Solid State vs Tube Watts: Need Help

[billfitzmaurice]

I seriously feel like my previous post has simply been ignored.

Not at all, it was well stated and for the most part technically correct. That's in stark contrast to the emotionally based posts by those who don't know a watt from a joule, let alone grasping the concept of transfer function.

 

[chadds]

OP, are you playing through the tuner and Boss unit?

 

[T.A.P Bass]

OP, are you playing through the tuner and Boss unit?

Yes sir, why do you ask?

 

[Ragnor]

and for the most part technically correct.

Aha!
Please, enlighten me by telling what part wasn't, so that I can either argue for it or take it into account for the next time.

 

[okcrum]

Ragnor, I think your post was fine. I think things would be much more clearly similar between solid and hollow state amps if all were rated at honest continuous (> 30 minutes) RMS power at the same distortion figures, say, 1% and 5%. This argument comes up periodically because people believe marketing hype concerning power output. Just because an amp will do 800 watts for 10-30 ms. doesn't mean it's an 800 watt amp. Many of these are more like 300 watt amps continuously. And therein lies the tube watt vs. SS watt myth.

Try getting 400 continuous watts bridged out of an SWR SM400. At least you can enjoy the eggs you can cook on top as well before it dies.

As an example, I've gotten 250 continuous watts bridged out of an SM400 for about 30 min, with forced air cooling through the case. At that point the heat sinks' temperatures were still rising, nearing 70 degrees C, the rating of the output transistors themselves. I had to stop the test before I killed the amp.

 

[Bob Lee (QSC)]

What the OP poster is talking about is why do solid state watt ratings and tube amp watt ratings not compare well. I predicted that folks would smugly chime in with "a watt is a watt" and I was vindicated.

There's nothing smug about a watt being equal to a watt, unless you're really bad at math.

On one of the numerous other "tube watt" thread it was pointed out that what we often get quoted for SS amp specs is wildy er..distorted. Solid state amps generally have higher peak instantaneous output. Marketing types caught wind of this and ran with it. So you see amps specced for 400 watts, 800 watts etc in scenarios that do not reflect what a bassplayer ordinarliy would want to do with a bass amp.

No, that's not true. Just look at how often you see FTC power ratings on amps. You rarely see "peak" ratings except in car audio, which has its own realm of marketing anarchy.

Tube amps usually tend to have softer, higher-impedance power supplies that gives clean peaks but sags with continuous power draw. That's usually not much of a problem because of their softer clipping characteristics that mask instances of overdriving. For example, you can drive a 300-watt tube amp to, say, 500 watts for short periods of time and the distortion will often sound unobtrusive or even euphonious, and will also tend to make it sound louder (as increased harmonic content often tends to do).

 

[seamonkey]

Somebody should take some measurements and prove all the claims.
Just about any PC these days is fully capable of charting the difference.

I predict just in the US at this very moment that are 1 million SS amps in cars, TV's, stereos, ipods, bass amps, ...
all being driven into high clipping and nobody is running for the hills covering their ears.

 

[bassboysam]

I predict just in the US at this very moment that are 1 million SS amps in cars, TV's, stereos, ipods, bass amps, ...
all being driven into high clipping and nobody is running for the hills covering their ears.

Ignorance is bliss

 

[Calaverasgrande]

There's nothing smug about a watt being equal to a watt, unless you're really bad at math.

No, that's not true. Just look at how often you see FTC power ratings on amps. You rarely see "peak" ratings except in car audio, which has its own realm of marketing anarchy.

Tube amps usually tend to have softer, higher-impedance power supplies that gives clean peaks but sags with continuous power draw. That's usually not much of a problem because of their softer clipping characteristics that mask instances of overdriving. For example, you can drive a 300-watt tube amp to, say, 500 watts for short periods of time and the distortion will often sound unobtrusive or even euphonious, and will also tend to make it sound louder (as increased harmonic content often tends to do).

Bob, you guys do a great job of putting real specs in your onesheets and manuals. In fact you are one of the least hyped up companies I know of in pro audio. You let your product speak for itself. Too bad your powered speakers came out after I got out of sound reinforcement! You make great power amps that happen to be solidstate. Not to my knowledge, bass amps (though some guys put a preamp on top and use it as such) so I wouldnt say you have a dog in this fight.
I think what we are kicking around here are more the Ampeg, SWR, Behringer etc approach to power output ratings. I have literally seen power quoted as one cycle of some arbitrary fequency. No distortion figure given. (ampeg to be exact) With those parameters an amp can put out an instant of 1000 watts, but in real world situations may only be capable of 300 watts. Nevermind that the number they silkscreen on the back of the amp rarely has any qualifier other than "4 ohms minumum".

And yes it is smug. This debate is not vapor. Of course I know a watt is a watt. That the same folks re-iterate that phrase ad nauseum does nothing to educate anyone or help to solve this conundrum for bass head buyers. It is worse because, if you read this whole thread it has probably been said a dozen times. Pretty good indicator that they didn't bother to read more than the first two posts and then regurgitated what they always do.
There are plenty of folks like me that don't just talk about tubes being louder than solidstate. We live it. We bought amps based on watt ratings printed on the back of the head, plugged them in and they were not able to keep up. Like I said I had all kinds of issues with amps not being loud enough in the past. I tried solid state, tube, hybrid, you name it. For about 10 years I went thru amps like most bassists go thru strings. I finally got a good loud amp that was...all tube. YMMV.

It's funny how a 450 "watt" head made now can't put out like a mere GK400rb. But wait that amp is only 200 watts! (And its solid state!) Well Gk was conservative in their rating for that amp, and that amp is louder than a behringer/ampeg/swr 200 watt amp.


Question:Why are tube watts louder than SS watts?
Answer: The way they evaluate watt ratings for bass heads varies with manufacturer, most significantly when comparing tube and solidstate amplifiers.
non-answer: Watts are watts regardless of what you are talking about.

 

[Munjibunga]

I seriously feel like my previous post has simply been ignored.

What did it say?

 

[Ragnor]

What did it say?

A little scrolling up on the very same page as the post you quoted me on, you'll find this:

I think someone brought it up earlier in this thread, in which case you can see this as a confirmation.

A watt is a watt. How that watt is turned into sound, is dependent of the used speakers. Period. Tube-watt's aren't 'louder' than solid watt's, they are the same thing.
What does make a difference, is how many watts you are using. One of the main features of a tube amp, is that it sounds so nice when brought to overdrive (a.k.a. clipping). A clipped signal with the same peak value as a non-clipped signal, will have a higher AVERAGE VALUE. This means more average power will be brought to the speakers, meaning it will be louder.
In general, people avoid clipping SS-amps because, well, it sounds nasty in most cases. But how about this: turn your amp up all the way, then use a distortion pedal. With a bit of tweaking of the volume to prevent the amp itself from clipping, you'll find it goes pretty loud.

This is why transistor amps need more wattage than tubes, because people like to have them sound clean.
If you want a transistor amp to go as loud as a 300W tube amp, yet still sound clean, look into the 450W range. If you don't want it to sound clean, the 350W should do the job if you use a pedal.


My qualification for this answer?
I've been studying electronics for the past 6 years and continue to do so, while working closely with companies in the professional world. I've made a few audio amplifiers myself (from scratch, not a building kit like some people tend to suggest) and I am considering to do a class-D amplifier soon.

Ragnor, I think your post was fine. I think things would be much more clearly similar between solid and hollow state amps if all were rated at honest continuous (> 30 minutes) RMS power at the same distortion figures, say, 1% and 5%.

That's the 'problem'. They ARE! The problem isn't the way manufacturers rate their amps (to give a accurate rating, you'd need a few pages of wattages at different parameters, or a curve that only an engineer could make sense of). The 'problem' is that tube amps are used differently. Tubes are generally used in the clipping area, as I explained in my post.

A bit earlier in this thread, someone said that everyone who said "a watt is a watt" didn't bother to read the first few posts. Well, person, I did. And I responded with a much more extended answer which, if you had bothered to read, you would have found to explain why a tube amp tends to be perceived louder.


Still waiting for an answer form billfitzmaurice

 

[JimmyM]

A little scrolling up on the very same page as the post you quoted me on, you'll find this:

i think munji was making a joke.

 

[Calaverasgrande]

^^^^^^^^^^^^^^like Ragnor explained

Subjectively, there is a perceived difference. there are a number of plausible reasons for this, you may or may not agree with them, but they are plausible

tube amps have much higher distortion with rising level, unlike many SS amps which rise more gradually. This is not true in general, but it is probably a decent rule of thumb. We know higher distortion results in a louder perceived sound, all else being equal.

I would say these both mean the same thing. Maybe what you want to say is that solid state has a wider area of linearity wheras tubes, especially as operated in bass amps, are rarely linear for long.
If anything the problem with SS amps is that distortion is anything but gradual in its onset. 99% gain is clean, 100% is not.

 

[baron665]

I predict just in the US at this very moment that are 1 million SS amps in cars, TV's, stereos, ipods, bass amps, ... all being driven into high clipping and nobody is running for the hills covering their ears.

Only 1 million? I'd say more like 20-50 million.

 

[DanRJBrasil]

I use the 400rb all the time and I had a b2r, I couldn't hear much dif in volume

Bob, you guys do a great job of putting real specs in your onesheets and manuals. In fact you are one of the least hyped up companies I know of in pro audio. You let your product speak for itself. Too bad your powered speakers came out after I got out of sound reinforcement! You make great power amps that happen to be solidstate. Not to my knowledge, bass amps (though some guys put a preamp on top and use it as such) so I wouldnt say you have a dog in this fight.
I think what we are kicking around here are more the Ampeg, SWR, Behringer etc approach to power output ratings. I have literally seen power quoted as one cycle of some arbitrary fequency. No distortion figure given. (ampeg to be exact) With those parameters an amp can put out an instant of 1000 watts, but in real world situations may only be capable of 300 watts. Nevermind that the number they silkscreen on the back of the amp rarely has any qualifier other than "4 ohms minumum".

And yes it is smug. This debate is not vapor. Of course I know a watt is a watt. That the same folks re-iterate that phrase ad nauseum does nothing to educate anyone or help to solve this conundrum for bass head buyers. It is worse because, if you read this whole thread it has probably been said a dozen times. Pretty good indicator that they didn't bother to read more than the first two posts and then regurgitated what they always do.
There are plenty of folks like me that don't just talk about tubes being louder than solidstate. We live it. We bought amps based on watt ratings printed on the back of the head, plugged them in and they were not able to keep up. Like I said I had all kinds of issues with amps not being loud enough in the past. I tried solid state, tube, hybrid, you name it. For about 10 years I went thru amps like most bassists go thru strings. I finally got a good loud amp that was...all tube. YMMV.

It's funny how a 450 "watt" head made now can't put out like a mere GK400rb. But wait that amp is only 200 watts! (And its solid state!) Well Gk was conservative in their rating for that amp, and that amp is louder than a behringer/ampeg/swr 200 watt amp.


Question:Why are tube watts louder than SS watts?
Answer: The way they evaluate watt ratings for bass heads varies with manufacturer, most significantly when comparing tube and solidstate amplifiers.
non-answer: Watts are watts regardless of what you are talking about.

 

[sandmangeck]

This is past beating a dead horse. A bit of necrophilia w. your beastiality.

 

[dincz]

Somebody should take some measurements and prove all the claims.

Somebody already did that about 60 years ago.

 

[T.A.P Bass]

Ok, as the OP, I'd like to thank all of you for your opinions.... I've read your posts and have learned a ton...

My main concern is that I've owned my SVT-350H for about 10 years now. My band was playing out and my head was forgotten to be brought along... I borrowed another bassist's head, which happened to be a SVT-2Pro, set it up the same as I would my 350H with intent of that being a good starting point, what I noticed was that the 2Pro was much louder and had clearly more headroom as compared to the 350H...

Since the 2Pro is rated at 300 Watts and the 350 is a 350 watt head, how and why does the 2Pro perceive to be a louder amplifier??

As for those of you who have inquired, I know the BDDI scoopes the mids some, I tend to run my highs and lows flat with a bump in my low mids on the 350's graphic eq.... Like many had said so many times before, if it works for you, run with it...

 

[billfitzmaurice]

Since the 2Pro is rated at 300 Watts and the 350 is a 350 watt head, how and why does the 2Pro perceive to be a louder amplifier??..

Key word: Perceive. Different amps process the signal differently, so they subjectively sound different. Even different tube amps will sound different from each other. No one mistakes 60s era Fenders for Ampegs, and a 35 watt Portaflex sounds louder than a 50 watt Bassman. Chalking up the difference to a simplistic 'tube watts are different from SS watts' is just that, simplistic. And not true. A watt is a watt. It's how different amps process the signal that accounts for the perceived differences.

 

[KJung]

Key word: Perceive. Different amps process the signal differently, so they subjectively sound different. Even different tube amps will sound different from each other. No one mistakes 60s era Fenders for Ampegs, and a 35 watt Portaflex sounds louder than a 50 watt Bassman. Chalking up the difference to a simplistic 'tube watts are different from SS watts' is just that, simplistic. And not true. A watt is a watt. It's how different amps process the signal that accounts for the perceived differences.

+1 Same thing with solid state heads. Different power amp limiting designs, different reporting criteria (THD, frequency response range, etc.), and different hi passing or other low end control can make various 500 watt (+/-100 watts) solid state heads to be perceived very differently regarding max volume.

The tube/ss thing is kind of meaningless, unless all this other stuff is controlled (amount of distortion, etc., etc.).