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For tube sound, which is more important: preamp or power amp?

I have always loved the “tube sound” - warmth, midrange, soundstage. Through the years (since about 1975), I have owned many tube and solid state amps and preamps, in various combinations. Presently, I have a tube amp and a solid state preamp. But like most of you, I am thinking of making changes, again.  Not to cloud the discussion, the specific brands are not important.  I also listen to acoustic music, females vocals, love mini monitors, EL34s, NOS tubes, and don’t care that much about bass.  So you can see that my taste fits the tube sound very well. But I have had systems that are too warm, not enough dynamics or details, and fat in the low end, too.

okay, now to the discussion.  To produce the tube sound, which is more important: the preamp or the power amp?  Let’s talk in general, and (if possible? May not be) not tied to one specific piece/brand/model of equipment.  I know there are exceptions to any general rule.  Not sure if it makes a difference to your comments, but I have no phono and am running line stage only.

As an attempt to prevent the conversation as going in a big tangent, let’s assume equality of price/quality. i.e. not comparing a $10k power amps contribution to a system to that of a $1k preamp.  Let’s also assume that the amp (tube or solid state) can drive the speakers just fine, such that compatibility does not limit the decision. And ignore mono blocks versus stereo amp differences.  

two follow ons: I have  the perception that preamps give you more bang for the buck - meaning that it takes less money to get a great tube preamp compared to a great tube amp.  Agree/disagree? And second, I have never owned a tube dac or CD player, and will assume that tubes in either of these is less critical than in a preamp or power amp. Agree/disagree?

i am interested in your thoughts.

Bill
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james1969's avatar
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james1969
347 posts
 
Another reason to stay with 1 designer, they will make sure their components have synergy.
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wolf_garcia
6,737 posts
 
I've found that the "expense" of tube power amps based on tube replacement cost is assuaged by the fact (a fact to me anyway…which is as "facty" as I need) that often the tube amp is cheaper to buy relative to the sound quality of SS amps. Case in point: I compared some expensive SS amps here and there over the years to my faithful all tube (except the rectifier) Jolida 502P power amp and the Jolida, with nice sounding tubes, sounded simply better in every case, and was inexpensive…and now I own the best sounding amp I've ever heard, a Dennis Had "Inspire" SEP, which does require relatively efficient speakers but costs around 1200 (mine was slightly used) to 1500 bucks…an SS amp with this much mojo would be more money it seems. First Watt? 3 grand if you're lucky. And the Had amp has exactly 4 tubes. You don't like heat? I get that (sort of), but have never been bothered by tube heat unless I just burnt my fingers biasing or dusting or something…my mansion has AC anyway, and I can get my valet to dust if he hasn't been drinking.
toddverrone's avatar
toddverrone
840 posts
 
Unless, of course, you need the power and control a high power SS amp can provide. Then a tube pre is the best bet. High power tube amps tend to be big, heavy, expensive and hot, not to mention they go through tubes much faster than a tube pre..

I'd personally love a small, near field listening tube rig with some sensitive speakers. But right now I love the power and control my tube pre/class D setup brings to the table.. I'd miss that if I switched.
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atmasphere
11,979 posts
 
Hmm. What is "tube" sound?
Smoother and more detailed than transistor, more lower ordered harmonics which are harder for the ear to detect. Less higher orders that the ear easily detects as harshness.

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If you really really have to make a choice of which way to go, my money is on the tube preamp.

The reason is simple: I don't care how good your amp or speakers are, if the preamp looses definition, there is nothing you can do to replace it downstream. Tubes simply make more detail than transistors (and also without brightness); they are easier to listen to for hours too, so send that to your amplifier.

The problem here of course is if the amp isn't up to the task, you won't hear what the front end of the system is doing. I do regard the use of a tube preamp with solid state as a compromise.

If you really want to hear all that is on that LP or CD, get a tube amp to go with the tube preamp.

Some people think that they don't want the tube amp because of reliability or heat concerns. Tubes are easy to deal with (they are in sockets after all) and heat is a function more of what class of operation the amp employs rather than whether or not it has filaments. A solid state amp biased to the same level of class A operation will make 90% of the heat that a tube amp does. IOW, many tube amps run hotter because they are biased harder.

Transistor amps tend to be biased at very low currents; that's the main reason they make less heat. 
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