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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
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mganga
30 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🙂
f917025
81 posts
 
it's safe to swap to lower gain preamp tubes but you should be careful when you go the other way not to raise the gain too much,usually within the common types of the 12a 7 family(12au7 12ay7 12at7 12ax7)  it's ok to go one step up
so if the stock tube is 12at7 you can swap it for 12ax7 but ide use a low gain 12ax7 or 5751 tube just to be safe.there are also other parameters besides gain that are not the same but i would just worry about tone and not over boosting the gain. most audiophiles and guitar players miss the full potential of their tube gear since these days it's all chinese and russian ( extremely well matched and sorted ) crap inside those fancy 4k amps.  
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rikkipuu
278 posts
 
Following up on the reply from mganga,
I have a Decware CSP3 tube pre amp.  In addition to the standard volume attenuator there are adjustable pots for gain on both the input tube and on the output tubes.  My understanding of these pots is for "gain riding".   Adjusting the gain affects the performance of the tube (s) and changes the character of the sound so you can may it darker and syrupy or not.  This allows for fine tuning of the pre amp to find the sweet spot of the tubes.  The pots change the performance of the tubes a lot. This is a nice little tube pre amp.  It does benefit from changing out the stock tubes, particularly the rectifier tube.  

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