I use a Kairn, an Isobarik Aktiv Crossover and two AV 5125 amps to run a pair of Isobariks in active mode. The setup sounds nice and works fine except for one detail: After beeing fed a music signal the 5125 that handles the right channel takes around 8-10 seconds longer to wake up from standby than the left channel amp, and the output level from the Kairn must reach at least around 20 to make it happen - and it has to stay on or above that level to keep the amp from switching back into standby.
The left channel 5125 is however much quicker and easier to wake up, and it stays on, happily playing music, even if the output level from the Kairn is at low single figures. My guess is that this amp works the way it was meant to, so I am looking for a solution that can make both amps behave similarly.
I have seen that this issue has been mentioned on other Linn forums (without however being discussed in any detail) and I have also read additional info from Fredrik that changing the values of two surface mounted resistors fixes the problem:
R619 should be changed to 12 kΩ
R620 should be changed to 5.6 kΩ
Finding 12 and 5.6 kΩ resistors in an electronic components catalog is easy enough. But one must also specify what type of resistor one wants, as well as what wattage and voltage values to choose... Which for someone with a severely limited knowledge of the insides of electronics and components makes the thing very difficult...
So if anyone can help with complete and correct specifications for the resistors needed I would be very grateful!
It would also be interesting to hear if anyone has carried out this modification and has any personal experiences and/or observations to share?
Any input as to why not all 5125:s seem to behave the same way in this aspect would also be appreciated - is it due to manufacturing differences or due to degradation of the components involved? Does the 5125 generation of Linn amps really begin to show old age problems?
//Lars
Modifying sensitivity threshold for standby mode on AV5125?
Moderator: Staff
Hi Lars and welcome here!
What resistor you get is not crucial, you can solder almost anything there provided it fits in size. The original resistors are a small surface mount type (SMD) and these come in different sizes. For example 0805, 0604, 0402. I'm afraid I can't recall what size these are, perhaps 0604?
If you get the wrong size, it will work fine anyway except for being a little more tricky to fit. You might have to fit a tiny bit of wire to be able to connect both ends. You can even use standard through-hole resistors (typically 0.3 to 0.6W), if so you need to bend their legs to a U shape and solder them with one leg against each pad and the resistor in the air.
The voltage is nothing you need to worry about, the circuits are low voltage.
What resistor you get is not crucial, you can solder almost anything there provided it fits in size. The original resistors are a small surface mount type (SMD) and these come in different sizes. For example 0805, 0604, 0402. I'm afraid I can't recall what size these are, perhaps 0604?
If you get the wrong size, it will work fine anyway except for being a little more tricky to fit. You might have to fit a tiny bit of wire to be able to connect both ends. You can even use standard through-hole resistors (typically 0.3 to 0.6W), if so you need to bend their legs to a U shape and solder them with one leg against each pad and the resistor in the air.
The voltage is nothing you need to worry about, the circuits are low voltage.