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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
meiatflask
analogluvr
859 posts
 
 In my experience the pre-amp is much more important. Infind as you deal with smaller and smaller signal levels the component can impart a greater imprint on the sound.  However I would only use a solid-state amp for bass duty or if I had a speaker that was tough to drive. 
 I really feel that using terms such as "tube sound"  are very misleading however. I find as you approach state of the art  both topologies tend to sound more and more similar. Good tube sound is not lush and warm. In my experience good tube sound just tends to have slightly more realism, palpability, and is better at Soundstaging. 
 An additional benefit is that good tube gear seems to hold it's value better than solid-state. It makes me chuckle how there are these very expensive state of the art solid-state amps and 10 years down the road they're worth 1/20th of what they were initially. 
charles1dad's avatar
charles1dad
10,250 posts
 
I generally agree that as you approach very high levels of design and implementation the distinction between tube and SS  is diminished (but does not disappear). I find this narrowing more so for preamps rather than power amplifiers (the gulf is larger). This is why I have found tube amps more of a difference factor than tube preamps which can sound more like their SS counterparts. The tube amps seem to impart more of the  flesh on the bone or 3 D palpability aspect.
Charles
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almarg
9,670 posts
 
Analogluvr 11-12-2017
Good tube sound is not lush and warm. In my experience good tube sound just tends to have slightly more realism, palpability, and is better at Soundstaging.
+1. Excellent comment, IMO.

My experience, though, has been consistent with the comments by Keith, Charles, and Hk_fan, with tube power amps having tended to contribute more to those three qualities than tube preamps. I should add, though, that my experience with tube preamps has not been particularly extensive, and for the most part has involved well regarded vintage units (e.g., Marantz 7, Marantz 1’s). Also, to provide context, most of the speakers I have owned over the years have had benign impedance characteristics, and medium to high sensitivities.

Regarding your ground rule of...
... equality of price/quality. i.e. not comparing a $10k power amps contribution to a system to that of a $1k preamp.
... and your statement that...
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?
...I agree, at least in the case of medium to high powered tube amps. Tube watts tend to be expensive, for a given level of quality. So if highish power capability is needed in a given application, comparable quality between a tube power amp and a tube preamp might be hard to find at comparable prices. Which may tip the balance in favor of a tube preamp/solid state amp combination.

Regards,
-- Al

charles1dad's avatar
charles1dad
10,250 posts
 
Preamps have to drive the amplifier so consideration to proper impedance matching is needed. Once addressed a high quality tube or SS preamp should both perform well in the sense of "driving" the amplifier. listeners will then decide which sonic presentation they prefer. Power amps must contend with driving a speaker’s load which is the more daunting task in most cases. the differences between tube versus SS output devices are more prominent and stark. This is largely responsible for why I believe the power amp is the more crucial variable given its interaction with the speaker load. Preamp driving power amp is less demanding. As Al mentioned benign speaker loads, this compared to a difficult speaker load has definite implications regarding the chosen amplifier .My point is you’ll hear the tube/SS differences with the power amp and due to their innate sonic distinctions.







gpgr4blu
1,094 posts
 
I'm with Al.
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