i'm new to amps, so this might sound stupid. but i'v just got a new rig. Ashdown mag 300, with 4x10 cab. and i was wondering which as to run off the head, an 8 ohm cab or 4 ohm? just curious?
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ohms?
- Thread starter kayne
- Start date
With solid state gear you get more power usually running the lower resistance but if your head will only run down to 4 ohms and if you run a 4 ohm cab you can not add another cab So if you plan on adding another cab later get an 8 ohm and when you add another 8 ohm cab you will have an 4 ohm load and get the max out of your amp.
+1
You will get just under 3dB more from a 4ohm cab than an 8ohm, generally, when using a solid state amplifier. It isnt that much more.
If your amp can go down to 2 ohms, then get a 4 ohm cab, as you could still add another one. If the amp only goes down to 4 ohms, get an 8 ohm cab. Granted these ways you arent getting the maximum out of your amp, BUT, if you ever decide to add another cab, you wont have a problem
If you are totally positive you wont be adding another cab, then it would be better to get the 4 ohm cab, but you wouldnt notice too much of an increase volume wise.
If your amp can go down to 2 ohms, then get a 4 ohm cab, as you could still add another one. If the amp only goes down to 4 ohms, get an 8 ohm cab. Granted these ways you arent getting the maximum out of your amp, BUT, if you ever decide to add another cab, you wont have a problem
If you are totally positive you wont be adding another cab, then it would be better to get the 4 ohm cab, but you wouldnt notice too much of an increase volume wise.
Really? Hmm. That clears a lot up. Thanks dude.
I would definitely buy the 4 ohm cab..
for me, 8 ohm cabs only makes sense, if I use two of them.
but I won't use two 4x10, so I'd like to use all the power of my amp, not only ~60%
for me, 8 ohm cabs only makes sense, if I use two of them.
but I won't use two 4x10, so I'd like to use all the power of my amp, not only ~60%
Doubling the power (wattage) of an amplifier will give you 3dB more, 3dB is NOT a huge amount more volume. And as your not even getting fully twice the power at half the impedence, you will get less than 3dB more.
Who said anything about using two 4x10s? , could use a 4x10 and a 1x15?
Who said anything about using two 4x10s? , could use a 4x10 and a 1x15?
Yes I know, but why would I gig with a 8 ohm 4x10, If I can do it with a 4 ohm 2x10? (I'm doing it.. double the speaker surface=+3dB. double the impedance= -3dB. same speakers, brand, AMP..)
the max output may be reduced because of the 2x10... then buy a 4 ohm 4x10 instead
my approach, by the way.
3 dB is not much, but the other point: for 3 dB increase, you must double the amps wattage.
no offense, just my thoughts.
edit: 15"? never
anyway, I had a bad experience, too... OK, the cabs weren't the same brand, construction, woofers... but once I used a provided SWR workingpro (I think) 4x10, at 8 ohm. my amp puts out 300W az 4, 180W az 8 ohms.
it was WAY lower than my EBS 210, both rated at 100dB sensitivity (I know, don't trust factories..)
it was WAY lower than my EBS 210, both rated at 100dB sensitivity (I know, don't trust factories..)
Go to your amps minimum load... A handy resistance calculator for those, like me, too thick to work it out... http://www.1728.com/resistrs.htm
Yes I know, but why would I gig with a 8 ohm 4x10, If I can do it with a 4 ohm 2x10? (I'm doing it.. double the speaker surface=+3dB. double the impedance= -3dB. same speakers, brand, AMP..)
the max output may be reduced because of the 2x10... then buy a 4 ohm 4x10 instead
my approach, by the way.
3 dB is not much, but the other point: for 3 dB increase, you must double the amps wattage.
no offense, just my thoughts.
edit: 15"? never
Perhaps you guys can clear something up for me.... I have a SWR Workingpro 400 amp that is rated at minimum 4 ohms -
and is powering a hartke 210 at 8 ohms and a hartke 215 at 4 ohms. Should I run the cabinets in series or parallel to get the best performance? Running them in series I have a 6 ohm load right?
you have it the other way around... running them in series makes it 12ohms, parallel would run them in the 6ohm area.
series: 4+8= 12 ohm
parallel: 4*8/(4+8) = 2,66 ohm
2,66 ohm is kind of dangerous to your amp, 12 is not efficient..
maybe running 12 ohm is loud enough, and if that's your tone, go for it.. the amp is goint to push out ~100..150W max, 2/3 to the 210, 1/3 to the 215.
I think, the best way is to use the cabs alone..
it's important!!! using two speakers in parallel, the total impedance is going to be LESS then the lower impedance speker's !!
ooops my bad... like he said... it's 2.7 ohms... not good... don't do this (i'm fully awake nowparallel: 4*8/(4+8) = 2,66 ohm
)Sineas, you'r almost right.
You can calculate the total resistance of resistors in parallel as:
1/R = 1/R1+1/R2+...+ 1/Rn. If you have an 8 Ohm and a 4 ohm cabinett in parallel the resistance seen by your amplifier will be 2.7 ohms, wich could blow a amp rated to 4 ohm. Be sure you know what you're doing when your running cabs in parallel.
You can calculate the total resistance of resistors in parallel as:
1/R = 1/R1+1/R2+...+ 1/Rn. If you have an 8 Ohm and a 4 ohm cabinett in parallel the resistance seen by your amplifier will be 2.7 ohms, wich could blow a amp rated to 4 ohm. Be sure you know what you're doing when your running cabs in parallel.
series: 4+8= 12 ohm
parallel: 4*8/(4+8) = 2,66 ohm
2,66 ohm is kind of dangerous to your amp, 12 is not efficient..
maybe running 12 ohm is loud enough, and if that's your tone, go for it.. the amp is goint to push out ~100..150W max, 2/3 to the 210, 1/3 to the 215.
I think, the best way is to use the cabs alone..
Ok... am I understanding this right? The best performance and safest configuration is to run the 8 ohm 210 and 4 ohm 215 in series. Correct?
