#1
Hey guys, I have my Mark IV 1x12 combo as you can see in my sig. I want to build a 1x12 extension cab. Now my amp has one 8 ohm output and two 4 ohm outputs. The speaker from the combo is 8ohm, so that will obviously need the 8 ohm output. My problem is that pretty much all speakers come either 8 ohm or 16ohm, and since it will be a 1 speaker cab, there is no way to get it to 4 ohms. Anyone know how I can do this? Is there a way? Thank you
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#2
Why do you need it to be 4 ohms? If you want an extension cab, you need an 8 ohm speaker. Two 8 ohm speakers give you 4 ohm. This means that if you an 8 ohm extension cab and the 8 ohm internal speaker, you get 4 ohm and plug them into each of the 4 ohm outputs.
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#3
Quote by bshizzle911
Hey guys, I have my Mark IV 1x12 combo as you can see in my sig. I want to build a 1x12 extension cab. Now my amp has one 8 ohm output and two 4 ohm outputs. The speaker from the combo is 8ohm, so that will obviously need the 8 ohm output. My problem is that pretty much all speakers come either 8 ohm or 16ohm, and since it will be a 1 speaker cab, there is no way to get it to 4 ohms. Anyone know how I can do this? Is there a way? Thank you
You're doing it wrong.
You WANT to buy an 8 ohm speaker.
Those 4 ohm jacks are in parallel
When you connect BOTH speakers,
you need to connect both the Internal 8 ohm speaker AND the 8 ohm extension cab to the 4 ohm jacks.

8 ohms in parallel with 8 ohm = 4 ohms.


When you use only one 8 ohm speaker, use the 8 ohm jack.
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#4
I'm sorry, I'm not following this.

To my understanding, the speaker/s get wired TO the jack and then you plug a cable from that jack into your amp?
Gibson Les Paul Studio
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Quote by aerosmithfan95
I wanna know what some blues sounding chords I could use in the key of D Aeolian fifth mode of Melodic Minor.

Quote by szekelymihai
try looking for Cm, or any of those complicated jazz chords
#5
Quote by bshizzle911
I'm sorry, I'm not following this.
1 - Turn your amp off.

2 - Remove the plug for the internal speaker from the 8-ohm jack on the amp chassis.

3 - Insert the plug for the internal speaker into one of the 4-ohm jacks.

4 - Insert the plug for the cable that goes to extension cab into the other 4-ohm jack.

5 - Turn your amp on.

6 - ?????????

7 - PROFIT!!!
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#6
Uh that's not right, because for one, the internal speaker is 8 ohm......

nice try tho.
Gibson Les Paul Studio
Mesa Boogie Mark IV
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Quote by aerosmithfan95
I wanna know what some blues sounding chords I could use in the key of D Aeolian fifth mode of Melodic Minor.

Quote by szekelymihai
try looking for Cm, or any of those complicated jazz chords
#7
^Ehm yes that's exactly what you do...

Running two 8 ohm speakers gives you 4 ohms and then go into the 4 ohm jacks....
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#10
No, see you missed my point. I understand how to get two 8 ohm speakers to equal 4 ohms, But I'm asking how do I do it with a 1x12 extension cab that only has ONE speaker which is either 8 ohm or 16 ohm?
Gibson Les Paul Studio
Mesa Boogie Mark IV
Avatar 2x12

Quote by aerosmithfan95
I wanna know what some blues sounding chords I could use in the key of D Aeolian fifth mode of Melodic Minor.

Quote by szekelymihai
try looking for Cm, or any of those complicated jazz chords
#11
Well if the extension has an 8 ohm speaker and the internal is 8 ohm, then you have 2x 8 ohm speakers, right? 2x 8 ohm speakers resulslt in a load of 4 ohms. That means you plug the cab into the 4 ohm output and the internal speaker to the 4 ohm output.
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#12
Quote by bshizzle911
No, see you missed my point. I understand how to get two 8 ohm speakers to equal 4 ohms, But I'm asking how do I do it with a 1x12 extension cab that only has ONE speaker which is either 8 ohm or 16 ohm?


Gah, you're really not understanding here. When you use the 4 ohm jacks, you're going to be running the stock internal speaker (8 ohms) in parallel with the external speaker (also 8 ohms).
(1/8 + 1/8) / 1 = 4
Now, if we pop on over to the Mark IV Manual, it clearly states that you must use two 8 ohms cabinets to connect to the 4 ohm inputs (I'd copy the text, but it's password protected).
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#13
Ok I get it now. I didn't realize that each jack affected the other.
So using the 8 0hm internal and the 8 ohm 1x12 extension is like using one 8 ohm 2x12 cab except that each speaker is plugged in separately.

Seems kinda scary doing it tho. haha thanks
Gibson Les Paul Studio
Mesa Boogie Mark IV
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Quote by aerosmithfan95
I wanna know what some blues sounding chords I could use in the key of D Aeolian fifth mode of Melodic Minor.

Quote by szekelymihai
try looking for Cm, or any of those complicated jazz chords