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General question about tube preamps and gain

I have a (possibly moronic) question unrelated to my previous thread. This is a general question about tubes and gain.

So say you buy a tube preamp and it sounds clean and clear. You decide you want that dark, syrupy sound (classic tube sound?). So you buy tubes that impart this sound on the signal and install them.

Now installed, you notice that the more you turn the preamp volume up, the more the tubes impart that sound on the signal. But you can’t play it loud. 
So could you, theoretically, put attenuators (lets say -10db) between said preamp and the power amp to lower the output signal which you’d then turn the volume up and drive the tubes a little harder to impart more of the tube’s sound at lower levels?

I hope this makes sense. It does in my head but that don’t mean much.


gochurchgo
enliten
44 posts
 
A properly designed tube line stage for home audio should not have issues vs 'volume level' In fact tubes inherently have more linear operating range signal-voltage-wise than solid state typically. +/- 50V swings are not unachievable. Driving the tube stage 'harder' for wetter (more harmonics) is what musicians do, not necessarily what we want in high end audio.

But if that is what you really want, look up "vacuum tube filament starvation" via a search. This may be what you're really looking for. It could also be an adjustable thing.
gochurchgo OP
946 posts
 
Thanks. I don’t know where my acquaintance was headed with his question. I feel like my new preamp sounds fuller as I turn it up but I thought that with the passive I had before so..

anyway, interesting things to think about here.
newbee
4,843 posts
 
gochurchgo, FWIW I think your experience re systems sounding fuller at higher volume is not unusual, but I believe it has much more to do with the speakers than one's electronics. Most noticeable  in the bass  but also in the soundstaging which really opens up at higher levels.
coppy777's avatar
coppy777
226 posts
 
More distortion?   Really?
Seems to me that the knock on tube amps to begin with.  Okay, it's an amplifier.  The farther you are from clipping, the better.  My c-j amps and preamps sometimes have bit more gain than I prefer.  Years ago I took an Act2 pre back to c-j and had them attenuate the gain.  That lasted a couple of months until I had it returned to normal.  Careful what you wish for... you might get distortion you don't want.
mganga
38 posts
 
I used to have a Decware amp (TORII mk3) and a Decware preamp (CSP2+) both of which were wonderful.  Decware amps have gain attenuators and I found that I enjoyed music most with the amp gain turned to about 25% turn and the preamp to 75% turn.  It made the music more holographic, dimensional, real.  Both the preamp and the amp were tube designs but the preamp probably had a different distortion profile than the amp and it was this distortion profile that I like, so I turned up the preamp and turned down the amp.  Perhaps more 2nd harmonic distortion?  At least that’s what I always thought.  It was nice to be able to adjust the sound profile somewhat in this manner and it was cheaper than buying more tubes, which I of course did anyway🙂
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