if u know about amps the read this..

[nero1985]

i just got an amp Marshall AVT150 now, i have a crate 65watts amp and its louder thatn the AVT150! wich is supposed to be a 150watts amp, actually its the distortion channel that isnt loud OD1 and OD2 but the clean is pretty loud itself, i bought it used but im happy i bought it with a warranty so im going to take it and get it checked, but im just wondering wat could be the problem? im guessing its the tube cuz its used so maybe the tube is old, couls that be it?

[brett]

Hi.  It's kinda hard to tell from a brief description.
If the two channels use different pre-amp tubes, then it could be a pre-amp tube.  For example, someone might have put in a low-gain tube in it (eg a 12AT7 where a 12AX7 should go)
good luck with it

[dummysf]

I used to have a Marshall AVT150 I also thought it should be louder then it is,  then i read the manual , in the loudspeaker jack socket is written :

"... when an extension speaker is connected to the output (marked Extension) the full power of the 150W power amplifier is unleashed. PLease not that only an extension cabinet rated at 8 Ohms should be used.
This will provide a parallel load with the Internal Speaker of 4 Ohms minimum. "

The clean channel was also very loud compared to OD1 and OD2 on mine, and there is only one tube in preamp.
hope this helps...

[dummysf]

I forgot to say that this is meant for combo amplifier not for the head

[nooneknows]

Have you already checked the loudspeaker characteristics? a 100db cone is way louder than, for example, a 97db.

[Mark Hammer]

A bunch of other things being equal, a 100W amp with a modest-sized cab and speakers rated at 96db/1W efficiency, may well be noticeably less "loud" than a 60W amp with a slightly more ambitious cab and speakers rated at 99db/1W efficiency.

One thing that has come up in the past is also volume pot taper.  Do not, for one moment assume that because amp X is louder than amp Y when the Master Vol is set to 10 and the channel gain is set to 4, that amp X will continue to be that much louder as both channel gain controls are advanced.  It is "the oldest trick in the book" to use volume pots whose taper provides for 90% of all possible loudness in the first 1/3 to 1/2 of rotation, in order to make the customer think "Wow!  If it's THIS loud on 4, imagine how loud it is on 9!".  It doesn't take all that much of a tolerance in pot taper to inadvertently produce the same result either.

Even when the manufacturer has not deliberately adopted such a strategy, there are any number of other factors which can make two amps appear to be inverted with respect to which ought to be louder.  That an amp is rated to be able to deliver a certain amount of current into a given load, that does not mean the power supply is capable of delivering it.  Differences in speaker frequency response can also make one rig sound louder than another, simply because of which frequency bands your ears are more sensitive to.

And then there is the method used for rating amp power.  Ever seen those little teeny plastic speakers to add onto your computer that cost $9.99 an the box says 180W PMP even though the speakers run off 4 penlight batteries?  I rest my case.

[Doug_H]

Dude! Marshall owes you at least 85 watts! Get your money back!!!!

   


Seriously, here are some other considerations:

Open vs. closed back speaker cabinets- closed back cabs are very directional and the volume can appear to change depending on where you are standing. Don't know what your speaker setup is, but it's worth considering, along with speaker efficiency and etc like others have mentioned.

Make sure both wattage ratings are expressed as  R.M.S. (root mean squared)  watts. This is more or less a unit of "average" power, as opposed to "peak" power ratings, which are usually quoted to exaggerate car stereo and computer speaker claims (as Mark pointed out).

Keep in mind that true power ratings are based on clean power. Tube amps can sound louder because people typically push their output stages into distortion (part of the "tube sound"). Even "clean" sounds on a tube amp can have some distortion. In contrast, people don't usually push a SS output stage into distortion because it typically doesn't sound good.  I don't know anything about either one of your amps, but consider that too.

Finally, remember that companies can be snakey about the way they rate the power capabilities of their products. Sometimes they are just downright wrong. There is a right and wrong way to measure and rate power. With a tube amp it is with a pure sinusoid input producing a clean output signal through a resistive load. (Inductive loads like speakers can produce false high power measurements.) I don't know if Marshall is guilty of this sort of thing or not. Just remember that it is a numbers game.

IMO, my advice would be to ask yourself: Is it loud enough? and Does it meet my needs?

If so, then don't worry about the numbers. A true 150W rms amp is going to be godawfully loud.

Doug

[nero1985]

thanks you guys!

i really like the sound out of it but i think i need something louder than that, maybe like "dummysf" said i would need an extra speaker to get the full power of the amp, the other good thing is that it has "direct line out" so i can plug it to the PA and mic it at the same time, im thinking about changing the tube as well jsut incase cuz since i bought it used the tube might be old and it could need replacement

i know its a 12AX7 so wat tube would u guys recomend?

ALSO

it is a Closed Back Speaker, should i take back out (piece of wood) and maybe make a couple of holes on it to let the sound come out a little bit too?

thanks alot!

[Pedal love]

It sounds like the overdrive sections. I have no idea how this overdrive is configured. Post a schematic?pl

[Ripper]

The AVT series and the old valvestates run really hot inside.  I've fixed a pile of them.  The solder connections get weak and need to be redone and this usually fixes the problem.  Resolder the connections to the ic's and the caps and give it a try.  The solder connections for the pots also need some attention.   Marshall needed to include a small fan in these units to get rid of some of the heat that these produce.

[nero1985]

my AVT150 has 2 small fans in it but i dont know if they do any good

[RDV]

Valvestates are OK if you turn everything to ten, wide open. Not the clean mind you, but the dirty. Floorboard it.

RDV

[Pete-Galati]

thanks you guys!

i really like the sound out of it but i think i need something louder than that, maybe like "dummysf" said i would need an extra speaker to get the full power of the amp, the other good thing is that it has "direct line out" so i can plug it to the PA and mic it at the same time, im thinking about changing the tube as well jsut incase cuz since i bought it used the tube might be old and it could need replacement

i know its a 12AX7 so wat tube would u guys recomend?

ALSO

it is a Closed Back Speaker, should i take back out (piece of wood) and maybe make a couple of holes on it to let the sound come out a little bit too?

thanks alot!

I'm pretty sure that I heard that the preamp tube in the Valvestate amps, or was it the AVT amps, isn't even run at full voltage.  So it doesn't seem all that likely that it would be worn out yet.  Changing it would probably do nothing other than change your tone.

About the speaker, check to see if the speaker is the same as the amp's "Minimum Ohms".  That info might be somewhere on the Marshall website.  Because if a 150watt solid state amp's (an AVT is SS, even though there's one tube in the preamp) minimum ohms is 4ohms, and you're driving an 8ohm speaker, then you only have about 75watts to work with.

One of the blessings of solid state amps is that as long as you don't use less than the minimum ohms (which would be dangerous for you output transistors) then they aren't very sensitive about what ohm speakers you plug into them.  But the more ohms you have, the less power you have.

Pete