More cheap tips from the tweaky one - apologies for the long thread title
There are probably a number of users out there who don't use a Naim CDP or have a turntable, like some LP12 configurations, that make a connection between signal 0V and mains earth.
This post arose from lending my brother a 42.5 and an AndySNAPS that I've recently serviced.
Despite sounding marvellous in my system (giving my 112 a good run for it's money) upon installation in my brother's system it didn't sound right. In particular the bass end was much less taught and musical than it should have been. It was easily trounced by the Nait, which caused me some consternation!
My brother uses a Nait3 as a preamp to a NAP160, and we leave it plugged into the mains (but switched off) in order to make a connection between mains earth and signal earth (which is done inside the Nait, by design).
With a Naim CDP (like the CD5 I used for testing) this earth connection is made when the player is plugged into the 42. For those with an LP12 of certain configurations this will also be made via the TT.
Wondering if this was the problem we lashed a connection between a spare 13A mains plug earth and the turntable binding post on the 42.5.
The difference is quite difficult to believe, the 42.5 now sounding as good as I'd expected and particularly the bottom end became dramatically tighter and rythmic than without the connection. Noise floor seems to drop too.
So all of you without this connection go and make it NOW, it could be your cheapest upgrade ever!
The safest way is to get a 13A mains plug where the Live and Neutral can be removed, then connect a suitable length of wire to the earth pin. Plug in and connect to the preamp earth binding post, sit back, and enjoy.
Andy.
Posted on: 25 March 2002 by MarkEJ
...especially for someone like me who understands only the bearest (dangerous!) minimum about all this "0v" stuff.
Andy, can you spell out in simple terms the implications of this when applied to a system with the reverse emphasis; i.e. a Naim CDP and turntable with StageLine (for example), connected to a conventional RCA phono-equipped AC-fed preamp with 2 x XLRs to poweramps. This seems quite a common scenario.
I keep trying to work this out in my head, and I keep getting lost...
Best;
Mark
(an imperfect
forum environment is
better than none)
Posted on: 25 March 2002 by Andrew L. Weekes
quote:
Good to hear you've got them back in service. Is it just the snaps you've modded or have you tinkered with the 42.5 as well?
Snaps is rewired / modded, the 42.5 is pretty much standard, just recapped, new 'twistlok-style' DIN's, BNC changed to phono's and reconfigured for line level, switches cleaned (dismantled and managed to keep all the bits!), dry joints on volume pot resoldered and a few minor component changes (different caps).
Oh, and red LED changed for green.
Not much really.... 
Will remove balance pot soon, after my brother has given it a good run-in.
Sounds great, it's only downfall is lack of inputs and no remote - I'm working on the former, the latter is too much like hard work
Andy.
Posted on: 25 March 2002 by Andrew L. Weekes
Mark,
I'm not sure how mileage varies in non-Naim systems, experimentation is maybe called for.
All I know is in a Naim system, abscence of the mains earth connection at one point in the system = musical downgrade. It was true for my 42XO / 2x110 active system too - I made the connection in the PSU for that system (tuner source only).
It's easy to check individual items for continuity between mains earth and signal 0V, you only want one connection ideally, not sure what effect multiple ones will have, although I'd suggest it's best avoided.
It may be less relevant in other systems, e.g. Exposure make the connection in the power amp, so it's always there - my colleagues CD3 sounds just as good whether the connection is present in the CDP or not, but then his Creek tuner makes the connection too.
It gets really complicated...
Andy.
Posted on: 26 March 2002 by Lo Fi Si
I have also fitted an earth connection to my P3-uGroove-92R/180 system with the same results that Andy observed. The uGroove has an earth binding post fitted so it seemed like an obvious point to use.
Is this the best point to earth in a Naim system? I assume that having the earthing point at the start of the chain is the "best" place for it, giving the lowest earth impedence for the most noise sensitive components. Is this the reason that an all Naim system earths in the CDP?
Simon
Posted on: 26 March 2002 by Jez Quigley
Andrew, I can't bloody wait to get home to try this!! This is 'Best Thread 2002' for me.
Posted on: 26 March 2002 by Martinm
Andrew,
Is there any chance you can explain in complete muppet language for me?
Wondering if this would work between my planet and 72
Yours "two short planks" Martin
Posted on: 26 March 2002 by Lo Fi Si
Assuming your Planet does not connect the signal earth to the mains earth and you have nothing else in your system (tuner, VCR) then it would probably work in your system. I am not familiar with the Planet, but a lot of non Naim CDPs do not connect signal and mains earths.
As has been stated above do not fiddle about with the mains if you are not sure.
Simon
Posted on: 26 March 2002 by johno
Andy,
I have 3 turntables at present and a Meridian CD.
Linn LP12 Valhalla/Basic plus/K5
Rega Planar 9/RB900/Exact
Pink Triangle Export GTi/SMEIV/Dynavecta
Meridian 506
Amps / system..
Late 32.5 (post 85) with 72 boards
Hicap
NAP 250
(Spare Hicap, NACA5 and NAXO2-4 awaiting a NAP250 at the right price)
Mint Beech SBL's (4-5 years old)
I don't plan on keeping 3 turntables it just happened and I am having fun listening to them all at present... the PT is currently winning out.
If the Rega 9 is plugged in as well as the PT does this cover this earthing problem discussed?
Don't want the P9 to have an unfair advantage..
John
john
Posted on: 26 March 2002 by Bruce Woodhouse
My otherwise all-naim system used to be fronted by a Meridian 506 CDP, and no TT. This did not seem to need or benefit from the fix I subsequently had to make when the Audiolab arrived. I think this answers your question.
Bruce
P.S. Go active with those SBLS!
Posted on: 28 March 2002 by Phil Sparks
A sort of similar query - my main system is LP12/Armageddon and Rega Planet and 82 so I presume the LP12 does the earthing. However I also run a cable from one of the 82 tape outs to the aux in of a Nait in my bedroom, and then from that nait's tape out to another Nait in my study. This way I get NAT-01 level Radio 4 all around the house.
Andy - you said that Naits connect the system 0v to mains earth - so potentially I have 3 earth connections. I don't recall the sound going south when I plugged in the 1st nait. However I guess I should unplug the cable from the back of the 82 to check.
I would be cautious about disonnecting the earth in the mains plug of each nait. Do you know if there's an internal link within Naits that can be snipped?
Phil
Posted on: 28 March 2002 by Eddie Pugh
Earth loops
Should I be worried. I have a CDX/XPS front end into an 82 2XHi and 250 with an old Technics SL10 turntable(2pin mains plug) and a TagMclaren AV32R
processor which feeds into the VCR input on the 82 for the main front chanels and connects via a special dual phono to DIN directly to a 140 which biamps a KEF 100 centre. I haven't bothered with the rear channels
It all sounds fantastic on CD's and movies via an Arcan DV 88 DVD player
Is there any chance that I have an earth deficiency with this set up?
Eddie
