Originally Posted by pyltn
Read this conversation with interest. Thought I would add what I know about valve amps. I have a 60 watt per channel hi-fi valve amp. As far as valve sound goes I would describe it as a slightly smoother version of solid state amps. Compared to my own solid state amp (an Arcam Delta) my valve amp (an Icon Audio Stereo 60 MKII) still gives you all the detail and power that the Arcam does but somehow in a smoother way. It's a hard thing to define - sort of Solid State with some of the harshness removed. Less clinical I suppose. But not lacking in detail. And it sounds great on all the music I put through it - rock, pop, classical, reggae, electronica......
As for speaker matching, I've had no problems. I own a pair of PMC OB1s which are average efficiency and the Icon produces all the power I could need.
Regarding valve replacement, power valves will generally wear out before the pre-amp valves as they are working a lot harder. All valves are always going to be less reliable than transistors as they are subject to electrical but also mechanical wear and tear – each time an amp is switched on the glass envelope and delicate metal structures inside heat up and expand, then cool and contract when switched off. This expansion and contraction will eventually cause a valve to wear out. Having said that my Icon Audio is on it’s original valves after around 4 years use. And I also have a Fender Deluxe amp that is on it’s original valves after about 10 years. Replacing valves is pretty straight forward, just be careful of the glass. And check how your amp should be biased. My Icon is biased by the user with the aid of a multimeter. Pretty stright forward.
“Valve Watts” – there is no such thing. As others have said, a watt is a watt is a watt. But whereas solid state amp distortion is exhibited as clipping of the output signal which can do serious damage to speakers, a valve amp will distort it’s output in a much more benign way which is not likely to wreck your speakers. The upshot of all this is that a solid state amp needs to have a large amount of headroom to protect speakers and a valve amp does not. So a 100 watt solid state amp might be able to safely put out an average power of 25 watts plus 75 watts allowance for transient peaks before clipping occurs, whereas a 100 watt valve amp can probably safely output an average 50-75 watts and that much less headroom for speaker protection.
Valve amps are expensive and need looking after to some extent. My advice would be to audition each type and see what you think. I’m hooked. Plus they look sexy in a way solid state amps never could :-)
PS. NEVER switch on a valve amp if no speakers are connected. It will apparently do horrendous damage to it!
THere's no real basis to say that clipping harms speakers. Power harms speakers. The one thing you can say is if you have a tweeter, significant clipping adds high harmonics, thus increasing the signal level (power) to the tweeter, and tweeters can be killed that way. But I've run my 15 watt guitar amp, at full chat, directly into a decent JBL PA speaker. Lots of distortion, zero damage. DOesn't sound very good, though. You really need that big HF rolloff that a woffer's voice coil gives you to make clipped guitar sound right.
FWIW, the Mesa branded Sylvanias in my Fender guitar amp are from the 80s and continue to work great, and probably would be worth semisilly money if I wanted to sell them.
IMO, it's not differences in distortion per se that makes some tube amps seem louder (there are plenty of pretty good sounding silicon based stomp boxes around) it's that tube amps likely compress more than their transistor cousins. I think the tubes themselves exhibit compression, and in all but massively overbuilt output stages, the outpup transformer becomes a source of compression, etc. In some circumstances, compression sounds good. Tube amp compression (both guitar amps and hifi amps, IMO) can sound organic, natural, exciting, etc., and is going to be accompanied with at least a little clipping adding further exciting higher harmonics right in the frequency range our ears are most sensitive. Double whammy - - louder sound. But it's really because the output signal of the tube amp is different than that of the transistor amp, not because a tube watt is louder than a transistor watt, because they are not.