warning though, that these boxes, much like anything else in hi-fi (BMUs, too) can *never* automatically be seen as a 'magic bullet'!:nono:

Marco.Rarely is there a one size fits all solution. This highlighted that perfectly.

[NRG]

I can confirm that the effects in the two systems are polar opposites.

It is very baffling that what I have heard in my system, and others in their systems, is an opening of the soundstage, with more space, air and realism.
In Oli's system the RTZ removed the air and space that was already there making the soundstage flat and dull.

The conclusion can only be that it is system dependent.

I do reiterate that I am more than happy that I have put one into my system as it has been a very worthwhile upgrade.

Or maybe it fixes an issue in your system Alan that is not apparent in Oli’s...

I do find this suggestion that your system needs to be ‘balanced’ somewhat contrived, has anybody defined what a balanced system is in reality....without going to odd extremes.

[YNWaN]

I do find this suggestion that your system needs to be ‘balanced’ somewhat contrived, has anybody defined what a balanced system is in reality....without going to odd extremes.

As far as I can see, nobody has made such a suggestion. The only reference to ‘balanced’ is with regard to balanced mains transformers (BMU devices) - which is what they are called.

[NRG]

It’s in one of the other grounding box threads....

[YNWaN]

Ah, is it - I’ve rather lost track (interest) in the maze of interweaving ‘grounding box threads’. As you suggest, I would agree that the whole concept of requiring a ‘balanced’ system for the benefits to be audible is just marketing FUD to cast doubts on negative experiences.

[AJSki2fly]

After the second, more intent listen, I had more concerns. The transients had been lost and the (artificially reproduced) room acoustics on the recording were missing. I suspected this in the first evaluation but was sidetracked by focusing on the effect it had on the bass.

Again we discussed what we heard.

I was absolutely convinced that the normally cavernous soundstage had gone, the chest cavity was no longer audible and everything sounded a little flat.

We then took the RTZ grounding box out.

As I suspected, the sounstage returned to its huge size, transients returned and to be honest, it was just better all round.

The ambience and detail was completely sucked out by the RTZ and I am totally perplexed by it.

In Alan's system, the result is totally the opposite. It helps his system to perform better but here it killed everything. Alan's had better space in the soundstage and definitely appeared more revealing. I think I now need to revisit Alan's system and do the same tracks there.

What I can now say, CONCLUSIVELY, is that it does do something. It just may not be entirely desirable.

Oliver, a really great insight into one of these grounding boxes. It does leave the question about whether to try one or not very open. When I start to feel better from my op I think I will have a go at making my own grounding box, I have about half of what I need and the other bits of magic on the web are about £50-80 for a simple one, this is based on several weeks of web searching.

It will be interesting to see if I get any result whatsoever, a bit of fun anyway. I might then do a trial of a BMU, can anyone advise on a reasonably priced one that it effective?

Cheers

Adrian

[Bigman80]

Yes it certainly does!

The box is a bit of an enigma. The price is a massive factor. Most of the other brands have been described as softening the sound but this one did the entire opposite.

I don't pretend to understand exactly what it does or how it does it but on both occasions it had an audible effect.

Airline do affordable, well built BMUs. I'd start there.

[AJSki2fly]

Yes it certainly does!

The box is a bit of an enigma. The price is a massive factor. Most of the other brands have been described as softening the sound but this one did the entire opposite.

I don't pretend to understand exactly what it does or how it does it but on both occasions it had an audible effect.

Airline do affordable, well built BMUs. I'd start there.

I had a look at https://airlinktransformers.com/category/standard-balanced-power-supply and they are as you say reasonably priced, I think the BPS1000 - Standard Balanced Power Supply for £225 would do me fine, allowing it to simply feed two extension blocks. I just need to find if I can trial it.

Thanks

[Bigman80]

I doubt that they do a home trial. However, they usually sell on pretty well so I wouldn't be too concerned about buying one. Better still, you could make your own.

[anthonyTD]

Hi Ali,
Does your BMU's secondary centre tap go directly to mains ground, or a seperate earth rod ?
A...
Yes indeed, I built mine with a double pole RCBO on the secondary and double pole MCB on the primary.

[anthonyTD]

Hi Oliver,
That is how things should be done :) the BMU is a transformer, ie; with a seperate primary, and secondary, if there is no direct connection between the primary, and secondary, then the only issue your consumer unit will see in a fault situation, is over current, which is why the aditional trips are needed on the secondary.
A...
Mine is a DIY BMU and has MCBs in both legs. It's also substantially earthed and complies fully with the latest regs.

With two small kids in the house, it's a must that everything is safe.

[Bigman80]

Hi Oliver,
That is how things should be done :) the BMU is a transformer, ie; with a seperate primary, and secondary, if there is no direct connection between the primary, and secondary, then the only issue your consumer unit will see in a fault situation, is over current, which is why the aditional trips are needed on the secondary.
A...Ah, thanks Anthony.

I will double check but I'm 100% sure it conformed to regs when we built if.

[AJSki2fly]

I doubt that they do a home trial. However, they usually sell on pretty well so I wouldn't be too concerned about buying one. Better still, you could make your own.

Mmm, whilst I am pretty practical I am quite cautious when dealing with electrickery. Even though I am an IT Technical Support bod and repair stuff, I find dealing with something I can't see a bit daunting. Having experience a lithium thermal event and also a reasonable shock from a DC battery pack that was shorting it has made me a bit wary of dealing with the unknown and don't if I have the confidence to build effectively what I presume is a transformer of sorts?

If its not hard to do maybe I could be convinced.

[Marco]

As far as I understand it, any BMU must be fitted with safety devices in the secondary, as there is no other direct connection between primary and secondary. And without those safety measures in place, how would the primary, which is connected to the house CU, 'know' [other than in an over-current situation] what is happening on the secondary?

If I've misunderstood that, then one of our resident techies can correct me:)

Marco.

[Bigman80]

Mmm, whilst I am pretty practical I am quite cautious when dealing with electrickery. Even though I am an IT Technical Support bod and repair stuff, I find dealing with something I can't see a bit daunting. Having experience a lithium thermal event and also a reasonable shock from a DC battery pack that was shorting it has made me a bit wary of dealing with the unknown and don't if I have the confidence to build effectively what I presume is a transformer of sorts?

If its not hard to do maybe I could be convinced.If you aren't confident, just buy one. Nothing worse than worry so buy one matey.

[AJSki2fly]

As far as I understand it, any BMU must be fitted with safety devices in the secondary, as there is no other direct connection between primary and secondary. And without those safety measures in place, how would the primary, which is connected to the house CU, 'know' [other than in an over-current situation] what is happening on the secondary?

If I've misunderstood that, then one of our resident techies can correct me:)

Marco.

That is my understanding to from what I have read. Because with a BMU you effectively have say 115v on the live and 115v on the neutral side, making a total 230v supply. In a normal domestic circuit the circuit the circuit breakers are just on the live side, which is 230v, the neutral 0v, so a dead short issue onto live only needs to be considered. However with a balanced power supply both have a voltage so either side if they dead short can cause a dangerous, so my understanding is live and neutral need there own circuit breakers.

What I do not understand is how equipment that was designed to work say with Live 230V and Neutral 0V will work with 115V on Live and 115V on neutral, Perhaps someone could explain in layman's terms?

[Bigman80]

Just plugged the Krell into the BMU.

I actually think the sound is a fair chunk cleaner than going directly into the wall.

I'm not sure of I prefer it though. How odd.

[AJSki2fly]

Just plugged the Krell into the BMU.

I actually think the sound is a fair chunk cleaner than going directly into the wall.

I'm not sure of I prefer it though. How odd.

Could it be that the Krell was designed to take into account the possibility of a dirty or unstable power supply and that by then putting a clean on in it exaggerates aspects of the design? Or maybe you just need listening time to get used to a cleaner version.

[Macca]

Or maybe what sounds 'cleaner' isn't in fact anything to do with it being cleaner but entirely another effect.

Obviously whatever the grounding box is doing it isn't reducing noise as it would do that in any system, BMU or not. It might 'sound' like that is what it is doing but making a spurious leap from 'it sounds like the noise floor is lower' to the 'noise floor will be measurably lower' makes no sense. You can't determine what is happening on a technical level just by listening.

[Bigman80]

Or maybe what sounds 'cleaner' isn't in fact anything to do with it being cleaner but entirely another effect.

Obviously whatever the grounding box is doing it isn't reducing noise as it would do that in any system, BMU or not. It might 'sound' like that is what it is doing but making a spurious leap from 'it sounds like the noise floor is lower' to the 'noise floor will be measurably lower' makes no sense. You can't determine what is happening on a technical level just by listening.Well, I can't argue with needing some sort of technical measurement to demonstrate why, but it's pretty obvious to me that it's having an effect.

[Macca]

Well, I can't argue with needing some sort of technical measurement to demonstrate why, but it's pretty obvious to me that it's having an effect.

But in this case a subjective degradation of the sound, same as I found when I tried a BMU.

[Bigman80]

But in this case a subjective degradation of the sound, same as I found when I tried a BMU.Ah, well, it may not be degrading the sound....yet. I was stating an audible difference being heard.

I have allowed the system to warm Up.

I'll give it a thorough listen.

[Macca]

Ah, well, it may not be degrading the sound....yet. I was stating an audible difference being heard.

I have allowed the system to warm Up.

I'll give it a thorough listen.

I meant with the grounding box you had a subjective degradation.

My point was that with BMU and grounding boxes it is not a case of one size fits all. In some systems there is no effect, in others degradation, in others a slight improvement. Logically this would indicate to me that whilst they do something to influence perceived sound quality it clearly isn't by the methods claimed (reduced noise, distortion) since that could reasonably be expected to have a beneficial effect on any system.

Most likely they are actually adding noise/distortion which in some set ups is perceived as beneficial and in others as detrimental.

[Bigman80]

I meant with the grounding box you had a subjective degradation.

My point was that with BMU and grounding boxes it is not a case of one size fits all. In some systems there is no effect, in others degradation, in others a slight improvement. Logically this would indicate to me that whilst they do something to influence perceived sound quality it clearly isn't by the methods claimed (reduced noise, distortion) since that could reasonably be expected to have a beneficial effect on any system.

Most likely they are actually adding noise/distortion which in some set ups is perceived as beneficial and in others as detrimental.Ah I see.

[Firebottle]

What I do not understand is how equipment that was designed to work say with Live 230V and Neutral 0V will work with 115V on Live and 115V on neutral, Perhaps someone could explain in layman's terms?

The 230V is in reference to the Neutral, meaning that the Live is 230V above potential of the Neutral.

With balanced mains the two 115V secondaries are in anti-phase, so the difference between the two is 115+115=230V.

[anthonyTD]

Also, a BMU by its very nature has to have a reference point on the secondary, which is how you gain two lives, instead of a live and neutral, if there is no reference point, then its just a one to one transformer, and thus NOT a Balanced Mains Transformer!
And Olivers findings on the Grounding box are very interesting, and has shed more light on what may be happening with these things, its definitely given me a better understanding of what's going on, and why its effect [whether you see it as a positive or negative] will be very system dependant.
A...

[Marco]

My point was that with BMU and grounding boxes it is not a case of one size fits all. In some systems there is no effect, in others degradation, in others a slight improvement. Logically this would indicate to me that whilst they do something to influence perceived sound quality it clearly isn't by the methods claimed (reduced noise, distortion) since that could reasonably be expected to have a beneficial effect on any system.


Yes, but as the level of said noise/distortion present will vary in every system, then logic indicates that the efficacy of a grounding box will vary, depending on the level of said noise/distortion, and therefore is why its effectiveness will vary, from system to system.

For me, that's why there is a perceived positive effect with these boxes, directly proportional to the level of 'problem' existing that the box has been designed to fix. And if there's no problem to fix in the first place, then complicating a system's grounding path will likely be perceived, sonically, as a negative.

It's rather like 'fancy' mains leads. You've tried some in your system, and perceive no difference, yet in others (such as mine) the difference is easily heard, and that could simply be because my mains supply is noisier or more distorted than yours (and/or my equipment more sensitive to it) - and so it is with grounding boxes, if they're also addressing noise and distortion, which is why they're so system dependent.

Quite simply, if there's no, or little existing problem to fix, which the box has been designed to address, then you're not going to get much benefit from its use!

Marco.

[Marco]

Also, a BMU by its very nature has to have a reference point on the secondary, which is how you gain two lives, instead of a live and neutral, if there is no reference point, then its just a one to one transformer, and thus NOT a Balanced Mains Transformer!


Good point, mate. There are some right frauds/charlatans out there, posing as electronics 'gurus' or 'artisans';)

Laughable, really!:D

Marco.

[earsopen]

This thread has become a right mish-mash. Originally about a grounding box, then somebody threw in balanced mains units (which are a completely different kettle of fish) - what a mess.

Now, when people talk about 'these boxes' who knows which of the two they are speaking about?

The danger is that a conversation alternating between 'grounding' (an unused rca for instance to a grounding box), and 'earthing' (to do with balanced mains) could be seriously misinterpreted.

Dangerously so.

Incidentally, I use both in my system so they can work in harmony, and both have improved sound quality here. However, the BMU was not so successful on power amps, but on source equipment is excellent.

[Bigman80]

[/QUOTE]Incidentally, I use both in my system so they can work in harmony, and both have improved sound quality here. However, the BMU was not so successful on power amps, but on source equipment is excellent.[/QUOTE]

I've spent a couple of hours swapping the Krell in and out of the BMU.

What has become apparent is that when the Krell goes into the BMU, it gains a little more lucidity but loses some of the "natural touch"

To be honest, the clarity when it's in the BMU is very addictive. Whether it'll say in the BMU or go back directly to the wall will be decided when I can play my test track. Can't do that until it gets back from being fine tuned.

[anthonyTD]

Your right Bob,
Hopefuly the two threads can be seperated.
A...
This thread has become a right mish-mash. Originally about a grounding box, then somebody threw in balanced mains units (which are a completely different kettle of fish) - what a mess.

Now, when people talk about 'these boxes' who knows which of the two they are speaking about?

The danger is that a conversation alternating between 'grounding' (an unused rca for instance to a grounding box), and 'earthing' (to do with balanced mains) could be seriously misinterpreted.

Dangerously so.

Incidentally, I use both in my system so they can work in harmony, and both have improved sound quality here. However, the BMU was not so successful on power amps, but on source equipment is excellent.

[Marco]

Hi Bob,


This thread has become a right mish-mash. Originally about a grounding box, then somebody threw in balanced mains units (which are a completely different kettle of fish) - what a mess.


Well, both are designed to address certain issues, and in the process claimed to improve the performance of a system. My point is very simply that the efficacy of either is directly proportional to the level of 'issue' that exists to address, and which is why the improvement perceived by the use of either device is very system dependent:)

Marco.

[Bigman80]

It's a 750va Anthony.

[anthonyTD]

Ahh, ok.
A...

It's a 750va Anthony.

[Bigman80]

Ahh, ok.
A...Is that important??

[anthonyTD]

I just wanted to be sure the BMU you were using was adequate to supply the Krell, and everything else with ease.
Is that important??

[Bigman80]

I just wanted to be sure the BMU you were using was adequate to supply the Krell, and everything else with ease.Does it?

[bumpy]

My point is very simply that the efficacy of either is directly proportional to the level of 'issue' that exists to address, and which is why the improvement perceived by the use of either device is very system dependent:)

Marco.

This even more emphasises the need for dealers to offer home demos. If I knew it would make an improvement in my own system I would buy it.

[anthonyTD]

remind me which Krell model it is ?
Actualy, It should state its consumption on the back panel.
Does it?

[NRG]

Does it?

Unless I’ve got this wrong it would seem not. Full power consumption is listed as 1400w for your amp so with a power factor of 1 it would draw 5.8amps at full output. 750va is approx 3 amps.

[Bigman80]

Unless I’ve got this wrong it would seem not. Full power consumption is listed as 1400w for your amp so with a power factor of 1 it would draw 5.8amps at full output. 750va is approx 3 amps.Looks like i was right about putting it directly into he wall.

[anthonyTD]

Exactly!
A...

Looks like i was right about putting it directly into he wall.

[Bigman80]

Exactly!
A...I was told when I/we first built it NOT to put a power amp in it. I never did but the intrigue was worth exploring.

It's out now and will stay out.

[anthonyTD]

Agree, 3KVA, would be the least I would feel comfortable with.
Unless I’ve got this wrong it would seem not. Full power consumption is listed as 1400w for your amp so with a power factor of 1 it would draw 5.8amps at full output. 750va is approx 3 amps.

[Marco]

This even more emphasises the need for dealers to offer home demos. If I knew it would make an improvement in my own system I would buy it.

Indeed, Chris, which is why I suggested on one of the other threads, discussing grounding boxes, that if a manufacturer or dealer is serious about selling either product in quantity, they should offer demo units, which potential customers could use to assess the efficacy of such devices in the context of their system, prior to potential purchase - and forums are the ideal vehicle; that is if you've not been (justifiably) banned from almost every one in existence!:eyebrows:;)

I know that some manufacturers offer 30-day money back guarantees with their products, but personally that wouldn't interest me (indeed I've never bought a single thing for my system that way), as a) if it's not suitable, you've still got the faff of having to repackage and return it [a task I detest doing, which is one of the reasons why I'm not a box-swapper], and b) you're reliant on the trust of the company concerned actually refunding your money - and promptly...

No, if a dealer or manufacturer potentially wants my business, then *they* can make the required effort, and also take all the risk, by loaning me the item in question to audition, and if I like it after having tested it for a sufficient period of time, only then will they get my money. And if I don't like it, and it's a suitably large item, then they can arrange a courier (at their cost) to come and uplift it.

*That* is how I do business!:cool:

Marco.

[anthonyTD]

No harm done Oli,
At least you know why now!:eek::)
I was told when I/we first built it NOT to put a power amp in it. I never did but the intrigue was worth exploring.

It's out now and will stay out.

[Bigman80]

No harm done Oli,
At least you know why now!:eek::)Absolutely!!

[struth]

You don't run amp much past idle so it was probably OK but best to have headroom

[Firebottle]

I'll bring my power meter next time and we can see what the Krell actually takes at idle and typical listening level.

[Bigman80]

I'll bring my power meter next time and we can see what the Krell actually takes at idle and typical listening level.Coolio!!

[Ali Tait]

Hi Ali,
Does your BMU's secondary centre tap go directly to mains ground, or a seperate earth rod ?
A...

Hi, goes to mains earth.

[struth]

Unless I’ve got this wrong it would seem not. Full power consumption is listed as 1400w for your amp so with a power factor of 1 it would draw 5.8amps at full output. 750va is approx 3 amps.In an ac circuit things are not as simple as a straight dc calculation if memory serves. You have to take into account the reactance

[struth]

750va should work it at about 2.2amps I think at 230v.

It's just my guesstimate though. I'm old and not been doing electronics for 40 years..

Sure one of the ee's will be able to refine it. That's the figure for the bmu

[NRG]

In an ac circuit things are not as simple as a straight dc calculation if memory serves. You have to take into account the reactance

I didn’t use a DC calculation I used an AC one with a power factor of 1...a lower power factor would require more amps.

230v is Europe harmonisation not UK reality which is 240v

[Ali Tait]

Bloody 250v here..

[Ali Tait]

In fact I just measured it- 252v. Sheesh!

[Marco]

Jeez, mate, any valves you use must be getting roasted!:eek:

Do you go through a lot of lightbulbs, too?:D

Marco.

[Pharos]

I am old and haven't done formal electronics for 40 years, but ingrained in my memory is;

Power factor = VI Cos Fi.

[Barry]

I am old and haven't done formal electronics for 40 years, but ingrained in my memory is;

Power factor = VI Cos Fi.

Not quite,

Power factor = Cos (phi),

where phi = the phase angle between the voltage and current vectors.


VA is the power available or dissipated (in Watts) for a purely resistive load (that is, has a power factor of 1). All practical speakers present a load having a complex impedance (resistance + j reactance). In those cases the maximum power obtainable is

VA * Cos(arctan(reactance/resistance)).

Which is less than that available to a purely resistive load.

[Ali Tait]

Jeez, mate, any valves you use must be getting roasted!:eek:

Do you go through a lot of lightbulbs, too?:D

Marco.

LOL, surprisingly not. Can’t be good for the electronics though, it’s right on the edge of allowable maximum.

[anthonyTD]

Great! :)
Hi, goes to mains earth.

[Marco]

LOL, surprisingly not. Can’t be good for the electronics though, it’s right on the edge of allowable maximum.

Indeed. Might be worth making a call to your energy supplier and see if it can be reduced, oh and don't buy any dodgy Chinese valve amps, 'designed to run on UK mains'!

Aye, maybe 220V (just), but certainly not 252V!!:eek:

Marco.

[earsopen]

"My point is very simply that the efficacy of either is directly proportional to the level of 'issue' that exists to address, and which is why the improvement perceived by the use of either device is very system dependent"


Who says that you need to have 'issues' to address for these, both balanced mains and grounding boxes, to be effective?

They can make substantial improvements even when you think your system sounds good in the first place.

The only way to find out, is to try them.

[blackmetalboon]

T
"My point is very simply that the efficacy of either is directly proportional to the level of 'issue' that exists to address, and which is why the improvement perceived by the use of either device is very system dependent"


Who says that you need to have 'issues' to address for these, both balanced mains and grounding boxes, to be effective?

They can make substantial improvements even when you think your system sounds good in the first place.

The only way to find out, is to try them.

I did ask in the grounding box thread about how potential problems manifest themselves audibly in our systems but didn’t get a solid answer. Why spend time, effort and money trying to fix a problem that may not exist in your system?

[Barry]

Indeed. Might be worth making a call to your energy supplier and see if it can be reduced, oh and don't buy any dodgy Chinese valve amps, 'designed to run on UK mains'!

Aye, maybe 220V (just), but certainly not 252V!!:eek:

Marco.

If it is on the edge of the maximum allowable voltage, but not above it, the electricity company has no legal obligation to do anything about it. If it is consistently either under, or over the permitted voltage range (and preferably complained about by more than one user), then the supplier is legally obliged to do something about the situation. It is easily remedied by asking for a qualified electrician from the energy supplier to select an appropriate tap on the transformer in the local sub-station feeding your property.

[Ali Tait]

Indeed. Might be worth making a call to your energy supplier and see if it can be reduced, oh and don't buy any dodgy Chinese valve amps, 'designed to run on UK mains'!

Aye, maybe 220V (just), but certainly not 252V!!:eek:

Marco.

Haha I know the local guys, spent the last two years on and off at a project for grid transformer replacements at the local main substation. Not much can be done in this instance sadly.

[hifinutt]

Matey, if you come and get me and drop me off home after, I'm more than happy to bring it. That said, the conventional wisdom is not to plug a power amp into them.

No idea why. It could also be Bullshit

thanks ollie
interesting to talk to folks at bristol show , one company has been there for past few years and they sell these .

http://www.puritanaudiolabs.com/products/ground-master/

i guess they are similar ? they dont cost a lot

[Bigman80]

thanks ollie
interesting to talk to folks at bristol show , one company has been there for past few years and they sell these .

http://www.puritanaudiolabs.com/products/ground-master/

i guess they are similar ? they dont cost a lotI don't know mate. This requires a ground rod outside. Seeing as nobody knows how the RTZ does what it does, it's impossible to tell!

[Ali Tait]

If it is on the edge of the maximum allowable voltage, but not above it, the electricity company has no legal obligation to do anything about it. If it is consistently either under, or over the permitted voltage range (and preferably complained about by more than one user), then the supplier is legally obliged to do something about the situation. It is easily remedied by asking for a qualified electrician from the energy supplier to select an appropriate tap on the transformer in the local sub-station feeding your property.

Not in this particular case Barry.

[Barry]

Not in this particular case Barry.


Why not Ali? I thought you were in the business.

[Ali Tait]

I am lol, that’s how I know. One of the engineers used to live near me, he says it’s always been high due to an old local trannie with a buggered tap changer. Won’t be changed until it reaches the end of its operational life.

[Barry]

I am lol, that’s how I know. One of the engineers used to live near me, he says it’s always been high due to an old local trannie with a buggered tap changer. Won’t be changed until it reaches the end of its operational life.

Ah - I hadn't realised the tap changer was a mechanical switch. I assumed it would be done by literally re-selecting the transformer tap by hand.

[Ali Tait]

Yes it’s both usually, it’s common for them to go faulty though, for certain makes of transformer. We are talking about gear that’s often 40-50 years old though.

The new 90MVA grid transformers we installed in the main substation have motorised tap changers that tap automatically depending on demand. One was found to be faulty during commissioning and had to be replaced.

The old transformers had been in service since 1952 so I guess they’d had their money’s worth!

[Macca]

The old transformers had been in service since 1952 so I guess they’d had their money’s worth!

Pah! I remember when if a transformer didn't last at least a hundred years we demanded our money back!

[Ali Tait]

LOL those days are gone, can’t see these new transformers lasting as long as the old ones.

Things used to be built to a standard, now they’re built to a price.

[struth]

LOL those days are gone, can’t see these new transformers lasting as long as the old ones.

Things used to be built to a standard, now they’re built to a price.

True. over in France on a dig, they pulled up a ww1 valve up and it was still as smooth operating as it was when made.

[Ali Tait]

Aye, since it was all privatised, gotta keep the shareholders happy. Still, keeps me in work.