Statement 'SS amps can't get through the mix' myth or truth?

[Rutger]

Hi,

You often hear this said/written by many (if not all) guitarists who use or have been using a solid state amplifier in a (live) band situation. They hire a studio/barn with their band and use the PA and gear that's allready in there, or just use their own ss-amp that they bought once for home use. But then they have a really hard time to try to get through the mix and be heard. And when they get through, their gear have never sounded worse than with that amp. And they need at least 3 times more power than with a tubeamp!

Actually this is a wide spread and accepted opinion and has allmost become a definition of ss-amps. But I'm wondering... is it really because of the amp being solid state, or are there other factors involved? I mean, the technology is whidely accepted and preffered in audio equipment and bass-amplifiers, so why is it so bad in combination with electrical guitars?

This topic is meant to bust the myths about solid state guitar amplifiers. So please shoot and share your opinions, experiences, stories and knowledge!

[Enzo]

And while we are at it, let's ague which way to put the toilet paper hanging off the roll.

Tube based amps are my personal choice,   but they can hide in the mix as effectively as can a SS amp.

One has to ask one's self, "am I a guitar player standing out here with a band around me, or am I a part of a band standing out here?"  One needs to always be aware of where one sits in the overall mix, just as you need to be aware your D string is not twice as loud or half as loud as the other trings/

[phatt]

And while we are at it, let's ague which way to put the toilet paper hanging off the roll.

Tube based amps are my personal choice,   but they can hide in the mix as effectively as can a SS amp.

One has to ask one's self, "am I a guitar player standing out here with a band around me, or am I a part of a band standing out here?"  One needs to always be aware of where one sits in the overall mix, just as you need to be aware your D string is not twice as loud or half as loud as the other trings/

Touche Enzo. :tu:
Phil.

[joecool85]

Mostly the reason why SS amps aren't heard as well as tube amps has very little to do with the amp itself, but almost entirely the speaker.  Put a high quality Celestion or Eminence driver in an SS amp and it will cut through the mix just fine.  Needing only ~20w or so.  Put a crappy chinese knock-off speaker with 90db/watt or less SPL into a tube amp and no one will hear it over anything and what they do hear will be crap.

Unfortunately for now the market is such that high end guitar gear is normally tube with nice speakers and lower end great is SS with cruddy speakers.  There is no need for it, just that's what people want...for now.

[J M Fahey]

joecool has hit the nail in the head, and the others have mentioned valid points too.
And, although there is a small tube advantage which I will explain later , there is no way SS amps "need at least 3 times more power than with a tubeamp!" with the SAME speakers.
Fact is, the usual and very unfair comparison is between an SS 30W beginner amp, with a no name (or even Celestion) 10" speaker, light magnet (G10D25 ; G10L35), relatively low efficiency (92/94dB, just check their datasheets) and a Tube 30W, which may be a VOX AC30, 2x12" Vox Blue, 101dB efficiency, or a Matchless (1 Greenback, 97dB + one Vintage 30, 100dB) or in the 50W arena, a Peavey Bandit, 50W, 1x12" mid price/quality Eminence compared to a Marshall Plexi driving a 4x12" 1960 cabinet.
Hey !!! I compared 30W to 30W and 50W to 50W, didn't I? :loco
Now with the same speakers things change a lot: I sold *lots* of 100W SS heads, by demoing them with a Mesa cabinet, the 4x12" slant one with two Black Shadows below in a closed box for body and 2xCelestions on top on a semi open half for bite.
You do *not* want to stand in front of that box, driven by tube or SS alike.
I also regularly sell my SS B300 bass heads to guys who then  *sell* their Tube Ampeg SVT heads but keep the "fridge" 8x10".
Why would they do that? Obviously "good" SS works for them.

As you can see, only 2 of the SS Fahey B300 heads are on; all 4 would be too much even for that very loud band.

Now to admit part of what you say: power and speakers aside, tube amps do not sound "louder" (a watt is a watt and the speaker couldn't care less where it came from) but usually an overdriven tube amp still keeps some of the original harmonics, and its own distortion waveform is often funky, both factors contributing to an easier to distinguish sound (because of its "flavor", not because of power ), so much so that "different power tubes sound different" while *most* SS amps produce exactly the same dull boring "perfect" squarewave, so an overdriven 2N3055 "sounds" exactly the same as a TIP142, a 2N3773 , an MJ15022 or a clipping LM3886 for that matter.
Anyway, some of that funkyness can be introduced into SS amps to enhance their "flavor" and produce very usable amps.
When speaking of SS amps most people think of JC120, Polytones or even classic Kustoms, I do not think they are a good example because they avoid the problem altogether, by being used clean, they prove nothing.
I very much like classic Randalls, some Gallien, Laney, Crates and Peaveys, even the humble Bandits, or Fender Stage 160.
The Rolls Royce of SS amps are the Pearce, Pritchard, Bluetone, and the Roland Blues series. AFAIK of course  8|

[KMG]

The old battle - SS against the Tubes.
Let's leave aside the preamp. It is different story.
Let's talk about not overdriven PA.
The  main difference is the negative feedback depth.
Due to deep feedback depth SS PA has low magnitude of long "tail" exponentially decreasing harmonics, also it has low output impedance.
Tube PA with feedback depth 3-7 dB has output impedance about 10-30 Ohms.
Also it has big enough magnitude of nearest harmonics, so its output spectrum occupies wider area.

These harmonics are perceived by the human ear is not as unpleasant overtones, but how the coloring the sound.
The high output impedance of the tube PA leads to producing higher sound pressure at speaker resonances.
So the tube PA sounds different and louder (at some frequences) against SS PA at the same power rating.

[teemuk]

^Today it's pretty much a standard of solid-state guitar amps to use negative current feedback to increase output impedance and have higher (voltage) gain at speaker resonances. Similarly to tube amps. In fact, they've mostly been that way already since mid 1970's if not longer.

The simple truth about loudness difference is just that people like cranking tube amps and cranked, distorting amps are inherently louder because of the compressed dynamic range. I commonly hear the tube guys say that they can cut through the mix even with a 5-watt amp. The fact is: Try running those amps clean and they will have harder time cutting through the mix. Tube amps are regarded as being louder -only- because they are very commonly pushed to distort. Cutting through factor then comes from proper EQ:ing that doesn't turn the whole thing into a buzzy mush. And yes, you can achieve that not-cutting-through effect with tube amps too.

So, a good solid-state amp through a decent speaker setup should have no problem whatsoever in cutting through the bandmix. If there's some, then it's a user error.

And before anyone even says "soft clipping" this is a typical output of a clipping tube power amp running to a resistive load:
Trainwreck:

Blackface Fender:

Not soft, in fact, therribly distorted. A good solid-state amp is easily on par with it.


A reactive load coupled to a high output impedance will skew the output wave a bit, at least if the distortion originates from preamp but it will likewise do so in a solid-state amp that has a high output impedance:
Fender Blackface: low volume, preamp OD

Same amp, same setting, except master volume high. Resonance/gain-induced peaks run to rail voltage limits and they are clipped:


Yeah, I know that the scope captures look bad because the traditional myths teach us that hard clipping is bad and harsh sounding (and nasty hard-clipping solid-state can't be cranked because of that) but soft-clipping is good (which is why cranked tube amps sound great and can be so much more louder). But the truth is different AND we don't hear with our eyes. This is a Blackface Fender, all-time great and classic tube amp design. Cranking that amp will result to what we see on the screen and it sounds great. Yes, hard clipping can sound great and many tube amps hard clip. Many. classic. tube. amps. It's also friggin loud because the dynamic range is compressed to square wave territory. You can also achieve this with any decent solid-state amp. Crank them and they are louder; if it turns to farty, mushed buzz, learn to use the damn EQ.

[KMG]

Yes, complex (voltage/current) feedback solves speaker dumping problem.
But DIYers rarely use this type of feedback.

I told about not overdriven PA.

About overdrive - when SS PA begins to overdrive, feedback path begins broken and amplification factor rises up to hundreds thousands. This lead to very sharp edges of clipping.
In tube PA amplification factor rises by about 3-7 dB (if feedback exists), so edges of clipping remains defined mostly by output tubes V/A transfer curve.

Width of flat tops of SS PA clipping increases proportionally input signal rising.
In tube PA, two things happen - in part increases the width of flat tops, and partly the signal "grows inside", forming an increasing step. This leads to signal compression.
In the case of overdrive, the intelligibility of the sound of tube PA is obtained higher than that of SS PA.
Conclusion - do not overdrive SS PA.

[guitarkitbuilder]

And before anyone even says "soft clipping" this is a typical output of a clipping tube power amp running to a resistive load:
Trainwreck:

Teemuk,

Would you characterize the crossover distortion in this oscilloscope image as "typical" or "severe"?  Do you find the crossover distortion is more pronounced in the oscilloscope view with a resistive load?  I was recently looking at an amp that looked just like this in the scope and my thought was that I needed to make some adjustment to smooth out the crossover, but I'm not sure what normal should look like.

[teemuk]

Yep, it's quite typical for fixed bias amps. When overdriven they go to grid conduction mode causing the bias points at grids to shift, which then causes the crossover effect. It naturally exists with reactive (speaker) loads too but usually the non-linear frequency response skews the waveform and the distortions isn't so obvious to spot.

There are few methods to lessen the effect: First is to make sure that grid conduction can never happen. A clever solution is placing some solid-state clipping diodes to the grid that will limit the voltage excursion. Second method is altering the time constants of the coupling. Third method is introducing notable series resistance to the grids. Fourth method is driving the grids with a DC coupled low impedance source (buffer).

[guitarkitbuilder]

Teemuk,

I should have clarified that my question concerned SS amps, even though the scope photo is of a tube amp.  Is your answer the same for SS, with the exception of grids?

[teemuk]

No, my answer is not the same for solid-state. Most of them have an architecture where crossover distortion caused by DC bias shifts doesn't exist. In generic transistor amps the crossover distortion is created by entirely different mechnanisms, mainly due to insufficient idling current of the output and driver transistors.

Usually, if solid-state amps have crossover distortion the bias setting is originally set "cold" and the crossover distortion is there all the time, not only when you overdrive the amplifier. This makes it particularly nasty because low amplitude signals are constanly affected by it and the percentage of distortion would be relatively lower with higher output signal amplitudes, in other words if the amp was all the time running closer to its maximum output power.

So: No, most solid-state amps shouldn't have this issue and if they do then the bias setting is either intentionally or unintentionally "cold". Some older amps were intentionally set this way because the designers had problems with designing succificient thermal compensation schemes. In modern amps this issue should no longer really exist.

[will316]

  Dimebag never had problems cutting through the mix...Just sayin'... He also never had problems reproducing his sound on record live-yet he always laid down a trackor two in the studio with a tube amp yet left it at home when he hit the road. (can't remember which brand of tube amp he used, but his Randalls always rocked and didn't break down)

[Rutger]

Wow, didn't expect this topic would go this way. Great

There's another so called 'explanation' about this cutting through the mix. It says that it doesn't have anything to do with loudness or efficient speakers, but with the frequency response. Tubeamps would have the right frequency response and right harmonics that would explain why a tube cuts so well through the mix and ss don't.

Any thoughts on that?

[teemuk]

^I partially agree but you can't generalize that theory.

Yes: proper frequency response definitely helps cutting through the mix. It's basically one key part in it too. If you ever done mixing of recorded media, or actually even dialled your amp to fit to the overall bandmix, you've encountered this phenomenon: You more or less isolate your instrument to a specific band of frequencies and try to keep other instruments away from that band of frequencies. You more or less try to get every instrument to occupy their own specific band. This way they won't "fight" each other and you have a mix that retains a lot of clarity. Usually its a kind of compromise but the main idea is nevertheless that. Frequency response is damn important, that's why I mentioned in one of my earlier comments that folks who have problem cutting thru need to learn to use that EQ  (tone controls).

Another thing that EQ:ing can do is shaping overall distorted tone. Let's say you hit a gain stage with a signal high enough in magnitude to cause clipping distortion. If you do it with full bandwidth the clipping of high-magnitude low frequencies will remove most of the high frequency signal content. The tone looses all its clarity and note separation and basically sounds like farty mush. Decent amp designs (that is, in amps designed to distort) reduce the magnitude of low frequency content drastically because of this. Not only does it help in regard of clarity, reproducing higher frequencies also means lower average power draw than reproducing the lower ones. So again reducing low frequencies can enhance clarity; lesser output power demand usually means lesser amount of severe overdriving and choking of the output stage. Thus a 5W amp with proper EQ:ing that reduces bass pre-clipping can sound much nicer and "clearer" cranked than a 50W amp being distorted at full bandwidth. The latter can be earshatteringly loud mushy buzz that just buries (or gets buried in) the entire mix, while the other can actually "hold together" and fit to the mix quite piercingly. Overall the actual difference in loudness likely isn't all that great.

In addition to that, EQ:ing post clipping can remove higher order harmonics (basically all the obnoxious fizz that you'd hear from 4kHz and above), so it can again make a distorted tone sound much nicer. And then you have all the spicing up that you can do with mid-range notching or boosting. Yes it makes a heck of a difference.

The problem in your theory is: Both tube and solid-state amps EQ. Also, the overall EQ depends a lot on the amp model. Tube amps don't have some specific response any more than solid-state amps have one. All in all, a good chance is that those responses are actually quite alike on most parts.