Bose B1200 |
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CJS-90
New Member Joined: 19 October 2015 Status: Offline Points: 4 |
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Posted: 19 October 2015 at 3:05pm |
Hello!
So I'm no expert with amplifiers hence this post. I work for an IT recycling company and we've just had 2 x Bose B1200 amplifiers arrive. I have a small PA setup myself so I used my speakers/mixer to plug everything in to test. Now, when I test them: 1 x amplifier appears to be set up just for bass bins (as there is absolutely no treble, just punchy bass & a little bit of mid that comes out of my speaker) 1 x amplifier appears to be set up just for tops (there's literally no bass at all, only mid & treble). This test was done with the same cables, same song (just playing from my phone) and speaker (only 1 plugged in). It's also the same with both channel inputs/outputs on each amplifier. My question is: Were they like this from the factory?... because apart from a couple of small yellow stickers, there is visibly no difference between the amplifiers. Any help would be greatly appreciated! Kind regards, Chris.
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cravings
Old Croc Joined: 30 January 2007 Location: Ireland Status: Offline Points: 7441 |
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doesn't sound right.
these amps are MC2 made, think T1000. what is the speaker you're using to test? there's no way it's a biamped speaker and you're somehow connecting to one set of pins and then the other? not using the middle out of the amp, just a / b? those amps don't have any filter, so there's a problem somewhere. check your speaker lead is 2 core, check it's joining pins +/-1 at each end on the speakon. |
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James Cotton
Registered User Joined: 27 July 2006 Status: Offline Points: 44 |
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Googling around it looks like there were filter cards available for these amps, maybe yours has them installed.
Looking at this ebay ad..... There's a sticker on the back showing a 402 eq card installed on the A channel. Any sign of stickers like these on your amps? Not sure if the eq cards just applied a little eq to fix the Bose sound or if they were a full crossover card but it's worth a look. Maybe whip the lids off and see if the cards are there?
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CJS-90
New Member Joined: 19 October 2015 Status: Offline Points: 4 |
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To update this
I've just opened them up. One of them that appears to only provide lows looks to have a "Panaray MB/02" card, and the one that provides mides & highs has a "MA12 II Stacked" in there. Does that mean anything to anybody on there? Google doesn't bring up much.
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CJS-90
New Member Joined: 19 October 2015 Status: Offline Points: 4 |
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I thought I'd also add, I contacted Bose themselves and they didn't really give me much information. I just got passed around and given a few email addresses who never really gave me a clear answer, but kept forwarding to other people in different departments.
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imageoven
Old Croc Joined: 28 March 2007 Location: Scotland Status: Offline Points: 2186 |
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Iirc pull the cards out and you will have full range amps back again. There may be jumper links I'm not remembering - a photo would help
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Keep pushing on, things are gonna get better.
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Conanski
Old Croc Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2515 |
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The Panaray MB4 and MA12 are install components of a column array speaker system they have, I expect the crossover would be around 250-300hz. As suggested just pull the cards out and see if the amp passes fullrange audio, if not you may have to fabricate some jumpers to complete the circuits. |
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simonp1100
Young Croc Joined: 01 September 2008 Location: Bristol Status: Offline Points: 1103 |
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Put up a photo of the inside of the amplifier and a few pics close up of the input cards.
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bass*en*mass
Old Croc Joined: 03 September 2009 Location: "unknown" Status: Offline Points: 4009 |
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i`ve had one of these amps years ago, also fitted with some PIP cards, if i remember correctly its really as easy as suggested, take the cards out and possibly switch a DIP..
(not sure on the DIP, once opened you will see it or not, its been a while since i had mine open) |
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Natedub
Registered User Joined: 07 January 2013 Status: Offline Points: 126 |
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The Bose B1200 is a hybrid of the mc2 t1000 with the t1500 transformer. The crossover cards can be removed easily as suggested, cant remember the exact details but I contacted Mc2 at the time for help and they were very helpful.
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