Do I go active with my Linn 5140s ?

The Chakra amp manual says that the per-channel gain controls are only for when Aktiv cards are installed. If you aren't running Aktiv the manual says you should leave them at setting 3 (which is 0 dB gain).

Perhaps for older amps different advice was given?

Okay, I think I got this figured out now.

The older Linn amps have a fixed gain, unlike the amps from the "C" series Chakra and forward. The fixed gain is essentially identical in all of the older amps. For example, it is 28.6 dB for the LK 85/140, 28.5 dB for the Klout, 28.6 dB for the AV 5125. I note that in the owner's manual for the "C" series Chakra amps, the gain is adjustable, with an asterisk at 28.6 dB, which is the gain for the older amps. The new Majik series Chakra amps also have this. So 28.6 dB must be the default gain setting. When you say that setting 3 is 0 db gain, I take that to mean that setting 3 is actually 28.6 dB. The "0" is actually the deviation from 28.6 dB

When you install an Aktiv card in the old amps, the treble card, and sometimes the bass card, has a little adjustable dial on it to adjust signal strength. Some of the adjustments will even mute the Aktiv board. When the dealer installs the Aktiv card, he will adjust the dial of the signal strength to tune the amp. There's a chart in the owner's manual for the setting to be recorded so that you know what it is.

I am not familiar with the new Aktiv cards. However, my speculation is that the new cards may not have the signal level adjustment. Rather, the signal level adjustment appears to have been moved into the amp.

So with the old set-up, the amp gain is fixed, the card is adjustable. And with the new set-up it is reversed. It is the amp that has the adjustable gain, and it is the card that is (I'm guessing) fixed. Is this correct? Are your new cards without an adjustable signal strength dial? That would explain things.

Anyway, the purpose of the adjustment is to tune the amp, so by all means play around with it if you wish. However, the Linn dealer who installed the cards should have already tuned it. You might want to check what the settings are so that you can restore them in case you mess things up and want to return to the original setting.

Sorry to Dfwlistener for hijacking his thread.

Correct, for the new Linn amps the signal strength/gain control is on the back of the amp for each channel. There are several settings (including mute). There is no setting on the card itself.

This makes more sense to me as the gain can be adjusted without opening the cover of the amp. The Linn dealer just sent a guy out, installed the cards, and did no testing or setup. In fact he admitted he couldn't hear well anyway so it would be better if I setup. I believe he was more of an electrical technician than an audio setup expert. A little disappointing given how much I've spent at the dealer.