Don't know about Butler but if you read the fine print for Monarchy, it's "no global negative feedback" at the bottom of some page. At least it was for the SE-100.
Zero Negative Feedback Amps with High Power
I am interested in getting "feedback" (heh) from posters here on high-powered zero negative feedback amps. Three hybrid tube/ss models that come to mind are the Monarchy SE 160 & 250 or the Butler TDB 2250.
What's your general opinion on zero feedback amps? Is there an appreciable different in sound quality?
Care to comment on high powered hybrid tube amps? Or the models I list above? Are there other alternatives out there that I should consider if I want to go down this route?
Info about myself, to be helpful: I only have experience with negative feedback ss amps, fyi, and run low-sensitivity speakers (Maggies). I listen to classical music mostly and really prize tonal balance and weight rather than things like sound stage or bass impact.
What's your general opinion on zero feedback amps? Is there an appreciable different in sound quality?
Care to comment on high powered hybrid tube amps? Or the models I list above? Are there other alternatives out there that I should consider if I want to go down this route?
Info about myself, to be helpful: I only have experience with negative feedback ss amps, fyi, and run low-sensitivity speakers (Maggies). I listen to classical music mostly and really prize tonal balance and weight rather than things like sound stage or bass impact.
9 responses Add your response
Ralph - I'd say 150W into 8 ohms and above. But I was really trying to get discussion going on a topic that struck me as curiously ignored. There's a significant minority of audiophiles who like high-sensitivity speakers so they can use zero-feedback design amps and there are a significant minority of audiophiles who like panels and other low-sensitivity speakers. Those tastes aren't mutually exclusive necessarily and the intersection, the amps I asked about, seem to receive little attention. I wanted to elicit experiences and opinions. |
You might want to read this: http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php Can't agree with the post directly above, unless you include the idea that the amp is mismatched with the speaker. IME amps without feedback handle more complex material with greater dexterity. |
I'd hazard a guess that true "Zero Negative Feedback Amps with High Power) are not too common. High powered amps without global feedback might be more common, Ayre, Pass and Threshold come to mind, I guess there are others. IMHO (YMMV, etc.,etc.) judicious use of feedback might be getting more negative feedback (ha!) than is warranted, in fact it might be beneficial. There are many factors to be considered when choosing an amp, over stating the importance of one or a few factors out of context of the whole might cause one to dismiss some other wise good or even better candidates. But most of us do seem to prioritize things differently and if that's tantamount in deriving your short list, I suppose it's as good as any. It wouldn't be to me. |
My VAC Phi 70 monos (300B PP no feedback) and Counterpoint are of zero NFB design. Transient control is a bit of an issue with them. They sound very "open" and "airy" when playing simple passages. But symphonic stuff sound a bit congested and "fuzzy" compared to amps with NFB like the better VTLs and Tube Research Labs (SS and tube). |
Some feedback is said to improve the whole spectrum of sonic experience tightening up just about all frequencies. Have you auditioned no feedback amps and still find that's what you want? If so there is a custom amp builder in Canada Maple Tree Audio by Prof. Loyd Pepard who can probably build what you want. |