Aktiv Cards for Ninka


I have a 2250 power amp and the AV 5103 System Controller, together with bi-wired Ninka Sprs -heavy granite stands. What are the requirements for Activ cards and how would these improve the sound? Speaker cable (8ft.pair) is LK400. Musical taste - primarily classical and occasional jazz. Speakers are positioned either side of a 34" TV, about 12" from the rear wall and approx 36" on the sides. Can the position be changed to advantage ? Thanks anyone.
almaro
The first thing you need is another amp. The 2250 is a two channel amp. You need four channels of amplification for active biamplification of Ninkas (or six channels for active triamplification).

The second thing you will need are stereo Aktiv cards.

There are a variety of ways you can go Aktiv withn Ninkas. Here is the simplest with your set-up.

Buy another two channel Linn amp. Another 2250 would be good since you already have one. However, you could use an LK 85, or an LK 140 as well. Linn amps all have the same gain.

Then put a stereo bass Aktiv card in one amp and a stereo treble Aktiv card in the other amp.

Connect everything together and you're all set. Make sure that the speaker cable is connected to the correct speaker inputs on the Ninkas. Your owner's manual will show you how to connect on the back of the Ninka.

Instead of buying another 2250, you could sell it and buy an AV5125. Then put the stereo treble and bass Aktiv cards in the AV 5125, using four of the five channels of the AV5125 for your Aktiv set-up.

Or, you could keep the 2250, add an AV5125 and three Aktiv cards (one stereo treble card and two stereo bass cards). One goes in the 2250 and the other two go in the AV5125. Now you have a triamplified Aktiv system. Connect to the Ninka as diagrammed in its owner's manual.

There are other possiblities using non-Linn amps but this would involve purchasing a Linn tune-box to hold the Aktiv crossover cards. And then you would have to be careful to make sure that the gain of the other amps matches your 2250.

The simplest thing for you to do is to add another 2250 amp, put a stereo bass Aktiv card in one and a stereo treble Aktiv card in the other.

One other important point to note.

You can certainly go Aktiv using the new Chakra amps; however, the Aktiv cards for the new Chakra amps are not the same size as the Aktiv cards for the discontinued Linn amps. They're not interchangeable. So if you start to mix and match old and new Linn amps, you will have to get the right card for the amp you're going to put it in. When you go to purchase Aktiv cards, it is very important that you specify which amp the cards are for so that you buy the right ones.

As far as sound goes, it is not a small upgrade to go Aktiv. It is a huge upgrade. It will be particularly noticeable in dynamics. Since you mentioned that you listen to a classical music, it would be quite beneficial to go Aktiv since classical music is much more dynamic than other music.
Markphd,

Thanks so very much for your detailed and extremely helpful response. You have given me a great deal to think about and consider and I am most appreciative. I don't think I can move on any of this yet, but it's good to have a such a clear reference handy when I'm ready to make the move.. Thanks again so much.
Markphd,
A quick followup to your 7.03.06 response if I may. You have suggested that I could use an LK85 as a second amp as a possible alternative to another 2250 or AV 5125. I have an LK280 and Spark and I am wondering if this could serve the purpose equally well or, if such a combination would adversely effect the sound in any way.Your opinion on this would be very much appreciated. Thanks.
Almaro:

There is no reason why you cannot use the 2250 and the LK 280 together, at least if you use the unbalanced connections on the back of the 2250. Because Linn encourage upgrading through multi-amplification, they make it easier by matching the gain on their amps so that they can be mixed and matched. However, things do change over time, and products change as you go up the chain. So sometimes you have to watch closely.

For example, the LK 280 has a voltage gain of 28.5 dB. If you use the unbalanced connections on the 2250, they have a gain of 28.3 dB. This is not a problem.

However, the balanced connections on the back of the 2250 have a gain of 22.3 dB. This is sufficiently different from the LK 280 that it may be a problem, i.e the drivers connected to the 2250 may sound less loud than the drivers connected to the LK 280, for a given volume setting. It may or may not be a problem. I would suggest sending an e-mail to Linn through their website on this point. They're pretty good in answering questions about their products, although it may take a few days for a response.

So, I see no problem using the unbalanced connections, but the balanced connections might be. See what Linn has to say.

The reason I suggested the LK 85, LK140, 2250, AV 5125, or even the Majik, is that they all have internal Aktiv card slots that will fit the old style Aktiv cards, i.e. the pre-Chakra cards. I do not think that any of the other Linn amps, such as the LK 280 have an internal Aktiv card slot. This means that if you wanted to go Aktiv, you would have to purchase a Tunebox to hold the Aktiv cards, which is an additional expense, on top of the additional cabling required.

Thus, you can passively biamp using the LK 280 and 2250 right now. However, Aktiv biamping would require a Tunebox as well as the Aktiv cards.

By the way, Linn recommend that when you biamp, the better amp should run the tweeters. In your case, use the 2250 for the tweeters and the LK 280 for the mid/bass drivers, although you can certainly switch them around and experiment.

When I went to passive biamplification, I noticed some improvements. First of all, the amps ran a bit cooler since each amp was only powering one set of drivers. I also noticed a slight increase in background detail and better dynamics. However, I did not find the change to be huge and I wondered whether it was worth the extra amplifer cost. On the other hand, when I went to Aktiv, the difference was huge. So you should not judge what you will get in Aktiv biamplification based upon what you get with passive biampflication. I think that passive should just be an intermediary step (probably for budgetary reasons) on the road to Aktiv, rather than a final destination in its own right.
Markphd:

Once again I am in your debt for a very informative and helpful response - thank you so much. When I take into consideration the various options you have suggested, including now the mixing of the 2250 and LK 280, I find I am leaning more toward the simplest solution as originally proposed i.e an additional 2250 or .......

As you have indicated, I could use the 280, (provided I pay careful attention to the different voltage gains of each amp), but from your other observations, I tend to see it a compromise, albeit a respectable one and I suspect I would have to eventually move on to somethng more in line with the more simple suggestion above. With this in mind, I think it might better serve my purpose to sell my 280/Spark - I also have the LK1 preamp - to offset the expense of another 2250 - or also sell my 2250 and buy the AV 5125, Activ cards et.al.......(Now if only I had a paper clip I could trade for a new house...!!!!). You have been so very helpful (and patient) and if it's not too presumptive, I would be most apprecitive of any comments or additional thoughts you might have. Thanks again so very much.