How do tube Watts compare to SS Watts?

Bartokfan. A pentode is a vacuum tube that has three grids, namely a control grid, a screen grid and a suppressor grid. The screen grid was added to isolated the control grid from the plate to reduce Miller effect.

A tetrode is a tube that has a control grid and screen grin (no suppressor grid). The suppressor grid is added to reduce secondary emissions from the anode.

A Triode has no screen or suppressor grid.

Triodes, Tetrodes and Pentodes can all be used in a push-pull or single ended configuration. When used in single ended configuration they all have to run class A, in push-pull they can be run in either class A or B (or combination thereof.)

Tetrodes and Pentodes have their screens grids biased to +. If you bias the screed grid from the anode, it is know as triode mode. If you bias the screen grid from a tap on the primary winding of the output transformer, it is called ultraliniar mode. If you bias the screen grid from the power supply, it is called tetrode/pentode mode.

The method of biasing the screen grid alters the character of the tube slightly. Many amps have a switch to toggle between two of these modes.

A KT90 is actually a kinkless tetrode (the KT stands for Kinkless Tetrode). I believe that is actually a pentode with the suppresser grid tied to the cathode. And EL34 is an example of a pure pentode.

Regards
Paul

Rascal52240, a Watt is a Watt is a Watt. It is a measurement. An inch on a ruler is the same as an inch on a tape measure. That said, Watts needs to be considered as part of an equation. Your Thiel's 22's have a nominal impedance of 4 Ohms and a minimum impedance of 3 Ohms. Better ss amps may double their power into that load. In your case as a matter of measurement ss Watts may be 2X more powerfull than tube amps with the same standard 8 Ohm rating. Thiel designs their cross-overs in such a manner so as to provide a steady impedance for the amp, which helps maintain steady amplitude. Some argue that, these steps drain the ultimate apparent power from the system. The point of all this is; Thiel's respond best to lots of quality power. Of course, your room and ultimate sound levels will determine just how much power you need. For many years I used the same ss c-j amp you are currently using on earlier Thiel's CS 2's. Those 2's had an easier 6 Ohm nominal, 5 Ohm minimum load. A move to a much better 250 watt amp demonstrated qualities I never new my CS 2's were capable of. Jim Thiel told me himslelf that his power recommendations were based on the standard 8 Ohm rating of quality ss amps that were capable of doubling down, and if one were to choose tube amps, one should double those power recommendations. Comparable tube power usually costs more than the same ss power. Doubling that tube power can get a bit expensive. With a budget of $1K, I'd suggest you use ss watts. Furthermore, very few integrateds have the guts to really make Thiels sing, it usually takes a dedicated power amp to get the most from Thiel's, especially when you get away from the smaller 2 ways. An old audiophile cliche' that some how seems to work more often than it should, suggests that one should double the manufactures' minimum recommendation. For your Thiel 22's that would mean 200 watts into 4 Ohms. A quality 200 watt per channel tube amp might be hard to find for under $1K. To drive your Thiels, that money may be better spent on better ss watts.

Smooth explanation, thanks. This explains why the KT88 and KT90 have different characterits in voicing. And as you know every KT90 amp will have different circuitry/ quality trans, and that also every model KT90 tube will possess somewhat different characteristic. So tubes can be a big wide open field, whereas ss amps, is "what you see is what you get" Not much can be done for a ss amp. Its all "hard wires". Great tubes can offer that much more . Tube amps with a hefty trans, can be considered an ss amp with the added benifits of musicality of tubes.
btw where do the 6550's fit in. I have a DEFY 7 sitting waiting for a preamp. Very interesting looking tube. Shorter than the KT90 but wider. Very unique looking tube. I know I will prefer it over the JOR's KT90's. The 6550 may be one of the best tubes for classiacl/orchestra. I'm betting on it. The KT90 can be a bit "raw"/"steely"/"cold", but definetly has some slam and a full midrange/good bass. The highs roll a bit. I'm guessing the 6550 kicks in more high fq's, with a "softer bass" I'll post a review whenever I get a pre, maybe next month.

>>whereas ss amps, is "what you see is what you get" Not much can be done for a ss amp. Its all "hard wires"<<

I think Nelson Pass, Hervé Delétraz, Charles Hansen, etc. etc. have proven that is quite untrue.

Thank you.

rascal, listen well to unsound advice. he has firsthand knowledge and based on my exp with jolida 60 wpc and$$$ he is right on the mark. a watt is a watt basically. thiels need POWER! an old tube amp is no more powerful than a new used tube amp. shop around awhile if you can but 60 wpc in a tube is not more than 60 watts from ss even if the ss has a rolled off clipping circuit like NAD offers. unsound has spoken with thiel himself and is really doing you a great service. 60 wpc may sound good but 100 is going to make them sound as good as they should. fwiw, in your $$$ range the sonic differences between tube amps is not as imp. as wpc in the case of driving low eff. speakers. ;)