Mark Bass Head problem

[ZombieBassist]

So about a week ago, my friend gave me his Mark Bass little mark II head and SWR Big Bertha cab. The reason was he simply said didnt have much use for it anymore, as he had switched to playing guitar a few years ago and has grown to prefer it since (heresy!). This is a very good friend of mine and I'm also in his band, so he has no reason to rip me off or anything like that.

Anyways, I got the rig about a week ago happy as could be. I've been using a 300 watt solid state for the past 3 years, and never had a head/cab setup. so you can imagine how quickly my excitement dropped to hook it up only to find its not working!

Instead I get a loud, distorted bass tone that is terrible. Essentially, imagine something similar Cliff Burton's tone on Anesthesia or an overdriven Chris Wolstenholme's tone in Hysteria.. Not saying those are bad, but its similar to the only sound the head makes. None of the tone knobs made much difference, as it was still a very murky and distorted tone. Tried switching out cables (where in which I confirmed it must be the head and not the cab) and noticed that ANY sound going into the head, even the lightest pluck, the clip light goes on.

So is this an input problem? If I open this thing up would I be able to fix it, and if so how?

Thank you for any help you can contribute!

[MIJ-VI]

Have you eliminated the possibility of oxidized effects loop jacks by plugging in a patch cord?

[ZombieBassist]

Originally Posted by MIJ-VI

Have you eliminated the possibility of oxidized effects loop jacks by plugging in a patch cord?

Nope. I dont even know what that means to be honest. What exactly does it mean and what does that do?

[bass4worship]

Put a cable between the sent and return then plug up normal. If the amp sound normal then the it the jacks or use a small patch cable.

[ZombieBassist]

i am positive its not a cable issue. I have tried 3 different cables going from the bass to the head. Same result. And its not the cab, because there is sound coming out of it and its the clip light on the bass head that remains on constantly.

[MIJ-VI]

Originally Posted by ZombieBassist

Nope. I dont even know what that means to be honest. What exactly does it mean and what does that do?

The effects loops on many (if not most) bass amps are in series between the amp's pre-amp and its power amp:

Pre-amp-->effects send jack -> (external effects unit) -> effects return jack-->power amp.

When no cables are plugged into the effects send and return jacks the switches on the jacks complete the connection between the pre-amp-->to the power amp.

These jack switches become oxidized over time leading to an intermittent connection between the pre-amp and the power amp causing weird distortion or static-like sounds.

To test for this with your amp, just plug a guitar cable or a shielded patch cable (like the kind used to daisy chain effects pedals) into your amp's effects send and return jacks.

If the distorted bass tone you described goes away, then the effects loop jacks need to be cleaned with electrical contact cleaner.

If the distorted bass tone doesn't go away then there's something else wrong with your amp.

[elgecko]

Originally Posted by ZombieBassist

i am positive its not a cable issue. I have tried 3 different cables going from the bass to the head. Same result. And its not the cab, because there is sound coming out of it and its the clip light on the bass head that remains on constantly.

A bad speaker can still put out a sound...but if you're saying your clip light is constantly on, the head may be fried.

...and you're sure it's not your bass or the speaker cable?