How do tube Watts compare to SS Watts?


I have Theil 2.2 speakers, which have a low sensitivity (86dB), but I would like to get an intergrated tube amp. Or even all tube. But I don't know how many tube Watts I'll need to drive the Theils. My guesstimate is @ 50wpc for intergrated tube amps, but that could be wildly off. Are their mathematical conversion formulas? Second, if there is a rough range, might you be kind enough to suggest a few worthy candidates that, wheather new or pre-listened, are under $1,000 USD (e.g., Cayin model xxx). Thank you most kindly.
rascal52240

Showing 5 responses by bartokfan

My jadis OR with KT90's will drive your speaker. Used, $1500. Also look at the Ming Da tube amp with KT90's/new at $900. The Cayin KT88 "might" work. But I surmise it may be a tad on the soft side. There's not many tube amps used under $1K that will offer "slam". 2 imporant factors that go into makinga great tube amp that has "punch" is the quality of trans and the quality of tubes. Neither of which come cheap. ....There are ss amps under 41K that will give some authority, but as far as fatigue factor and lack of musicality, I couldn't live with it.
Depends on the tube. SET amps with 300B, 845 are low power, "no slam" "no authority", but a midrange and highs to die for, WITH THE RIGHT SPEAKER. So scratch those off my list. ...KT88's. I heard one cheap chinese 88 and also rolled 88's in my JOR. Absoluetly no authority. Very very weak on any speaker with 90db or lower. I havea Jadis DEFY sitting on my floor waiting for a preamp, has the 6550 tube. Very very nice looking tube and should be an improvement over my KT90 Jadis OR. The seller told me has "magic". Then there is the EL34, which doesn't look too interesting. Looks like a cheap KT90. There are other SET tubes like the 2A3 (ck name?), same issues as the 300 and 845. There are a few other tubes, but these are the most used in designs. Comes down to speaker first, then amp. So only the "beefy" KT90 does the job. I'm expecting the 6550 to come through as well. These are push/pull tubes. Sorry ss amps are not "my cup of tea". None.
I stand corrected. What i mean to say is that on most speakers, SET amps, 300, 845's will not provide the current necessary to produce tension, "slam". I've had KT88's in my JOR and the result was total failure. The amp lost all its "authority". So I also place KT88's in "SET" category, even on a push/pull design. I have not heard the Cayin KT88 yet, that might change my opinion. Point is, some tubes in many designs do not offer the body in MOST speakers that a decent ss amp will offer. Put any SET amp with a Vandersteen and then put a decent ss amp. SET's will not drive the speaker. Tubes can make great music, that is IF you can find the right speaker. As you point out its a combination of the 2. Much easier done with any ss amp, tubes work only with certain speakers.
Please correct if/where I err.
Greg, thats interesting. Not sure what a pentode is. Is the KT90 a pentode? If yes then all these 3 tubes are used in amp circuit designs that are different from SET designs using the 300 and 845 tube. Rascal, I also prefer Kreisler over Heiftz. Oistrakh was my prefered violinist, but I recently sold off his 6 cd set In Prague, oop. The set had too much romantic era stuff, which I don't care for. I love Gideon Kremer's recordings, except the Schnittke 4 vc's, which fault lies with Schnittke. Even though Schnittke is one of my top fav composers, his 4 vc's left me uninterested. Read my reviews on amazon.
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.