Based on your detailed assessment, it sounds like I may lean towards the Celsetion A in the LTD or the Swamp Thang speaker. (I think?)
I tend …
That’s an excellent motif to break down some speaker types. The differences between JR LTD and JR IV are basically in looks and speaker, as the circuit is very similar and based on the same tube layout. 😉
So this left us with the Jensen C12N in the LTD and, as you mentioned, Celestion Greenback, Eminence Private Jack, Eminence Swamp Thang and there is also a version with the Celestion A-Type. Lets go! 😛
In my opinion, you get four different flavors, so it’s better to choose wisely and towards your expectations regarding the amp!
The A-type has some scoop on the mid-range, well-balanced and pronounced highs without piercing trebles, and the lows are very present without flabbiness. It’s a speaker that is based on British philosophy. You can expect a good airy clean sound with lots of headroom and great low end in the dirt spectrum.
The Greenback is a classic! Tamed highs, great attack on the mid-side and the lows are not so pronounced but still have a significant presence and behavior. Those have a flatter response than the other 3, they are punchy and dynamic, and you can get them to roar without any aggressivity on the high-mids and high frequencies.
The Private jack is also a British-focused speaker. It’s more aggressive on the high frequencies for sure; the low end is very tight and with no exaggeration, and the mids are round with less presence on the upper-mids side, but still very present. The balance of this speaker is known, that classic British flavor with all the frequency range positioned to balanced with the slightly more pronounced highs.
The Swamp Thanks is an American brother of these! This is the speaker that will behave better with more aggressive and dirtier tones! More Sustain, more dynamics, tight, fat and chunky on the lower frequencies, midrange full of attack but rounded and a significant presence on the high frequencies. So if you want to hit some drive this is the one for you 😛
The Jensen C12N is another American flavored speaker; some will say that it is the Blackface one in this collection! The highs are very musical and defined, the mids are very dynamic and behave well, the lows are tight and powerful. They are known to have a great overall attack and the trebles being a little fizzy, but nothing that you cannot tame immediately with the eq in the amp. Beautiful roomy and rich cleans and very warm dirtier tones. Excellent balanced and natural sounding speaker.
I based my opinion on the charts that I have attached for your reference, and in my experience of almost 15 years of being an amp tech. I got to play so many types of speakers and installed so many of them that I felt like a fish in the water writing these lines 🙂
Lets us know which one you choose