I used this rig live already and the TX600 worked well with both one 1x12 or two 1x12 cabs.
Honestly, at the beginning, I had the same impressions, lack of power making me thinking, 600w really?
But then I experimented to understand better how this head works and I found out that the TX600 works more as a ClassA guitar amp than a general Class-D light bass amp. I'll try to explain best I can:
All the ClassD I had until now (the last one was the Aguilar TH500) works more or less at the same.
Let's resume in this way, you get an extremely punch and high output level already when you turn the master from 7 to 10 o'clock. You can go ahead usually up to 1-2 o'clock keeping listening to an increase of volume than usually you start to hear the bass clipping and you have to stop the volume run.
Even if you low the gain, you will hear a very low increase up to the maximum level. Each time I played live with my last rig 1-2 o'clock was the maximum I can get.
The TX600 works differently and to understand better you need to abandon the visual idea to have high output with a small amount of your master volume knob.
First of all, it's important to set the gain at a maximum possible level before it clips (guitar tube amp concept) and to help to reach that, the TX600 gain start to flashing yellow when you're reaching the top and red when you got it. So yellow is good or a little less is better.
Then you will see how the Damp works. The control has a real gradual increase.
From the 7 to 11 o'clock the range increase of the volume is very slow, probably designed for practicing home/studio, than from 11 to 1 o'clock even if the knob range make a short run, the head start to increase the volume faster, than from 1 o'clock to the maximum the increase is very fast, short increases and you will hear several differences even between two dots, a fast boosting of power to make you think, hey what's happening it?
The fun thing is that, if you set the right amount of gain as well the preamp (speaking of, is a boost type, not cut/boost, very important difference) you can have the master knob to the maximum, with all the power output and never a clipped tone.
I attached some pics to resume the explanation. If you need more help please let me know.
Ciao.
View attachment 2863592
View attachment 2863593