Question about wpc on tube amps

I have been kind of looking at tube amps based on what people seem to think about them.

Here is my question- whenever I look at the wpc, they are remarkably low vs. a solid state amp for the money. 

It leaves me scratching my head. Then, somewhere I read that you can't compare a tube amp with a solid state amp . Something along the lines of "10 watts of tube power equals 100 watts in a SS amp". 

What? Is this real?  Seems unlikely to me. 

Are the wildly low power ratings on the tube amps I am looking at simply due to the fact I am looking at $1,000 amps vs the bajillion dollar amps you guys buy?

Would I be better off spending the money on a tube preamp for the "tube" sound I always hear about. 

I am running Magnepan . 7's  with a Bryston amp. Since the . 7's are power hogs are tubes even a realistic thing for me in my lowish budget? 




@timintexas as you've already concluded, in your case - I'd second the notion of buying a really good tube preamplifier and pairing it up with your Bryston instead.

I have the .7s and love them in my office system. I run them off of a Roguw Sphinx v3 which can be bought used here for around $1000-$1300. It runs them with no issue, powerful and musical, detailed and never breaks a sweat. Highly recommended, I stream Roon through a Bluesound Node to the Rogue.

First of all:

1. Observe systems synergy! Speakers that are high current / high excursion, demand specific amplification, and the experience will not be a good one unless the amp is specifically designed for that task.

2. Tube amplifiers operate with output tansformers. The taps of the output transformer define which speakers they are designed to drive. Hence, it is vital to get the right match. (Eg right size shoe for the foot - if not, you can't run, or worse, it will even bleed..)

3. Watts define only what is the RATED peak output of an amplifier.Also, the ratings apply for power into a RESISTOR. Solid state amps can put out LESS than the rated powr into an actual speaker, while tube amps put out MORE into an actual speaker than into a dummy resistor used for rating. A push pull tube amp with lots of feedback only slightly more than rated, but a zero feedback SET can put out even up to x10 the rated power into a real loudspeaker.

However, the wattage only implies PEAK SPL capacity. 

In every amp we are going to observe problems before that peak spl is reached.

Solid state amps show signs of strain already below 1% of their peak wattage output. Single ended triode amps show strain around 50% of their rated peak output, provided their power supply is adequately designed (many commercial models are not - not the fault of tube technology, but result of cutting corners to make sales).

Also, we cannot generalize tubes / solids...

Among solid state amps class A low feedback designs can handle much higher output without distortion, so for example, an 50W class A solid state amp can put out about 0.5 clean watt. (Clean enough for my personal demands.) For a class B solid s amp, the clean power is much lower. (I found it's non-existent, but others will find a few adequate watts there...)

For tube amps, the clarity of watts is defined by the power supply, which you will not find out based on the watts number.

For example, a tube amp rated for 1W output but with a power supply that is designed to supply a 300W demand will be able to deliver a cleaner output than a 200W class A solid sate amp. Of course, the 200W amp can go much louder, but the perceived quality at the 20-200W range will be much inferior to the milliwatt to few watts range.

In short, when going for watts alone, then usually:

1 SET watt = 10-100 solid state watts (provided the SET has ample power supply - if not, it might not even be 1 watt..._)

2 Push-pull tube watt = 5-20 solid state watts

Also, provided the tube amps are matched with speakers that they were designed to drive. (Eg have the appropriate taps! )

We often hear complaints that tube amps cant drive a high current speaker, because its impedance drops to 1.7R or something similar low value. The issue is not with the tube technology, but those "conoisseurs" who are so clueless they want to drive 1.7R speakers off 4R and 8R taps....  Talking about trying to squeeze in a watermelon into an orange juicer! Such loads need a tube amp that has a 2R or even better, a 1R tap... that's another story, but something that has to be clear to everyone who is new to tube amps and wants to find the right tube amp match.

BEFORE YOU LOOK AT WATTS, MAKE SURE THE AMP HAS THE RIGHT TAPS TO DRIVE YOUR SPEAKERS. And not the brochure specified bogus number. The actual measured real impedance, which is specified by the dip.Sadly, a lot of manufacturers nowadays lie shamelessly, calling even 2-3R speakers as 8R...

When a loudspeaker is advertised as: "This is an 8R loudspeaker that dips to 2R at 120Hz" , then that means that it's a 2R loudspeaker, not 8R! You need a 2R tap to drive it, 8R tap will be entirely completely insufficient and utterly useless. Not because it's an inadequate tube amp by itself, but because the delinquent is choosing the wrong shoe for the foot, so to speak.

As in life, not all shoe fits all feet. Just because it does not fit, does not mean it's poorly made shoes, and would be terrible on the feet of those whom they were made for....   systems synergy is all. ;






Sorry but the answer is clear and simple.  You aren't going to drive Maggies well on $1,000 of tube amp.  Unless (just possibly) you listen at a very low level; even there you would be far better off with solid-state.

Greet overall suggestions here…

But since you’d already mentioned you’re going to get a preamp to run with that excellent Bryston, definitely look into a decent used Rogue audio pre at that money. But there are other brands that do really well at lower cost to offer well designed and great sounding tube pre’s. Van Alstine and Quicksilver come to mind. It would just be a matter of matching with your Bryston. 

Tubes are awesome…but there are solid state pre’s that do magical stuff too. I was looking at quite a few different tube pre’s until I tried an SPL preamp. Blew my mind. Holography, stage, depth and a touch of warmth. Not to mention the clarity and separation. No longer want a tube pre - at least not until I can afford a really, really nice one. But a nice SS with discrete components can still get you something special.