I did an A/B comparison with them to a real Pre Rola G12H30 55 hz (102 014 Pulsonic cone) with the USA Celestion rep 17 months ago. They are definitely brighter than a real Pre Rola, but less bright than the Anniversary. They are also louder than a Pre Rola by a good 25%.
When A/B'd to the Pre Rola, it approximated the same mid tone, but only after I turned the treble on the amp completely off. With the PR, you could you use your treble knob. The lows were also higher voiced than the PR as well.
The Celestion rep (don't choke now!) told me that since they were built to new specs, and not broken in, that he figured playing them 4 hours per nite, 4 nites a week, for four months, at club volume would get them loosened up and broken in. I hope this doesn't scare you guys off of them, but it sure did scare me.
I'm lucky to play my guitar "at club volume" about 2 hours per week, not 16. By the time I did the math, using the Celestion rep's calculations, they would break in after about 32 months.
I hear the 20 watt doesn't take as long to break in though. Go figure. And the 20 watt models in the 1974X come "pre-aged" from Celestion, but are proprietary to the Marshall 1974X 18 watt combo.
Celestion should probably consider doing that to the Heritage H30...however, YMMV.
