Fact checking a GC employee

S

stratguy23

New member
In a Guitar Center yesterday, I heard an employee explaining amps to a customer.

The employee made 3 claims:

"A 100-watt solid state amp only goes up to 100 watts. But the tubes in a 30-watt tube amp actually pushes its power over 30 watts."

"A 30-watt tube amp is actually louder than a 100-watt solid state amp."

"Tube amps are better than solid state amps for pedals because they have more headroom from the tubes."
​

Each of these statements made me pause, but I don't have sufficient technical expertise to judge their truth.

How accurate were the employee's claims?
 
Re: Fact checking a GC employee

claim 1: kinda has to do with how the output wattage is rated, and they usually measure the output when the power amp distorts a certain amount. Solid state power amps are more often designed to (or it is a design limitation that they) operate really clean up until they overload, near the full volume of the amp, and distort harshly. It's near the top of the amps volume that they take the output measurement.
Tube amps are rated and designed usually with power amp distortion being wanted or acceptable. The wattage measurement is taken when the output stage is distorting that certain amount, but most of the time this is not at the full volume of the amp, they knew that you can crank it past when the power tubes break up and still have it sound good, but they still take the wattage measurement at a sort of arbitrary amount of power amp breakup to have a baseline between audio equipment.
By the time a marshall that was rated 100W at x% harmonic distortion could be putting out 120W when cranked all the way.

claim 2: I'm no psychoacoustics expert but it's something kinda like: Tube amps put out more even order harmonic content especially the 2nd harmonic which is very strong and musical, and the ears are sensitive to it. The output transformer in a tube interact with the speaker as well, generating more harmonics, tubes also tend towards asymmetric signal clipping which sound better than square wave distortion, and increasing the punch and reactivity of the speaker to the amp pushing it. The amp will sound louder and feel more alive!
Solid state amps generate more odd order harmonics and square wave hard clipping distortion cuz when they get overloaded they just chop the whole top of the audio wave off. odd harmonics, the ear is less sensitive to and/or most people find less pleasing, and hard clipping sounds very rough. Also they don't have the interaction of the output transformer and the speaker cuz they don't use an output transformer, and a tube amp may be putting out more watts than it's rated at whereas the 100W solid state is really topped at 100W.

Plus, due to the logarithmic nature of hearing ad sound pressure, it takes about a 10x increase in power to sound twice as loud, and doubling your wattage while keeping everything else the same gets you about 3db increase in volume, just enough for most people to notice it's louder.

then you have to factor in the speaker sensitivity, some 12" speakers are much as 9db louder than others, so decently louder. The efficiency of the speaker is the final factor in volume, and so say if you run any tube amp through a speaker that puts out 96db when you feed it 1W from the tube amp and stand 1 meter away, a solid state amp plugged into a 103 db speaker is gonna be much louder when the SS amp is at 1W and you're 1M away.
and then every time you double speaker area you get 3db added volume I think?
so the end result depends on the cab and speakers a LOT.

So take a 30W tube amp like an Ac30 with alnico blues, which has 2 very loud very efficient 12" speakers and it's full of second order harmonics and it's putting out more than 30W by the time you dime it, and run it against a 100W marshall MG with a MG412. It has 100W, but to get all 100W you have to dime it and by then you don't have the pleasing harmonics you have odd harmonics fizzing your sound, your speakers don't react the way they would to a tube amp and the cheap speakers are inefficient to boot.
So the AC30 is going to sound louder *in this case*. It could be different if you swapped cabs, but the harmonics and reactivity of the tube amp will generally make you want to play more and play louder.

Claim 3: Tube amps distort with pleasing harmonics and asymmetric clipping which which make you guitar and your FX sound generally good. And you can use overdrive pedals to push the first tubes into distortion that is smooth.

SS amps distort in an uglier way, they technically have MORE headroom in most cases, but when they hit the headroom ceiling they sound really bad, whereas tubes sound *better* after the ceiling.
 
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Re: Fact checking a GC employee

All you had to say was GC employee, and you knew they were not going to communicate the facts.
 
Re: Fact checking a GC employee

stratguy23 said:
How accurate were the employee's claims?
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I can't speak a lick about the accuracy of his statements, but would you like to take out a Pro Coverage policy on them in case you find something wrong with them later on down the road?
 
Re: Fact checking a GC employee

ICTGoober said:
All you had to say was GC employee, and you knew they were not going to communicate the facts.
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Many years ago, I was buying a used Ibanez RG at Guitar Center, and I asked the guy at the pickup counter if he had any trem-spaced pickups. He stared at me for a minute, then set a Hot Rails on the counter. In hindsight, I'll give points for trying.
 
Re: Fact checking a GC employee

The true, burning question here is:

What are you doing at a Guitar Center?
 
Re: Fact checking a GC employee

Empty Pockets said:
GC guy understands the basic concepts but not the actual physics and science.
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In my experience there are no hard and fast rules to these questions and the science gets pretty complex.

I will just speak to my observations to such questions over the years:

A 50 watt Marshall tube amp in triode ( about 20 watts) absolutely buried a 100 watt Fender SS amp through the same speakers. Of course the SS amp was pushing an 8 ohm load and would have been louder pushing 4 ohms. This load factor doesn't matter to a tube amp's loudness.
An 18 watt Marshall is louder than a JTM45, both run in their sweet spots.
The AC30 is louder than a JTM45.
A 50 watt plexi or JCM800 is significantly louder than a JTM45 or an AC30.
A 50 watt Marshall is as loud as a 100 watt Marshall, but the 100 watt pushes more bottom end.
A 50 watt Fender bassman is as a loud as a 50 watt Marshall.
An 80 watt Fender Twin Reverb is usually louder than a 100 watt Marshall.
The Marshall DSL15 is stupid loud on the red channel (louder than a JTM45), but less loud than the SS 20 watt Orange micro (run dirty) on the green channel.
The Marshall Vintage Modern isn't very loud for its wattage ratings. The 50 watt VM is more like JTM45 loud, and the 100 watt is more like 50 watt Jubilee loud.
The DSL40 measures 49 watts clean.
The efficiency of the speaker matters more than the numbers of speakers or the wattage rating. The design of the cabinet matters more than the number of speakers.

Whether an amp takes pedals well or not has little to do with it being tube or SS. It might and it might not.
 
Re: Fact checking a GC employee

LLL said:
What are you doing at a Guitar Center?
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I was killing time before a nearby appointment. As per the above comment, GC is a good source of used guitars here in Los Angeles.

I appreciate the observation that speaker efficiency figures prominently into loudness.

My personal experience contradicts the claim that tubes are by definition better than solid state for pedal platforms. There's too much variety amongst tubes for such a blanket statement.
 
Re: Fact checking a GC employee

Lake Placid Blues said:
Whether an amp takes pedals well or not has little to do with it being tube or SS. It might and it might not.
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To wit:
a Fender FM 100H
a Hughes & Kettner Tubemeister 18
a Fender Hot Rod Deluxe
a Fender Performer 650
 
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