Re: Marshall JTM-45 vs Fender Tweed amp.. volume problem
im not a amp tech or anything but like i said alone works great from waht i can hear and its just been serviced not long ago with new practicly everything and the guy that did it is a pro thats worked on amps for like 20 years or something.. i dont know much about amp circuitry or anything to check it for myself
ill agree with TGWIF and Vasshu. G12T75s are fat bassy speakers, but not much mids and rolled off treble. They can easily get lost in the mix when there is a fat sounding bass player - and even more so when there is anotehr guitarist using fairly cutting/present speakers.
You amp has the power, but its not being converted into sound energy the best way by your choice of speakers.
G12T75s are great for 100watt high gain marshalls, which generally dont have a lot of bottom end, they tame the treble and fatten up the bottom end in a closed back 4x12...ie: perfect for a hot rodded jcm 800 or 900 because they make the huge cutting power of the 100 watt hi gain amps tame enough and warm enough to sound good with a band.
Your amp is of the old skool marshall, which has a wider frequency response (but still plenty of power - remember a 100w amp is only 3db louder than a 50 watt amp). It all comes down to what part of the sonic spectrum finally gets thru your speakers and to your ears. The speakers you have actually are the opposite to what would best complement the great amp you have. Its not even such a big deal about db sensitivity on your speakers (even tho thats still very important), its more about what frequencies are being heard. The db sensitivity is a maximum decibel level at whatever frequency the speaker peaks at.
Have a look at the frequency graphs on the celestion website and youll see that they all have different frequency peaks and troughs. What the kind of equates to is like using a parametric equalizer, boosting a certain frequency, and then moving the frequency up or down till it fits best with the band. Too much treble and that often gets eaten by the drummer's cymbals. Too much bass and the bass player swamps you. All you are left with is a narrow space somewhere below where the vocalist usually sits. Unfortunately in your case, the guy with the deville is owning all of those frequencies with his bright quartet of 10's. The good news is, with the right 2x12 combination, your tone will be sweeter, warmer and fatter than his.
So you have 3 options, all of which are worth looking at.
Firstly the simple matter of volume: Do the rest of the band have trouble being heard? if so, then the other guitarist needs to turn down somehow, by just turning down his volume and/or treble or maybe looking at changing his speakers.
If not, then you should look at some more present sounding speakers such as the ones recommended. brigher sounding ones like G12H30s should be perfect for a groovy amp like yours, or maybe a pair of v30s if you really want to cut thru.
However, before dropping the dough on new speakers...try runnning your amp thru the speakers on the other guitarists cab combo speakers and seeing if there is an appreciable difference. If your amp is still seemingly under gunned, then maybe you need new tubes and a rebias before anything else. If you have been running at 10, it wont take long at all to wear out a new set of tubes - even a matter of weeks or possibly days in some cases.
Once you know your amp is running full steam ahead, then a new pair of speakers in your 1922 and you will be owning the stage with epic vintage Marshall tone.
Good luck!