I had two sets put up. An SVT Blue Line with a straight back from '69 or '70 (etched lines) and my 78 SVT with my 78 towel bar. The Blue line stack. Well conserved, recently retubed (not sure about the caps) and the straight back. VS My 78 stack with towel bar. Also recently retubed and recapped. First I tried my 78'er. Sounded OK. Then switched over to the Blue Line stack. This one sounded FANTASTIC! Tighter, louder, warmer, rounder. So much better. So at first I thought I was getting sick... was this my SVT I loved so much. I was thinking of selling mine and buying the Blue Line. Thank God my guitar tech came along and adjusted the bias. Now the two heads had a comparable bias. WOW, world of difference! Now my head sounded even better than the Blue Line. As loud, as warm but tighter! After that I could start the 8x10 A/B test. The straight back IS the better sounding cab. Louder, rounder, punchier. Everything the 78'er has but better. A week after that, I played a show with a guy who normally uses an 06 Ampeg 8x10. This time he used my 78'er. He was blown away. So much tighter, clearer and punchier. Hahaha! I'm now thinking of buying that straight back. Test drive the three 8x10's (I also have a 73'er which I couldn't test, a 78'er and the straight back) and sell one of them. The 'worst' sounding that is. Conclusion: cabs make a difference. A lot! But what struck me the most was the whole bias thing. Mine was biased at 75 and the Blue Line at 60. Gonna do some more testing with this.