#1
I recently acquired a Marshall Mode Four MF350 from a police auction for the really cheap price of $400.
I found out that the amp does not sound as warm and rich as a Marshall should. this leads me to believe that i need to replace the preamp tubes. I've looked at some high gain preamp tubes but am not really sure what to go with?
someone had suggested buying two Electro-Harmonix 12AX7EH Preamp Tube which are relatively reliable and good value preamp tubes. also, since I'm already taking the head apart, i should replace the fuses and fans on the back as well so i can get this thing running like it should. I'm looking to save money rather than just going out and buying a new head.
Since Korg, Marshall's American distributor, does not supply this amp in America, where i live, its hard to find the exact replacement parts.
Any suggestions?
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#2
i think theres 2 12ax7s.

Its a hybrid, how hard those valves are working to actually make a difference to the sound i dont know. You may find replacing the valves will help a little, but the tone will be shaped by the rest of the SS circuitry more so than the 2 valves they thrown in.

Also with amps like this, they arent really designed to be user servicable, so who knows how far you'll have to dig to get to the valves, or if theyre socketed.

Try some JJs, ehxs are kinda too bright.
#3
thanks for the input. what do you think will make the largest difference in tonality in the circuitry that can be replaced?
as far as servicing this amp, i'm studying physics in college and have a general knowledge of the circuitry and a wide variety of tools to help. i'm trying to make this as inexpensive as possible and if i damage the amp, it wont entirely be missed.
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#4
Quote by beckyjc
i think theres 2 12ax7s.

Its a hybrid, how hard those valves are working to actually make a difference to the sound i dont know. You may find replacing the valves will help a little, but the tone will be shaped by the rest of the SS circuitry more so than the 2 valves they thrown in.

Also with amps like this, they arent really designed to be user servicable, so who knows how far you'll have to dig to get to the valves, or if theyre socketed.

Try some JJs, ehxs are kinda too bright.


+1
changing the tubes will help a little bit. not with the amount ofgain but it will help with the character of the gain. i had a randall rh300 hybrid and going from a jj ecc83 to a groove tube 12ax7r made slight tonal differences.
also +1 to the JJ tubes.

what i do recomend to help the tone is an eq pedal if you dont have one.
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#5
A total redesign of the amp. You could try replacing caps, modifying the tonestack, providing its not all smd.

If it was me id just sell it and get something i liked the sound of from day 1.
#6
Quote by beckyjc
A total redesign of the amp. You could try replacing caps, modifying the tonestack, providing its not all smd.

If it was me id just sell it and get something i liked the sound of from day 1.


I got a quote from my local Guitar Center and they were going to give me $125 for the head and cab. The cab has Celestion Vintage 30's which sound amazing. through any head. brand new the go for $145 each. I can not even trade in for the solid state amp i would like to get. i still cant make up my mind about solid state vs tube, but thats a completely different subject.

im going to replace the preamp tubes with some jj's to see what it does first with a trial and error approach.
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#7
Do not sell it to guitar center.

Stick it on ebay, its more work but you'll get the most profit from it.

Ive heard the mode 4 cabs are pretty good, and if they do have v30s itd be worth keeping.
#9
Mode 4 Cab, if its the big over sized one has Celestian K100s in it.

epic cab is epic.

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#10
Quote by Tom 1.0
Mode 4 Cab, if its the big over sized one has Celestian K100s in it.

epic cab is epic.

This
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#11
i read online that it has V30's in it. but ill have to open my cab up just to be sure
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#12
and yes its the big oversized one
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#13
Keep the cab, sell the head.
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#14
ya don't waste any money buying tubes for that head.

goddamit blackstar dudes.

I can't even begin to understand how their design philosophy is even cost effective or efficient.

here's all these op-amps on a 9volt supply. whoops we need some 350vdc too.
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Last edited by AcousticMirror at Oct 3, 2011,
#15
Ive checked out some high gain replacement amp heads, and I'm between a couple that are in my budget:
Peavey 5150
Bugera 6262
or i could break my bank and get a Marshall JCM800

I know that its all up to how my ideal sound, but i cant make a decision
GEAR
Epiphone Les Paul Custom Black
Seymour Duncan SH-6 Distortion Set
Boss MT-2 Metal Zone
Marshall Mode Four MF350
#16
Dude I really don't want to upset you, but I have to say something; $400 for that is horrible. If guitar center offered you $125 that means they intend to sell it about double that. At a police auction that should have been $100, maybe $200 at the most. I think you are the victim of the 'its big, its loud, it must be expensive' train of thought.

Sorry but I feel you should know.
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