mwood:
I'm assuming your preamp has a resistive volume control. If that's the case. the "higher" the volume setting the less resistance. That's preferable for better sound. It's been the case for decades that many home audio preamps have much more gain than they need or is desirable. If your volume settings run only up to, say halfway before maxing out, your preamp has too much gain. Your tube preamp 3-5 db gain was actually better suited to your system than the 9db gain preamp.
Excess gain preamps that result in volume settings between 1-5 have trained users to expect that. When a preamp with a resistive attenuator is used mostly between 5-9 (on a scale of 10) that's ideal, but seems wrong due to previous experience with excessive gain preamps. The output voltage of the preamp should drive the amplifier to maximum power output at just about the full volume setting. That's when the attenuator is resisting the least and converting as little as possible of the voltage gain to heat.
My 30 Watt class A is louder than my 100 Watt Class AB?
Curious observation…
I had just done some work on my DIY Hiraga 30 Watt Class A amp, and decided I would do an A/B comparison with my Adcom GFA 545.
To my great surprise, when I switched from the Hiraga to the Adcom, leaving everything else in the set up the same, and when I turned the music back on, it needed to be turned up to play at the same volume.
Input impedance is different, and I’m wondering if this is what could be causing this counter intuitive finding? Hiraga is around 33K and the Adcom around 100K.
Wondering if anyone has any thoughts as to why this is what I’m experiencing.
Thanks