The Linn Ninka loudspeakers are modern looking, great performers,
and really good value for money. I was never sure
why Linn stopped making them - they can still be obtained
at bargain prices on the secondhand market.
Now, I love my Ninkas as part of my Linn system, but they have one shortcoming which manifests itself in my listening room, which has polished wooden floors and a lot of reflecting surfaces. When played at moderate or high volumes, I find the tweeters on the Ninkas seem to take off and sound somewhat strident for my ears.
Because it is not currently fashionable to make preamplifiers with any form of tone controls, the only solution to this problem is by modifying the room, speaker positioning, and the usual games of choosing mellow sounding speaker and mains cables.
After some thought I decided to overcome this slight high frequency dominance by a simple modification to slightly reduce the signal reaching the tweeters. Any modification to equipment of any value must be fully reversible, with no damage to the original product. I understand that Linn themselves used to recommend a modification to the crossover boards, to be carried out only by dealers, which had much the same effect.
However, this modification can be removed in seconds, and does not require dismantling the speakers in any way. This is the circuit diagram of the two parts of the crossover circuitry:
There is no need to remove the plates fitted to the back
of the NInkas that facilitate different modes of wiring.
Keep it as it comes from the factory, configured for Single
Wire Passive. In this mode, terminals 2 and 9 are
In the Single Wire Passive mode we use sockets 9 and 7 to bring the signal from the amplifier to speakers. Also with the configuration plates set in this way, sockets 1 and 7 are joined. This brings in the "positive" signal wire to both tweeters and bass speakers. Also, sockets 2, 9 and 8 are joined. This is to allow the "negative" signal to reach both large speakers and the tweeters.
What we want to do to effect the modification is to place a small series resistance in the tweeter (treble) circuitry. You will notice that in the original crossover design, (from the circuit diagram) there is a resistance in series with a capacitor which then feeds an inductance in parallel with the tweeter. I have not taken my crossovers apart, and do not know the values of these components. I would guess that the series resistance is in the order of about three ohms. (Can anyone improve on this?)
easiest way to create an opportunity to insert a
resistance in the treble crossover circuitry, is as
Slacken off the round collar on socket 2. This is the top socket (above the negative sign, below the word "wire").
The collar, which acts as a nut to conduct signal from the configuration plate to the actual socket, could be removed; but no need. It might get lost! Once slackened off this collar can no longer fulfil its task of making a contact between the configuration plate and the socket on which it spins. As thinks stand now, the treble (tweeter) circuitry is disconnected!
To make good the treble crossover circuitry again it is necessary to inject some signal. This of course can be done by plugging in a link from the bottom socket marked LINK to the top. It can be seen from the picture of the plate that all three sockets are joined together by an insulated copper strip.
It is necessary to make up a resistive link cable to bridge the two "LINK" sockets to complete these modifications. The value of this depends totally upon your ears and desires.
It is possible to achieve this by buying resistances of these values. Buy some 10 watt resistances and experiment. Finally I used 1.0 Ω but any value from about 0.5 Ω makes quite a difference. I used sleeving that came to hand.
Remember to switch your hifi amplifier off before making any adjustments to the circuitry. Also I hold no responsibility any consequential damage if you attempt these modifications. Be sure to get the circuitry correct - a short circuit could damage your amplifier. When trying any new configuration, always start from a very low volume when switching on again.
The effect of changing a component in a crossover network will have an effect of all aspects of the speaker performance - not least it will slightly change the impedence of the speaker as a whole which the amplifier is having to "see". The speakers may require slight re-positioning. To my ears, my Ninkas still retain their crisp bass, and transparency, but they have lost a little bit of their tendency to shout when strong treble signals are present.
If you have any comments or questions about this modification, do please get in touch.
Don Lodge 2014.