This amp can give you a case of TOS (Toxic Option Syndrome), so I'll try to cover some of the main features as I've experienced them.
There's only one input jack, with a toggle for active or passive bass circuitry. I've only used the active switch position.
I'm using it to drive SWR cabs, a 1x15 and a 4x10 (older US-made models). The SWR 350x head would not drive this setup at any useful volume without clipping. The Carvin has more than ample power to drive it in three different modes:
1) Bridged mode (chained cabs), 1200W into 4 ohms (2 8-ohm cabs). I haven't tried this one.
2) Standard mode, two monobloc amps run one into each cab, producing up to 275 watts per cab. It's possible to cut the wattage to each cab separately.
3) Bi-amped mode, with an internal crossover, 275w each per 8-ohm cab. This permits me to send (for example) <200Hz inputs to the 1x15, and >200Hz to the 4x10. In this mode I can also control the watts sent to each cab.
For my setup, the bi-amped mode makes a strikingly audible difference, and sweeping the crossover frequency makes a big difference. This is a really nice feature. There is a toggle switch between bi-amped and standard modes. For bridged mode, you need to rewire everything.
There's a drive knob which adds a bit of overdrive to the pre-amp (and makes things louder, so you need to cut the master volume). It's not intended to be an overdrive effect, but it adds a little bit of tube effect.
There's a compression knob up to 3:1 compression (I've had best luck at about halfway, so I can control any reasonable dynamics myself, but errors get compressed away)
There's a contour knob that controls the amount of mid-frequency cuts for slap sound. This is a good deal faster and easier than trying to adjust the 9-band graphic EQ for scoop AND allows the graphic EQ to be used for something different.
Which gets me to the 9-band graphic EQ. You get plus or minus 12db centered on frequencries from 50Hz to 5KHz. I've found these to be easier and more intutive than twiddling with the EQ on my bass itself. There's a toggle switch to take the entire graphic equalizer out of the path (and an optional foot switch to do the same thing, which I didn't buy). This lets you use the contour knob for some numbers, then cut that and switch in the graphic EQ for others. It's pretty easy.
Beyond this is a 5-band semi-parametric setup - bass and treble shelf controls for below 50Hz and above 5KHz, and a 3-band parametric in between, permitting plus or minus 12db boosts or cuts at three dialable frequencies from 100Hz to 5KHz. So far, I've been using this as a notch filter to cut frequences that cause resonating rattling of whatever starts vibrating in the room. Works like a champ.
Besides the knobs to control master volume and individual power sent to each cab, the front panel has two more toggle switches, one to mute the speakers (and phones, but not tuner), and one to cut the effects loop in and out of the signal path. The effects loop cutout can also be controlled by a foot pedal I don't have.
So to sum up:
knobs: Master volume, crossover frequency, amp1 output, amp2 output, contour, compression, and drive.
Bass, Low mid, mid, high mid, treble knobs for semi-parametric eq, with frequency sweep knobs for the three mids.
switches: active/passive input, graphic EQ (footswitch optional), effects loop (footswitch optional), bi-amp crossover enable, mute. Finally, a master power switch.
Moving around to the back of this beast:
First, we have the footswitch jack for foot control of graphic EQ and effects loop (in and out of signal path).
Then we have the outputs for speaker 1 (low frequencies, the 1x15), speaker 2 (high frequences, the 4x10), or one central output for bridged mode. Each cab output accommodates either speakon (high power) cables, or 1/4" jacks.
Below the speaker outputs are four more jacks, one for a tuner, one for headphones, and 1/4" jacks for biamp send/receives for amp1 and amp2. These allow the amp outputs (in biamped mode, the output frequences are controlled by the crossover knob on the front) to be sent to an external processor if desired, and then returned. Alternatively, these signals can be sent to a power amp and not returned.
Note that plugging in headphones doesn't mute the speakers. If you wish to listen only through headphones, you must unplug the speakers physically from the head.
There are 1/4" jacks for effects loop send and receive.
Finally, there is a section for direct line output. In addition to the output 3-prong jack, there is an output level knob, and buttons to control whether the straight bass input is sent out, or whether the master board out there sees the effects of all those knobs and switches (the raw or processed input).
The head itself weighs 23 pounds.
Now for my sound impressions:
First, this head has all the power you might want for any reasonable application. I like that you can send the processed signal to the PA system if you want. For my little stack of a 1x15 and 4x10, I doubt I'll ever turn the master volume up as much as halfway - and I'm on the active input! Power is not an issue.
The equalization has been hard to judge, because there is just so damn MUCH of it (including what's on the active bass itself). I've found that just a trifle of graphic EQ bass boost and mid-treble cut, about 3db of each, makes a listenable sound, but no EQ at all is also very nice. In short, if you're looking at a Line 6 combo unit with half a dozen different sound-effect weirdness sounds, you aren't going to want the BX1200. Its main strength seems to be clean, flat power, very modest tone modification, excellent handling of room acoustics, and moderate compression.
I did try plugging a flanger into the effects loop. Note that the input into the effects is post-EQ, compression, contour, and drive. This worked as expected, adding a little ring and body to the bass if done tastefully, or producing squealing weirdness if cranked up.
For what it's worth, the head is well shielded against hum.
I received the unit about 10 days after ordering it. There was a brief backorder of a few days at the time.
For $650, I just don't think you can beat it.
There's only one input jack, with a toggle for active or passive bass circuitry. I've only used the active switch position.
I'm using it to drive SWR cabs, a 1x15 and a 4x10 (older US-made models). The SWR 350x head would not drive this setup at any useful volume without clipping. The Carvin has more than ample power to drive it in three different modes:
1) Bridged mode (chained cabs), 1200W into 4 ohms (2 8-ohm cabs). I haven't tried this one.
2) Standard mode, two monobloc amps run one into each cab, producing up to 275 watts per cab. It's possible to cut the wattage to each cab separately.
3) Bi-amped mode, with an internal crossover, 275w each per 8-ohm cab. This permits me to send (for example) <200Hz inputs to the 1x15, and >200Hz to the 4x10. In this mode I can also control the watts sent to each cab.
For my setup, the bi-amped mode makes a strikingly audible difference, and sweeping the crossover frequency makes a big difference. This is a really nice feature. There is a toggle switch between bi-amped and standard modes. For bridged mode, you need to rewire everything.
There's a drive knob which adds a bit of overdrive to the pre-amp (and makes things louder, so you need to cut the master volume). It's not intended to be an overdrive effect, but it adds a little bit of tube effect.
There's a compression knob up to 3:1 compression (I've had best luck at about halfway, so I can control any reasonable dynamics myself, but errors get compressed away)
There's a contour knob that controls the amount of mid-frequency cuts for slap sound. This is a good deal faster and easier than trying to adjust the 9-band graphic EQ for scoop AND allows the graphic EQ to be used for something different.
Which gets me to the 9-band graphic EQ. You get plus or minus 12db centered on frequencries from 50Hz to 5KHz. I've found these to be easier and more intutive than twiddling with the EQ on my bass itself. There's a toggle switch to take the entire graphic equalizer out of the path (and an optional foot switch to do the same thing, which I didn't buy). This lets you use the contour knob for some numbers, then cut that and switch in the graphic EQ for others. It's pretty easy.
Beyond this is a 5-band semi-parametric setup - bass and treble shelf controls for below 50Hz and above 5KHz, and a 3-band parametric in between, permitting plus or minus 12db boosts or cuts at three dialable frequencies from 100Hz to 5KHz. So far, I've been using this as a notch filter to cut frequences that cause resonating rattling of whatever starts vibrating in the room. Works like a champ.
Besides the knobs to control master volume and individual power sent to each cab, the front panel has two more toggle switches, one to mute the speakers (and phones, but not tuner), and one to cut the effects loop in and out of the signal path. The effects loop cutout can also be controlled by a foot pedal I don't have.
So to sum up:
knobs: Master volume, crossover frequency, amp1 output, amp2 output, contour, compression, and drive.
Bass, Low mid, mid, high mid, treble knobs for semi-parametric eq, with frequency sweep knobs for the three mids.
switches: active/passive input, graphic EQ (footswitch optional), effects loop (footswitch optional), bi-amp crossover enable, mute. Finally, a master power switch.
Moving around to the back of this beast:
First, we have the footswitch jack for foot control of graphic EQ and effects loop (in and out of signal path).
Then we have the outputs for speaker 1 (low frequencies, the 1x15), speaker 2 (high frequences, the 4x10), or one central output for bridged mode. Each cab output accommodates either speakon (high power) cables, or 1/4" jacks.
Below the speaker outputs are four more jacks, one for a tuner, one for headphones, and 1/4" jacks for biamp send/receives for amp1 and amp2. These allow the amp outputs (in biamped mode, the output frequences are controlled by the crossover knob on the front) to be sent to an external processor if desired, and then returned. Alternatively, these signals can be sent to a power amp and not returned.
Note that plugging in headphones doesn't mute the speakers. If you wish to listen only through headphones, you must unplug the speakers physically from the head.
There are 1/4" jacks for effects loop send and receive.
Finally, there is a section for direct line output. In addition to the output 3-prong jack, there is an output level knob, and buttons to control whether the straight bass input is sent out, or whether the master board out there sees the effects of all those knobs and switches (the raw or processed input).
The head itself weighs 23 pounds.
Now for my sound impressions:
First, this head has all the power you might want for any reasonable application. I like that you can send the processed signal to the PA system if you want. For my little stack of a 1x15 and 4x10, I doubt I'll ever turn the master volume up as much as halfway - and I'm on the active input! Power is not an issue.
The equalization has been hard to judge, because there is just so damn MUCH of it (including what's on the active bass itself). I've found that just a trifle of graphic EQ bass boost and mid-treble cut, about 3db of each, makes a listenable sound, but no EQ at all is also very nice. In short, if you're looking at a Line 6 combo unit with half a dozen different sound-effect weirdness sounds, you aren't going to want the BX1200. Its main strength seems to be clean, flat power, very modest tone modification, excellent handling of room acoustics, and moderate compression.
I did try plugging a flanger into the effects loop. Note that the input into the effects is post-EQ, compression, contour, and drive. This worked as expected, adding a little ring and body to the bass if done tastefully, or producing squealing weirdness if cranked up.
For what it's worth, the head is well shielded against hum.
I received the unit about 10 days after ordering it. There was a brief backorder of a few days at the time.
For $650, I just don't think you can beat it.
