Hey fellas I'm running an Egnater tourmasterCombo- Im running the amp speakers (8ohmz) and external Marshall cab (8ohmz)-my amp is set at 4ohmz! I was told that is the proper way. But what I want to do is swap speakers in my Marshall cab to Celestian vintage 30s- I know they need to be 8ohzm but what about wattage on the invidual speaker ? Do I have some play room? My tourmaster is running 100watts!
Speaker swap
- Thread starter RileyJ1
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dystrust
Well-known member
Re: Speaker swap
Second, since the OP didn't say how many speakers are in the Marshall box, it's impossible to know for sure which impedance is needed. In a 2x12, a pair of 16 ohms speakers in parallel yields 8 ohms. Your answer to use 8 ohm speakers in series-parallel is correct for a 4x12.
To calculate maximum amp wattage, multiply the lowest wattage speaker by the total number of speakers. Even with a pair of 60W speakers, the OP will be fine.
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First of all, Vintage 30s are either 60 or 70 watts depending on which spec you believe.
Second, since the OP didn't say how many speakers are in the Marshall box, it's impossible to know for sure which impedance is needed. In a 2x12, a pair of 16 ohms speakers in parallel yields 8 ohms. Your answer to use 8 ohm speakers in series-parallel is correct for a 4x12.
To calculate maximum amp wattage, multiply the lowest wattage speaker by the total number of speakers. Even with a pair of 60W speakers, the OP will be fine.
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L
Little Pigbacon
Guest
Re: Speaker swap
Yes.
Yes.
Re: Speaker swap
Just so I am clear Im running at 100watts The 2x12 that is in the combo(8ozhm) and a 4x12 cabinet with vintage 30s at 60watts (8ozhm speakers a piece ) wont hurt the amp. Don't mean to repeat but want to be sure - because my current cab has 4 30watt 8ozhm speakers and its fine but increasing watts to 60 a piece- I want to be sure its not going to hurt my amp.
Just so I am clear Im running at 100watts The 2x12 that is in the combo(8ozhm) and a 4x12 cabinet with vintage 30s at 60watts (8ozhm speakers a piece ) wont hurt the amp. Don't mean to repeat but want to be sure - because my current cab has 4 30watt 8ozhm speakers and its fine but increasing watts to 60 a piece- I want to be sure its not going to hurt my amp.
L
Little Pigbacon
Guest
Re: Speaker swap
Increasing the power that the speakers in 4x12 can handle? No, it's not going to hurt anything.
Let's recap:
You have two speakers in the combo that make an 8-ohm load.
Your Marshall cab is 8 ohms.
Each speaker in the Marshall cab is 8 ohms.
You're replacing each of those speakers with a Vintage 30 that's 8 ohms and handles 60 watts.
You're going to leave the cabinet wired series-parallel (the way it is now).
The Marshall is going to be connected to a speaker output on the back of the combo.
The impedance selector on the back of the amp will be set to 4 ohms.
Is any of this not right?
Increasing the power that the speakers in 4x12 can handle? No, it's not going to hurt anything.
Let's recap:
You have two speakers in the combo that make an 8-ohm load.
Your Marshall cab is 8 ohms.
Each speaker in the Marshall cab is 8 ohms.
You're replacing each of those speakers with a Vintage 30 that's 8 ohms and handles 60 watts.
You're going to leave the cabinet wired series-parallel (the way it is now).
The Marshall is going to be connected to a speaker output on the back of the combo.
The impedance selector on the back of the amp will be set to 4 ohms.
Is any of this not right?
L
Little Pigbacon
Guest
Re: Speaker swap
Yes, as long as it's wired series-parallel (it is or it wouldn't have 8ohm speakers in a 412), which is essentially two separate 4ohm cabs wired each in parallel sitting side by side that are then wired together with each other in a series.
Yes, as long as it's wired series-parallel (it is or it wouldn't have 8ohm speakers in a 412), which is essentially two separate 4ohm cabs wired each in parallel sitting side by side that are then wired together with each other in a series.
L
Little Pigbacon
Guest
Re: Speaker swap
The two 16-ohm speakers in the combo are wired in parallel for an 8-ohm load. The 8-ohm 4x12 gets added in parallel to that for a resultant 4-ohm overall load. So you would set the switch to 4 ohms.
The two 16-ohm speakers in the combo are wired in parallel for an 8-ohm load. The 8-ohm 4x12 gets added in parallel to that for a resultant 4-ohm overall load. So you would set the switch to 4 ohms.
Re: Speaker swap
The 212 is still an 8ohm cab because it's pair of 16ohms are wired parallel which is basically 16 divided by 2
(individual speaker ohms divided by the number of speakers within the cab)
Running both your 8ohm cabs together creates a 4ohm resistance for the amp.
(just like parallel wiring would make a pair of 8ohm speakers into a 4ohm cab, or a pair of 16ohm into an 8ohm cab)
Remember, your 412 is really two 4ohm cabs (8ohm speakers divided by 2) that are then connected in series.
The 212 is still an 8ohm cab because it's pair of 16ohms are wired parallel which is basically 16 divided by 2
(individual speaker ohms divided by the number of speakers within the cab)
Running both your 8ohm cabs together creates a 4ohm resistance for the amp.
(just like parallel wiring would make a pair of 8ohm speakers into a 4ohm cab, or a pair of 16ohm into an 8ohm cab)
Remember, your 412 is really two 4ohm cabs (8ohm speakers divided by 2) that are then connected in series.
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