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Old 19th July 2013, 03:50 PM   #1
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Smile Guitar Speaker Cab/ PA Mixer Amp

Hi recently I picked up a cab which had a Celestion G12 speaker in it but the amp had bee removed. I Connected the speaker to an ADS 60 Mixer Amp. It is working although it gets pretty hot. The sound is great for Blues/Rock as it doesn't do clean. Has anyone else done this or have experience. I would appreciate advice.

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Old 19th July 2013, 03:59 PM   #2
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Old 19th July 2013, 08:43 PM   #3
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Chances are that the amp is defective. A blown transistor or output IC. Does the amp have the correct fuse? What is the impedance of the speaker?
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Old 19th July 2013, 09:16 PM   #4
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Yea the fuse seems to be correct. The speaker impedance is 8 ohm. I wonder if I have wired the speaker to the amp correctly. There are no output sockets as such just a row of screws to connect wires to marked "Priority, then different impedance options, followed by a 100v option. I have the positive speaker wire connected to the 100v ant the negative is connected to the 8 ohm. Is this wrong?
Thanks for the reply.
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Old 19th July 2013, 11:06 PM   #5
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Quote:
Originally Posted by Ukulelegordy View Post
Yea the fuse seems to be correct. The speaker impedance is 8 ohm. I wonder if I have wired the speaker to the amp correctly. There are no output sockets as such just a row of screws to connect wires to marked "Priority, then different impedance options, followed by a 100v option. I have the positive speaker wire connected to the 100v ant the negative is connected to the 8 ohm. Is this wrong?
Yes, that is wrong. You need to connect negative to ground and positive to the 8 ohm tap. The 100 volt tap wants to see a 100v transformer at the speaker end, which would be used for distributed sound applications like school paging PAs and the like.
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Old 20th July 2013, 08:08 AM   #6
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Quote:
Originally Posted by Ukulelegordy View Post
Yea the fuse seems to be correct. The speaker impedance is 8 ohm. I wonder if I have wired the speaker to the amp correctly. There are no output sockets as such just a row of screws to connect wires to marked "Priority, then different impedance options, followed by a 100v option. I have the positive speaker wire connected to the 100v ant the negative is connected to the 8 ohm. Is this wrong?
Thanks for the reply.
As already mentioned, that's wrong, ground and 8 ohm is what you should be using - however, such amps are really for 'voice only' or background music, they aren't very high quality.

But on the plus side Loudthud's suggestion doesn't apply, a blown transistor can't damage the speaker.

An interesting point though - what kind of impedance do you actually get connecting across 100V and 8 ohm?.
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Old 20th July 2013, 08:51 AM   #7
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Well thanks for the replies. I've re-wired the speaker as suggested negative to ground and positive to 8 ohm. The result is no output at all not even a buzz. So I then connected the negative to the 100v output whilst leaving the positive in the 8 ohm output. This gives a sound more like what I'd expected from a pa type amp clean and not overheating?
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Old 20th July 2013, 10:26 AM   #8
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Actually, a blown transistor can damage a speaker if it causes a DC offset on the output and there is no protection circuitry, but (good to hear) this was not the case.
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Old 20th July 2013, 10:41 AM   #9
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Thanks for the replies folks I guess the mystery for me now is why I can only get an output when I'm connected to the 100v output? And I have safety concerns. I was thinking of gigging this amp tomorrow but I think I will hang fire for a bit!
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Old 20th July 2013, 11:47 AM   #10
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Actually, a blown transistor can damage a speaker if it causes a DC offset on the output and there is no protection circuitry, but (good to hear) this was not the case.
We know it can on normal amps - but not on a 100V line amplifier because it has a transformer on the output, so no DC connection to the speaker.
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