New bass problems?

nukebass · Post by **nukebass** » Fri Aug 03, 2007 5:22 am

Okay, I hate to write this, but here goes...

I've had my DCM for a few weeks now and I've finally broken the strings in and it plays wonderfully. The pickups have great output and the tone variance is great with the control options. Now the downside. I think I have a pretty bad ground hum, but I'm not sure the best way to diagnose it. The hum is much worse than it is from my 79 4001, but I'm a bit leary to open it up and start hitting solder joints. I got it used so it isn't under warranty. Any other DCM owners experiencing something similar?

Also, what's the best way to trouble shoot the connection? I could just retouch all the joints to check for cold joints, but I'd rather have an attack plan before opening it up. I'll probably go and buy a different cable today just to make sure I'm not getting an antenna effect.

My first question should probably have been, "how much more noise prone are the new pickups compared to the old pickups?" I could be worrying over nothing.

The other thing I need to know is is bridge pitting and plate scratching common? Here's the best picture I could get:

http://s191.photobucket.com/albums/z195/NukeBass/?action=view&current=DCMbridge.jpg

The reflection makes it hard to get good detailed pictures, but I think you can see some scratches in it.

I get paranoid when I buy new (or relatively new) stuff

johnallg · Post by **johnallg** » Fri Aug 03, 2007 11:46 am

Ryan, the 11k high gains will be a little more hum prone than the older 8k high gains you '79 has, but not excessive. You might have a grounding problem. Start here and read that and the other referenced thread and then see if that is what you are experiencing.

Also, I don't have personal experience with chroming problems, but I wouldn't think a few month old bass should show pitting. MHO

kcole4001 · Post by **kcole4001** » Fri Aug 03, 2007 11:49 am

Try playing in another room. My house has at least one room with varying degrees of really bad ground hum. It's just old wiring & improper routing (of the house wiring!) at fault.
I believe hotter pickups will 'pick up' more hum than others, if it is present in the circuit.

The pitting seems to be very rare, however.

gray · Post by **gray** » Fri Aug 03, 2007 1:37 pm

I doubt there's anything wrong with the bass, I'll bet, as well, that it's just situational.
I've had all manner of hums from my basses in all kinds of places. In my house, they don't hum at all. At our drummer's house, where we practice around all kinds of electrical implements, I get differing degrees of hum depending on which bass I use, but much more than at my house. And when we play out, anything can happen. Believe it or not, when we played the main stage at Alpine Valley last year, I got way more hum there than at my own house. However, just like at our drummer's house, there's a lot more at work there, in terms of other electrical devices on that circuit or whatever. At my house, there's very little else on.
Also, the amp itself can be partly to blame. My old SVT 350 buzzed like crazy, but my current rig (in a rare display of acceptable function) does this far less.
As for the pitting, my bridge PU cover is a little bit funky in reflected light, but my old 77 4001's is WAY funky. Bridge itself seems okay.
I suppose if it bothers you enough, it's new enough that you could get a new one without worry.

johnallg · Post by **johnallg** » Fri Aug 03, 2007 4:57 pm

I had a louder hum problem with the high gains while standing in my practice room - turned out to be the TV 8 feet away on the other side of the wall. That is one reason why I shielded the routings and pickguard on my 4003.

Still, I would check the black ground wire going to the bridge pup's height adjusting screw. Make sure it is at the top touching the pup surround - try using a thin screwdriver and moving the eyelet around while it is humming and see if it changes.

BTW, is it humming in tune? For what you paid for it it shoud!

gray · Post by **gray** » Fri Aug 03, 2007 7:27 pm

TV hum drives me nuts. Neon signs as well.

bob_atherton · Post by **bob_atherton** » Sat Aug 04, 2007 1:14 am

Our rehearsal room hums so much it almost becomes another member of the band! When we gig we sometimes get a little hum but most of the time it is almost silent.

nukebass · Post by **nukebass** » Sat Aug 04, 2007 3:52 am

Thanks guys! I have noticed TVs are a pain for noise. I can tell when the one in the other room is turned on. I also bought one of those high dollar fancy monster cables and that seemed to help at my house a bit. I'll check all the connections with a voltmeter and Thursday I go back to the place where the hum was really bad so I'll see if the cable helps. If not, then it's time to check the ground connection (I'll have to remember to take a small screw driver with me to mess with the pickup surround ground).

These hum problems should be solved when my 4004 finally shows up! Oh, when will that be?

rikk · Post by **rikk** » Sat Aug 04, 2007 5:41 am

Also check computer monitors. They can cause hum as well.

johnallg · Post by **johnallg** » Mon Aug 06, 2007 10:44 am

Actually anything with a cpu or display in it will also cause a rasping hum. I can make it to the kitchen from my practice room, and the microwave and stove will cause humming also.