z4zed
New Member
Posts: 14
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Help!!!
Feb 16, 2014 16:25:59 GMT -7
Post by z4zed on Feb 16, 2014 16:25:59 GMT -7
Had band practice today, and buddy plugged my head into my cab. plugged the 4ohm out of the amp into a 16ohm cab. I didn't notice until after practice 3hrs later. Amp is running fine and sounds fine but can I run this mismatch safely and how do I know if I have caused any harm. Depending on what you read online some people say its a safe mismatch others say not so much. some helpful insight would really be appreciated. amp is a remedy (obviously) with master volume and was running with two channel levels at about 11 oclock and the master at 900. Thanks in advance
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Post by Jaguarguy (Mike) on Feb 16, 2014 16:48:04 GMT -7
No harm. Not necessarily recommended but won't harm head.
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Post by Pete aka shouldb on Feb 16, 2014 16:50:37 GMT -7
No problems at all - so long as the cab/speaker has a higher ohm rating than the output of the amp, no harm has been done (4ohm out of amp into 16 ohm speaker is just fine)
Now, if it had been the other way around, that would be bad............
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z4zed
New Member
Posts: 14
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Post by z4zed on Feb 16, 2014 17:01:40 GMT -7
Thanks guys appreciate the quick replies!
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Help!!!
Feb 16, 2014 17:33:55 GMT -7
Post by "Z" Steve on Feb 16, 2014 17:33:55 GMT -7
BTW - welcome to the forum! These folks are great!
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Help!!!
Feb 16, 2014 19:34:13 GMT -7
Post by Maddog on Feb 16, 2014 19:34:13 GMT -7
No problems at all - so long as the cab/speaker has a higher ohm rating than the output of the amp, no harm has been done (4ohm out of amp into 16 ohm speaker is just fine) Now, if it had been the other way around, that would be bad............ EXACTLY!!!!!!
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Help!!!
Feb 17, 2014 2:17:34 GMT -7
Post by muZician on Feb 17, 2014 2:17:34 GMT -7
no problem at all. normally, if your amp has a robust output transformer (being able to carry higher currents) also the other way around is no issue. tube output stages are self limiting in case of current overload. as an example if you use an airbrake set at the first attenuation level and you have a 16 Ohm cab and use the 16 Ohm output of your amp, your output stage will "see" about 9 Ohm impedance. no issue for Z amps!
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Post by helmi on Feb 17, 2014 6:02:08 GMT -7
Had band practice today, and buddy plugged my head into my cab. plugged the 4ohm out of the amp into a 16ohm cab. I didn't notice until after practice 3hrs later. Amp is running fine and sounds fine but can I run this mismatch safely and how do I know if I have caused any harm. Depending on what you read online some people say its a safe mismatch others say not so much. some helpful insight would really be appreciated. amp is a remedy (obviously) with master volume and was running with two channel levels at about 11 oclock and the master at 900. Thanks in advance helpful hint. dont let your budde touch your amp anymore. personally, anybody who doesent pay enough attention to plug the cab into the right ohm outlet, I dont want ANYWHERE near my amp. welcome to the forum.
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z4zed
New Member
Posts: 14
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Help!!!
Feb 17, 2014 11:59:05 GMT -7
Post by z4zed on Feb 17, 2014 11:59:05 GMT -7
Had band practice today, and buddy plugged my head into my cab. plugged the 4ohm out of the amp into a 16ohm cab. I didn't notice until after practice 3hrs later. Amp is running fine and sounds fine but can I run this mismatch safely and how do I know if I have caused any harm. Depending on what you read online some people say its a safe mismatch others say not so much. some helpful insight would really be appreciated. amp is a remedy (obviously) with master volume and was running with two channel levels at about 11 oclock and the master at 900. Thanks in advance helpful hint. dont let your budde touch your amp anymore. personally, anybody who doesent pay enough attention to plug the cab into the right ohm outlet, I dont want ANYWHERE near my amp. welcome to the forum. Partially my Fault, herniated a disk in my back this week and have been on painkillers so not thinking the clearest. The cab I have is used and the previous owner I assume changed the wiring changing the cab from 4ohm to 16ohm. The plastic tag says 4 ohm but there is 16 in ink written below in large numbers. He just saw the original tag and plugged it in. Had I been more with it I would of explained it to him or checked for myself. I just assumed I had hooked it up. Only afterwards did it even cross my mind that "hey I don't even remember plugging my head into the cab"
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Help!!!
Feb 17, 2014 13:29:38 GMT -7
Post by Pete aka shouldb on Feb 17, 2014 13:29:38 GMT -7
no problem at all. normally, if your amp has a robust output transformer (being able to carry higher currents) also the other way around is no issue. tube output stages are self limiting in case of current overload. as an example if you use an airbrake set at the first attenuation level and you have a 16 Ohm cab and use the 16 Ohm output of your amp, your output stage will "see" about 9 Ohm impedance. no issue for Z amps! Really? I thought the attenuators were in series with the speaker coil, so the amp would "see" a higher value? 16 Ohm speaker, plus Air Brake = 16+ whatever ohms? Are you saying the AirBrake is in parallel with the speaker? I certainly agree that the Z amps are built like tanks, so nowhere near as "fragile" as many out there, for sure!
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Feb 18, 2014 1:32:54 GMT -7
Post by muZician on Feb 18, 2014 1:32:54 GMT -7
Pete, the Airbrake is an L-pad. Simplified one resistor in parallel with the output of the amp and then one resistor in series with the loudspeaker. The first parallel resistor is 25 Ohms. So even if the loudpeaker is disconnected the amp "sees" 25 Ohms. Then you have the variable selectable resistor in series with the louspeaker. The series connection of these 2 is seen by the amp as connected in parallel to the first 25 Ohms. So the amp will always see an impedance less than 25 Ohms (which is safe). The real circuit is a bit more complicated (also to allow bedroom level). If you want details send me a PM. The real secret of the airbrake is, as you say above of Z-amps, it's built like a tank with top quality components. By the way the only reason I know why we should always choose the right amp output impedance to be connected to the speaker is that doing so we have perfect power matching. If we use an attenuator we kill the power matching in the first place...impedance matching is less important. Francesco
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Feb 18, 2014 16:45:29 GMT -7
Post by Pete aka shouldb on Feb 18, 2014 16:45:29 GMT -7
^^^ I am educated and thanks for the info - I have never seen an Airbrake up close, just a BrakeLite. I am just thankful that Z amps are so robust, and yet sound SO good that these things matter less than with other more "tender" amps
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Feb 19, 2014 1:32:05 GMT -7
Post by muZician on Feb 19, 2014 1:32:05 GMT -7
^^^ you say it :-)
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Feb 19, 2014 4:36:29 GMT -7
Post by DRZ on Feb 19, 2014 4:36:29 GMT -7
No problems at all - so long as the cab/speaker has a higher ohm rating than the output of the amp, no harm has been done (4ohm out of amp into 16 ohm speaker is just fine) Now, if it had been the other way around, that would be bad............ EXACTLY!!!!!! +1000
DR.Z
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z4zed
New Member
Posts: 14
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Help!!!
Feb 20, 2014 15:22:50 GMT -7
via mobile
Post by z4zed on Feb 20, 2014 15:22:50 GMT -7
Thanks guys for the help. Great forum to start and then get the Doc himself to answer. Great customer service. You've got a convert here!
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