Never Owned a Tube Amp and Want Advice

There are trade-offs, aside from cost, with going for more power.  With some brands of amps, the cheaper, lower-powered version sounds better when playing at modest volume level than the higher cost, higher priced brethren.  This can be the case with solid state too.  I tend to find higher powered tube amps to sound a little bit brittle and hard (harsh?) sounding.  But, it is still far better to get an amp compatible with your power requirements and accept the less significant trade-offs.

You need to hear these things for yourself.  It is hard to say what you will like and dislike and how you would value the particular attributes of any given amp type, never mind particular model.  If you can, listen to a modestly powered EL34 or EL84 amp (a popular tube in lower cost amps that sounds very good), a higher powered amp using KT 88 or KT120 or KT150 tubes, and an output transformerless amp, like the Atmasphere S-30 or M 60 amps.  Of the more common tube types, I am a big fan of the 6L6 tube, but, those put out less power than the other tube types I've mentioned.

To be perfectly clear, energy stored in the supply is how an amp can handle an orchestral crescendo that would cause it to exceed its continuous power rating, correct?

No. The extra energy is useful to reduce IMD at higher power levels. Essentially it allows the power supply to have less noise- and less noise in the power supply results in the lower IMD of the amp.

Since this is a conversation about having enough power, what about going for a larger tube amp like 100 wpc.

As you increase the power of most tube amps, the output transformer has to be able to handle that power and at the same time make bandwidth. The problem is this basically doesn't happen; with output transformers as you build progressively larger devices, bandwidth is increasingly more difficult to obtain. For decades, 60 watts was the 'sweet spot' for push-pull tube amps, where they could make the power and still have the bandwidth needed (5-100KHz). You may not think that bandwidth above 20KHz is important, but unless you have a great degree of feedback (above 35dB or so) that bandwidth is important to prevent phase shift which can cause issues with tonality and the soundstage presentation.


Another thing to think about is the simple fact that 100 watts is not a great deal of power over 60 watts insofar as the ear is concerned- its slightly less than 3dB which is barely louder to the ear. But a 100 watt amp might have other properties (assuming bandwidth isn't an issue) at lower power levels that could be in its favor. So its a mixed bag.

OTLs get around the bandwidth issue by getting rid of the output transformer, so that tradeoff does not exist in them when going to higher power levels- a 200 watt OTL can be as fast, dynamic and transparent as a smaller one.

A small tip that I didn't know coming from a SS background.

Don't run your new tube amp without a load attached as it can destroy the unit. You may be especially tempted to do so right when to get it as you would like to A/B it against your old SS equipment while keeping both at operating temperature.

Fortunately I got lucky and didn't destroy my Frankenstein 300bs when I did this many years ago.

Yes, tube amps are sort of the opposite of solid state when it comes to running with no load or accidentally shorting the speaker leads (big problem for solid state, no big deal with tube gear).  

Another helpful hint for someone auditioning with tubes for the first time:  If you turn off the tube amp to switch things up, wait a few minutes before turning it back on.  Quickly cycling from on to off to on again can cause some tube amps to misbehave.  I've heard some loud crackling and I have seen rectifiers put on a light show when that is done.