Sansamp good. Cycle hum, bad!

MattyH · #1 06-13-2011, 01:53 PM

So I picked up a Sansamp Bass DI today. Holy crap, why didn't I get this sooner. I've been struggling lately with my rig. My horn on my Ampeg 410 HLF has a nasty hiss. But with the horn off, It kills my tone from my Hartke LH1000. Now that I have the Tech 21, I can keep the horn off, and dial in incredible tones. I still haven't tried all the shaping. It's so sensitive and versatile. I love it. I'm kind of interested to pair it with a Crown Power amp my friend has laying around. Just wanted to get that out!

Now, my remaining problem. My 62 Jazz has terrible cycle hum through the single coils with dimmer switches and poor power around. (Almost every wedding venue I do). It can get SOOO loud. I had to turn the lights off in my practice room to hear what I was really getting out of my Sansamp. I recently had it shielded with the Stew Mac shielding paint, but alas, no change. I've heard guitars and basses with this used in it, and they were quiet. Should I have another layer of paint applied? Or should I get some copper? Any fixes that wont include me switching pickups or having to do a complete re soldering job? Haha. It's getting unbearable, and I can't hope the venues will have adequate power or lighting that wont cause this. Because that's hardly the case.

Thanks!

MattyH · #2 06-13-2011, 01:58 PM

Unless there is an INCREDIBLE set of hum canceling J's that people have and trust!

scottbass · #3 06-13-2011, 02:09 PM

Does the humming stop - or at least quiet down A LOT - when you touch the strings? If so, the problem's in your bass, is due to the nature of the single coils, and will be reduced somewhat (but not completely) by full-surround copper shielding of the cavities. Don't neglect to ground all your shielding using dedicated ground wires to a single connection point - your jack.

If, however, the humming stays very loud even when you are touching the strings, there is something else going on. You should first try a different instrument cable, then check the grounding of your bridge. No relief from these two actions? Then it's probably due to the amp.

MattyH · #4 06-13-2011, 02:26 PM

Quote:

Originally Posted by scottbass

Does the humming stop - or at least quiet down A LOT - when you touch the strings? If so, the problem's in your bass, is due to the nature of the single coils, and will be reduced somewhat (but not completely) by full-surround copper shielding of the cavities. Don't neglect to ground all your shielding using dedicated ground wires to a single connection point - your jack.

If, however, the humming stays very loud even when you are touching the strings, there is something else going on. You should first try a different instrument cable, then check the grounding of your bridge. No relief from these two actions? Then it's probably due to the amp.

Well its interesting. When I touch the strings, it will go away sometimes. I found that if the dimmers are being used, the hum will get louder while playing, IF the power is real bad. For example, I played the Tribeca Rooftop last week. They're under construction, and the dimmers on the stair lights were causing bad buzz, even when I played (making it worse when I plucked sometimes). When we turned the dimmers on the stairs OFF, it went away completely. Other times, if I touch the knobs, the strings, the jack, it'll go away (usually the case). Even today when I touched the Sansamp it went away. I have brand new cables all around. Even patches. I'll probably just have to have the entire bass shielded. Under the guard, under the bridge, get the cavity re-shielded, etc.

MattyH · #5 06-13-2011, 02:39 PM

Quote:

Originally Posted by scottbass

Don't neglect to ground all your shielding using dedicated ground wires to a single connection point - your jack.

Can you explain this? When it comes to stuff like this I'm semi clueless. I now how to shred the 4 string, but when it comes to technical stuff, I turn to my luthier! Haha. I just want to have some sort of idea.

Gear_Junky · #6 06-13-2011, 02:43 PM

Does the SansAmp have a ground lift switch and did you try it?

MattyH · #7 06-13-2011, 02:55 PM

Quote:

Originally Posted by Gear_Junky

Does the SansAmp have a ground lift switch and did you try it?

It does, but it didn't help much.

scottbass · #8 06-13-2011, 04:08 PM

Quote:

Originally Posted by MattyH

Can you explain this? When it comes to stuff like this I'm semi clueless. I now how to shred the 4 string, but when it comes to technical stuff, I turn to my luthier! Haha. I just want to have some sort of idea.

Solder an insulated wire to each individual piece of copper foil. Run the wires through the cavities to where the jack is. Solder the other end of each wire - along with the wires from the bridge ground, the case grounds on each pot, and the two pickup ground (or "-") wires to the sleeve contact of the jack.

FWIW, I've always considered running separate ground wires to the jack to be a bit of overkill. I have never had a problem with jumping from one ground spot to another and then connecting just the last ground spot to the jack.

Here's a diagram. If it were my bass, I would solder a piece of wire to each piece of copper foil and then solder them all to the same spot (on the pot) as the black and green ground (or "-") wires from the pickups.

chaseman · #9 06-13-2011, 04:23 PM

Sub'd.

I have a similar problem, but when I've been playing for an hour or so the amp hums, but not before. Touching the strings relieves this, but touching my iPod in its dock makes the hum terrible. Would shielding help this?

**BullHorn** · #10 06-13-2011, 04:25 PM

Sub'd.

I don't really relate to this, but what I am interested about is what will be your and your band's reaction after using the SABDDI.

Mine and me hated it.

cableguy · #11 06-13-2011, 04:26 PM

Quote:

Originally Posted by Gear_Junky

Does the SansAmp have a ground lift switch and did you try it?

I'm not positive but I think the ground lift only works for the XLR.

mdogs · #12 06-13-2011, 08:14 PM

Quote:

Originally Posted by BullHorn

Sub'd.

I don't really relate to this, but what I am interested about is what will be your and your band's reaction after using the SABDDI.

Mine and me hated it.

That is a first, I don't really know anyone who hates the sound of it... BTW, NEVER ask the rest of the band (ok, maybe the drummer) how you sound

MattyH · #13 06-13-2011, 09:42 PM

Scottbass, thanks for the diagram. I'm gonna have my luthier look at it and see what he can do. My bass has the stack knobs, but he'll be able to figure something out. This is after I shield the hell out of it first. That'll be the first fix attempt.

As for my band mates not liking the Sansamp, I don't think it's possible. They know their instruments, but when it comes to bass, they probably couldn't even tell the difference! Me on the other hand, am in love with it!

MattyH · #14 06-13-2011, 09:52 PM

Also, quick question. Is there a place I can buy copper shielding tape, like a Home Depot or something? So I don't have to wait on a shipping order? I play in a wedding band, and I have 3 gigs this weekend. I'd like to shield it quick. I wasn't able to find anything online besides Stew Mac, GC, Amazon, and random online shops.

MattyH · #15 06-14-2011, 06:27 AM

scottbass · #16 06-14-2011, 07:59 AM

Quote:

Originally Posted by MattyH

Also, quick question. Is there a place I can buy copper shielding tape, like a Home Depot or something? So I don't have to wait on a shipping order?

I bought mine from StewMac. I have never seen self-adhesive copper foil/tape in a retail store. That's not to say there isn't any, just that I've never seen any.