Ralph, re your post about 4-16 ohms at various frequencies not being a problem if the tube amp has 10db or high NF seems correct. As you know, I posted links to Soundstage and Stereophile bench tests of the ARC VS-115 and Ref 150 tube amps. Both amps use similar amounts of NF (about 12 to 14db) and have similar output impedances of about 1 ohm off the 8 ohm tap. The output FR of both amps was about +/- 1 db over the audible FR spectrum when driving a simulated speaker load that had similar impedance fluctuations as staed above. Atkinson said the output FR might even be tighter off the 4 ohm tap where output impedance was 50 to 60 percent of the 8 ohm tap output impedance.
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- 24 posts total
- 24 posts total