Tube amps and speaker ohms

Tvad, This info came from the horse's mouth. I've never seen it in print, its what Ty told me.

Re impedences, there was an excellent thread in which Duke participated, within the last 6 months, where in not only were speaker impedence loads discussed but amp output impedences were also discussed. Amp putput impedences are seldome discussed and their impact is not generally understood. Most folks assume they are constant but they are not, they rise and fall with frequencies and have considerable impact of the sound which is produced by a speaker. You might be able to ferret it out by looking up some of the threads in which he participated. And, I think you are right the Ralph could help explain, but I can't recall if he participated in that particular thread. Maybe you could start a thread and get a discussion of this going and invite Duke and Raplph to participate. This may help you. Good luck......

Thanks, Newbee. Personally, I believe it'd be beneficial to Ty's potential customers if he published some impedance specs, but in the end that's his business. I'm only speaking as a consumer.

Though I realize they vary, I'm not that interested in delving into amplifier output impedances. No amp manufacturer publishes these specs, so it's info not readily available to buyers, which frankly makes Stereophile's reviews with bench tests so useful. It'd be a PITA to rent the required testing gear, and to learn to bench test amps that I buy or bring in to demo.

I'll trust my ears based on choosing gear that meets general guidelines. The Leben/Castle combo works. The Rogue/VR4 combo works. Overall, more amps work with higher impedance loudspeakers than with speakers that have low impedance dips.

For me, this is the "take away" from the thread you referenced in your most recent post.

I am fast coming to the conclusion to stop looking at "watts per channel" as an efficient means of determining how powerful an amplifier is.

My experience tells me that the power supply and transformers play the biggest role in this, as opposed to whatever reading was obtained when the amp drove a 1 KHz signal through an 8 ohm resistor, or what a company chose to rate an amplifier. Music is not a test tone, it is dynamic, and loudspeakers are not an 8 ohm "dummy load", they are FAR more complex.

Tubes, also seem to have something to do with this whole thing. For example, a 2A3 has less "measured" power (usually, about half as much) than a 300B, but in my experience, the 2A3 does a better job in providing "real world" power to a loudspeaker than a 300B. Similarly, a KT77 looks SO close to an EL34, but they are very, very different tubes, with very different power characteristics. And, for what it's worth, a KT88 is a strong tube. At least as strong as a 6550 or KT90, though the Ei KT90 tube seems a bit more extended in the lows.

In no way am I saying that measurements are something to completely ignore, but clearly, the engineers designing these tests have yet to figure out what is the important criteria, and the means to go about testing it. Until I am told of a better way, playing music through an amplifier and a pair of speakers, and listening with my two ears is going to be the way I test...

Instead of playing games why not spend 2K and pick up a pair of excellent hurricane amplifiers and put power worries to rest.

Thanks for the responses - seems like a real friendly forum.

To some extent, it looks like almost any tube amp will represent a bit of a gamble as long as I retain the B&W 804S's. That's why I was looking at the more affordable chinese brands first, before I consider investing more.

I've not long had the speakers (love the midrange when paired with my Sugden, but the combo tends towards brightness), but would definitely consider trading them for some similar sized speakers that present an easier load and would widen my choice of amps. I always wanted to audition some Spendors but never got around to it - maybe I should now.

I think I'll probably go for a tube amp first though and just see how it works. Another amp I was considering is the Ming Da MC34-AB. Rated a little higher in terms of wpc, but using EL34's I believe. It seems to be more well known, so there there may be someone here who's tried one with B&W 8 series.

Above all, I don't think I want to stick with a transistor amp as, from what I've experienced so far, tubes seem to reproduce music the way I like. A smoother top end, an open midband and a full-bodied bottom end. I do like a powerful bass, so that may present problems given that my speakers appear to demand a lot of watts to produce that. To be honest, I also like the idea of tubes because I can then experiment with different tubes in order to 'fine tune' the sound - something I've enjoyed doing with my guitar and headphone amps.