Marshall Microstack, Sweet sounding amp.

I've used a 15W Cube amp in a pub full of people; don't think I had to push the volume over #3. And if memory serves me correctly, that's one 8" speaker!

I've upgraded since to a Cube30X amp - same thing, used in the pub, didn't need to go above #3 on the volume control. At home it's generally set somewhere between #1 and #2, and that's plenty loud! There's even a "power squeeze" feature on the 30X that lets you use it as a 5W amp - even then, it doesn't need to be much over #2.

I like LOUD, but we do have neighbours - although, when they've been playing their music loud, I've been known to point my amp in their direction and turn it up to about #5 - funny how they usually turn it down when I do! Of course, when they do turn it down, so do I......

:D :D :D

Vic

I use an old Marshall SL 100...a '68 manufacture date. I swapped the 4 X12 and 4 X 12 in the two cabinets for just one cabinet with 2 X 12 and two driver horns...

As far as 15 watts go on your setup...the speaker impedance must be...like 2 ohms!

The sound of a tube amp is GREAT if...and only if...you set the head up on the cabinet...and not on the floor. (Sort of like why you should drink a beer out of a glass instead of the bottle.) You may want to see if this is the case with your own setup. I'm of the opinion that the notes being played out of the speakers vibrate the fillaments in the Telefunkens at the same freq...so I refer to it as "chassis feedback"!

Cat

I thought you were talking about one of these :lol: :

http://www.troymusic.com.au/tstore/930014006921.html

I've got one and they're only about 4" tall!

About the loudness of tube amps...before I got my Blues Jr, I had a Roland 15X Cube (15 watts)

I asked my mom to stand in the far room of the house and tell me when she could hear me playing...and I had to almost crank the Cube for her to hear me.

I did the same thing with the Fender Blues Jr (15 watts), and she could hear me with the master and volume both at around 5! Insane.

So yes, tube amps are a lot louder...despite still being classified as "15 watts". I've read reports that a Fender Blues Jr, when cranked can get as loud as 40W.

It's true. It's because tube amps are arbitrarily rated for power at some fairly low total harmonic distortion level like 5%. We tend to like 'em cranked up full blast, where they make far more distortion and far more watts. And the harmonics in the distortion then make the sound seem much louder than when it's clean.

No 40 watt tube amp should sound "quiet." If it won't put out volume, get it checked out.

It's because tube amps are arbitrarily rated for power at some fairly low total harmonic distortion level like 5%.
I read somewhere that there are rated at the point that they start to break up (distort)? So a fifteen watt tube amp would be louder than a 15 watt Solid state amp. I don't know how the rate the power of SS amps.

Here's what a friend of mine, who builds some very sweet tube amps, wrote when we discussed this some time ago:

"30 watts RMS is 30 watts RMS. However, tube amps can be turned up, putting out power well past their RMS rating. Yes the distortion increases, but that's what we want! Solid state amps on the other hand, for the most part, are what they are. With them 30 watts is 30 watts. When you turn them up past that, they get distorted, but the output doesn't actually increase.

It woulds almost seem silly to try to gig with a 12 watt solid state 1 x 12" amp. On the other hand, gigging with a 12 watt 5E3 tweed Deluxe with 1 x 12" is quite common, as one of those simply kicks ass for its size and power."

Speakers have more to do with volume than the power of the amp.

A speaker's loudness is called it's sensitivity. This is also called SPL (sound pressure level) and efficiency. A speaker is usually rated with just one watt of power applied at one meters distance.

Take two common speakers,

98dB @ 1W/1/M- this speaker will produce 98 decibels of volume with only one watt of power applied at one meters distance.

103dB @ 1W/1M- this speaker will produce 103 decibels volume at one meters distance.

So the second speaker is always going to be 5 decibels louder with the same power applied. That's quite a bit.

Everytime you double the power to the speaker you get about 3 decibels increase in volume. So...

1 watt- 98dB
2 watts- 101dB
4 watts- 104 dB
8 watts- 107 dB
16 watts- 110 dB
32 watts- 113 dB
64 watts- 116 dB
128 watts- 119 db

Now let's compare speaker #2

1 watt- 103 dB
2 watts- 106 dB
4 watts- 109 dB
8 watts- 112 dB
16 watts- 115 dB
32 watts- 118 dB
64 watts- 121 dB
128 watts- 124 dB

Now let's say you had speaker #2 in a 15 watt amp maxed out. You will get about 115 decibels volume.

Now you have speaker #1 in a 60 watt amp maxed out. You will get about 116 decibels volume.

So, as you can see, the speaker's sensitivity or efficiency plays a huge role in the volume of an amp. In this example, the 15 watt amp would be just as loud as the 60 watt amp.

And this is one way you can get more volume out of your amp, by swapping the speaker for a more efficient model. However, that speaker may not sound as good. Bass frequencies require far more power to produce than high frequecies. A speaker with good bass response that will really pump out the low end will usually have a lower sensitivity rating than a speaker that puts out all high frequencies (or has poor bass response).

So, a very efficient speaker might be super-loud, but it might also sound super harsh. :shock:

And you might have noticed this before. You get a little amp, but it is impressively loud. But it is harsh. This is because they put a cheap speaker in it made of lightweight materials. It will scream volume, but it is super harsh as well.

Then you get a great sounding speaker that will thump your chest. But it isn't so loud. That's because it's made of much heavier materials and can handle and pump the bass. But this takes lots of power, it is work to move speakers like this.