I have a '59 Fisher X-100 that was restored a few years ago. The tubes are: '58 long black plate RCA 12AX7's Reflektor (USSR) EL84's GE phase inverters Mullard Blackburn rectifier Since upgrading my speakers to Spendor SP3/1R2's, I've been less than thrilled with the Fisher. I don't think that efficiency is the issue - the Spendors are 88dB efficient @ 8 ohms, and there is no indication that the Fisher is working overtime (the volume is normally set around 9 or 10 o'clock). Conventional wisdom says that vintage tube amps typically have a lush, fulsome character, and yet my Rega Brio-R when paired with the Spendors has a fuller midband, more bass, and a less strident top-end. The Fisher has less weight and is tonally unbalanced vs. the Rega. (All of the tone knobs on the Fisher are set to 12 o'clock, ie: flat.) I have experimented with driving the Spendors off the Fisher's 4 ohm taps, and that sounded really awful - dull and slow. So what's going on here? Is this simply a synergy mismatch or is this indicative of the Fisher needing some attention? Or are the Spendors just revealing the limitations of the Fisher?