Very Basic Tube/SS Pre-AMP/AMP Question

I'm running a tube preamp with a solid state amp and really like it a lot. Prior to that all my experience was with solid state, but I think my tastes are leaning towards tubes. I'm starting to experiment with different tubes now, which is another neat way to tweak the sound. I think the combo you're considering will impress you greatly. Oh yes, and make sure to heed Phild's advice. What is that ratio again? The amp should have 10-100 times the input impedance of the preamp's output impedance? Definitely do a search on this matter.

Tubes in preamps make a lot more sense than in power amps, so yes it is a good choice, and your particular choices in mfrs are excellent as well, both are at the very top of the game in their respective areas. Tubes excel at signal purity and in keeping the circuits simple, which are very good things. But they are not nearly as well suited to delivering very high currents into very low impedances, which will always limit their ability in power amp applications. This is just basic physics and there's nothing anybody can do about it. Lots of people love tube power amps, but usually they either have musical tastes which allow them to overlook the flabbiness in the bass, or are willing to put up with the heat and maintenance of 300+ wpc tube amps. Re input impedance, if the amp's input impedance is over about 10kOhms, you're probably ok, more's better.

The problem with tube amps is that they don't generally perform as well at the frequency extremes as ss. As Karls notes this is because of the limiting factor that tubes have into low impedance loads presented by the loudspeakers. The transformer, if well designed will help but offers other distortions that can never be overcome and the signal is compromised in the flux. The result is fatter bass, slower sound and high frequency performance that comes up short most of the time. The debate revolves around the pluses and minuses of each approach. Which is the worst of two evils or which one would you rather live with long term?

Tubes run hot, have to be replaced often because they are typically biased high to extract better performance. Oh the hastle, who needs it? But tubes DO capture the presence and harmonics of the performance to a greater extent than ss. At least most would agree with that.

Now if one could have a tube amp that could provide what it does so very well, the presence and "thereness" AND control the bass and offer the speed of ss, now we're talking about the ideal amp. Does such an amp exist? With limitations of the speakers used, Output Transformer Less OTL amps offer this type of performance. They also run even hotter because it requires even more tubes to provide the current required into lower impedance loads. So they have THEIR limitations in application. Some will sacrifice the extra heat for the performance offered. It could even make you find a speaker that works with them so alluring is the sound.

The Berning zh270 otl has less limitations because it maintains control AND power into low impedance loads. Its approach is completely different than other OTL's but its performance is certainly on a par with its brethren. Plus it doesn't run the outputs anywhere near what other tube amps do, 100 watts at idle. This is certainly a lot less than most Class A ss amps.

The real issue is what do you really want, tubes done right without the inherent limitations in application vs. transistors which get almost everything right except the "you are there" emotional connection to the event? It is a relative question to where you are on the path to sonic bliss, but if you are an agnostic about what you are listening to, this post may be for you.

I've tried various combinations and for now have settled on a passive/buffered preamp with my Conrad-Johnson tube amp. There is no right or wrong answer. Common wisdom says to try a tube preamp with a ss amp. I have but I still haven't found the right match. For me, I get better results with the tube amp and passive preamp.

As for tube amps not having the frequency extension of their ss counter part, this can also be true of tube preamps. I've compared a few tube preamps against ss preamps and passive preamps. The tube preamps can sound sweet but can also roll off the frequency extremes, some more so than others. In my opinion, its more important to ask yourself what type of sound you are looking for. Even within the vast range of tube gear there's a significant difference in sound.

One generalization based on my own limited experience is that CJ gear seems to have a very nice midrange sweetness that I truly love. On the other hand, ARC is more neutral and extended but not much "magic" in the midrange. Its all a matter of personal preference.

As for tubes being high maintenance, I don't consider rebiasing the tubes every few months or replacing them every couple years a major issue.

Many thanks to everyone for the great advice. I particularly liked what Tubegroover said about presence or "thereness". I've been listening to mostly acoustic music these days and some of the older recordings are poorly produced. I am not after a sound that is overly analytical--In fact I think my ultimate desire is to conjure Miles and Bird right in my own livingroom. I think tubes will get me closer to the magic of a live acoustic performance. "Thereness" is a very good desciption, if I understand you correctly.

Also, thanks to T-bone for the great tips on local audio shops. I will be down in Akihabara this weekend! I would greatly appreciate any other recommendations you may have.