Tubes?


I have Revel Salon 2 speakers. Sensitivity is about 85 db. and 4 ohms. They are power hungry speakers. Currently, I am driving them with McIntosh 601's and a McIntosh solid state preamp. I was look looking at a pair of McIntosh MC2301. They are tube amps rated at 300 watts into 2 - 8 ohm loads. I listen to all types of music (sometimes at very high levels). I never run out of power with the 601's, but I am very intrigued with tubes. This may be a misconception, but I remember some friends who played guitar saying, tube watts were louder than solid state? Perhaps this is not really true or not true regarding home stereo. Perhaps the best idea is to keep the 601's and get a good tube preamp?                          Thanks, Dave 
128x128tobor007
@tobor007  Something you might want to keep in mind is that making an amplifier work hard for a living will result in harsher less involving sound. This is simply because the amp will make more distortion.

Tube amplifier power is expensive relative to solid state (which is why the industry went in that direction decades ago) but tubes still offer something that is almost impossible to do with transistors. Smoothness- greater detail and depth... but the problem you are up against is that in most rooms your speakers are near criminally inefficient. What I mean by that is you can count the number of amps that actually sound like music on one hand that also have the power you'll be needing to accurately portray musical peaks. Especially in the case of tube amplifiers, getting bandwidth at the same time as getting the power you need is almost impossible due to the constraints of the output transformer. The more power an output transformer can handle, the less bandwidth it has. Most tube amps of 200 watts struggle to do 20Hz to even 15KHz!


To avoid phase shift which affects the soundstage and tonality, you need that bandwidth (or else way more feedback than can be applied to a tube amplifier)! We make an output transformerless tube amp that makes over 500 watts, but its not practical for a speaker like this, I'm thinking mostly out of budget constraints as it costs about $147,000 for a set. But it makes the bandwidth no worries.


So if you are wanting the musical aspects that primarily are offered by tubes, you might want to think about getting a set of speakers that are easier to drive! There is absolutely no reason why a more efficient speaker would have any less resolution and you'll certainly experience greater dynamic punch as higher efficiency speakers have less thermal compression; I really can't think of a good reason to have a speaker with such low efficiency. So if you really want to get the most out of your amplifier dollar investment, you'll be doing yourself a huge favor to get something that's a bit easier to drive.

To illustrate how important this is, imagine instead of 85dB that the speaker is instead 95dB. The amplifier you would need to make the same undistorted sound pressure would be 1/10th the power! Instead of 500 watt you would only need 50, and there are many 50 watt tubes amps that would suit. The dollar investment goes down- you flush less dollars down the loo and get greater satisfaction out of the system.
The sound of most but not all tube amps is dominated by the output transformer... yes tube rolling will matter but mostly it’s output which essentially same guys designed your 601 autoformers.... iF you really do like the speakers and the way the sound in your room, work the preamp hard. Definition lost there is gone forever.
I think Ralph and I have been round the mulberry bush on trading speaker efficiency for distortion - sure you can get higher output but at what cost ? Lightweight cones have breakup modes in the passband, horns ( I own them ) are mechanical multipliers, large baffles same... the astute audiophile just knows which distortion they savor
Having said that, I have heard low efficiency speakers driven by several of Ralph’s smaller amplifiers and they sound sublime :-) but certainly not at the SPL you seek.
And it does crack me up when phase accuracy of the amplifier gets mentioned with speakers that start out the impulse test 180 out or with midrange wired out of phase...

it’s a system people :-)