SuperCap, HiCap & FlatCap and earth loops
Posted by: NAIM-Collector on 11 January 2003
I notice the NAIM power supplies will allow the connection of three power amplifiers to the audio output.
I can understand allocating the opportunity for one NAP-250 or two NAP-135s but this allows for all the above.
Does this have a detrimental effect on the connected amplifiers, issues of pre amplifier output impedance to power amplifier input impedance springs to mind.
While we are involved with maters of a technical nature does connecting two HiCaps to a NAC-82 compromise the star earthing due to two power supplies connected to two AC outlets.
If the multiple earth path is a dramatic concern when the subject of RCA plugs is raised then the above configuration would definitely create significantly greater amounts of reference earth potential variation than two RCA cable connected side by side onto the same earth strip at each end.
I can understand allocating the opportunity for one NAP-250 or two NAP-135s but this allows for all the above.
Does this have a detrimental effect on the connected amplifiers, issues of pre amplifier output impedance to power amplifier input impedance springs to mind.
While we are involved with maters of a technical nature does connecting two HiCaps to a NAC-82 compromise the star earthing due to two power supplies connected to two AC outlets.
If the multiple earth path is a dramatic concern when the subject of RCA plugs is raised then the above configuration would definitely create significantly greater amounts of reference earth potential variation than two RCA cable connected side by side onto the same earth strip at each end.
Posted on: 12 January 2003 by Hans 67
I have understand (from reading this forum) that the earth of the powercord of the ***Cap's are connected to the case. And the case and powercord's earth are NOT connected to the signal ground from the ***Cap's. Thus there will be NO groundloop (if I am correct)!
This also makes the 2 independent supplies in the FlatCap 2 possible.
Greetings, Hans
This also makes the 2 independent supplies in the FlatCap 2 possible.
Greetings, Hans
Posted on: 12 January 2003 by NAIM-Collector
Yes Hans that is correct, I checked my NAC-52 and the SuperCap case has the same potential as the mains but the pre-amp is floating WRT the mains earth.
It is interesting to note that the NAC-52 case is the same potential as the signal ground (BNC earth).
Thanks....
It is interesting to note that the NAC-52 case is the same potential as the signal ground (BNC earth).
Thanks....
Posted on: 13 January 2003 by Hans 67
That the case of the NAC's are connected to signal ground seems very logical because: which ground otherwise? There is no other ground connected to the NAC's!
The NAP's are connected the same way as the CAP's: the case is connected to mains ground and the signal ground is floating.
The CD-players have ALL grounds and the case connected together. This is the reference ground! I think, because some say the NAC's case is the reference and others say (write?) the CAP's signal ground.
Interesting:
connecting 2 CD-players to 1 NAC will create a groundloop!
Hmm, I thought of this at the moment I was writing this post.
I do not know how the other components are connected to ground.
Does anybody out there knows it?
Greetings, Hans
The NAP's are connected the same way as the CAP's: the case is connected to mains ground and the signal ground is floating.
The CD-players have ALL grounds and the case connected together. This is the reference ground! I think, because some say the NAC's case is the reference and others say (write?) the CAP's signal ground.
Interesting:
connecting 2 CD-players to 1 NAC will create a groundloop!
Hmm, I thought of this at the moment I was writing this post.
I do not know how the other components are connected to ground.
Does anybody out there knows it?
Greetings, Hans
Posted on: 13 January 2003 by Manu
From a previous answer:
"The signal ground starting point (star grounding) is the preamp power supply. The preamp is the center point of the system for signal.
This ground star has to be tied to mother earth at some point, not necessary the center. Naim choses to do it at the source. That's a logical choice: you have only 1 CDP, but you can have multiple PSUs (this earthing must be unique)."
In the case of 2 hicaps on a 82, signal pass through only the PSU1, this one is the center point.
2 Naim CDP plugged on a NAC create a ground loop. Both player will sound confused, even if no hum is produced.
Never do an A/B demo with 2 Naim players connected to the same preamp.
Emmanuel
All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.
"The signal ground starting point (star grounding) is the preamp power supply. The preamp is the center point of the system for signal.
This ground star has to be tied to mother earth at some point, not necessary the center. Naim choses to do it at the source. That's a logical choice: you have only 1 CDP, but you can have multiple PSUs (this earthing must be unique)."
In the case of 2 hicaps on a 82, signal pass through only the PSU1, this one is the center point.
2 Naim CDP plugged on a NAC create a ground loop. Both player will sound confused, even if no hum is produced.
Never do an A/B demo with 2 Naim players connected to the same preamp.
Emmanuel
All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.
Posted on: 14 January 2003 by Hans 67
How about it? I do not know, but I can think of 3 possibilities:
1: the case is connected to the mains ground (NAP style)
2: the case is connected to the signal ground of the preamp stage (NAC style)
3: the case is connected to the signal ground of the power amp stage?
If the case is connected to the mains ground (1) or to the signal ground of the power amp stage (3) then the case is floating when you use the NAIT 5 as a preamp. And because Naim recommends to use the NAIT 5 as a preamp both situations will not be.
Thus the case is connected to the signal ground of the preamp stage (2)!
Can anybody confirm this or correct me.
So, is this the reason why Naim does NOT recommend using the NAIT 5 as a poweramp (it is not in the manual)?
Greetings, Hans
1: the case is connected to the mains ground (NAP style)
2: the case is connected to the signal ground of the preamp stage (NAC style)
3: the case is connected to the signal ground of the power amp stage?
If the case is connected to the mains ground (1) or to the signal ground of the power amp stage (3) then the case is floating when you use the NAIT 5 as a preamp. And because Naim recommends to use the NAIT 5 as a preamp both situations will not be.
Thus the case is connected to the signal ground of the preamp stage (2)!
Can anybody confirm this or correct me.
So, is this the reason why Naim does NOT recommend using the NAIT 5 as a poweramp (it is not in the manual)?
Greetings, Hans
Posted on: 17 January 2003 by NAIM-Collector
I notice with interest a couple of replies (thanks guys) to question two of my query.
This is the response from the interest from 418 lookers.
Nobody commented on the issue raised WRT the connection of up to three amplifiers to a power supply.
"I notice the NAIM power supplies will allow the connection of three power amplifiers to the audio output.
I can understand allocating the opportunity for one NAP-250 or two NAP-135s but this allows for all the above.
Does this have a detrimental effect on the connected amplifiers, issues of pre amplifier output impedance to power amplifier input impedance springs to mind."
Any comments......
This is the response from the interest from 418 lookers.
Nobody commented on the issue raised WRT the connection of up to three amplifiers to a power supply.
"I notice the NAIM power supplies will allow the connection of three power amplifiers to the audio output.
I can understand allocating the opportunity for one NAP-250 or two NAP-135s but this allows for all the above.
Does this have a detrimental effect on the connected amplifiers, issues of pre amplifier output impedance to power amplifier input impedance springs to mind."
Any comments......
Posted on: 17 January 2003 by drps
The AV1 connects two one of the power amp connections, So you could be running 135's with an AV1 and fill all three. Only have AV1 and 250's myself, with one spare.
Paul
Paul
Posted on: 18 January 2003 by Martin Payne
quote:
Originally posted by NAIM-Collector:
I notice the NAIM power supplies will allow the connection of three power amplifiers to the audio output.
I can understand allocating the opportunity for one NAP-250 or two NAP-135s but this allows for all the above.
Does this have a detrimental effect on the connected amplifiers, issues of pre amplifier output impedance to power amplifier input impedance springs to mind.
Yes.
When driving efficient speakers I have found 2x135s better then 4x135s.
I presume that this is down to input impedances.
With Isobariks, the benefits of the extra power outweighed that problem, though.
quote:
If the multiple earth path is a dramatic concern when the subject of RCA plugs is raised then the above configuration would definitely create significantly greater amounts of reference earth potential variation than two RCA cable connected side by side onto the same earth strip at each end.
You only get an earth loop when the earth path is split, the re-joined.
After the earth is split where it goes to the multiple power amps, it does not re-combine at any point downstream.
This is star earthing - all earth paths radiate out from one point (the PS or NAC) and do not re-join.
cheers, Martin
E-mail:- MartinPayne at Dial.Pipex.com
Posted on: 19 January 2003 by Kenny Ferguson
quote:
Originally posted by Hans 67:
How about it? I do not know, but I can think of 3 possibilities:
1: the case is connected to the mains ground (NAP style)
2: the case is connected to the signal ground of the preamp stage (NAC style)
3: the case is connected to the signal ground of the power amp stage?
If the case is connected to the mains ground (1) or to the signal ground of the power amp stage (3) then the case is floating when you use the NAIT 5 as a preamp. And because Naim recommends to use the NAIT 5 as a preamp both situations will not be.
Thus the case is connected to the signal ground of the preamp stage (2)!
Can anybody confirm this or correct me.
So, is this the reason why Naim does NOT recommend using the NAIT 5 as a poweramp (it is not in the manual)?
Greetings, Hans
Does anybody know the answer to the above question from Hans? I am currently using a borrowed NAC-72 powered by my flatcap2, with my Nait5 acting as the power amplifier.
thanks,
Kenny
Posted on: 19 January 2003 by dave simpson
quote:
Never do an A/B demo with 2 Naim players connected to the same preamp.
Emmanuel,
What's the situation with an all-naim rig using a naim cdp and naim tuner...is there a ground loop with both connected to the rig at the same time?
regards,
dave
Posted on: 19 January 2003 by Manu
Dave, you took me by surprise... I don't know for sure.
In my experience, no problems: CD players sound alike with the tuner in or out.
I have to check inside tuners. Here we don't see Naim tuners often (the radio is crap).
I'm sure Naim has handeled this situation.
Emmanuel
All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.
In my experience, no problems: CD players sound alike with the tuner in or out.
I have to check inside tuners. Here we don't see Naim tuners often (the radio is crap).
I'm sure Naim has handeled this situation.
Emmanuel
All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.
Posted on: 19 January 2003 by Niko
Naim tuner ground is connected to the RF-input shield. At least where I live, that RF-shield is connected to mains ground at some point in the block of apartments. I avoid the creation of an earth loop by connecting the CD player to an unearthed outlet. Don't know if I hear any benefits but I am atleast sure that I have a single earth reference for the system.
Niko
PS. CDX case seems to be connected to the signal ground by a small resistor so it's not floating even though I've disconnected the earth connection via the mains plug.
Niko
PS. CDX case seems to be connected to the signal ground by a small resistor so it's not floating even though I've disconnected the earth connection via the mains plug.
Posted on: 20 January 2003 by dave simpson
Thanks Emmanuel and Niko,
I hear a slight degradation when using my cds with a Nat101 powered up. Disconnecting the NAT's interconnect from the 102 doesn't appear to change the signal quality however unplugging the Nat's AC from the power strip improves the CDS' performance noticeably. I haven't tried powering off the NAT yet leaving it's AC plug in the strip...guess that would narrow it down a bit more (though meaningless in the long run since I'd still be forced to live with a cold NAT all the time).
Hmmm...sounds like I need to try a cheater plug (lifts the AC ground) on the NAT since CDS is primary source...or is it an issue in my situation--my antenna is indoors and ungrounded.
thanks again,
dave
[This message was edited by dave simpson on TUESDAY 21 January 2003 at 01:59.]
I hear a slight degradation when using my cds with a Nat101 powered up. Disconnecting the NAT's interconnect from the 102 doesn't appear to change the signal quality however unplugging the Nat's AC from the power strip improves the CDS' performance noticeably. I haven't tried powering off the NAT yet leaving it's AC plug in the strip...guess that would narrow it down a bit more (though meaningless in the long run since I'd still be forced to live with a cold NAT all the time).
Hmmm...sounds like I need to try a cheater plug (lifts the AC ground) on the NAT since CDS is primary source...or is it an issue in my situation--my antenna is indoors and ungrounded.
thanks again,
dave
[This message was edited by dave simpson on TUESDAY 21 January 2003 at 01:59.]
Posted on: 20 January 2003 by rohit
thanks Dave for asking this again and Niko for an answer, see here.
Isn't disconnecting the ariel when not using the NAT easier ?
JV mentioned that any new format naim player would be a different box (from the naim CDP). if they both tied to earth independently...we'd loop again.
Isn't disconnecting the ariel when not using the NAT easier ?
JV mentioned that any new format naim player would be a different box (from the naim CDP). if they both tied to earth independently...we'd loop again.
Posted on: 20 January 2003 by dave simpson
Isn't disconnecting the ariel when not using the NAT easier ?
Good idea Rohit....a bit safer also. (eliminates the "lightning rod" potential with a dodgy ground)
regards,
dave
p.S. thanks for that link also!
Good idea Rohit....a bit safer also. (eliminates the "lightning rod" potential with a dodgy ground)
regards,
dave
p.S. thanks for that link also!
Posted on: 21 January 2003 by Niko
Tuner ground isn't connected to the mains ground via the power plug (only to RF-shield). Therefore, if you are using an indoor antenna, that's connected only to your NAT, you shouldn't have any earth loop problems via your tuner.
Niko
PS. Information is based on my own system measurements (NAT02), admins hopefully jump in if I am generalising too much..
Niko
PS. Information is based on my own system measurements (NAT02), admins hopefully jump in if I am generalising too much..
Posted on: 21 January 2003 by dave simpson
Therefore, if you are using an indoor antenna, that's connected only to your NAT, you shouldn't have any earth loop problems via your tuner.
Sounds like my problem is simply just an additional power supply degrading the hi-fi's AC line then.
Thanks Niko,
dave
Sounds like my problem is simply just an additional power supply degrading the hi-fi's AC line then.
Thanks Niko,
dave
Posted on: 21 January 2003 by rohit
thank you Niko,
so the RF shield (also NAT signal ground) to earth is installation specific.
with an indoor/RFshield-not-to-earth (external) antenna installation...we seem covered.
if the RF shield were connected to earth remotely, the CDP-NAC interconnect should be disconnected to lose the (local)CDP earth refr, at least for optimal NAT performance.
Naim, please comment if the above is still inaccurate/incomplete.
[This message was edited by rohit on TUESDAY 21 January 2003 at 21:50.]
so the RF shield (also NAT signal ground) to earth is installation specific.
with an indoor/RFshield-not-to-earth (external) antenna installation...we seem covered.
if the RF shield were connected to earth remotely, the CDP-NAC interconnect should be disconnected to lose the (local)CDP earth refr, at least for optimal NAT performance.
Naim, please comment if the above is still inaccurate/incomplete.
[This message was edited by rohit on TUESDAY 21 January 2003 at 21:50.]