I posted the following on the vinyl forum on audioasylum on March 31. You do have to remove the board to do the change. The procedure to make the change is easy if you are used to working with static sensitive components and very dangerous if you are not. Linn strongly suggested having a authorized shop do the work, and I would concur. Although the actual procedure is straightforward, the possibility of damaging the unit are also high. It works with very low level signals, so minor grounding issues can damage the unit.
Although my local dealer told me it was possible to add the wire back once it was cut, the procedure sounds like it might be somewhat difficult, given the ferrite beads. So, I am not sure I would treat this as a reversible process.
FYI - I have not real experience doing this change.
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Linn support send me the following. They strongly suggested not doing this procedure yourself, unless you are used to working with components that are static sensitive. They recommended having your local Linn dealer do the work.
Symptom
The Linto power LED turns from green to red during loud passages of music. This may coincide with some distortion or a reduction in sound quality.
What causes this?
This is a design feature the red LED is warning you that the input signal is too high for the amplifier circuitry to handle comfortably and the signal is being clipped or is close to being clipped. This happens when a high output Moving Coil cartridge is used with the Linto, and usually only on louder passages of music.
About the Linto Gain Reduction Modification
If the above symptoms happen fairly often, the Linto should be modified to reduce its gain. It is recommended that Lintos not showing these symptoms should not be modified. The Linto effectively has two gain settings:
High Gain Setting when the Linto is dispatched from the factory, it is set to the high gain setting. This is because it provides the best all round performance for the vast majority of Moving Coil cartridges.
Low Gain Setting the simple modification detailed below converts the Linto from high to low gain. The gain is reduced by 10dB when this procedure is carried out. This will greatly reduce the chance of overload when a loud passage of music is played using a high output cartridge.
Some technical information contrasting the two gain settings:
High Gain Low Gain
(factory setting)(after modification)
Audio input level 150uV nominal 500uV nominal
Gain 64dB at 1KHz 54dB at 1KHz
Maximum input 6.7mV at 1KHz 19mV at 1KHz
Equipment required
No1 Posidriv (Supadriv) Screwdriver
Fine snips or side-cutters
Parts required
None
Estimated time for the completion of this task: 30 minutes
Caution - Static sensitive components inside - you must wear an anti-static wriststrap, connected to Earth throughout this procedure to avoid damaging the Linto.
Modification Procedure
1. Disconnect the Linto from everything and especially the mains.
2. Remove sleeve from Linto and carefully set aside.
3. Unplug the two connectors going to the main board (power supply and LED connections)
4. Remove the four screws holding the main board into the tray (two inside and two holding the connectors
to the back panel)
5. Carefully lift the board out of the tray DO NOT USE FORCE. If the board is not easily removed, you will probably find that you have forgotten to remove a screw or that it is caught up on something.
6. On the underside of the board you will see two U shaped wire links protruding from the board. Each link has a pair of ferrite beads attached to it (links without ferrite beads would be susceptible to RF interference). The links are not difficult to spot, as they (along with a couple of capacitors on some boards) are the only features on the underside of the board.
7. Snip both links at the mid-point of each link, between the ferrite beads. Move the two sides of each link far enough apart to avoid the possibility of them ever touching.
Important If a ferrite bead breaks off, falls off or is loosened during this procedure then snip off and remove the protruding piece of wire completely.
8. Re-assemble the Linto fit all four screws loosely, adjust position until correct, tighten the back panel
screws first, ensuring the sockets are correctly positioned and then tighten the two board screws.
9. Reconnect power supply cable and LED cable.
10. Re-fit the sleeve and audition the unit.
