high power tube amps vs ss

Ralph, I tried your experiment of ramping up the gain. I was playing an EMI CD of Tchaikovsky (sp?) Nutcracker. The dynamic range is between 20 and 30 db. I never made it beyond 95db. At that point, external distortion made me turn the gain down. I'm referring to wifey. She threatened to throw a bucket of water on my gear. She introduced at least 90db of negative feedback and the odd ordered harmonics from her screaming really hurt my ears. Any suggestions?

I've owned a LOT of tube guitar amps and a couple of SS and hybrids...tube amps are simply snappier and make people happier. I do use SS bass amps though, as you need extreme power for that. Same with tube hifi amps...60 watts per side with 90db speakers and a SS sub (so sue me) shake my walls if need be, so I bet this sort of thing would shake yours. Also regarding heat...with only 4 KT120s there is not too much more heat than a recent partly class A SS amp I was using, but the tube heat is expected...a Twin Reverb will make the beer on top of it sweat all over the place...just a warning.

Almarg.....I am not sure what solid state amps you are speaking of. Not all ss amps DOUBLE IN POWER OUTPUT when the load changes. My McIntosh MC352,350w per channel Amp does not change in power output for 8,4 or 2 ohm loads. So I am perplexed by your statement. It also seems to me that you are lumping all SS amps together and thats not fair. Nice system and I bet those speakers are 95db sensitivity or better so they work well with the Tube amp. I wish I could hear it.

Jallen I just put in a pair of MAZDA CIFTIES-12AU7's and I really like the top end end on these. Awesome sounding tube made in 1962 for the French Military.

Thanks very much, Matt. Yes, the Daedalus Ulysses, in the configuration I have that was introduced about 3 years ago which includes "all poly" crossover capacitors, is 98 db/1W/1m. It also has a very flat impedance curve, as well as high power handling capability, all of which makes it unusually versatile with respect to amplifier selection.

Regarding your question, what I said was "the power capability of a solid state amp into 4 ohms MAY [emphasis added] be as much as twice its capability into 8 ohms."

As you probably realize, the power capability of MOST solid state amps will be substantially greater into 4 ohms than into 8 ohms, in many cases approaching twice as much, and in some cases equaling twice as much. Two ohms may be a different story, of course, as a lot of amplifiers will not do well dealing with such a heavy load.

As you indicated, though, your McIntosh MC-352 amplifier has the same output rating into 8, 4 and 2 ohm loads. That is essentially a consequence of the unusual autoformer-based design of its output circuits. I am not aware of any non-McIntosh amplifiers that use a similar approach.

As opposed to a tube amplifier utilizing an output transformer, however, the solid state + autoformer approach provides considerably lower output impedance/higher damping factor (damping factor being spec'd at 40). As a consequence of that it WILL, like most solid state amplifiers, to a very close approximation double actual power DELIVERY (as opposed to CAPABILITY) as load impedance is halved, AS LONG AS it is operated within its 350W or so capability, and as long as the impedance of the speaker is a reasonable match for the output tap on the amplifier that the speaker is connected to.

In contrast to most tube amps, that essentially places the MC-352 in what Atmasphere refers to as the voltage paradigm camp, i.e., its output voltage for a given input will be essentially constant regardless of load impedance, as long as the amplifier is operated within its capabilities.

Regards,
-- Al