Ohms?
- Thread starter Aden
- Start date
random_guy
New member
Re: Ohms?
It's what buddhist monks do while meditating. Say it with me "ooohhhhhmmmmm"
Aden said:
It's what buddhist monks do while meditating. Say it with me "ooohhhhhmmmmm"
Metalman_666
Well-known member
Re: Ohms?
I'm not sure that you should hook up anything other than a 4 ohm rated cab to the 4 ohm speaker outs on the head. As far as I know you're only supposed to match the ratings of the head and cab. Hopefully someone else can tell you more though.
I'm not sure that you should hook up anything other than a 4 ohm rated cab to the 4 ohm speaker outs on the head. As far as I know you're only supposed to match the ratings of the head and cab. Hopefully someone else can tell you more though.
Low_fidelity2100
New member
Re: Ohms?
Is it a tube or solid state head?
Is it a tube or solid state head?
Re: Ohms?
It's pretty simple
You can send a LOWER load rating like 4 ohms to a higher rated cabinet such as an 8 or a 16, no problem - it will sound a little weaker and quieter, not necessarily a huge difference, but some may disagree.
YOU CANNOT do this in reverse -i.e. you CANNOT send a higher rating like a 16 ohm output to a 4 ohm cab or you will hurt the amp and the transformer. BAD BAD BAD
Another thing - as you add cabinets you must cut the ohms in half, that is why there are 2 - 4 ohm outputs. What this means is - if you want to use 2 cabinets that are eight ohms, then use the 4ohm outs - 2 cabs x 2 4 ohm outs = 8 ohm load. Same with 16 ohms etc etc.
Also, DO NOT mix ohm ratings, in other words don't use a 16 ohm and a 8 ohm cab on the same amp - it might not be a good thing.
It's pretty simple
You can send a LOWER load rating like 4 ohms to a higher rated cabinet such as an 8 or a 16, no problem - it will sound a little weaker and quieter, not necessarily a huge difference, but some may disagree.
YOU CANNOT do this in reverse -i.e. you CANNOT send a higher rating like a 16 ohm output to a 4 ohm cab or you will hurt the amp and the transformer. BAD BAD BAD
Another thing - as you add cabinets you must cut the ohms in half, that is why there are 2 - 4 ohm outputs. What this means is - if you want to use 2 cabinets that are eight ohms, then use the 4ohm outs - 2 cabs x 2 4 ohm outs = 8 ohm load. Same with 16 ohms etc etc.
Also, DO NOT mix ohm ratings, in other words don't use a 16 ohm and a 8 ohm cab on the same amp - it might not be a good thing.
shredaholic
New member
Re: Ohms?
A 4x12 rated for 16ohms might be able to be rewired so it's a 4ohm cab. If each speaker inside is 16ohms, then you can rewire it so it's a 4ohm cab.
Assuming all the speakers are 16ohm, currently inside it's wired so 2 are in parallell, giving 8 ohms, but wired in series with another 2 in parallell. 8ohm + 8ohm in series is 16ohms.
What you'd want to do is wire them all in parallel, as that would make the resistance 4 ohms in total.
This is the dual jack arrangement modern Marshall 1960A and 1960B cabs have on the back of the cab; they fit the cabs with 4 16ohm speakers, and then the small circuit board connected to the 2 jacks changes how the cab is wired, depending on whether you plug into the 4 or 16ohm input jack.
A 4x12 rated for 16ohms might be able to be rewired so it's a 4ohm cab. If each speaker inside is 16ohms, then you can rewire it so it's a 4ohm cab.
Assuming all the speakers are 16ohm, currently inside it's wired so 2 are in parallell, giving 8 ohms, but wired in series with another 2 in parallell. 8ohm + 8ohm in series is 16ohms.
What you'd want to do is wire them all in parallel, as that would make the resistance 4 ohms in total.
This is the dual jack arrangement modern Marshall 1960A and 1960B cabs have on the back of the cab; they fit the cabs with 4 16ohm speakers, and then the small circuit board connected to the 2 jacks changes how the cab is wired, depending on whether you plug into the 4 or 16ohm input jack.
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Re: Ohms?
Yes, I am pretty darn sure...
else, you can meet me at the repair shop with my 2 classic Marshalls which I run at 8 ohms into 16ohm cabs.
Maybe if the amp really overheats and blows, I can have some top sirloin ready so we can barbeque on the tubes. I call dibs on the EL34's. You can cook on the tranny and the pre's.
Yes, I am pretty darn sure...
else, you can meet me at the repair shop with my 2 classic Marshalls which I run at 8 ohms into 16ohm cabs.
Maybe if the amp really overheats and blows, I can have some top sirloin ready so we can barbeque on the tubes. I call dibs on the EL34's. You can cook on the tranny and the pre's.
Re: Ohms?
Yes, I am pretty darn sure...
else, you can meet me at the repair shop with my 2 classic Marshalls which I run at 8 ohms into 16ohm cabs.
Maybe if the amp really overheats and blows, I can have some top sirloin ready so we can barbeque on the tubes. I call dibs on the EL34's. You can cook on the tranny and the pre's.
Yes, I am pretty darn sure...
else, you can meet me at the repair shop with my 2 classic Marshalls which I run at 8 ohms into 16ohm cabs.
Maybe if the amp really overheats and blows, I can have some top sirloin ready so we can barbeque on the tubes. I call dibs on the EL34's. You can cook on the tranny and the pre's.
aleclee
Major General GAS
Re: Ohms?
In general, though, a 2:1 mismatch either way is considered relatively safe though older Marshalls are known to have somewhat delicate output trannys.
In SS amps, it's the opposite. A load that's too low can cause the output transistors to fry while it's completely safe to use a higher-than-nominal load at the expense of ouput power.
Sorry, I trust Randall Aiken more than your tech. From http://www.aikenamps.com/TI_Aiken_Q&A.html:OlinMusic said:
Simply put, a cab with impedance that is too low will work the tubes harder, shortening tube life, while a cab with impedance that is too high is what threatens major damage.
In general, though, a 2:1 mismatch either way is considered relatively safe though older Marshalls are known to have somewhat delicate output trannys.
In SS amps, it's the opposite. A load that's too low can cause the output transistors to fry while it's completely safe to use a higher-than-nominal load at the expense of ouput power.
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