Tubes?

My comments are not theory nor intended to be a blanket statement for all SS & tube amps. This is how things have played out for me over the past decade.

I had a Parasound HCA2200ii that is 250x2 or 750x1. I listened to one for several years and then picked up a 2nd to try them as monoblocks. While having both, I took a leap of faith and bought a pair of Audio Research Classic 120s. These are 110 watts each. I did A-B testing against a single Parasound and both. The ARC amps had more volume and an overall sweeter sound in both comparisons. I later bought the Parasound HCA 3500 as I always admired that beast and had the same result....those 110 tube watts still out performed the SS amps. My old preamp is B&K so I later picked up a B&K 200.2 s2 amp that is 250x2. This is my backup amp in case my tube amps have any trouble. I recently had some tubes fail that are way past their expected life. Long story, but I feared there was other issues and took the ARC amps out of the system to consider a trip to the shop. I hooked up my B&K and I just sighed with disappointment. The music simply doesn’t have the realism I get from the tubes. Now I did something weird but it was a cool experiment. The more I thought about the ARC amps, maybe it was simply a bad tube so I should have at least tried swapping tubes before lugging them to a shop. I replaced the bank of 4 where I had some red-plating. I hooked that amp back up for the R channel while the B&K was still running the L channel. I didn’t get the SPL meter out but the R speaker was significantly louder where the soundstage was shifted where the voices were almost centered on the R speaker. I would use the balance and go back and forth and it was remarkable even with just one speaker how much better the tubes sound. I realize I am not in the best class of SS amps here but Parasound and B&K are both well reviewed and respected amplifiers.

NOW....the cool factor here, my Platinum Audio Quattro floor standers have an efficiency rating of 86db!! This shouldn’t work, right?!?! What’s going on here. Don’t get obsessed with high wattage ratings. I haven’t heard one, but a friend of mine that has decades of tube amp experience recently got an ARC REF 75. These amps are said to be magical at only 75wpc. He was blown away at the dynamics he gets from his Wilson Audio Sophias. This would most likely be all the power any of us would ever need.

If you like your speakers, take the leap of faith and choose a tube amp. You may need to change speakers later, but once you sit back and spend an evening with the music they create, you will never go back! I tried to like SS better as there is no maintenance or worry of tube failure. There is no on-going expense of replacing tubes. All that doesn’t matter as the tubes are simply superior in the music they create....IN MY SYSTEM.

Good luck!

@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.