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Naim NAP 200 overheating / Kudos KS1 speaker cable

M

Molyvos

Member
My system is NAP200, NAC202, LP12, Linn Tukans, and having just moved house I needed some longer speaker cables that were less bulky and easier to manoeuvre than NACA4/5.

Reading various posts online I settled on what I thought would be ideal: 9m lengths of Kudos KS1, with Naim connectors on amp end and banana plugs speaker end, with jumpers.

However, within about an hour of listening to music from TV (connected to AV in DIN on 202 from TV headphone socket) the 200 cut out and was extremely hot to the touch. Turned everything off and tried again next day with a portable music player (A&K Kann) attached to 202 Aux 1 via Din and same thing happened again.

My LP 12 is currently with a local guy for service so not tried that yet.

Has anyone experienced the same issue with this cable, or is it more likely that the amp has developed a fault? Prior to unpacking after the move it had been boxed and put in the loft for around 18mths, although had caused no problems over many years use before that.

Thanks.
 
KS1 is fine with Naim amps, especially at 9 metres, as long as they are properly terminated.
What is the service history of the amp, and how old is it? Sounds like it may need some attention.
 
hifi-dog said:
not inadvertently got a short? many people on naim forum using ks1 with no issues reported.
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A short would kill the amp in no time.

Whatsisnaim said:
KS1 is fine with Naim amps, especially at 9 metres, as long as they are properly terminated.
What is the service history of the amp, and how old is it? Sounds like it may need some attention.
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NAP200s don't go wild like the older 250s do if they're not serviced. I don't think it is this.

Molyvos said:
having just moved house I needed some longer speaker cables that were less bulky and easier to manoeuvre than NACA4/5.
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Hmmm, where did you move to? Seriously. Where is your nearest FM transmitter?
 
Thanks for all the replies.

The NAP 200 is a 2006 model, which I bought second hand from a hifi store in Chester. It has not been serviced since then, but has never given me a problem until now.

No idea about FM receiver I'm afraid. Only other info is that before setting up my equipment here I had an electrician install a dedicated circuit (3 double sockets) for my hifi units.
 
Just curious. I once saw a wildly unstable Naim amp on a hill that was line of sight to Wrotham about 26 km away. I fixed that with some inductors on the amp output. I suspect this would fix your issue too, but that doesn't address the cause.
 
I had this exact issue with a NAP200 and it turned out to be a problem with the speakers. Rob Ritchie got schematics from Kef and traced the fault/fixed it - I’m hazy as it was long ago but maybe a blown/faulty inductance coil?

As part of troubleshooting I’d swapped cables a couple times without any change, when I swapped in a MF 3.2 from the AV system it actually blew the amp, fortunately it was a cheapish fix, the NAP just shut down until it decided it was cool enough.
 
Kudos KS-1 is rather thin at 15AWG, it was originally designed for internal loudspeaker wiring and later on marketed as a standard speaker cable. While I cannot say that is the culprit of the overheating problem, I suspect it is a contributor. I wouldn't strangle the amplifier with thin speaker wire at those lengths, there is likely a price to pay, specially in bass performance. Bass heavy naim amplifiers like the 250 and the SN3 will benefit sonically from the KS-1, but I wouldn't go past 5 meters, preferably less.
 
Should have tried this sooner, but switched cables back to the original NACA4 and amp remained cool to the touch. Tried Kudos again and amp soon got hot, so must be cables. As a couple of you have said, the cause could be the longer length. I'll have to hope the dealer will at least allow an exchange (will play safe and go with NACA5), if not a refund.
 
Glad you found the problem.

Nuts that even modern Naim amps do this. Is it unique to Naim, or are their other brands?
 

Molyvos said:
Should have tried this sooner, but switched cables back to the original NACA4 and amp remained cool to the touch. Tried Kudos again and amp soon got hot, so must be cables. As a couple of you have said, the cause could be the longer length. I'll have to hope the dealer will at least allow an exchange (will play safe and go with NACA5), if not a refund.
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NACA5 is a safe bet, but note that it’s short lengths of speaker cable that Naim power amps don’t like, not long lengths, in order to meet their inductance and capacitance requirements.
Naim recommend a minimum length for NACA5 of 3.5 meters, with 5 to 10 metres optimum. The optimum length for virtually all other cables will be longer, not shorter.

In view of this, I can’t help thinking that there is something else amiss if you are having problems with long lengths of an alternative cable as popular with Naim users as KS1.
 
I take your point Whatisnaim. The only other difference is that the Naim cables have four plugs at the speaker end, while the Kudos use jumpers made from the same KS1 cable. I know the Kudos are directional, but the jumpers are only 7 inches long and have no markers so I can't tell if they follow the same direction as the main cables. If they didn't, could that cause the amp to overheat?
 
I can’t imagine that directionality of the cable is a factor here, especially one with a simple construction like KS1.

If the cables are a factor you might investigate @MJS idea about it picking up interference. Perhaps routing the cables differently could be worth a try, if necessary perhaps moving the speakers of necessary, if only temporarily. I’m sure MJS would have more experience of thos stuff than me.
 
A4 and A5 are part of the amp inductance calculation so other products are never recommended unless they match the spec of the NAC. Here it doesn’t and we see the consequence.

Also worth noting that, lack of problems aside, the 200 is well overdue a service. You’ll find the difference on return astonishing.
 
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