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As the graph demonstrates (3W, 4Ω, 30Hz to 20kHz), THD always ties directly to correct bias. Curve 1 shows proper bias. Curve 2 overshoots by 10%, curve 3 by 30%. The difference of 0.2% and 4% THD between correct and pushed settings is significant. Sadly, these days very few valve amp manufacturers run fixed bias. Even though it offers higher output power and more accurate bias when properly implemented, most don't trust their customers. If owners must face multi-meter probes and hard-to-reach access points of course, they shouldn't be trusted. Auto bias thus became the default hifi solution. Yet it doesn't allow for tube monitoring. Many an upset amp has been returned for service only to be diagnosed with a faulty tube. The customer feels stupid, the manufacturer grudgingly absorbs warranty ship charges without proper cause. Yamamoto's auto bias gets around this with a meter that shows actual bias current but they're in the distinct minority. [Below, Octave's High-End 2009 exhibit with Dynaudo Sapphire speakers.]

For such reasons, Andreas Hofmann prefers fixed bias. To not confound owners, he has implemented an unusually precise and idiot-proof scheme with differently colored LEDs that are coupled to precision op amps. Without any tech know-how, anyone can monitor and set this bias to perfection. It's German ingenuity at work, no hard hats required. Perhaps that's another reason why Octave is big in Japan. That country is notoriously selective about its hifi imports. Hopeful parties routinely deem it the hardest market to break into. With Octave operations spanning two decades, the firm has a proven track record and its models enjoy unusual longevity within their lineup [Jubilee preamp below].

The company has shown stability and a very conservative approach both to business and in how its products require no hand holding or outré speakers to work as advertised. You could call it Tubes for Dummies and Everyman. Which still fails to justify why one should continue bothering with the archaic vacuum tube. As proud new owner of the MRE-130 monos and numerous SETs, I naturally have an opinion. But I also count amongst my review gear ModWright's massive KWA-150 all-transistor machine and Nelson Pass' FirstWatt F5. If Octave has laid to rest the usual power/drive concerns to make speaker selection no longer contingent on output devices (or vice versa), which type of properly liquid listener might gravitate to the MRE-130s over transistor behemoths?

From Octave's forum, we learn that "...usually, we outfit the two ECC82 positions of the MRE-130 with different types due to their different functionality. The one in the middle tends to be RTF (former East Germany) or GE NOS issue depending on availability. The other used to be a Yugoslav EI currently not available. GEs closely approach the RTF. Current production options would be the ECC 802 and ECC82 by JJ (we prefer the 802 and it is suitable for both positions). GE types are also marketed as 5814As (sonically a bit slimmer) and occasionally one finds a GE 6189 which is virtually identical to the 5814." Here's what's under the hood.