Hi there
People may have seen news of recent devastating flooding along Australia’s east coast.
I am helping family and friends try to get some music happening to cheer them up and one home has multiple speakers running from the autoformer shown in the photo.
Electronics were flooded and destroyed. I have loaners but the only amp that will easily fit is a Naim Nait or NAC90 which as standard for Naim need long Naim cables because they have no output inductor.
My question is will the autoformer provide this missing inductance?
Thanks, sp
People may have seen news of recent devastating flooding along Australia’s east coast.
I am helping family and friends try to get some music happening to cheer them up and one home has multiple speakers running from the autoformer shown in the photo.
Electronics were flooded and destroyed. I have loaners but the only amp that will easily fit is a Naim Nait or NAC90 which as standard for Naim need long Naim cables because they have no output inductor.
My question is will the autoformer provide this missing inductance?
Thanks, sp
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The inductance required is tiny and so I wouldn't use what you show there.
You could just use a 0.47 ohm resistor in series with the positive speaker lead which should provide enough isolation from a possible capacitive loading. Place the resistor at the amp terminal end of the wire.
(It never ceases to amaze me why so called high end gear has such basic design flaws 🙂)
You could just use a 0.47 ohm resistor in series with the positive speaker lead which should provide enough isolation from a possible capacitive loading. Place the resistor at the amp terminal end of the wire.
(It never ceases to amaze me why so called high end gear has such basic design flaws 🙂)
Hi Mooly, thanks for replying but I have to use the autoformer because there are speakers in several rooms.
sp
sp
Hmmm, I wouldn't like to say with certainty. I suspect it would be OK but no guarantees. You could still add the series resistor in the feed to the transformer.
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A smart Naimaholic would be aware that Naim (NACA4) cables were actually a standard, economy type of PVC sleeved, heavy gauge twinflex - the kind you could buy as one of several varieties of commercial speaker or DC power leads etc, for a much cheaper price if you checked the supplier catalogs.
Check the specs: https://community.naimaudio.com/t/naca4-versus-naca5-speaker-cable/3972
These don't include conductor centre spacing but a careful measurement of original leads with verniers should help because attempting to match capacitance and inductance values will prove too difficult and time consuming.
You may not find this exact spec today but facts boil down to it being multistrand flex. copper wire with a certain CSA of copper and centre spacing and I've occasionally found cheap Asian product in electronic parts stores that fits the bill admirably. It's usually clear rather than black but as expected, it doesn't make any discernible difference.
Check the specs: https://community.naimaudio.com/t/naca4-versus-naca5-speaker-cable/3972
These don't include conductor centre spacing but a careful measurement of original leads with verniers should help because attempting to match capacitance and inductance values will prove too difficult and time consuming.
You may not find this exact spec today but facts boil down to it being multistrand flex. copper wire with a certain CSA of copper and centre spacing and I've occasionally found cheap Asian product in electronic parts stores that fits the bill admirably. It's usually clear rather than black but as expected, it doesn't make any discernible difference.
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Thanks all, I have naim cable but it’s mounted in the walls of my house, I was just trying to help someone with the best spare amp I have.
I will move to plan b which is a behringer pa type amp which should work fine.
sp
I will move to plan b which is a behringer pa type amp which should work fine.
sp
Good day
Information from old Naim forum about cables
……
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
…..
Some popular Rotel amps also lack inductors and curiously some have inductors fitted for certain geographical markets only which seems bizarre to me.
I haven't used output inductors for at least 40 years, no problem.
If you can keep it stable into any likely load without an inductor, that's fine, but leaving out an inductor to force customers to use a special inductive cable is weird.
Local EMC standards forcing better immunization than elsewhere? Inductors fitted in response to customer complaints in the neighbourhood of Tokio Tower?
Why not ?
If you have excellent speaker cable for normal cost (not audiophiles costs) and you not need change cable anymore because you get excellent cable from amps supplier for yours amps you not need any inductors inside amps 🙂)
Well quite possibly something like that 🙂 Unfortunately the manual doesn't list the geographical areas)
Thats still a 'low' feedback design. Nothing wrong with that approach if that’s your philosophy, but you have to accept that there’s no magic here. Either there is sufficient phase margin at HF with a capacitive load or there isn’t and the loop gain has to be tailored to suit. The other option is a low value resistor in series with the output - IIRC some of the earlier Naim amps did this. Looks like that’s also the case in Mooly’s post #18 if I’m reading it correctly with R647 and 648 - but strange that the Al’s are not damped with a parallel R and that the Zobel is after the L.
All amp (feedback and non- feedback, with or without output L) outputs ring when driving a capacitive load.
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