I had no idea most class A type amps switch into alternate AB power after a set threshold. This is really cool though. Just looking for advice on a great solid state choice in the 2k - 3k range. So far Pass designs are king. Let me know if there are any others. Bryston??
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Most folks around here know that the boys at Coda were Threshold designer engineers... Threshold is the company that Nelson Pass sold before starting Pass Labs... The Coda stuff definitely has the Pass characteristics and run very high levels of Class A. You can occasionally find a few of their amps in your price range. |
puffbojie -- What’s the reason for your inkling towards class A amplifiers? I’m not trying to discourage you, but going for a pure class A amp (i.e.: which rules out high bias or class A to A/B shift designs) - with the potential and worthwhile sonic advantages they carry - within a limited budget and high wattage requirement is nigh on mutually exclusive. It seems to me there’re a lot of "class A" designs labeled as such which really aren’t, and in case you’re intend on pursuing true, pure class A I’d say stick with what is really that (and forget about 100+ watts, let alone >50 watts), or go with any other design that isn’t strictly class A and stop thinking about them as anything other. Largely I believe it’s a marketing ploy to boast class A capabilities which really aren’t (instead pseudo this and that), not least connecting them with high wattage specifications - a combination that’s supposed to sell as an audiophile’s (sonic) wet dream. There are likely class A/B designs out there that, while they wouldn’t claim to be anything other than class A/B can have sonic traits that go closer to pure class A designs than those designs that flaunt class A "to some extend." A number of “tricks” have been used to claim both high power and Pure Class A. While it is perfectly OK to bias an amplifier into partial Class A while allowing additional power for short term transient headroom often this is done without declaring the true operating parameters. Commonly the amplifier is claimed to be “Pure” Class A, and yet only delivers Class A performance up to a percentage of its output power. Other schemes have been invented that cause the amplifier to vary its Class A operation depending on how loud the music is. The idea being that it only runs in Class A to as high a power as needed moment to moment, and thence avoids the heat. This causes the music to modulate the amplifier’s design parameters, and in turn introduces other forms of distortion. http://www.pureaudio.co.nz/?page_id=165 To my mind it’s about being honest with the design a manufacturer is going after, and call it by its right name. I’m aware that where class A to a limited extend (i.e.: pseudo) is more or less (usually less) openly declared is to inform the potential buyer what may be inherent to the design, but it’s still trying to sell a trait that in its diminished state may have marginal effect among many other design decisions, or even severe compromises. If anything I’d go after designs that are topologically simply and "no nonsense," and if you’re still going after pure class A I’d have a keen eye on what really is and what isn’t (and lower your wattage expectations to no more than 30-40 watts). From personal experience I can recommend the pure class A amplifier Belles SA-30 (30 watts), but its class A/B sibling SA-100 is said to be sonically very close. I can imagine those can be had used in the $3k range. |
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