Speaker Cables, A Special Note (from ye olde Naim Audio)

[Craig B]

I stumbled upon this some time ago, may have been on the Naim Forum. In addition to the cool BOD sketch (remember those in the Hi-Fi comics?), what I find interesting is that this note, which was included in the box with the amplifiers before NACA4, described two different recipes for twisting up ones own 'speaker cables. We've all heard tell of the 4 sq mm twisted pairs, but I've certainly never heard any mention of 2.5 sq mm ones.

Another interesting bit is that, although Naim mentioned no specific minimum length, they specified maximum lengths for each conductor size, i.e. 12m max for 2.5 sq mm and 20m max for 4 sq mm (the latter the same as for NACA4/A5). On the other hand, there is an oblique suggestion that 6m pairs may be optimal, with them having quoted about 200pF capacitance for a 6m pair (i.e. circa 33.33 pF/m), and circa 4µH inductance for the same 6m length (i.e. circa .67µH/m). Strangely, there is no clarification as to whether this was for one, the other, or both conductor sizes.

Seems to me that the lengths would have to be different to hit those values.

 

[marshanp]

The requirement to use specified cables in order to compensate for shortcomings in an amplifier's design strikes me as a good reason to look elsewhere for one's "audio equipment".

That, and being any less than 100% silent when not playing music...

 

[Bob McC]

Naim trolls just can't help themselves.
Their response is Pavlovian.

 

[Craig B]

Naim trolls just can't help themselves.
Their response is Pavlovian.

I hear you, Bob. I stuck this in 'Classic' thinking it might get less flack; plus it is old, like me.

For whom the bell trolls, is it?

 

[Arkless Electronics]

I find those who won't listen to science, engineering or fact but would repeat the mantra of "I know nowt about engineering BUT it must be fantastic cos it says Naim on it. Stands to reason innit" rather more perverse than so called trolls whose "crime" was to point out real world fact. In audiophilia it happens regularly and not just regarding Naim of course!

 

[Gervais Cote]

Warning : I’m not an electronic engineer..........but :
I was using a pair of 14 gage twisted speaker cables with my Naim NAP 110 and replaced them with a 4m long pair of NACA5 speaker cables and here is what I noticed :

-The harshness of the treble disappeared
-The bass notes became more dynamic by a small amount
-The temperature of the amp went down by 8 Celsius degrees running the amplifier at same output level

Same tests with a Quad 405 didn’t show any difference when switching from a speaker cable to another.
Also tried the Linn K20 speaker cables and the results are exact same as the Naim cables.
I also ran the same test with my Exposure IV mk2 amplifier and again, softer treble with the Naim or Linn cables but the difference wasn’t as huge as with the Naim NAP 110.

It’s very clear to me that when using a vintage Naim or Exposure amplifier, Naim NACA 4, NACA5 or Linn K20 is the way to go. Similar cables with same configuration, wire gage and similar length will probably give the same results.

 

[Jim Audiomisc]

Yes, when using am amp that isn't "unconditionally stable" you may well need to either use specific cables (and length) or simply add some series inductance to avoid instability causing a degrading of behaviour. Whereas an amp that is stable removes this requirement. May also mean the 'sound' is less dependent on your choice of cables.

However it isn't nuclar fisics to make an amplifier that is unconditionally stable. (ahem) Although early designs like those from RCA may not have been. 8-]

The symptoms reported (inc, the change in operating temperature) can be taken as signs that the amp was probably undergoing bursts of RF oscillation whilst playing the music. The choice of cable that stopped this probably took the place of having a small series inductor on the amp output.

 

[Craig B]

Warning : I’m not an electronic engineer..........but :
I was using a pair of 14 gage twisted speaker cables with my Naim NAP 110 and replaced them with a 4m long pair of NACA5 speaker cables and here is what I noticed :

-The harshness of the treble disappeared
-The bass notes became more dynamic by a small amount
-The temperature of the amp went down by 8 Celsius degrees running the amplifier at same output level

Same tests with a Quad 405 didn’t show any difference when switching from a speaker cable to another.
Also tried the Linn K20 speaker cables and the results are exact same as the Naim cables.
I also ran the same test with my Exposure IV mk2 amplifier and again, softer treble with the Naim or Linn cables but the difference wasn’t as huge as with the Naim NAP 110.

It’s very clear to me that when using a vintage Naim or Exposure amplifier, Naim NACA 4, NACA5 or Linn K20 is the way to go. Similar cables with same configuration, wire gage and similar length will probably give the same results.

Interesting, you're 14 gauge conductors translate to 2.5sq mm. Do you happen to recall roughly how long your twisted pairs were? Twists per foot?

My main point in posting the above was that it seemed unlikely that the 2.5 sq mm and 4 sm mm twisted pairs once espoused by Naim would have the same electrical parameters at 6m lengths; not to open a discussion of the relative merits/demerits of Thiele network inclusion/exclusion by way of a 'resistively damped inductor in line with output of about 3-7µH usually' (according to our Jez), or absence of same.

Having worked the typical 'hookup wire' cable specs in Excel, I suspect that the 6m capacitance and inductance values were for 2.5 sq mm. This seems inline with Naim having eventually dropped any mention of 2.5 sq mm and specifying a minimum length of 3.5m of 4 sq mm cable pairs, with 5 to 10m as optimum, and 20m as maximum.

 

[martin clark]

@Craig B

Nice find!
JV himself often said the same on the old, old (old!) Naim forum: post text from a far-away place, a long time ago:

TopShow ThreadPreviousNext

Date: November 27, 1999 06:23 AM
Author: julian vereker
Subject: vaults again

Date: 25-Nov-99 02:49
Author: julian vereker
Subject: culled and edited from the vaults

In the manual, we advise that you should use Naim loudspeaker cable
with our amps. It is part of the amplifier output circuit which
expects a certain inductance and a very low capacitance (see below).

If your Naim amp is destroyed by using unsuitable cables, it is a
clear failure mode and is not normally covered by warranty.

julian

PS pulled from the past:

Date: 26-Aug-98 02:07
Author: julian vereker
Subject: Cables Again

Please can I draw your attention to the following notes:

****Ed's Note: MANY CABLES WILL 'WORK' IN PARTICULAR SYSTEMS, BUT IF
THE SPECS ARE VERY DIFFERENT FROM NACA5, THEN PROBLEMS MAY OCCUR WITH
CERTAIN SPEAKERS****

FOR INFO THE RELEVANT SPECS ARE:

1.3 - 1.5microHenries per metre (Loop)

MAX 20picoFarads per metre

About 25milliOhms per meter (loop)

MIN Length 3 metres

**ED**

and: refering to Litz type high capacitance cables.

*****ED's Note: DO NOT USE THESE TYPES OF CABLES WITH NAIM POWER AMPS
IF YOU WISH TO HAVE NAIM'S WARRANTY - PLEASE SEE YOUR OWNERS
MANUAL*****

----------------------------------------------------------------------
----------

(http://conference.realwebsite.com/Forums/Index.cfm?CFApp=16&Message_ID=42678)​

 

[Craig B]

@Craig B

Nice find!
JV himself often said the same on the old, old (old!) Naim forum: post text from a far-away place, a long time ago:

TopShow ThreadPreviousNext

Date: November 27, 1999 06:23 AM
Author: julian vereker
Subject: vaults again

Date: 25-Nov-99 02:49
Author: julian vereker
Subject: culled and edited from the vaults

In the manual, we advise that you should use Naim loudspeaker cable
with our amps. It is part of the amplifier output circuit which
expects a certain inductance and a very low capacitance (see below).

If your Naim amp is destroyed by using unsuitable cables, it is a
clear failure mode and is not normally covered by warranty.

julian

PS pulled from the past:

Date: 26-Aug-98 02:07
Author: julian vereker
Subject: Cables Again

Please can I draw your attention to the following notes:

****Ed's Note: MANY CABLES WILL 'WORK' IN PARTICULAR SYSTEMS, BUT IF
THE SPECS ARE VERY DIFFERENT FROM NACA5, THEN PROBLEMS MAY OCCUR WITH
CERTAIN SPEAKERS****

FOR INFO THE RELEVANT SPECS ARE:

1.3 - 1.5microHenries per metre (Loop)

MAX 20picoFarads per metre

About 25milliOhms per meter (loop)

MIN Length 3 metres

**ED**

and: refering to Litz type high capacitance cables.

*****ED's Note: DO NOT USE THESE TYPES OF CABLES WITH NAIM POWER AMPS
IF YOU WISH TO HAVE NAIM'S WARRANTY - PLEASE SEE YOUR OWNERS
MANUAL*****

----------------------------------------------------------------------
----------

(http://conference.realwebsite.com/Forums/Index.cfm?CFApp=16&Message_ID=42678)​

Thanks Martin,

I've a saved copy of all of JVs old Naim Forum posts here, myself. I find they still make for interesting reading, despite them typically being 1/2 of a very brief conversation (more often than not, a rebuke ).

Craig

 

[martin clark]

Craig,

Similarly - somewhere, I know, I have a Naim / JV comment that refers to buying a standard RS stranded cable (size given for local equivalent to be sourced by those who couldn't buy from RS, then) - to be twisted into pairs, at a given rate (the same c.3 twists per foot, iirc). Simple but helpful stuff, back then ...from the MD.

ATB.

 

[Gervais Cote]

Interesting, you're 14 gauge conductors translate to 2.5sq mm. Do you happen to recall roughly how long your twisted pairs were? Twists per foot?

My main point in posting the above was that it seemed unlikely that the 2.5 sq mm and 4 sm mm twisted pairs once espoused by Naim would have the same electrical parameters at 6m lengths; not to open a discussion of the relative merits/demerits of Thiele network inclusion/exclusion by way of a 'resistively damped inductor in line with output of about 3-7µH usually' (according to our Jez), or absence of same.

Having worked the typical 'hookup wire' cable specs in Excel, I suspect that the 6m capacitance and inductance values were for 2.5 sq mm. This seems inline with Naim having eventually dropped any mention of 2.5 sq mm and specifying a minimum length of 3.5m of 4 sq mm cable pairs, with 5 to 10m as optimum, and 20m as maximum.

All of my speaker cables are 4 meter long including the twisted ones, Naim and Linn.
As for the number of twists per foot, I don’t know as they are braided and I bought as is.

 

[Craig B]

All of my speaker cables are 4 meter long including the twisted ones, Naim and Linn.
As for the number of twists per foot, I don’t know as they are braided and I bought as is.

When you say that they are braided, is that as in Kimber 4TC style, or something else?

 

[wylton]

...somewhere, I know, I have a Naim / JV comment that refers to buying a standard RS stranded cable...

It's in the original C.B. Naim Owner's manual. I used it myself until Naim brought out the NACA4, then I dutifully upgraded to NACA5, but with the current active system I have, I'm using Atlas Hyper Bi-Wire, because it's neater and more convenient and because it sounds good too.

 

[Arkless Electronics]

As some will be aware I make an add on set of boxes which completely remove the need for any specific cable or length of cable.

 

[Gervais Cote]

When you say that they are braided, is that as in Kimber 4TC style, or something else?

Braided with something like this :
https://www.amazon.ca/-/fr/Manchon-...ocphy=9000574&hvtargid=pla-452814206144&psc=1

 

[djftw]

When you say that they are braided, is that as in Kimber 4TC style, or something else?

With Naim? I hope not, I had a pair of their cables I bought on eBay because they were a lot of copper for the money (I needed 7-8m runs at the time) and with B&W 603s3 they turned a Rotel Power Amp into a space heater and cooked it. Rotel exchanged the amp for free (out of shear embarrassment I think) the speakers were a difficult load, but still... replaced with NACA5 on dealers recommendation (and it was rather better VFM than it is these days) and the amp barely got warm. I have concluded high capacitance cables are a terrible idea with solid state full stop!

 

[Craig B]

It's in the original C.B. Naim Owner's manual. I used it myself until Naim brought out the NACA4, then I dutifully upgraded to NACA5, but with the current active system I have, I'm using Atlas Hyper Bi-Wire, because it's neater and more convenient and because it sounds good too.

Thanks Wylton, that does ring a bell!

RS 357-946 appears to be long gone as stock no, however, two rsdelivers dot com sites (AE and CY) still list it, with the description being WIRE 56/0.3 BLACK and the manufacturer called NEUTRAL. Clicking on the NEUTRAL brand link and selecting the Hookup and Equipment Wire category, lists RS stock no. 521-0549 76/0.26 4 mm² in Black by the 100m roll.

I may ask around the local electrical/appliance repair shops and see if I can source something similar for a lockdown 'something to keep me hands busy' project.

 

[Craig B]

With Naim? I hope not, I had a pair of their cables I bought on eBay because they were a lot of copper for the money (I needed 7-8m runs at the time) and with B&W 603s3 they turned a Rotel Power Amp into a space heater and cooked it. Rotel exchanged the amp for free (out of shear embarrassment I think) the speakers were a difficult load, but still... replaced with NACA5 on dealers recommendation (and it was rather better VFM than it is these days) and the amp barely got warm. I have concluded high capacitance cables are a terrible idea with solid state full stop!

That's why I was asking, as there were/are a lot of Kimber style knock-offs floating around over here, many of which were hand made by dealers in their spare time.

I have an Excel workbook that I put together in order to calculate classic Naim amp speaker cable compatibility. Putting Kimber 4TC specs into the lookup table returns a minimum length recommendation of 15.56m (keeping total inductance in line with that of the recommended minimum of 3.5m of A4/A5). Trouble is, the maximum length calculated is 2.35m (based upon keeping total capacitance in line with that of 20m of A4/A5).

IOWs, any length of Kimber is a black hole into which no Naim amp should travel.

 

[wylton]

It was definitely 56 strand, in Red and Black, in fact it wasn't all that long ago that I threw mine out, it having been in the cupboard for many years. TBH though, Linn's K20 is just as good and is neater too.