Re: MXR 10 band eq
depends how you use it....its all about how it interacts with your tubes.
if you run an eq before your preamp, then it will change you guitars tone (obviously) and you can add some bottom or whatever...however if you are already distorting your preamp tubes then adding bass will usually make it just sound flabby.
Re: gain:
the gain knob on your metalzone increases the amount of distortion right? Gain on its own is not distortion. Gain is an increase in level. So...if you increase the gain of a signal into a clean amp with plenty of headroom, all you will get is an increase in volume. However, if the amp (whether preamp tubes or a clipping circuit in a pedal) is already clipping, you will not get a large difference in volume, but you will get a lot more distortion. The way hard clipping pedals like an MT2 work is by running a lot of gain in to a circuit (read: clipping diodes) that will distort. Gain on an eq pedal is not like that...each slider only increases the level of each particular frequency band or part of the circuit.
Now if you do that to a preamp tube (i.e. your marshall's preamp) then you will get clipping from the preamp tubes, not the pedal itself. The more gain you run each slider at, the more the preamp tubes will saturate. The thing is.....marshalls generally sound killer when over driven...heres why:
Too much bass before a preamp tube causes flabbiness and mud, so what Marshall amps did way back when the JTM was around was trim off a lot of bass before the preamp and have a very high gain, trebkly circuit. Then later, in the poweramp section, the excess treble from the preamp was trimmed, and some extra bass was added to make up for the loss in the preamp. The more modern marshalls with super high gain often do a combination of this and also have a didode clipping circuit for extra distortion. Gain and distortion are not the same thing. A lot of gain can cause clipping/distortion, but gain on its own is only an increase in level.
So...for your 800 marshall...crank the bass frequencies on a 10 band pedal and all you will do is make your preamp go all wooly, because for a really crunchy sound, the preamp needs a brighter, less bassy tone. Eqs can work great as mid/treb boosters tho in that scenario, and by cranking the mid/treb gain levels, your preamp will scream.
HOwever, you mentioned you wanted more bottom right? So..the best place to get more ass in your bass is to run an eq in the fx loop of your amp. (i dont know which 800 you have because they dont all have fx loopss) You can add titanic amounts of bottom end there and it will sound huge (think of how those boogie amps sound with their built in eqs). Its because in the real world, big amps like jcm800s do not often get driven so hard that the power tubes are clipping hard, so they generally have enough headroom to amplify the extra bass from the eq. This effect is diminished the more the master volume gets to 10 tho! Marshalls tend to fatten up of their own accord if you run the power tubes towards the louder end of their capabilities, but often can sound a bit weedy and buzzy at low volumes. JCM 800s all tend so sound better the louder they are.
So what to do then? Well, and eq in the loop will add plenty of bass and you can make a huge scoopy sound, but only to certain volume levels on the master...after that the power tubes will get flabby much the same way a preamp tube will. What this means is the eq pedal will work more effectively at lower volume levels, and less effectively at higher levels....but obviously you wont need it at high volume becasue the amp will be doing its big robust fat marshall thing that they are renowned for!
Re: the six band..yeah one of those will fit the bill (especially if used in the loop).
Heres a signal chain recipie for a killer marshall sound:
1.good axe
2. Tube screamer type pedal (read boss sd1, mxt gtod etc). these are good cos they trim both some bass and a little treble too, and add some of their own clipping and sustain/harmonics to your sound.
3. preamp tubes (set to respond how you like to the unaffected guitar signal)
4. eq pedal in the fx loop if you want more bottom or a scoopy sound.
5. Power tubes
6. The right speakers!
So for a really agressive heavy low end chugga chugga sound, you actually need less bass before the preamp, and more added after the preamp has given you all the grit and distortion/sustain you are after.
Having said all that crap about eq pedals..IMHO if you want a bigger bolder, bassier or whatver kind of sound, its the speakers that will give you the missing piece of the puzzle...cos they are actually what you are hearing at the end of the day. Id rather have good the right speakers than any eq bandaids in my signal chain any day of the week.
