Driving a Tube bass amp for guitar.

  • Thread starter Thread starter rayc
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rayc

rayc

retroreprobate
Hello folks,
I have a Marshall Superbass MkII. It's great for bass and guitar particularly now that I have a 4 x 12 cab for use when playing guitar. The Superbass is a meaty 100w but doesn't have a gain stage or master vol - just a vol control for each of the two channels (both clean).
To get a good Marshall overdriven tone what should I use to drive tha amp? I have a couple of pedals but am after the sound of the tube amp driven rather than a pdeal amplified if that makes sense.
What should I put between the guitar and the amp?
 
That's been every guitar player's hunt for the last 912 years. There's always a new pedal that is supposed to be a 'Dumble-In-A-Box', or whatever. You can now join that hunt; try every pedal out there, and in maybe 10 years or so think you are almost there.

I know it's sacrilege, but you can tweak the amp slightly in a way that is easy to return it to stock. Without drilling a single hole, you can add a Master Volume, then basically turn it into a JCM800. Try a Hot Plate. Try an SD-1, then mod the SD-1 to find out if you like that. Try a CMAT Mods Brownie. Then be ready to try a million other pedals.
 
The first thing I would try is just a straight clean preamp to drive the input harder. After than, you're back the ranjam's advice.
 
Maybe a nice boost with some high end, just to drive it a little bit more.

Or, have you tried just turning it up? That's the only way I know of to get the tubes and speakers really driving.
 
You can also try an attenuator between the amp and cab, it can act somewhat as a Master Volume....letting you crank the input volume without blowing out your ears.
My faves are the Weber MinMass...but many others out there.
 
+1 on the attenuator suggestion. My favorite approach.
 
I did have an attenuator & that did mean I could crank & get a big hot sound but the amp tech informed me that earlier Marshalls, (mines a 79 and he includes that in the range), and attenuators don't get on - that he's done a fair bit of work on Marshalls that have been used with hotplates/tube cubes etc and they end up damaged.
I thought about using my presonus blue tube mic preamp, probably attrracted by the Tube driving tube concept but the presonus Blue tube isn't really a tube pre; it uses the tube to colour the signal.
I used to use an ancient Ibanez Renometer (big old EQ reallY) that had a high boost & loved using that but it's not too healthy a boz at present.
I suppose I'm really asking whether I should add flavour to the guitar sound as it goes in (big muff, Blues OD pedal etc) or just something that'll crank up the signal & push the amp a little harder on the way in.
I also talked to the tech about a mob & he said it's a simple thing to turn the superbass into a superlead & etirely reversable but urged me to not go down that road.
Thoughts?
 
Ray, I don't know if your tech is right about Marshalls and attenuators. I'd get a second opinion. Tons of people use attenuators on Marshalls - new and old - every day and have for years. Marshall even made their own product called a "powerbrake" I think. That kind of amp is gonna have to be cranked. I know you don't go after high gain tones, so maybe just something that will boost the front end and a good attenuator is all you need.

If you plan on re-selling it down the road, a mod may not be the best choice. But if you plan on keeping in, a non-destructive mod wouldn't be a bad idea. Or just sell it right now and buy something more suited to what you want.
 
gonna be hard to drive that front end into anything resembling high gain. Bass amps are usually designed to be clean in the front end.
So you're gonna need a pedal that has some distortion built into it rather than simply drive the front end harder.

there's a zillion of them ...... I like Fulltone stuff but there's just so many on the market ...... let us know what you try.
 
This isn't really a 'bass' amplifier; more a regular Marshall with a couple of larger value coupling capacitors. Maybe a different slope resistor in the tone stack. But it isn't a night-and-day different design.
My best guess is that some techs don't like attenuators with some vintage Marshalls is because they are just a little on the edge design-wise, with some not having Screen Grid resistors. Now add flaky tubes, and then sprinkle a bias setting that is too hot and you have a recipe for bad things happening. But if you have Screen Grid resistors (and any schematic I've seen shows them), and you bias a little cooler than what 'the Internet' tells you to bias to, you should be OK with an attenuator. Here's another idea; if this is a 100-watt head, pull two output tubes.
After that, YouTube the CMAT Mods Brownie.
 
I wonder if this woul be any good???

Marshall JH-1 Jackhammer Pedal
 
OK Gents. I have the answers I need - can't really push the front end into OD as it's not set up for it so either a) use an attenuator, b) use a pedal to push & colour or c) get the mod.
I'll get an 2nd opinion on the attenuator from a tech & try a few pedals - I'm sure I can borrow a few to add to the couple I have.
Thanks folks.
Oh, I won't sell it as it's too good with bass.
 
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