A very recent experience: Last week my neighbor emailed me, as he usually does when he has a question about his very expensive audio system. He recently purchased a new $30K phono stage (39db gain according to mfg spec) which is fed by a SUT suited to his previous phono stage (which had 42db gain, minimum). Between the phono stage and his amplifiers, he was using a very high quality passive attenuator. With his new phono, he was noticing that the sonics were occasionally anemic during orchestral crescendos and on similar demanding passages, and he wanted me to help him decide which of two more powerful power amplifiers he should now buy, in order to fix his problem.
I noted that he currently owns an 8W SET powering a pair of speakers rated at 105db(!), and I told him his problem should hardly be an indication of a need for more amplifier power. (8W should produce 107db spl at 10 feet from a 105db speaker, based on my calculations.) Instead, I advised him to save his $$$; I guessed that his upstream components were not driving his amps to their full output. Indeed, if I assumed that his SUT was providing about 5.0mV at its outputs (i.e., the voltage output of a typical HO MM), I calculated that the signal voltage delivered to the amplifiers via the passive attenuators was less than 0.5V, not enough to drive most amplifiers to full output. To prove the point, I lent him my vintage Quicksilver preamplifier which can provide quite a bit of gain via its active linestage section, although I don't know precisely how much gain in db. Once we inserted the Q into his signal path in lieu of the passive attenuator, all was well, and I left it with him for a couple of days. I have no intention of parting with my Q, so he bought an (expensive) active linestage of his own. Now he's "cooking with gas". What was striking to both of us is that the active stage made his system sound better in all respects, not just on musical peaks. And strangely, this applies also to digital, where gain should not have been a problem.
The story has no moral, because he has now also made a deposit on a more powerful amplifier even though I proved to him he did not need it. I am happy to help him, because, besides the fact that he is a nice guy, listening to his system after each "upgrade" allows me to educate myself on the price/performance ratio prevalent in high end audio, at no cost to me.
I noted that he currently owns an 8W SET powering a pair of speakers rated at 105db(!), and I told him his problem should hardly be an indication of a need for more amplifier power. (8W should produce 107db spl at 10 feet from a 105db speaker, based on my calculations.) Instead, I advised him to save his $$$; I guessed that his upstream components were not driving his amps to their full output. Indeed, if I assumed that his SUT was providing about 5.0mV at its outputs (i.e., the voltage output of a typical HO MM), I calculated that the signal voltage delivered to the amplifiers via the passive attenuators was less than 0.5V, not enough to drive most amplifiers to full output. To prove the point, I lent him my vintage Quicksilver preamplifier which can provide quite a bit of gain via its active linestage section, although I don't know precisely how much gain in db. Once we inserted the Q into his signal path in lieu of the passive attenuator, all was well, and I left it with him for a couple of days. I have no intention of parting with my Q, so he bought an (expensive) active linestage of his own. Now he's "cooking with gas". What was striking to both of us is that the active stage made his system sound better in all respects, not just on musical peaks. And strangely, this applies also to digital, where gain should not have been a problem.
The story has no moral, because he has now also made a deposit on a more powerful amplifier even though I proved to him he did not need it. I am happy to help him, because, besides the fact that he is a nice guy, listening to his system after each "upgrade" allows me to educate myself on the price/performance ratio prevalent in high end audio, at no cost to me.
