Tube Amps Watts vs SS amp

It is the clipping that is important. Glass clips softly, sand hard.

May want to consider a solid state amplifier with a little more ‘meat on the bones’ to emulate (75% or so) tube sound but maintain the high damping factor and needed power. Consider used GamuT D200 or possibly older Clayton Audio amplifier. Both amps are built to last.

As others have said, tube amps provide a more usable power band than most solid state amps.  I've been in audio for over 40 years, and have listened to countless amps, and of this I have no doubt.  Another point on most tube amps is that the output transformers allow these amps to deal with complex loads quite well.  Sonically, I have always found tube amps to be less fatiguing in the mids and highs.  

That said, the tradeoff is the low end.  AR9s, even with a massive tube amp, will be soft in the bottom end.  This is the biggest tradeoff in my view.  That, and the dynamic compression that occurs at higher volume on tube amps, will lead to a choice.  If recreating the energy of a concert, with gut punching bass is what you're looking for, best in class solid state is hard to beat.  

Roberjerman, I went back and looked at the Heresy's timeline. It does date back to 1957 but it was called the H 700. It was given the Heresy name with an update in 1972 which was probably the year I got them as they were marketed at the time as new speakers. The K horn is the longest running production speaker of all time! I remember listen to them at the store I eventually got the Heresys at. They were being powered by Marantz Model 9 mono amplifiers and a Model 7C preamp. The turntable was a Thorens TD 124 with an SME arm. I don't remember the cartridge. That was the absolute State of the Art at the time. It had no problem doing realistic volume levels.

My understanding is that the concept of “bandwidth” is very important. Perhaps more important for tube amps than solid state. But I have a First Watt SIT-3 which is a low watt solid state amp. It apparently has some bandwidth to it because it drives my Magico A3s well. They have a sensitivity of 88dB, an impedance of 4 ohms and recommended minimum power of 50 watts. The SIT-3 drives them just as well as my Bryston 4B3, which has a lot more power. But what I would like to know from the group is: how is bandwidth measured? How do you calculate bandwidth?

Bandwidth is important to keep phase shift at a minimum. To this end, phase shift is minimized if bandwidth is 10x the maximum frequency to be amplified (20Hz, so 200KHz required) and also 1/10th the lowest frequency to be amplified (20Hz, so 2Hz response required). Bandwidth is measured by either a sine wave or square wave; with a sine wave the signal is applied to the circuit and the output observed to be within usually + or - 1/2dB to be considered ’flat’; with a squarewave rounding of the edges can be seen to show a rolloff at high freqencies and tilt on the top of the squarewave shows a rolloff at low frequencies. This is fairly easy for transistor amps, and there are tube amps that meet the ’2Hz-200KHz’ requirement too, but to my knowledge they are all OTLs (Output TransformerLess).


Keeping phase shift linear has to benefits: more accurate presentation of the soundstage and more accurate presentation of tonality. As an example of the latter, if there is a rolloff at 10Hz, phase shift will cause a lack of impact up to about 100Hz despite the amp measuring flat to 20Hz on the bench. This is why if there is a problem at 50KHz it can often be heard as well, since phase shift artifacts will exist down to 5KHz. Again, this will be interpreted by the ear as a tonality.


So one takeaway: three things affect tonality: actual frequency response (which is different from bandwidth), distortion and phase shift.