Have you read the manual? The aux sends are not all set up the same.
This is from a review I found:
A common way to arrange the effects send system on a budget desk is to provide more aux buses than send controls, and then use some kind of switching system to move the sends from one bus to another. Tascam have taken a quite different approach on the M-2600, providing eight aux buses which are permanently addressed by two stereo sends and four mono sends.
Sends 1 and 2 are arranged as a stereo pair, with Level and Pan controls, fed from the Channel signal. Sends 3 and 4 are similarly set out but this time they are fed from the Monitor path. Normally, both sets of stereo sends are pre-fade, enabling the user to set up stereo cue mixes from either the channel signals or the multitrack outputs, but a single Post button switches both stereo sends to post-fade operation for use as stereo effects sends. As cue is only needed while recording, and given that you can never have too many effects sends while mixing, this would seem like a very good arrangement.
The remaining four sends are dedicated post-fade effects sends, Aux 5 and 6 being permanently fed from the Channel signal path. Sends 7 and 8 are switchable, so that they can be fed either from the Channel or Monitor signal. Because so much is switchable between the Channel and Monitor path on the M-2600, the Monitor section itself offers only Level and Pan controls plus an overload LED and Mute switch. The overload indicator only flashes when the signal exceeds 25dB above the nominal operating level, so there's no lack of headroom, and the Mute button has an amber status LED to signify that the signal is muted.
Does this help?
Alan,
