Confused about matching Genz Benz Amps and Cabs

[Dinosaur Punk]

I really interested the Genz Benz Shuttle Max 12.

Ed Friedlands review here explains how this is really 2 discrete amps, each capable of 600 Watts into 4 ohms.

The Genz Benz cabinet site here shows only the GB 212T-UB, GB 410T-UB-4, GB 810T-UB as being 4 ohms out of the box.

I was hoping to pair the GB 1288T-UQ and the GB 212T-UB for my full range rig, but it doesn't look like the GB 1288T-UQ is available in 4-ohm configuration.

Would it result in lop-sided sound to run the 4 and 8 cabinets simultaneously? Would it damage the amp? It would probably be difficult to balance output...

Also, I am hoping to also use the same amp in a practice configuration by pairing it with a smaller 8 ohm cabinet. Is anyone doing this? What's your experience? I am thinking the STL-12T or the STL-210T paired with one side of the ShuttleMAX 12.0 will take the power down to 300 watts and therefore be compatible.

Lastly, is anyone using either of these configurations with a low B, active bass? Wondering how it handles the low-b configuration.

[billfitzmaurice]

Just because an amp is rated at 4 ohms doesn't mean you should use it with one cab at 4 ohms. Most of the time you shouldn't, as it limits future expansion, and there's absolutely no benefit to "getting all the watts out of my amp".

[Dinosaur Punk]

Thanks for the reply.

The Genz Benz ShuttleMax 12 actually has separate outputs, each for a 4 ohm load.

I am not sure I completely agree with your statement that "there's absolutely no benefit to "getting all the watts out of my amp"." This is based both on my (admittedly unschooled) knowledge of what happens when a bass amp reproduces a tone and also on my anecdotal experience recently comparing two different amp configurations in the same setting. Essentially the amp with more head-room provided much greater clarity as well as low frequency, even if the overall perceived volume was roughly the same. And I noticed the change in sound quality before I even knew there was a different amp in the mix, so it was definitely noticeable.

I am actually currently running my Trace-Elliot AH500-X at 50% power because I generally pair it with an 8-ohm cab. it sounds great. However, when it's got a full 4-ohm load, it doesn't change the sound much, but the amp acquires a certain liveliness and clarity that it doesn't show with just the 8-ohm cab. Just my perceptions.

[steve_rolfeca]

Originally Posted by Dinosaur Punk

I am not sure I completely agree with your statement that "there's absolutely no benefit to "getting all the watts out of my amp"." This is based both on my (admittedly unschooled) knowledge of what happens when a bass amp reproduces a tone and also on my anecdotal experience recently comparing two different amp configurations in the same setting. Essentially the amp with more head-room provided much greater clarity as well as low frequency, even if the overall perceived volume was roughly the same. And I noticed the change in sound quality before I even knew there was a different amp in the mix, so it was definitely noticeable.

I am actually currently running my Trace-Elliot AH500-X at 50% power because I generally pair it with an 8-ohm cab. it sounds great. However, when it's got a full 4-ohm load, it doesn't change the sound much, but the amp acquires a certain liveliness and clarity that it doesn't show with just the 8-ohm cab. Just my perceptions.

Most of us have experienced the sound of an amp "opening up" when running into a lower impedance. The trouble is, it's really hard to do an apples-to-apples comparison.

Usually, we get to 4 ohms by adding a second cabinet. How much of the sonic benefit is from the "extra" watts, and how much is simply because we're moving more air, and getting the speakers up closer to our ears?

Even if you can get hold of a 4-ohm version of the same cabinet, I've heard it from reputable sources that 4 and 8 ohm drivers tend to sound different because of the changes that have to be made to the voice coil, in order to vary the impedance.

[steve_rolfeca]

Originally Posted by Dinosaur Punk

The Genz Benz cabinet site here shows only the GB 212T-UB, GB 410T-UB-4, GB 810T-UB as being 4 ohms out of the box.

I was hoping to pair the GB 1288T-UQ and the GB 212T-UB for my full range rig, but it doesn't look like the GB 1288T-UQ is available in 4-ohm configuration.

Would it result in lop-sided sound to run the 4 and 8 cabinets simultaneously? Would it damage the amp? It would probably be difficult to balance output...

Also, I am hoping to also use the same amp in a practice configuration by pairing it with a smaller 8 ohm cabinet. Is anyone doing this? What's your experience? I am thinking the STL-12T or the STL-210T paired with one side of the ShuttleMAX 12.0 will take the power down to 300 watts and therefore be compatible.

Back to the original questions, you won't hurt the big SMax if you run it with unbalanced loads. But with no level trim for the two power stages, you won't be able to match levels.

Judging from the specs, it doesn't look promising. GB quotes the 212T as 102dB at 1 watt / 1 meter, vs 97.5dB/1w/1m for the 1288T-UQ. With the 212T being driven by the full 600 watts, and the less sensitive 1288T-UQ only receiving 375, you wouldn't hear a whole lot of the Quad. It would probably make more sense to go with either a pair of Quads, or a pair of 212's. Regardless, any of these stacks would be stoopid loud...

Running a smaller 8-ohm cab at 375 watts for practice won't be a problem, as long as you keep your levels within reason.

[RickenBoogie]

+1 there would be a bigger advantage to running two of the 4 ohm 212's than running one of each. What you gain by running 2 identical cabs is equal to more than the sum of the parts. It's like 1+1=3.

[agedhorse]

No problem at all running one channel at 4 ohms and the other at 8 ohms, and the balance should be close enough to work well with any of the cabinet in the line. There's no advantage or disadvantage to working within the 4 ohm minimum load other than the advantage of increased power output. The amp is DESIGNED to operate properly at 4 ohms per channel.

[Dinosaur Punk]

Originally Posted by agedhorse

No problem at all running one channel at 4 ohms and the other at 8 ohms, and the balance should be close enough to work well with any of the cabinet in the line. There's no advantage or disadvantage to working within the 4 ohm minimum load other than the advantage of increased power output. The amp is DESIGNED to operate properly at 4 ohms per channel.

Thanks very much for the authoritative response. I just (literally minutes ago) ordered the ShuttleMAX 12.0. Part of the reason I did this is Genz Benz's (your) active presence in the TalkBass community.

I haven't made a decision about cabs yet, but it's nice to know I've got options.

[agedhorse]

Glad you are "on board" man!

You have plenty of options, that's what the Max 12.0 is all about.