"Dual mono" and True Dual Mono

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"Dual mono" and True Dual Mono

Post by Spannko » 2019-09-13 17:11

[Split from "Playground for practical listening exercises"]

Thomas, I’m interested in how you achieve “completely separate ground plane(s) for each channel”, and where the connection is finally made? (Unless they’re fully floating, if that’s the correct term).

As you know, I’ve been fettling with mains wiring for the past 18 months and my latest hypothesis is that there may be advantages in ensuring that not only the equipment grounds, but also the safety earth and/or the live’s and neutral’s are as electrically separated as possible PROVIDED none of the equipment grounds are connected via an Interconnect (which would introduce an earth loop). One advantage of this approach is that each component can have a power cable and/or flex optimised in accordance with its current requirements too.

Unfortunately, this approach rules out 99% of hifi on the market, but for high end systems it might be worth investigating further.
Last edited by Spannko on 2019-09-14 14:19, edited 1 time in total.

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Re: "Dual mono" and True Dual Mono

Post by ThomasOK » 2019-09-13 17:44

Completely separate grounds for the left and right channel means that the only place the grounds of the two channels come together is at the AC power strip or the wall.

Even equipment that is dual mono in construction normally has the left and right signal grounds connected together. This is easily tested by checking for continuity between the two grounds with a VOM. With my current system you have separate left and right grounds in the cartridge, phono stages, preamps, power amps and speakers. So the grounds only come together at the power strip.
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Re: Playground for practical listening exercices

Post by Spannko » 2019-09-13 19:35

ThomasOK wrote:
2019-09-13 17:44
Completely separate grounds for the left and right channel means that the only place the grounds of the two channels come together is at the AC power strip or the wall.

Even equipment that is dual mono in construction normally has the left and right signal grounds connected together. This is easily tested by checking for continuity between the two grounds with a VOM. With my current system you have separate left and right grounds in the cartridge, phono stages, preamps, power amps and speakers. So the grounds only come together at the power strip.
Since you’ve found that distancing the point at which the components talk to one another to be beneficial (or is it, argue/fight with one another? Or to put a more technical slant on it, modulate one another) what do you think about taking the connection nearer to Mother Earth by connecting at the consumer unit/service panel?

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Re: "Dual mono" and True Dual Mono

Post by matthias » 2019-09-14 21:31

Spannko wrote:
2019-09-13 19:35
ThomasOK wrote:
2019-09-13 17:44
Completely separate grounds for the left and right channel means that the only place the grounds of the two channels come together is at the AC power strip or the wall.
Even equipment that is dual mono in construction normally has the left and right signal grounds connected together. This is easily tested by checking for continuity between the two grounds with a VOM. With my current system you have separate left and right grounds in the cartridge, phono stages, preamps, power amps and speakers. So the grounds only come together at the power strip.
Since you’ve found that distancing the point at which the components talk to one another to be beneficial (or is it, argue/fight with one another? Or to put a more technical slant on it, modulate one another) what do you think about taking the connection nearer to Mother Earth by connecting at the consumer unit/service panel?
+1
I wanted to post the same question, but Spannko was first:-)

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Re: "Dual mono" and True Dual Mono

Post by ThomasOK » 2019-09-17 22:39

Spannko wrote:
2019-09-13 19:35
ThomasOK wrote:
2019-09-13 17:44
Completely separate grounds for the left and right channel means that the only place the grounds of the two channels come together is at the AC power strip or the wall.

Even equipment that is dual mono in construction normally has the left and right signal grounds connected together. This is easily tested by checking for continuity between the two grounds with a VOM. With my current system you have separate left and right grounds in the cartridge, phono stages, preamps, power amps and speakers. So the grounds only come together at the power strip.
Since you’ve found that distancing the point at which the components talk to one another to be beneficial (or is it, argue/fight with one another? Or to put a more technical slant on it, modulate one another) what do you think about taking the connection nearer to Mother Earth by connecting at the consumer unit/service panel?
I'm not sure I completely follow that question. This might have something to do with the different way AC is run in the UK compared to the US. In my system the grounds from the components all come together in the power strip where it then connects to the wall outlet, then back to the electrical panel (or circuit breaker box). In my case the electrical panel is connected directly to a 8 foot ground post in the earth outside the house on the other side of the wall from the panel. This is something I installed as originally the only ground was to the cold water pipe which ran the full length of the house and past a meter, which required a wire bridge around it since it is electrically insulating, before making it to the actual ground.

So I'm not sure how you would take the connection closer to mother earth.

I suppose one possible extension of the separate left and right grounds would be to have another circuit breaker and AC wall outlet so that you could have one channel on one circuit and one channel on the other, keeping the grounds separate back to the panel. A lot of work but it might be interesting.

But the whole earthing thing gets much more complex when you look at various ideas from different audio companies. Nordost has outlet strips with no switches or filtering but which put a half Ohm resistor between the plug and the AC ground line on every outlet except one. This one is supposed to be used for the preamp or integrated amp as that is what everything else connects to. The idea is to force all grounds through the preamp as the central point. That strip also has a ground post on it and they recommend that you put a separate ground rod in the earth as close to the system as possible and run the wire to that post. This is said to improve things by giving an even better ground, although they do mention that the practice is against the electrical code in the US.

But now they have taken it even further as they have boxes they call artificial grounds. You plug an RCA, or XLR or other connector into this device through the banana socket on it and a special cable and it gives a ground to be used when you can't put a designated line attached to a ground rod in your room. It is apparently based on technology from Entreq in Åstorp, Sweden. But, of course, Nordost has improved on it and put it into a nice heavy machined aluminum box, on which they machine out the heads of the screws so you can't see inside. There are some explanations of what it does but what is actually in there is very sketchy.

I don't know if any of this relates to what you are asking, but it certainly indicates what some people feel is necessary for proper grounding.
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Re: "Dual mono" and True Dual Mono

Post by lejonklou » 2019-09-18 09:08

ThomasOK wrote:
2019-09-13 17:44
Completely separate grounds for the left and right channel means that the only place the grounds of the two channels come together is at the AC power strip or the wall.

Even equipment that is dual mono in construction normally has the left and right signal grounds connected together. This is easily tested by checking for continuity between the two grounds with a VOM. With my current system you have separate left and right grounds in the cartridge, phono stages, preamps, power amps and speakers. So the grounds only come together at the power strip.
Sorry, I haven't paid proper attention to this discussion. Perhaps because it was buried in a 78 page long playground thread instead of having its own - which it deserves and therefore I made one.

With most HiFi units, even when they are said to be built as dual mono, the signal grounds are not separated but join one another, either on the circuit board or by going into the same chassis ground. This causes a ground loop, sometimes multiple ones, when the unit is connected to the next unit, as the RCA interconnects carry two grounds - left and right - which once again meet in the next unit. And if the signal ground is connected to the chassis ground, there are additional loops created by the grounds in the power cords, which meet in the power strip.

Ground loops are bad for the music. Sometimes a loop picks up hum or other noise, but even when it doesn't, it "muddies the water" of the reproduction. It's usually not until you remove it that you notice its degradational effects.

With my true Mono units - SINGularity, Sagatun Mono and Tundra Mono - where each channel is housed in its own case and with the floating signal ground layout that I use, left and right signal grounds never meet. They run completely separated all the way from each coil in the cartridge to the coils in each speaker. They don't meet in the power strip.

The chassis grounds are arranged as a star and meet only in the power strip. Interestingly it still matters in which order the power cords are plugged into the power strip, and I have yet to hear a star grounded strip sounding better than the best regular strips.

Left signal and left signal ground run as an isolated chain from cartridge to speaker. Right signal and right signal ground run as an isolated chain from cartridge to speaker. The two don't meet each other and they are shielded on their journey by the chassis grounds.

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Re: "Dual mono" and True Dual Mono

Post by matthias » 2019-09-18 11:33

lejonklou wrote:
2019-09-18 09:08
Left signal and left signal ground run as an isolated chain from cartridge to speaker. Right signal and right signal ground run as an isolated chain from cartridge to speaker. The two don't meet each other and they are shielded on their journey by the chassis grounds.
IMO, the question of Spannko and me:

Where should LSG and RSG from the speakers be earthed?

IMO, the best would be to run a power cable with three earth wires to the audio system.
One earth wire carries all chassis grounds, the other two carry separately LSG and RSG.
Near the earth rod all three earths are connected together to the rod.

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Re: "Dual mono" and True Dual Mono

Post by lejonklou » 2019-09-18 11:56

matthias wrote:
2019-09-18 11:33
IMO, the question of Spannko and me:

Where should LSG and RSG from the speakers be earthed?

IMO, the best would be to run a power cable with three earth wires to the audio system.
One earth wire carries all chassis grounds, the other two carry separately LSG and RSG.
Near the earth rod all three earths are connected together to the rod.

Matt
Your question makes no sense. RSG and LSG should not be earthed. As I wrote above, they are isolated from the chassis grounds and don't meet anywhere.

If your question refers to a system built with other components than mine, where frequently RSG, LSG and chassis ground are connected, your question doesn't make any sense either. They're joined in each unit and you don't have the option to move the point where they join somewhere else.

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Re: "Dual mono" and True Dual Mono

Post by matthias » 2019-09-18 12:16

lejonklou wrote:
2019-09-18 11:56
Your question makes no sense. RSG and LSG should not be earthed. As I wrote above, they are isolated from the chassis grounds and don't meet anywhere.

If your question refers to a system built with other components than mine, where frequently RSG, LSG and chassis ground are connected, your question doesn't make any sense either. They're joined in each unit and you don't have the option to move the point where they join somewhere else.
Fredrik,

just for my understanding:

What do you with your speaker return and chassis ground in Tundra Mono?

In my system RSG and LSG are separated all way from the source and are connected at one point in the dual mono power amp.

Thanks

Matt
Last edited by matthias on 2019-09-18 12:21, edited 1 time in total.
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Re: "Dual mono" and True Dual Mono

Post by lejonklou » 2019-09-18 12:20

matthias wrote:
2019-09-18 12:16
lejonklou wrote:
2019-09-18 11:56
Your question makes no sense. RSG and LSG should not be earthed. As I wrote above, they are isolated from the chassis grounds and don't meet anywhere.

If your question refers to a system built with other components than mine, where frequently RSG, LSG and chassis ground are connected, your question doesn't make any sense either. They're joined in each unit and you don't have the option to move the point where they join somewhere else.
Fredrik,

just for my understanding:

What do you with your speaker return and chassis ground in Tundra Mono?

In my system RSG and LSG are separated all way from the source and are connected at one point in the power amp.

Thanks

Matt
They are separated.

That is in my opinon the best way to do it.

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Re: "Dual mono" and True Dual Mono

Post by matthias » 2019-09-18 12:30

Fredrik,
thank you for clarification.

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Re: "Dual mono" and True Dual Mono

Post by Defender » 2019-09-18 15:41

but would they not meet each other in the source component as soon as you use a digital source?

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Re: "Dual mono" and True Dual Mono

Post by Defender » 2019-09-18 15:54

I see ... but in this case no ground loop

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Re: "Dual mono" and True Dual Mono

Post by ThomasOK » 2019-09-18 16:54

Defender wrote:
2019-09-18 15:41
but would they not meet each other in the source component as soon as you use a digital source?
Yes, and there lies the dilemma. If I plug the CD12, the Kremlin the HAKAI or the subwoofer crossover into the system I have now bridged the left and right signal grounds (and likely connected it to AC ground as well unless they are floating ground units). So how to listen to a source besides the LP12 and not have that unwanted contribution to the sound. I know how to get around the streamer and subwoofer problem - just use two streamers, two DACs, two subwoofers, two amps and two crossovers. Unfortunately that entails twice the money and twice as much space. The latter is no small problem considering the three full 4 shelf Harmoni racks I already have and the rather ginormous subwoofer. I suppose you could also get two identical tuners and tune them to the same channel, with the same problems noted above, but I'm at a loss as to the CD player.

Would it work to disconnect the ground wire in one of the RCAs going to the preamp? Would that cause other problems? Hey, Fredrik, how about a mono DAC that also isolates the grounds of the two channels coming into it so you can plug a streamer and a CD player into it and still keep the purity of the Sagatun Monos?

I have not done any real comparisons yet, too busy with other things, but I have been running my system as above - one source and no subwoofer - for over a month and it certainly sounds good.
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Re: "Dual mono" and True Dual Mono

Post by Defender » 2019-09-18 19:25

Thomas do you remember your answer in the Tunda stereo thread where I mentioned the „balanced“ loudspeaker terminal output - I think Nelson Pass means he lifted the signal from the ground so its floating.
Not sure why he called it balanced.
Anyway I think some companies lift the signal ground from chassis ground with a thermistor and that might also work in the case of a dac or other equipment but means to modify the equipment.

Maybe your problem is not as bad as soon as your other equipment is connected to input 1-4 in Sagatun Mono so when you flip the switch down all grounds are separated and only in the case of flipping the switch up to hear your dac the grounds connect through the dac. But you can still enjoy perfect separation for your most important source.
Disconnect the ground wire on one RCA and this channel is off - thats my understanding.

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"Dual mono", True Dual Mono, and Proper Grounding

Post by Ron The Mon » 2019-09-18 19:40

ThomasOK wrote:
2019-09-18 16:54
Defender wrote:
2019-09-18 15:41
but would they not meet each other in the source component as soon as you use a digital source?
Yes, and there lies the dilemma...

Would it work to disconnect the ground wire in one of the RCAs going to the preamp? Would that cause other problems?
An easy solution is to buy an all-Naim system and use DIN cables. That solves 3.25 of the 4 "problems" proposed here.

An easier, and much cheaper, solution is to buy inline RCA-to-RCA transformers for all cables.

I have done both and can say the Naim solution sounds better. However, I personally don't think the "problem" is that large. If it was, Fredrik would be offering all his phono amps dual-mono.

Tom has done something quite important and should really be the focus of this thread; proper (and safer) grounding of a home electrical system. I have no experience of electrical distribution outside of the United States. Inside the United States, I have a LOT of experience with practical application, knowledge of codes (including past examples), and crazy nut-job hi-fi experiments (done by me).

It is very common in the U.S. to have a home electrical system's ground connected to a cold water pipe. Often there is a jumper across the water meter so the electrical system is grounded to a further buried pipe deeper in the "earth". Sometimes these bonds are broken. Even if the bonds are secure, and without corrosion, there are still ground loops present, and they will vary because of temperature, humidity, vibration, and impurities in the water.

With the advent of copper water pipes, some homes have a combination of copper and lead. This is disaster for two reasons; the first is if you have an earth connection across these two dissimilar metals, corrosion will occur at the joint and your pipes will eventually burst. "Ground-Loop" could also be called voltage or current difference. Ohm's Law will show a voltage (and current running) drop across two points having a floating resistive difference.

The safest, easiest, cheapest solution is to do what Tom has done and drive at least an 8-foot ground rod outside and disconnect everything electrical from any water pipes.

The sound quality of your hi-fi will improve and you will be up to code. Be aware this is not always a simple matter. Most retailers offer the bare minimum. You really need a thicker, longer solid copper earth rod; 12-foot is good. It must be near a moist area as it is the mineral impurities in the water that increase the electrical connection to "earth". I have often hit rock after four-feet. The top end of an earth rod must also be a foot or so below ground and that connection "earthed". This also prevents lawn mowers and edgers wearing down the copper. Be careful not to hit a water pipe, sewer, or other below ground-level items.

Like most boys, my son wanted a set of walkie-talkies when he was about 10. This pre-dated iPhones. I had a theory I proved showing there were many earth-loops in electrical systems. We followed the power delivered to my house back to the main reduction transformer. Along the way an incredible discovery was made; the grounding of every pole was severed. Most were cut at the very bottom right at the connection to the earth rod.

This was coincidentally within a month of my son's birthday so I bought him walkie-talkies. We alternated who was inside the house and at the poles comparing listening results. We always agreed 100% and the result was that properly grounding the pole's 0-Volt to earth sounded best.

I have since gone back and replaced previously damaged earth wires over the years, this has improved the sound marginally. My main point is reduce all ground loops before they get to your hi-fi.

The impetus for starting my journey is interesting if anyone is interested.

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Re: "Dual mono" and True Dual Mono

Post by ThomasOK » 2019-09-18 20:23

Defender wrote:
2019-09-18 19:25
Thomas do you remember your answer in the Tunda stereo thread where I mentioned the „balanced“ loudspeaker terminal output - I think Nelson Pass means he lifted the signal from the ground so its floating.
Not sure why he called it balanced.
Anyway I think some companies lift the signal ground from chassis ground with a thermistor and that might also work in the case of a dac or other equipment but means to modify the equipment.

Maybe your problem is not as bad as soon as your other equipment is connected to input 1-4 in Sagatun Mono so when you flip the switch down all grounds are separated and only in the case of flipping the switch up to hear your dac the grounds connect through the dac. But you can still enjoy perfect separation for your most important source.
Disconnect the ground wire on one RCA and this channel is off - thats my understanding.
Actually I asked Fredrik about making a change to the Sagatuns such that the ground lines would be cut off by the flip switch and was informed that it was not possible. If I remember correctly, all signal grounds in a Sagatun Mono are internally connected and there are problems in trying to do it differently. Possibly Fredrik will explain it further.

My understanding on the cabling is that you can disconnect the ground on the interconnect for one channel on a stereo device and that channel will still transmit as the other channels' ground will complete the circuit (since the two are connected internally). But this may not work with Sagatun Monos due to the separation of their signal grounds, so you are likely correct. I believe Fredrik experimented with this some time ago but that was before the Sagatun Monos existed. I'm not an electrical engineer so I'm a little outside my depth here.

As Fredrik mentions in his very informative reply, there is no connection to the AC ground of the signal grounds in my system as currently connected. So the whole idea of separate left and right AC lines is unnecessary and may even be counterproductive.
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Re: "Dual mono" and True Dual Mono

Post by ThomasOK » 2019-09-18 20:25

So apparently we need to go and reconnect the grounds on our electrical poles now. Probably best not to attempt during a lightning storm.
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Lightning and Grounding

Post by Ron The Mon » 2019-09-18 20:43

ThomasOK wrote:
2019-09-18 20:25
So apparently we need to go and reconnect the grounds on our electrical poles now. Probably best not to attempt during a lightning storm.
Most likely. Not true.

Yes, you might need to climb your local electrical pole to get better sound. Lightning/electricity always takes the path of least resistance. Local poles do not provide the greatest height; and if grounded properly, there is no danger.

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Re: "Dual mono" and True Dual Mono

Post by Defender » 2019-09-18 21:03

Thomas if you have some minutes you need to google: audiophile club athens by ken barnes
at 2:07min in the video you see how to do it - this guy knows it (its really funny) ;)

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NOT FUNNY

Post by Ron The Mon » 2019-09-18 21:54

Defender wrote:
2019-09-18 21:03
...search: audiophile club athens,...

in the video you see how to do it - this guy knows it (its really funny) ;)
I watched your linked video and it saddens me.

What I wrote above is not funny or a joke. It is based on science and current U.S. electrical code. If you wish to mock me and call me a fraud, send Fredrik a Private Message and have me banned from here.

I take hi-fi reproduction very seriously. I may sometimes kid here but nothing I have written should be considered a joke.

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Re: "Dual mono", True Dual Mono, and Proper Grounding

Post by lejonklou » 2019-09-18 22:28

Ron The Mon wrote:
2019-09-18 19:40
ThomasOK wrote:
2019-09-18 16:54
Defender wrote:
2019-09-18 15:41
but would they not meet each other in the source component as soon as you use a digital source?
Yes, and there lies the dilemma...

Would it work to disconnect the ground wire in one of the RCAs going to the preamp? Would that cause other problems?
An easy solution is to buy an all-Naim system and use DIN cables. That solves 3.25 of the 4 "problems" proposed here.

An easier, and much cheaper, solution is to buy inline RCA-to-RCA transformers for all cables.

I have done both and can say the Naim solution sounds better. However, I personally don't think the "problem" is that large. If it was, Fredrik would be offering all his phono amps dual-mono.

Tom has done something quite important and should really be the focus of this thread; proper (and safer) grounding of a home electrical system. I have no experience of electrical distribution outside of the United States. Inside the United States, I have a LOT of experience with practical application, knowledge of codes (including past examples), and crazy nut-job hi-fi experiments (done by me).

It is very common in the U.S. to have a home electrical system's ground connected to a cold water pipe. Often there is a jumper across the water meter so the electrical system is grounded to a further buried pipe deeper in the "earth". Sometimes these bonds are broken. Even if the bonds are secure, and without corrosion, there are still ground loops present, and they will vary because of temperature, humidity, vibration, and impurities in the water.

With the advent of copper water pipes, some homes have a combination of copper and lead. This is disaster for two reasons; the first is if you have an earth connection across these two dissimilar metals, corrosion will occur at the joint and your pipes will eventually burst. "Ground-Loop" could also be called voltage or current difference. Ohm's Law will show a voltage (and current running) drop across two points having a floating resistive difference.

The safest, easiest, cheapest solution is to do what Tom has done and drive at least an 8-foot ground rod outside and disconnect everything electrical from any water pipes.

The sound quality of your hi-fi will improve and you will be up to code. Be aware this is not always a simple matter. Most retailers offer the bare minimum. You really need a thicker, longer solid copper earth rod; 12-foot is good. It must be near a moist area as it is the mineral impurities in the water that increase the electrical connection to "earth". I have often hit rock after four-feet. The top end of an earth rod must also be a foot or so below ground and that connection "earthed". This also prevents lawn mowers and edgers wearing down the copper. Be careful not to hit a water pipe, sewer, or other below ground-level items.

Like most boys, my son wanted a set of walkie-talkies when he was about 10. This pre-dated iPhones. I had a theory I proved showing there were many earth-loops in electrical systems. We followed the power delivered to my house back to the main reduction transformer. Along the way an incredible discovery was made; the grounding of every pole was severed. Most were cut at the very bottom right at the connection to the earth rod.

This was coincidentally within a month of my son's birthday so I bought him walkie-talkies. We alternated who was inside the house and at the poles comparing listening results. We always agreed 100% and the result was that properly grounding the pole's 0-Volt to earth sounded best.

I have since gone back and replaced previously damaged earth wires over the years, this has improved the sound marginally. My main point is reduce all ground loops before they get to your hi-fi.

The impetus for starting my journey is interesting if anyone is interested.

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Disconnecting the ground in one of the RCA's is not optimal. It works, and sometimes for the better, but not always. Because the still grounded RCA channel will sound better than the one with the ground broken. I have found it useful on subwoofer installations, where there's both left and right channel inputs.

Ron, you're correct that a single ground is the main benefit of DIN connectors. And for a while I was tempted to go down that route. It solves most ground loop problems, unless you tie the signal ground to the chassis in several units, which will then create ground loops anyway.

But then I tested separating left and right signal grounds. And this was even better than using a single ground. And in addition, there's the practical problem of which analogue interconnects to use between your units. And this made the difference even bigger, as I found that the Linn Silver interconnects - especially the early ones with no slits in the barrel - were way superior to any DIN interconnects that I'd found. (A caveat here is that the early Linn Silvers vary A LOT in performance, so if you want to be on the safe side, buying a new slitted pair is often a safer option.)

Separating left and right signal grounds all the way from the source to the speaker is in my opinion not a small benefit to musicality. It may appear subtle at first listen, but then it grows on you. And if you test joining the two somewhere along the path, you'll instantly feel NO, bring me back!

I'm aware it's currently only possible from an MC cartridge using SINGularities, but it's certainly something I'd like to implement in more source products. Although it's very costly!

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Lejonklou v Naim

Post by Ron The Mon » 2019-09-18 22:49

Fredrik,
Any prior post of mine should in no way be construed to claim Naim superior to any Lejonklou amps; regardless of the way they are earthed. I have not done such a comparison.

I have listened to Naim and Lejonklou products both long and short-term. I have never directly compared them. Both are well-built long-lasting amps. Both sound great (especially with Isobariks).

Ron The Mon

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Re: "Dual mono" and True Dual Mono

Post by lejonklou » 2019-09-18 22:52

I have to add that if you're using Sagatun Mono and Tundra Mono as amplification, a source with left and right channel grounds joined (i.e. most source components, digital and analogue, except for SINGularity), will not result in any ground loops. Because the only place where the left and right grounds are joined is in the source. And that works well, as there's no other point where the two meet again.

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Re: Lejonklou v Naim

Post by lejonklou » 2019-09-18 22:55

Ron The Mon wrote:
2019-09-18 22:49
Fredrik,
Any prior post of mine should in no way be construed to claim Naim superior to any Lejonklou amps; regardless of the way they are earthed. I have not done such a comparison.
OK. But why haven't you? Given that you take this quest so seriously. I do too and am more than interested in your findings!

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