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Tube Amp lower power vs higher power and cruising volume

After having Solid State my entire life thus far, I bought a PrimaLuna EVO 300 integrated and absolutely love it. I am currently driving 20 year old B&W CDM9NT's and it does a wonderful job, I never heard my B&W's have that much bass before, even at lower listening volumes. The EVO 300 is rated at 42W. Since I recently purchased it I have the option for a brief time without losing money to possibly move up to the EVO 400 integrated which adds 4 more output tubes and gives you 70W. I believe the 300 and 400 both use the same transformer because they both weigh the same 68 lbs. So my only reason for possibly doing this would be for future speaker upgradability having a little more power. I know my B&W's are not the most efficient and the 300 seems to be driving them very well, volume rarely goes past 9:30/10. So my question, if I get a higher power model, since I listen most of the time at comfortable listening levels, with a higher power tube amp will you have to turn it up higher to hit that cruising speed where it starts to open up? The 300 seems to hit that early and I listen at comfortable levels and good extended bass without having to crank it which is nice when I am listening at night and my wife and daughter are sleeping. Overall I am very happy with the 300 but while I have the option I am trying to decide if the extra for a 400 is worth it. Thanks
128x128jmphotography
charles1dad's avatar
charles1dad
10,250 posts
 
I agree with those who recommend staying with what you have. You’re very happy with your sound quality performance, congratulations . I’d appreciate this good situation and continue to enjoy it. It’s ’possible’ that the additional 4 output tubes for increased power could potentially alter the fine amplifier and speaker synergy currently achieved. So yes, leave (Very) well enough alone. BTW I agree with the perspective that the el34 tube is likely a very good match for the B&W tweeter.
Charles
mesch
3,527 posts
 
I would not move up for the sake of power unless I felt that my speakers were in need for more. To me the 4 additional tubes just complicates things. Very possibly providing more power without improving sound. Other's who have experience with both amps may chime in. I would only move up the line if it was proven to be that the more powerful amp sounded better,, and the money would not make greater improvement elsewhere in the system.

Running KT150s would improve power without additional tubes. Wether the sound is improved would be subjective. Would depend on the nature of improvements sought.

If I were seeking the sound provided by tube amplification (I am) I would not be in the market for speakers that are difficult to drive. Just my take based on preference and budget. 
tablejockey
3,953 posts
 
I've owned a PL HP(Evo400) for 5 years. 

Since your not listening at concert levels, you're good. It's not a 4's good, 8 must be better thing. You probably would be fine even if you did like to put the volume at 1:00+. Buy different speakers(more efficient) if you feel the need to satisfy your nervosa. Roll the two innermost tubes for a subtle change, power cord, power conditioning, AC regen, fuse. If itch persists, get the EVO 400, or even better get separates.
atmasphere's avatar
atmasphere
11,954 posts
 
Usually in tube amps (with output transformers) the smaller amps are the better sounding, usually on account of the output transformer, but also in how the power tubes are driven by the driver circuit (by far the lessor variable).


If you don't overload the amp I would see no reason to go for more power! It will just be wasted as heat, and highly unlikely that it would sound better. BTW the KT88s were likely more bright due to distortion rather than the tweeter (which is the same tweeter you were using with the EL34s). This is the same distortion that makes solid state amps bright- higher ordered harmonic distortion. A tiny amount more is audible as the ear uses them to sense sound pressure, so its very sensitive to their presence.
charles1dad's avatar
charles1dad
10,250 posts
 
@jmphotography,
In regard to the volume control setting (Plenty loud at only 9 30-10 o’clock). this has more to do with the amount of gain rather than amplifier power.
1 Your source may have a high voltage output.
2 The amplifier may have a low input voltage (High sensitivity).
3 The amplifier (Integrated) may simply be a high gain design.
Charles
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