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Looks pretty good Michael. The specs are in line with "ek-spec-tations." A little low on the EL34, but AB1 is higher bias than normal, and more class A means more heat, less power. Class A 845 is about right. They don't seem to be exaggerating power output too much, that's a good sign. The big thing you want to look for is the quality of the output transformers. Do they make their own? The physical appearance can be deceiving if they are potted inside a large can. That's where the money goes, or doesn't. Big, clear and powerful sound depends on good trannies and good parts inside. Also get a look at the insides, look for neat construction, not rat's nest. How much negative feedback? The distortion specs given are only at 1W into a resistor, the easiest possible load so disregard that. Adding negative feedback reduces distortion and allows more power at 1% distortion, but too much feedback starts to sound closed in unless they are very skilled. A poor transformer will have higher distortion at full power. 5-15dB is typical range of feedbck for tube amps, but sometimes they try for no feedback, that's when you need to see the power spec at 1% THD. It's hard to make high power, low distortion without feedback. Impossible without great transformer and circuit design and individual fine tuning, which is probably not the case with these models. In general, you'll want >91ish dB sensitivity speakers for the 20W amp and >88dB for the 40W amp. If you play symphonies add 3dB sensitivity to the speakers. If using DIY speakers don't forget to subtract 3dB from your midwoofer sensitivity for the baffle step correction. Did you see Hugh's Black Friday sale on Melody?
A few weeks ago I attended an audio show in Taichung, Taiwan. One of the rooms was filled with tube audio gear - amps, preamps, DACs. All the components that went into creating each of the amps, preamps, and DACs are made by the same company. This is to say they have total control over the quality (or lack thereof) of all the pieces used to build the audio components. Is there anyway you (the knowledgeable tube amp enthusiast) can tell whether this is a decent amplifier by looking at the specs I have pasted below? If you need more info, what information should I ask the company to produce? Max Output: 35W x 2 CLASS AB1Power Dissipation : 240WTube : KT88 x 4 6922EH x4 (6DJ8)THD : < 0.05% at 1wI/P Sensitivity : 0.7 VrmsO/P Impedance : 4 Ohms ~ 8 Ohms/16 OhmsI/P Impedance : 100K OhmsFreq. Response : 10Hz ~ 80KHz (¡Ó0/-3dB 1w )Power : AC100/110/120V; S.W.; 50/ 60Hz Signal to Noise Ratio : 90dBDimensions (H x W x D) : 420 x 410 x 290mmWeight: 30KgThank you for any responses.Michael