Tube amp heads can sound really great; when made in the right way and with just the right amount of care and attention with regard to component selection, they can blow pretty much any transistor amp out of the water from a tonal perspective. Part of the reason for this is just how well such amplifiers go with appropriate speaker cabs.
Good tone is the cumulative result of every piece of kit in your effects chain and rig. Not only is every stage just as important as the others, but the ways in which stages interact with each other is also of extreme importance when crafting a good solid tone.
Tube amplifiers give off a great, warm tone thanks to the imperfections of vacuum tubes when pushed even slightly beyond their natural limits. They create a phenomenal sound which just makes you feel all warm and fuzzy on the inside. This sound has a lot to do with the way in which your pre amp and power amp tubes work together, but what is also important is that you have a speaker setup which will truly represent that wonderful tone, instead of taking away from, or even obstructing it completely.
As we’ve discussed about how to choose a right speaker, I believe you’ve got some good skills on it. But there are more things need to be paid attention to. Even with amp heads, your speaker type and configuration should always be considered as an important part of your sound, as the type of speakers inside of a cabinet, the number and angle of those speakers and the onstage placement of different speaker cabs can have massive implications for your overall tone in the end.
Angled speaker cabs, single, dual, quad formation cabs, reflex ports, open/closed backs and parallel/series configurations will all have a massive effect on your sound. When considered properly and used in an appropriate way, your speakers will compliment your tube amplifier perfectly, and truly become a full part of the sound. Used in the wrong way, and all of the work put into crafting a good tone with your guitar, effects pedals and amp head will all be practically for nothing. My advice: spend the time to experiment with your speakers, and you can get them to work for you instead of against you.