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Ohms FAQ
- Thread starter IvanMike
- Start date
Yes, any amp with a bridging facility will of course take care of that when you select bridge mode. The earlier description implied that all you have to do is connect the load between left+ and right+ of any stereo amp (with or without a bridge mode), which of course would give you no sound at all.
Dincz, That will not work with all stereo amplifiers. I have a Crown Macro Tech I series. Always set all controls to off and remove the electric power chord. To bridge the left and right channels together, the left positive speaker output is connected to the speaker positive, and the right positive speaker output is connected to the speaker negative. The right volume control is not used and is to remain in the lowest position. The left side volume control will now control power output. The amplifier should now be placed in the bridged mode before plugging in the electric chord.
Read the manual then read the manual again before operating. Because of the amount of output check the speaker specifications before attempting
to send a signal through. Also match the wattage and ohms.
Read the manual then read the manual again before operating. Because of the amount of output check the speaker specifications before attempting
to send a signal through. Also match the wattage and ohms.
That load is not recommended by any amplifier company. 2 X 4ohm loads = 2 ohms. Then an additional 8 ohm load ? Is the amplifier rated to operate at 1 ohm, I think not. You will definitely damage your amplifier with that type of load or may hammer your speakers. You need to purchase a 4 ohm speaker system or 2 X 8 ohm speaker systems but first, please, let me ask you a question. How much amplifier power do you have ? Even more importantly, what are you trying to accomplish ? There is a way to wire your speakers together, however, I would need to see the speakers specifications before commenting further.
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Got a Carvin 410 with four 8-Ohm 200-watt speakers which I think is rated at 800 watts. This has to be a 8-Ohm cab, right? If I read the sticky right, four 8-Ohms speakers would only be wired as a 8-Ohms or 2-Ohms load (unlikely a 2-Ohm). Carvin doesn't say on their website but I am guessing their 410 4-Ohm cab has four 4-Ohm speakers and the 8-Ohm cab has four 8-Ohm speakers. Anyone confirm? Thanks!
Yeah, but 800w is program rating for 4 tens, don't go bridging some 1000w power amp thinking you can turn it up to 8.
I get ya. I was not sure about the Ohms on this cab until I did a A/B with a 4-Ohm CN212 using a GK MB800 and found the Carvin was a lot less efficient. With the master at full and the gain at noon it was breaking up. Still not sure if it was the cab or the amp, but I really think it was the later. I don't have anything bigger to find out.
Thanks
So to make sure I got this right a 450 watt head at 2 ohms will work with a 410 4ohm cabinet with a rating of "1,200 watts"?
It's not my rig btw it's my brother inlaws
It's not my rig btw it's my brother inlaws
The amp head can go as low (or hard) as 2 ohms load. Sounds like he has a SS amp, the 4 ohm cab will cause no problem with the amp as it will present less of a load to the amp. A SS amp will put out less power as it is less taxed. The lower the number in ohms the closer to a dead short you get. Two wires shorted together is zero ohms. That 4 ohm 410 most likely would be rated at half that 1200 with an "rms" rating and again at half that for bass guitar use so 300 watts input power.
His amp will most likely with a 4 ohm load output around 300 watts rms so the cab would be a good match. Speaker cab ratings are for what they can accept from an amp. It is the amp that "produces" the watts.
His amp will most likely with a 4 ohm load output around 300 watts rms so the cab would be a good match. Speaker cab ratings are for what they can accept from an amp. It is the amp that "produces" the watts.
May be a stupid question, but I combed through the first dozen pages and didn't see an answer.
There is a head (Hartke 2500) that is 250 watts at 4 ohms/180 watts at 8 ohms.......do all heads basically run at around half-advertised power when in 8 ohms?
I am debating between that head and the Ampeg SVT Micro Classic head. It is advertised at 200 watts at 4 ohms. There is no advertised 8 ohms wattage, so my main question is what is/does anyone know the wattage output for the Ampeg SVT Micro running at 8 ohms? (a single 2x12 SWR Workingmans cab)
In addition, anyone have any good and/or bad things to say about either head? I play in an indie rock band with 2 guitarists, drummer, and keyboardist who also plays vibraphone on some songs. My current amp (that I am getting rid of for one the aforementioned) is 160w (or 200w when I decide to bring the SWR 2x12 extension cab) and I have no problem being loud enough at the shows we play now. I just hope either of these two heads have enough "headroom" to maintain clarity & be powerful enough. Anyone with experience in either the Hartke or Ampeg would be appreciated
There is a head (Hartke 2500) that is 250 watts at 4 ohms/180 watts at 8 ohms.......do all heads basically run at around half-advertised power when in 8 ohms?
I am debating between that head and the Ampeg SVT Micro Classic head. It is advertised at 200 watts at 4 ohms. There is no advertised 8 ohms wattage, so my main question is what is/does anyone know the wattage output for the Ampeg SVT Micro running at 8 ohms? (a single 2x12 SWR Workingmans cab)
In addition, anyone have any good and/or bad things to say about either head? I play in an indie rock band with 2 guitarists, drummer, and keyboardist who also plays vibraphone on some songs. My current amp (that I am getting rid of for one the aforementioned) is 160w (or 200w when I decide to bring the SWR 2x12 extension cab) and I have no problem being loud enough at the shows we play now. I just hope either of these two heads have enough "headroom" to maintain clarity & be powerful enough. Anyone with experience in either the Hartke or Ampeg would be appreciated
Figure the Micro Classic between 100 and 120 watts. Most SS amps are this way.
The hartke is a staple workhorse.
The hartke is a staple workhorse.
Dumb Questions:
Amp rated 250W @4OHM and 175@8OHM so with a single 8 OHM cabinet will deliver 175W , with a 4ohm cabinet will deliver 250W , how much will push in 2 8OHM cabs ? 175 in each cab (total of 350W) or 125W to each cab (total 250W) ?
And what happens if I connect 2 cabs in series , let's say the cable goes from speaker output to one cab and from that cab to another cab and same for the second speaker output, so in series I can use 4 cabs?
Amp rated 250W @4OHM and 175@8OHM so with a single 8 OHM cabinet will deliver 175W , with a 4ohm cabinet will deliver 250W , how much will push in 2 8OHM cabs ? 175 in each cab (total of 350W) or 125W to each cab (total 250W) ?
And what happens if I connect 2 cabs in series , let's say the cable goes from speaker output to one cab and from that cab to another cab and same for the second speaker output, so in series I can use 4 cabs?
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Speakers do not put out "watts" they output sound (and better at waste heat). If the amp will output 250 watts @ 4 ohms then even two 1000 watt 8 ohm cabinets will not change the 250 watt output.
The only way to hook up four 8 ohm cabs with an amp that has a 4 ohm minimum is with two special built cables. Those cables have an amp end and two cab ends, both cab ends must be connected or neither will work. Running from one cab to another is still parallel, not series.
The only way to hook up four 8 ohm cabs with an amp that has a 4 ohm minimum is with two special built cables. Those cables have an amp end and two cab ends, both cab ends must be connected or neither will work. Running from one cab to another is still parallel, not series.
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Because of the way jacks are wired in speaker cabinets, daisy chaining them as you described is the same as running separate cables from the amp to each cabinet. i.e. parallel, not series.
Do not hook of 4 8ohm cabs to your amp in parallel. Unless you want a AMP-B-Q. That's WAY below the minimum 4 Ohm impedance load for most common solid state amps.
However, using 2 8 ohm cabs does allow you to take advantage of the maximum output power available through your amp, and also doubles the woofer cone surface area you have to move air (assuming the cones are the same). So that's a win/win.
However, using 2 8 ohm cabs does allow you to take advantage of the maximum output power available through your amp, and also doubles the woofer cone surface area you have to move air (assuming the cones are the same). So that's a win/win.
