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Why are "tube" watts different than SS watts?

Discussion in 'Amps and Cabs [BG]' started by Skel, Apr 22, 2006.


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  1. Skel

    Skel

    Jun 19, 2005
    Boulder, Colorado
    You would think a watt is a watt, like an inch is an inch. Yet, I have always known, as many others, that *tube* watts always means louder than SS. Is there a simple explanation for this?
     
  2. hartke20g

    hartke20g

    Apr 12, 2006
    miami, FL
    tubes can make the amp go beyond its normal limits. example: a 30 watt tube amp would be better to have than a 50 watt solid state because the tube amp can get to about 60-70 watts of power. the only downside (for most bassists) is that a tube amp creates its own distortion if it goes to a certain point beyong its limit. they also give you more of a "vintage/classic" tone.
     
  3. Skel

    Skel

    Jun 19, 2005
    Boulder, Colorado
    So you mean a tube amp has just more natural variance, so they rate it in kind of a worst case scenario? It doesn't make sense to me that a 100 watt Marshall with 4 6550's is so much less powerful than a 300 watt SVT with just 2 more 6550's. And yet the 100 watt Marshall is louder than any 350 watt SS amp I've ever heard. This is a weird measuring system.
     
  4. Christopher

    Christopher

    Apr 28, 2000
    New York, NY
    Do a search on this topic, and you'll open a can of worms.

    Technically, a watt is a watt is a watt. Some people profess that a tube watt is louder due to the psychoacoustic effects of the harmonics that a tube amp emphasizes as its pushed to its limits. But now you're talking about brain stuff, not electrical engineering.
     
  5. Skel

    Skel

    Jun 19, 2005
    Boulder, Colorado
    Maybe they need a new measuring unit to identify how loud the amp is. Watt doesn't seem to be working.
     
  6. Boomer

    Boomer

    Sep 17, 2003
    Hollywood, FL
    Tube amps are generally rated by the amount of clean power they can produce. They can produce a lot more power than the clean rating. When a tube amp is driven beyond that point they generally produce a "good" type of distortion, the kind that makes Marshalls crunch and AC-30's sing, etc.

    When a solid state amp is driven into distortion it produces a square wave and is considered unpleasant to most folks ears.

    HTH
     
  7. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    I find that to be their best feature!!!
     
  8. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    IIRC, there is a link to a thread in the FAQ sticky at the top of amps that deals with this. There are also a TON of threads on it as well. W/O going into the gory details, the simple explination is that the percieved volume of tube amps can be louder than SS amps (but it won't show up on a meter), AND, when a SS amp clips it sounds terrible and you wont turn it up past that point - A tube amp still soudns OK as it gradually starts to clip (some really like that tone), so you can keep cranking it.
     
  9. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    4 6550s should be more like 200 watts. Marshalls were designed for EL-34s (at least most of em, I think there were some off models in the 80s that may have used 6550s) which generate less than half the wattage of 6550s usually. But part has to do with the specific design. Marshalls were designed for tons of distortion, which also allows for more headroom. A SVT was designed for powerful, relatively clean tone. The volume tube vs SS has to do with both harmonics and the fact that they can generate 2x the rated wattage when they are pushed into OD/distortion.
     
  10. Skel

    Skel

    Jun 19, 2005
    Boulder, Colorado
    According to the "Tube Amp Book", Marshalls imported to the USA used 6550 tubes from 1974 to 1986. The distributor, Unicord, which is now Korg (I think) insisted on this - there was either a quality issue, an availabilty issue, etc. I actually called Marshall and asked them...they said Unicord demanded Marshalls in the USA used 6550's because they sounded more "Marshally" (like they knew more about Marshalls than *Marhshall*!). I think the EL34 versions sound much better because they break up much earlier. It always amazes me how many Marshalls are out there with EL34's in them, and they can't possibly be biased correctly unless the bias resistors have been changed, and many people don't know this.
     
  11. yamaha

    yamaha

    Apr 7, 2006
    Montreal
    To me, the difference in tube vs ss, especially with guitar, but also with bass, is richness of sound. I don't think there's actually more volume, but more fullness to it, more harmonics, more subtle variations in octave resonnance, more presence, almost like a rich loudness button. An electronic tone generator can give you a tone of 440 hertz, but play an A on an upright piano, then a grand piano, and finally a concert grand, and there's quite a difference, not necessarily in volume, but definately in tone.
     
  12. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    Im not sure why, but I know that when I was using a 3000 Watt SS power amp I ended up with blown speakers, but I couldnt really hear myself, but now I hear myself better with a 300 Watt tube amp.

    I also prefer the tone of tubes and like overdriving them.
     
  13. syciprider

    syciprider Banned

    May 27, 2005
    Inland Empire
    A watt is a watt. The actual question is tubes vs SS.

    Paging PBG and specplyrz
     
  14. It's because...

    SS amps get louder and louder until they reach a certain point and clip. The signal peaks and sounds terrible. Hurts your speakers and is yucky.

    Tube amps get louder and louder until they reach a certain point and clip. The signal peaks differently and sounds they way a lot of people love, this is tube distortion. This clipping doesn't hurt your speakers and isn't neccessarily yucky.

    Both amps would probaly have close to the same volume clean if the tube amp is biased right, but the fact that at that point you stop with SS and keep going with tubes is what makes them "louder"
     
  15. seamonkey

    seamonkey

    Aug 6, 2004
    Today's SS amps are not the same as ones that started this rumor many years ago. Even 25 years ago, blind test show guitar players couldn't tell much difference:
    http://milbert.com/articles/TvsT/tvtiega.html

    All anybody needs to do is takes some measurements today. There's all kinds of scope software available today. The difference will show up in the measurements.

    Clipping doesn't add that much HF harmonics compared to what's included in the input signal - see:
    http://www.rane.com/pdf/old/note128.pdf

    You'll find lots of examples of Tubes verses SS and "soft clipping". They all give examples using sine waves. Bass and guitars are complex signals. The low parts of the signal may clip, and as the paper points out the HF portion of the signal can continue to gain DBs. SS amps usually have no problem passing high frequency content when while the lows clip.

    You probably hear SS clipping every day, your car radio, your computer speakers, your TV. You probably don't even notice unless you turn it up so high that a majority of the content is clipping.

    You'll always find SS amps in concert sound systems. With limiters to prevent clipping but really to prevent LF compression as per the Ross paper above.

    Price, weight, and efficiency - SS is louder.

    Kevlar suit on.
     
  16. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    Despite your so called "blind tests," why do so many people use tube amps when the SS alternative would be lighter and a bit easier on the wallet? I can certainly tell the huge difference in sound between the models on my Boss GT-6B (which is an outstanding FX unit by the way) with a power amp into by Bergantino HT-210 and my Mesa 400+ into the HT-210. There are people who like SS sound better. Power to them. But I will not give up my tubes- they provide great tone and tons of power. And why does my 400+ get louder than any 1200 watt or less SS power amp that I have heard? And why do so many agree that, for the wattage rating, tube amps sound louder than SS amps?
     
  17. Specky showed up:

    If you can't get the REAL factual answers from what I've already posted here a few dozen times, I'm not wasting any more time explaining it.
     
  18. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    *insert spam here*
    And THAT is why SS is better than tube.
     
  19. Daywalker

    Daywalker

    Apr 13, 2005
    SOCAL
    Is there any sort of comparison for this? For instance, 300 tube watts is comparable to 1000 SS watts?
     
  20. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    Yeah, go to a store, and try them all out.

    Seriously, its hard enough to compare Ampeg watts, Mesa watts. GK watts, SWR watts, Eden watts, etc...

    Everyone has a different way of presenting their amps ratings and outputs and if you cant even come up with a accurate, solid standard among one side of the picture, how are you going to compare it to the other.
     

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