Tube 300w vs Solid-state 300w?

[Guitalia]

Cut the amplitude of the bass frequencies and compress the signal in your class D solid-state amp, as happens naturally in tube amps as they begin to distort, and the two will sound equally loud.

Most solid-state amps, including class D, amplify the full range of input frequencies accurately up to the rated output. Tube amps increasingly emphasize mid-frequencies as they approach the rated output. Our ears are most sensitive to mid-range frequencies, so we perceive tube amps as being louder.

Short version: at the rated output, solid-state/class D rigs are like studio monitor setups; tube amp rigs are closer to megaphones (cf. live Cream and live Mountain tube amp bass tones).

 

[chaosMK]

Tube amps seem to punch in around 3x equivalent solid state. Even ordered harmonics or whatnot. If you want a ton of power you can get a huge solid state amp. But tube power sections kind of do a thing when you drive them, bit of compression or spongey sag sometimes, clip transients in a cool (overdriven) way. That is what I like.

I had an Ashdown MAG 300 back in the day (economical at the time), was fine but not in nearly the same category on any level as the Mesa Bass 400 with KT88s that I ended up with later on and been using for 15 yrs.

 

[JW56789]

Watt, this again?

Hey, you can see the difference:

This . . .

. . . . MUST make smaller watts than this . . . .

. . . . and it was verified years ago:

 

[Gunga Din]

I played with an Ampeg SVT-HD 8 x10 and, earlier, a Trace Elliot AH250 with 2 x 4 x10. I preferred the Trace sound.

 

[micguy]

Tube amps and transistor amps with the same output power ratings will put out the same amount of clean sound. Tube amps can be pushed further into clipping before it becomes obvious that the thing is distorting, which means in practice you get a bit more out of them before it sounds bad. It's that simple, really.

 

[DJ Bebop]

Cut the amplitude of the bass frequencies and compress the signal in your class D solid-state amp, as happens naturally in tube amps as they begin to distort, and the two will sound equally loud.

Most solid-state amps, including class D, amplify the full range of input frequencies accurately up to the rated output. Tube amps increasingly emphasize mid-frequencies as they approach the rated output. Our ears are most sensitive to mid-range frequencies, so we perceive tube amps as being louder.

Short version: at the rated output, solid-state/class D rigs are like studio monitor setups; tube amp rigs are closer to megaphones (cf. live Cream and live Mountain tube amp bass tones).

I'm enjoying my Mesa WD 800 because it seems to restore some of those things from the tube sector to the class D.

Like the HPF filter to control the low frequency interplay with the speaker.

Tthe adjustable damping a lower damping that is also important factor in tube amps and speaker interplay.

Then the dynamic control, power tube emulation that can add some harmonic content and reaction to the power amp section.

I find this difference in the power amp section more notable than the tube front end that this and other amp manufactures employ. In the case of Mesa though, the tube is utilized and is not starved or just a gimmick. Both together, the tube and power amp treatment brings real "feel" to class D, imho.

 

[ThudThudThud]

I played with an Ampeg SVT-HD 8 x10 and, earlier, a Trace Elliot AH250 with 2 x 4 x10. I preferred the Trace sound.

Trace Elliot and Peavey 'watts' get louder than most other SS amps.

I've played both SS and Tube amps, and I'm just fine with SS + Emulation of some kind vs. lugging tube amps around.

 

[MultiScaleMale]

Watts at %THD

 

[agedhorse]

300 tube watts will seem louder because it IS louder. It has to do with how the signal from your instrument is processed. A tube amp processes the signal with a more symmetrical “soft clipping” which is carried to the load with less actual resistance (impedance) which in turn equals more actual power. I’m sure that someone like @agedhorse can weigh in here, and explain all about tubes and transformers vs transistors but there it is...

Except that tube clipping especially preamp and PI sections) are often not symmetrical and there’s MORE output impedance in a tube powered not less.

I think the rating at whatever % THD the manufacturer decides to use comes into play, since a tube amp will probably have more distortion at higher output. I will say though, I just switched from a Mesa WD-800 to a Mesa Prodigy (250 Watts all tube) and certainly did not experience a loss of output. If anything the prodigy seems louder.

The Prodigy is voiced very differently, voicing has a big impact on the impression of volume. The WD-800 had greater low frequency extension which requires additional power to reproduce. Also, if using an 8 ohm cabinet, that rated power must be compared with the 8 ohm power rating of the Prodigy (which doesn’t change with impedance due to the action of the output transformer).

Great post.

Just a quick side bar here. IMO, most of the magic of the SVT head, is it being coupled to the 8-10 Fridge which is where most of the “feel” comes from. Cabs are critical to one’s sound, but often overlooked.

A big component of perceived volume is the combination of the speaker cabinet and the distortion that is generated which falls into the range where the ears are most sensitive.

 

[Ender_rpm]

if you push a tube amp past its clean RMS, it can keep putting out power, sometimes up to 50% past its rated RMS. Thats part of why a 100 watt marshal head can blow speakers in a 100watt 412 Greenback cab. And a tube amp pushed to clipping will often (not always) sound good.

A solid state amp pushed past its peak will often sound like crap, harsh square wave output. CLEAN power? in theory, through the same speakers fed the same input signal, they should have equivalent sound pressure. In theory.

 

[Jack Butler]

Well speakers are a major factor in what will be "enough" for a given gig. Others have already touched on how overdriving tubes still produces a usable(often desirable) tone. So a watt is a watt, but pushing an SVT hard will sound better than pushing a 300w class D. Through the same cab, I'd feel more equipped playing a large room with an SVT than a 300w class D head. There's a reason(with a few oddball exceptions) that 300w is about the biggest tube head available, while SS/Class D are common at 800w. All that said, I still come back to speakers yet again. I played an Elf through a fridge and it was pretty eye opening how it sounded.

 

[john_g]

I have no idea why but, my SVT at 300 watts is MUCH (!) louder than my Markbass LMII at 500 watts through the same cabs. Like..alot.

 

[levis76]

300W solid state power annoys the neighbors, cops get called.

300W tube power terrifies the city, FEMA is deployed.

 

[Johnny Fingers]

As long as it’s loud enough an sounds good, who cares about how the sound got there. A good amp for bass just gets the job done. A crappy amp for bass doesn’t.

 

[DJ Bebop]

I have no idea why but, my SVT at 300 watts is MUCH (!) louder than my Markbass LMII at 500 watts through the same cabs. Like..alot.

I thing part of it maybe goes to that damping thing that is different between ss and tube amps. SS amps are at a high damping, tubes low. That interaction with the speaker cabinet will be different. Plus the tolerable distortion in tube amps

 

[john_g]

I thing part of it maybe goes to that damping thing that is different between ss and tube amps. SS amps are at a high damping, tubes low. That interaction with the speaker cabinet will be different. Plus the tolerable distortion in tube amps

Yah...tube amp goooooood

 

[DJ Bebop]

Yah...tube amp goooooood

I just notice playing with the damping on my WD in high the speakers sound tight and in mid to low, they sound fuller, bigger, as well as the amp.

 

[agedhorse]

A solid state amp pushed past its peak will often sound like crap, harsh square wave output.

This isn't necessarily true either. The way an amp clips depends very much on the design of the power amp and not tube versus solid state. In fact, global feedback has a greate influence on how an amp clips than the devices themselves. Both types can be designed to clip softly and with grace. Also, in order to get close to a square wave, the amp (either type) has the be driven so hard that it's in practice not a very desirable tone in general. The slope between the clipped and unclipped portion is critical in defining the shape of the waveform, a square wave has both a flat top and very steep sides (high dV/dT).

Here's a pretty good article about tube versus solid state clipping:
Tube vs. Solid State: The Truth Behind Tube Distortion

 

[Phud]

I've always heard a british amp like Marshall is rated differently than one from the USA.

 

[agedhorse]

Low damping can be both good and bad depending on the speakers being used, how they are tuned (the Q of the response) and even the room that you are playing in. So, it depends.