Tube Watts = SS Watts ??

[Koshchei]

A reputable cab maker told me recently that 50W from an all tube amp head is the equivalent of about 300W from a SS head. That seemed odd to me. I'm not an EE but it seems to be that, measured at the output of the amp, Watts are Watts. Or was he perhaps meaning to refer to damping factor?

Watts is Watts. Period.

It's a fallacy to assume that because a tube amp is heavier it must be louder. It's just a LOT less efficient.

 

[lfmn16]

 

[downunder]

This is a good generalization. In my experience, some solid state amps sound fine pushed into OD and many tube amps don't/can't actually make their claimed power unless they are pushed into OD.

In order for a wattage rating to be meaningful it needs to be accompanied by a distortion figure. For example the power for tube amps is often cited at 5% THD, which is relatively clean, and 10% THD which is perceptibly distorted.

A few examples: Based on various bench tests I have dug up on the internet it appears that Ampeg SVTs commonly make about 270W at 5% THD and Orange AD200B commonly make about 165W at 5% THD. Keep in mind SVTs are are considered 300W amps and AD200Bs are considered 200W amps. Both amps will make more than their rated power but only if pushed into noticeable OD. Generally a good solid state amp rated for 300W will actually make at least 300W, and it will be very clean.

Regarding the usefulness of a tube amp pushed heavily into OD. At some point the amp will continue to make more power, but it won't technically drive the speakers louder. When the amp is making clean power the output will resemble a sine wave. While the output resembles a sine wave, increased power is achieved by increasing the voltage. Increased voltage generates more SPL from the speaker.

When the amp is pushed into clipping, the way it makes more power changes. No more voltage is available so the waveform starts squaring off. The increase in power is partly because the average time the voltage remains at its max value increases, and partly because the density of the harmonics increases.

If the amp is pushed really hard it will cause the power supply to sag, meaning the peak voltage will actually decrease as the power approaches the maximum value. So you can push the amp to the point where an increase in power actually results in a decrease in SPL generated by the speaker.

Also when you push an amp into OD, energy is transferred from the fundamental into harmonics. This is why the low end washes out if you push an amp too hard into distortion. Although it's a bit difficult to comprehend, the squared off wave you see on the output of a tube amp is not actually DC, its a result of the generation of lot's of harmonics.

For the record, I own 28 amps that range in power from 12.5W to 2,500W. 20 are all tube, 4 are hybrids, and 4 are solid state. One of my solid state amps sounds almost identical to one of my tube amps, and many of my tube amps sound drastically different from one another. Rather than worrying about generalizations about tube VS solid state, just try a bunch of amps and buy the one that sounds best to you.

I have a GK 700RB that is rated at 380W at 4 ohms. Below is a bench test video that shows an SVT making 340W at 11% THD (see 10:06 in the video), and 240W at 6%THD (see 10:40 in the video). I own two vintage SVTs and my 700RB is slightly louder clean than the SVTs pushed into distortion, so in my experience watts are watts. Basically my 380W amp is slightly louder than my 300W amps.

This is a good generalization. In my experience, some solid state amps sound fine pushed into OD and many tube amps don't/can't actually make their claimed power unless they are pushed into OD.

In order for a wattage rating to be meaningful it needs to be accompanied by a distortion figure. For example the power for tube amps is often cited at 5% THD, which is relatively clean, and 10% THD which is perceptibly distorted.

A few examples: Based on various bench tests I have dug up on the internet it appears that Ampeg SVTs commonly make about 270W at 5% THD and Orange AD200B commonly make about 165W at 5% THD. Keep in mind SVTs are are considered 300W amps and AD200Bs are considered 200W amps. Both amps will make more than their rated power but only if pushed into noticeable OD. Generally a good solid state amp rated for 300W will actually make at least 300W, and it will be very clean.

Regarding the usefulness of a tube amp pushed heavily into OD. At some point the amp will continue to make more power, but it won't technically drive the speakers louder. When the amp is making clean power the output will resemble a sine wave. While the output resembles a sine wave, increased power is achieved by increasing the voltage. Increased voltage generates more SPL from the speaker.

When the amp is pushed into clipping, the way it makes more power changes. No more voltage is available so the waveform starts squaring off. The increase in power is partly because the average time the voltage remains at its max value increases, and partly because the density of the harmonics increases.

If the amp is pushed really hard it will cause the power supply to sag, meaning the peak voltage will actually decrease as the power approaches the maximum value. So you can push the amp to the point where an increase in power actually results in a decrease in SPL generated by the speaker.

Also when you push an amp into OD, energy is transferred from the fundamental into harmonics. This is why the low end washes out if you push an amp too hard into distortion. Although it's a bit difficult to comprehend, the squared off wave you see on the output of a tube amp is not actually DC, its a result of the generation of lot's of harmonics.

For the record, I own 28 amps that range in power from 12.5W to 2,500W. 20 are all tube, 4 are hybrids, and 4 are solid state. One of my solid state amps sounds almost identical to one of my tube amps, and many of my tube amps sound drastically different from one another. Rather than worrying about generalizations about tube VS solid state, just try a bunch of amps and buy the one that sounds best to you.

I have a GK 700RB that is rated at 380W at 4 ohms. Below is a bench test video that shows an SVT making 340W at 11% THD (see 10:06 in the video), and 240W at 6%THD (see 10:40 in the video). I own two vintage SVTs and my 700RB is slightly louder clean than the SVTs pushed into distortion, so in my experience watts are watts. Basically my 380W amp is slightly louder than my 300W amps.

you own 28 amps?! You are my hero! Where do you keep them all? It does my heart good to know there’s people like you (and me) out there.

 

[Ross W. Lovell]

A reputable cab maker told me recently that 50W from an all tube amp head is the equivalent of about 300W from a SS head. That seemed odd to me. I'm not an EE but it seems to be that, measured at the output of the amp, Watts are Watts. Or was he perhaps meaning to refer to damping factor?

No!

 

[baxter_x]

I have compared the SVT 2 against the SVT 4 a several years ago (check my signature). I can tell you, the 1200W fom the SVT 4 were simply putting out of business the SVT 2 with its all tube 300W.
A watt is a watt, as mentioned many times before.

 

[HarveyRobertson]

I owned a mesa boogie buster 200 watt all tube amp. and held onto it because I thought it was the holy grail being tubes and 200 watts.. I never really liked the tone. so I traded that for a Traynor 200 watt all tube bass head... all of which my Fender 800 digital amp blows away as far as perceived power and tone to my ears. plus is way lighter.

 

[/\/\3phist0]

Tube Watts = SS Watts


Yes

 

[GreyBeard]

Here is how I understand it. 50 watt tube amp will produce roughly 50 clean undistorted watts of power. A 50 watt SS amp will produce roughly 50 clean undistorted watts of power. A 50 watt tube amp can be pushed passed it's rated power into soft clipping which will sound louder than the 50 clean watt rating and in many cases is very musical and desirable. A 50 watt SS amp goes from clean to hard clipping without any soft musical clipping. So if it is averaging 30 watts output which is clean, it will often peak, especially with the E or especially with a 5 string B, on the attack of these lower strings producing an ugly farting sound whereas the tube amp will give you a nice musical crunch on the attack. This is ofcourse a very generalized explanation and I'm sure somebody will take issue with it.

 

[J-Mags]

All watts are not created equally.

Manufacturers typically use whatever their marketing department wants.

Watts... RMS vs Peak / Max

The stated output frequently is also whatever the marketing department wants, especially with class D amps. The stated output of tube amps is limited by the fact that more of the instrument-buying public has a basic knowledge of what kind of output is available from which tubes. You can't take a pair of 6550s and say you're getting 300 watts from them. But with Class D, it's more malleable.

I think old school watts actually are louder than new-fangled watts. My Acoustic 150 is objectively one zillion times louder than my (very loud, well-designed) Quilter Power Block 200, as measured on my zillionometer.

 

[Zbysek]

A reputable cab maker told me recently that 50W from an all tube amp head is the equivalent of about 300W from a SS head. That seemed odd to me. I'm not an EE but it seems to be that, measured at the output of the amp, Watts are Watts. Or was he perhaps meaning to refer to damping factor?

Let me point out the following:

if you make a research on the market amongst bass amp manufacturers, you will probably find out that they offer SS amps up to (usually) 800-1200 watts. On the other hand, all-tube amps' manufacturers (Ampeg, Fender, Orange) offer amps up to 300 watts. Do you think that it's because all-tube amps' users like to play less loud?

Don't get me wrong: I am happy SS amps user here. I have 3 SS amps (200, 300 and 500 watts) and only one all-tuber (20 watts).

 

[unbrokenchain]

I wonder if some of the comparison confusion doesn't arise from different types of volume and gain pots too.. kinda like car stereos that have 90% of the range in the first half turn of the knob.. gotta open it up wide to find out..

 

[beans-on-toast]

True that a watt is a watt. It’s the sonic content that makes a tube and solid state amp sound different. This is something that you have to HEAR to understand.

 

[Wisebass]

Hi seamonkey

A 3kg Solid-State amp will blow a 3Kg tube amp off the stage!

Now you created the first Kilogramm vs Kilowatt thread.

greetings

Wise(b)ass

 

[teemuk]

The usual generalisations fall short in two major aspects:
1. Most tube power amplifiers actually do not 'soft clip'. Soft clipping is a self-perpetuated myth, proven false by simply hooking the amplifier output to an oscilloscope. e.g. SVT output is flat out hard clipping and square-wavish at 400w output power. That's insignificant difference to rated output power when loudness is concerned. Even slightly above rated output power one can observe distinct 'flat top' peak clipping.

2. It overlooks the fact that several SS musical instrument amps incorporate compressor, limiters, soft clipping distortion effects and a myriad of tube emulations. It is pointless to compare HiFi solid-state amps with solid-state amps built for musical instrument amplification.

 

[MultiScaleMale]

Scientifically, a watt is a watt, but I think you can push tubes harder and still have a pleasant sound plus, people think that 500W is a lot more than 300W and it's really only a smidge more. So, my 50W Ampeg pf50t head can hang in gigs where I'd only consider 300W solid state as a minimum. Thus, tube watts must be more than soldi state watts. Tube watts are more usable than solid state watts.

 

[Wisebass]

The electricity that goes into an SVT is different than what goes into a micro?

Of course it' s different, the micro runs with microwaves!

Wise(b)ass

 

[LowRick]

View attachment 3572962

I wonder if some of the comparison confusion doesn't arise from different types of volume and gain pots too.. kinda like car stereos that have 90% of the range in the first half turn of the knob.. gotta open it up wide to find out..

Yeeeees......

or.....

1W = 0,5V x 2A

Just saying...

Watt?

 

[jdh3000]

I have a 150 watt line 6 guitar amp that will blow any other ss amp away with the same wattage. I'd put it up against any tube amp for volume and tone. Many "tube only" purist commented on how they couldn't believe it wasn't a tube amp.

I've never played through any two amp, ss or tube, that pumped out the same volume.

 

[Sparkl]

This is a good generalization. In my experience, some solid state amps sound fine pushed into OD and many tube amps don't/can't actually make their claimed power unless they are pushed into OD.

In order for a wattage rating to be meaningful it needs to be accompanied by a distortion figure. For example the power for tube amps is often cited at 5% THD, which is relatively clean, and 10% THD which is perceptibly distorted.

A few examples: Based on various bench tests I have dug up on the internet it appears that Ampeg SVTs commonly make about 270W at 5% THD and Orange AD200B commonly make about 165W at 5% THD. Keep in mind SVTs are are considered 300W amps and AD200Bs are considered 200W amps. Both amps will make more than their rated power but only if pushed into noticeable OD. Generally a good solid state amp rated for 300W will actually make at least 300W, and it will be very clean.

Regarding the usefulness of a tube amp pushed heavily into OD. At some point the amp will continue to make more power, but it won't technically drive the speakers louder. When the amp is making clean power the output will resemble a sine wave. While the output resembles a sine wave, increased power is achieved by increasing the voltage. Increased voltage generates more SPL from the speaker.

When the amp is pushed into clipping, the way it makes more power changes. No more voltage is available so the waveform starts squaring off. The increase in power is partly because the average time the voltage remains at its max value increases, and partly because the density of the harmonics increases.

If the amp is pushed really hard it will cause the power supply to sag, meaning the peak voltage will actually decrease as the power approaches the maximum value. So you can push the amp to the point where an increase in power actually results in a decrease in SPL generated by the speaker.

Also when you push an amp into OD, energy is transferred from the fundamental into harmonics. This is why the low end washes out if you push an amp too hard into distortion. Although it's a bit difficult to comprehend, the squared off wave you see on the output of a tube amp is not actually DC, its a result of the generation of lot's of harmonics.

For the record, I own 28 amps that range in power from 12.5W to 2,500W. 20 are all tube, 4 are hybrids, and 4 are solid state. One of my solid state amps sounds almost identical to one of my tube amps, and many of my tube amps sound drastically different from one another. Rather than worrying about generalizations about tube VS solid state, just try a bunch of amps and buy the one that sounds best to you.

I have a GK 700RB that is rated at 380W at 4 ohms. Below is a bench test video that shows an SVT making 340W at 11% THD (see 10:06 in the video), and 240W at 6%THD (see 10:40 in the video). I own two vintage SVTs and my 700RB is slightly louder clean than the SVTs pushed into distortion, so in my experience watts are watts. Basically my 380W amp is slightly louder than my 300W amps.

Basically I would just say that tube amps sound louder because of psychoacoustics. Our brain tends to hear higher pitched frequencies as louder compared to lower pitches. Since tube sound is harmonically richer than SS (especially when pushed) it will appear to sound louder and more "thick" than the SS counterpart.

Watts are watts but "loudness" does not directly relate to SPL and power output. So that does in fact explain everything IMHO.

 

[arbiterusa]

Threads like this are why agedhorse got pissed off and started getting unpleasant with people. I don't blame him a bit.