Acitvating Katans With AV5125

In this post there's a pictorial explanation of changing Linn's 2-way Katan speaker from passive operation to bi-active using stereo active cards inside a Linn AV5125 power amp.  They're in sequence order.

NOTE:  IF YOU ARE AT ALL UNSURE OR LACK CONFIDENCE, TAKE THE SPEAKERS AND AMP TO A LINN DEALER TO HAVE THIS WORK DONE.

THE SEQUENCE BELOW ARE THE STEPS I TOOK TO SUCCESSFULLY MAKE THIS CONVERSION.  IT WAS SUCCESSFUL FOR ME, BUT NO RESPONSIBILITY IS TAKEN FOR THE ACCURACY, OR OTHERWISE, OF THIS INFORMATION.

In original single wired passive form.  By removing all the collars on the terminals, the configuration cards that are recessed into the back of the speaker cabinet can be lifted out

Collars removed - each side of the configuration card there is a recess in the speaker cabinet, allowing for access to lift the cards out

There are 2 configuration cards.  Each one has a different configuration on each side - in this case 'single wire passive' is on one side of both cards.  Put the unwanted configurations back onto the connection terminals first, then the card you require with the required configuration facing outwards, then refit the terminal collars.

This is the reverse side of the 2 cards shown in the picture above.  Choices here are 'Katan active' and 'Katan bi-wire passive'

The 'Katan bi-wire passive' card has been fitted onto the terminals, then this 'Katan active' card has been laid on top

Collars are fastened back on and tightened.  Any blanking plugs inside the terminals need to be moved to new positions, freeing up the appropriate connections for active use.  Here I've used red = bass +ve; black = bass -ve; yellow = treble +ve, grey = treble -ve

Now to the amp.  Switch off and unplug the amp and disconnect the mains cable! Laying on a firm but covered surface (to protect the finish) top downwards, the amp looks like this.  There are 4 self tapping screws along the silver section which need to be removed.

The cover of the amp can then be slid off - the amp chassis slides out of the back of the cover.  Once removed, place the cover out of the way and somewhere where it won't get damaged.  Place the amp chassis on your work surface, base side down.

BEFORE PROCEEDING FURTHER, YOU MUST TAKE ANTI-STATIC PRECAUTIONS BY EARTHING THE AMP CHASSIS AND WEARING AN EARTHED ANTI-STATIC STRAP.  IF YOU DON'T KNOW WHAT THESE ARE OR HOW TO USE THEM, STOP NOW AND TAKE YOUR KIT TO A DEALER.  STATIC ELECTRICITY CAN DAMAGE THE CIRCUITRY!

This is the amp chassis without any active cards or support fittings.  The stereo active cards are going to be fitted top left in this picture - across the back of the amp

To fit the cards, the plastic circuit board stand-offs and screw are required.  These are usually inside the amplifier.  However, many amps will not have these installed as they have gone missing over the lifetime of the amp.  If your amp is missing these, or the ones for the mono card, please get in touch as I have complete sets available for purchase.
In the full kit there are long, medium and short stand-offs with a protruding thread at one end and a recessed thread at the other.  There is also one very small stand-off with recessed threads at each end.  The tall stand-off and the very small stand-off with recessed threads at both ends are used only for the mono card.  Fitting the stereo cards as described here uses the medium and short stand-offs that have a protruding thread at one end and recessed thread at the other, along with a short screw.  These are the stand-offs shown above

Fit the medium stand-off as shown above, into the threaded hole at the rear left of the amp.  Finger tight is enough - the threads are only plastic, so please take care.  A second picture of the medium stand-off is shown below.

ALSO NOTE THAT I HAVE FITTED THE BASS CARD INTO THE LOWER SLOT AND THE TREBLE CARD INTO THE UPPER SLOT.  ALL THE STEPS DESCRIBE THE SEQUENCE I USED FOR FITTING THE CARDS THIS WAY AROUND.  THEY CAN BE FITTED THE OTHER WAY AROUND, BUT CONNECTIONS WILL BE DIFFERENT, SO TAKE CARE.

A stereo active card.  This is the bass card for a Tukan (or a Katan, or a Sekrit)

For the first card being fitted, fit the short connection cable as shown above

Now slide the card into the lower set of slots in the back of the amp (you can see the green tabs of the card peeping through the amp's back panel).  The slots are the same height in the amp as the top of the medium stand-off fitted earlier

Another view of the first card sitting in situ.  Note that the card sits neatly on top of the medium stand-off fitted earlier

Now connect the connecting cable into the amp board as shown - channels 4 & 5.  In my install this is the bass card, so now Channels 4 and 5 will output bass information

Now fit the short standoff by feeding it through the installed card and then tightening into the thread of the medium stand-off.  Again, finger tight only - take it gently!

Now, repeat the last few steps with the top card, fitting the longer cable and sliding the card into the top slots in the back panel of the amp.  Connect the cable into the port on the amp labelled Channel 2 & 3.  In my install this is the treble card, so now Channels 2 and 3 will output treble information

If the card is fitted with the treble adjustment control, push out the black blanking plug to allow the control to protrude through the back panel.  Here the cards are both installed, the green tabs can be seen through the back panel, as can be the white treble control knob

Now fit the short screw through the top card and into the short stand-off.  Again, tighten enough just to hold the card in place - don't strip the thread or put the card under any pressure

Put the case back on the amp and refit the 4 screws in the bottom of the amp casing

NOW FOR CABLING.  AGAIN NOTE THAT THE SEQUENCE SHOWN BELOW IS CORRECT FOR THE WAY THAT I INSTALLED THE CARDS - BASS ON THE LOWER SLOT, TREBLE ON THE TOP SLOT.  IF YOU HAVE PUT THE CARDS IN THE OTHER WAY AROUND, THIS CABLING SEQUENCE IS NOT APPROPRIATE!

The way I installed the cards means:

Channels 2 and 3 are Treble

Channels 4 and 5 are Bass

If you have the labels that come with the active cards, now is the time to label up each channel on the back panel!

Connect an interconnect from Channel 2 output (in this case, this is Treble right) to Channel 4 input (in this case, Bass right).  If your interconnect claims to be directional, the arrows should point from Channel 2 to Channel 4

Repeat this with an interconnect from Channel 3 output (in this case, this is Treble left) to Channel 5 input (in this case, Bass left).  If your interconnect claims to be directional, the arrows should point from Channel 3 to Channel 5 

Now fit the interconnects from the pre-amplifier.  Here, Channels 2 and 4 serve the right speaker and so the right interconnect is connected to the input on Channel 2.
Channels 3 and 5 serve the left speaker so the left interconnect from the pre-amp is connected to the input on Channel 3.

Now connect up the speaker cables.  Note that they must match the outputs from the amp:  treble to treble, bass to bass.  Following through the colour coding I connected to the Katans, here Channel 2 yellow / grey go to the right Katan treble input, Channel 3 yellow / grey go to the left Katan treble, Channel 4 red / black go to right Katan bass; Channel 5 red / black go to left Katan bass.  Be careful to observe the correct polarity of connection throughout.

And thats the job done.

NOW CHECK ALL YOUR WIRING FROM END TO END, AT LEAST TWICE!   IF YOU ARE NOT SURE, GO TO YOUR DEALER!

Now disconnect your anti-static strap and refit the cover (by reversing the removal procedure).

Before you switch on your system, ensure the volume control is set to zero.  Now, play a track very very very quietly.  Check each speaker - make sure treble sounds are coming out of the tweeter and bass sounds are coming out of the bass driver on both speakers.  If not, immediately switch off and re-check all the connection paths.

Once you're sure that you're hearing the right sounds from the right drivers, turn up a little and re-check.  If its still all OK, enjoy your music!