Reaching out for help/advice on Linn Aktiv

[Tempur]

Dear Linn enthusiasts,

I am the owner of a modest Linn set-up consisting of a Majik-I and LK140 amplifier duo hooked up to a couple of Tukan speakers.   I have upgraded the Tukans with Ninka tweeters and of course they're active.   A few months ago, however, while playing music (loud) during a week-long heatwave, the LK140 just gave up.

At first, I wasn't too concerned thinking the fuse would have blown but, after replacing it and switching the LK140 on again, smoke came out and I ended up taking it to my Linn dealer who told me the end transitors where done for and quoted me $ 1000 to get it fixed.

Luckily, my brother still had a good LK140 from his previous set-up that I could adopt but it had a Keilidh bass card.  I replaced it with the Tukan card from my LK140 which made no difference whatsoever which made me think the Aktiv card had fallen victim to the heatwave as well.

The obvious next step was to have the Aktiv card replaced, which was carried out by the same Linn dealer with CHACT51 mono cards (the original stereo card is no longer available).

To everyone's surprise, however, the new cards didn't solve the issue; I have sound coming out of all speakers but it's flat and the low and mid bass range is notably absent.

I am at a loss now where to look for the problem.  Each component seems to be working fine individually (I checked the speakers whereas the Majik-I works fine with headphones) but not together.

Does anyone have an idea where to look next?

Any suggestions are much appreciated.

Tempur       

 

[petecallaghan]

I posted this on your other thread, reposting here in case the other thread is deleted:

Can you rewire the speakers as passive and drive them from either the Majik or the LK140?

The speaker drives might be damaged.

 

[Tempur]

I suspect one of the speakers might be at fault: I disconnected the tweeters from the Majik to test only the bass/mid range drivers (powered by the LK140).  At first, output stayed flat but when I increased volume, the units almost "popped" and now almost sound normal again.  There is, however, a difference between left and right units so either one or both bass drivers must have been damaged when the amplifier blew.

This is what Linn has to say about it (see the attached document): "When playing the music too loud (parties etc) or when driving a low powered amplifier into clipping the current across the voice coil can become excessive and cause the speaker voice coil to overheat."

I'm sure this is what happened

View attachment loudspeakers.pdf

 

[MickC]

I suspect one of the speakers might be at fault: I disconnected the tweeters from the Majik to test only the bass/mid range drivers (powered by the LK140).  At first, output stayed flat but when I increased volume, the units almost "popped" and now almost sound normal again.  There is, however, a difference between left and right units so either one or both bass drivers must have been damaged when the amplifier blew.

This is what Linn has to say about it (see the attached document): "When playing the music too loud (parties etc) or when driving a low powered amplifier into clipping the current across the voice coil can become excessive and cause the speaker voice coil to overheat."

I'm sure this is what happened

You might be able to tell by gently pushing the cone of the suspect drive. If you hear a faint scrape the voice coil is distorted.

Mick

 

[Simon at Grammo]

Hi @Tempur from your images my gut feel would be that you could save yourself some time fault finding the rest of your system. The power amplifier board shows a fairly significant amount of scorching and component damage. The damage could of course have been caused by many things within your system.  but, due to the damage within the power amplifier you may cause more harm to other components by looking for the root cause.

My opinion would be, however painful, revert to your retailer for direction.

Please don't think I mean that you are not able to find the cause yourself. It's more a point of safety and to minimise any further damage/expense that could be caused by component failure within your power amplifier. 

 

[akamatsu]

How is the system wired up? I assume LK140 on bass, Majik-I on treble. In Aktiv mode, if the Majik-I is driving the tweeters, make sure the pre and power sections of the Majik-I are not jumpered together. I fried both of my Tukan tweeters this way.

 

[akamatsu]

Those two jumpers should be removed in Aktiv mode. Sorry to whomever I stole this photo from.

 

[Tempur]

Thanks for all your helpful comments.  Turns out, one of the bass/mid-range speakers was fried.  I had them both replaced (quite a bargain!) and am enjoying my music again.  With the new speakers and bass cards, the sound balance is even better than before.  Remaining issue is LK140 overheating at high volume but was solved with 2" spacers under the LK140 and between the two amplifiers (they're stacked).