Members Dookietwo Posted November 19, 2014 Members Share Posted November 19, 2014 http://forums.prosoundweb.com/index.php/topic,152373.0.html Andy; Any idea what that switch may do?Doug Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted November 20, 2014 Members Share Posted November 20, 2014 I found the service manual and and it appears to be MONO/DUAL switch. Bridge or Stereo.Go to this link and click download pdf.Page 58 and zoom in is schematic and block diagragm is page 59 http://elektrotanya.com/ab_international_900a_1100a_922a_9420a.pdf/download.html Link to comment Share on other sites More sharing options...
Members agedhorse Posted November 20, 2014 Members Share Posted November 20, 2014 Nope, the switch is to select if the module is installed in the top position or the bottom position. It relates to where the inverted signal is obtained from for bridging and how it's injected into the opposite channel. Sensitivity switch is a small red 3 position switch located at the front of each module. Not all versions of the 1100 had this. Only the later ones. Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted November 21, 2014 Members Share Posted November 21, 2014 Ok are we on the same version of the amp model or?Read down the page http://forums.prosoundweb.com/index.php/topic,152373.0.html Link to comment Share on other sites More sharing options...
Members agedhorse Posted November 21, 2014 Members Share Posted November 21, 2014 Yes, the manual page is correct. The switch is set for which module position the module is installed in. 1/2 of the switch controls the ground lift function and 1/2 of the switch controls the inverted signal routing for the bridge function. The manual shows the 3 position sensitivity switch in the front, not all versions of the amp have this. You have to remember that this module was also used in some other amp models, and went through maybe 5 different revisions over 12 years or so. I am pretty familiar with this design as it's one that I supported for a lot of AB customers over the years. Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted November 21, 2014 Members Share Posted November 21, 2014 So you are saying there is an external module needed for bridged mode? I have seen this on the old GAS power amps. Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted November 21, 2014 Members Share Posted November 21, 2014 At this point only curiosity has me going on this Aged. Link to comment Share on other sites More sharing options...
Members agedhorse Posted November 21, 2014 Members Share Posted November 21, 2014 No. The switch defines the module function. The upper module supports the ground lift switch and the bottom module supports the bridge mono switch. The up/down slide switch selects what the mini toggle switch does on each module. The two modules are identical other than the position of the slide switch. Link to comment Share on other sites More sharing options...
Members Dookietwo Posted November 21, 2014 Author Members Share Posted November 21, 2014 Thanks Andy. I had ( somewhere ) the service manual for my AB International 900a but couldn't find it.Doug Link to comment Share on other sites More sharing options...
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