Noisy Europa 5 with loose wire

[rickstevenson]

I have a Europa 5 that has been sitting in its case for several years.  I put a battery in it (it was stored without one) and it mostly works but makes a lot of extraneous noises - muffled crackles, humming and sometimes rhythmic ticking.


I opened up the control cavity and there is nothing visibly wrong except for a loose wire.  It's a black wire with a white stripe, one of a twinned pair that comes from the direction of the pickups.  The end of the wire has been stripped of insulation and is clean copper with no solder residue.  In the attached pic you can see the end of the wire just to the left of the connector marked "3079".


Any suggestions for where the wire should go or other ideas about troubleshooting appreciated!  I have made several attempts to contact Alembic directly over the past couple of months but without any success.


Thanks,
Rick.

[rickstevenson]

Extra info: I don't remember where the wire was actually sitting when I opened the cavity.  The connector marked 3079 has 5 pins on the PCB and only 4 wires going into it, so that might be a big hint.  There's an empty hole in the connector where a fifth wire could go but there's no pin in the hole and I didn't see any sign of a loose pin in the cavity.  A wiring diagram would be really helpful!

[JimmyJ]

Rick,

We're happy to hear you are reviving your Europa! 

Since the bass has been on an extended vacation ... the first thing I would suggest is exercising all switches and pots, like 50 cycles each.  That action alone will often clear up noise issues.

I don't have any basses with Europa electronics but photos I've seen of others do NOT have that black/black-white wire.  I don't think that is stock so curious as to what it might be.  Also in the photos there are only 4 wires in that 5-pin connector so resist the urge...

Somebody with better knowledge of your electronics package will help out here soon.  Meanwhile, could you post a pic of the front of the bass so we can see if there is anything unusual?

Jimmy J

[rickstevenson]

Thanks, Jimmy J!  I'll grab a photo of the front and post it in the morning.  It's bedtime here.

[gtrguy]

Yep, I have never seen 'zip cord' used in an Alembic. I would trace it down. I wonder if it was an attempt to ground the bridge to something? Where does its twin go to?

[rv_bass]

Maybe someone else with a Europa can post a picture of their electronics cavity for comparison

[rickstevenson]

Meanwhile, could you post a pic of the front of the bass so we can see if there is anything unusual?

See attached.  I think all the controls are standard.

Yep, I have never seen 'zip cord' used in an Alembic. I would trace it down. I wonder if it was an attempt to ground the bridge to something? Where does its twin go to?

That could be it.  The other wire in the pair goes to the input jack.  Pic attached.

[rv_bass]

I wonder if it is soldered to the underside of the sustain block.  But that still doesn’t explain the clean bare end of the loose wire.

[rv_bass]

Can you lift the pickups and see where the wires go?

[JimmyJ]

Thanks for the pics.  Nice looking bass!

Right.  That is probably the answer, somebody trying to "ground" the strings.  I wonder what they did on the other end of that wire?  If you lifted out the bridge pickup we'd probably see.  (rv responded while I was typing - it could be that whoever did this may have just grabbed whatever wire they had handy.)

I'm fairly sure that on our basses that "grounding" scheme doesn't do anything, unlike on certain other passive instruments.  Correct me if I'm wrong.  But the evidence is that if there was a benefit to doing that Alembic would do it on all their instruments.

The more likely situation is that somebody was trying to correct what they thought was a ground issue but was actually RF being heard by the pickups which I believe are more sensitive and hear a wider frequency range than your typical passive bass pu.

At the same time, it probably doesn't hurt anything so we should concentrate on fixing your other noise issues. 

If exercising the controls did not clear up the sound then try to isolate if it is coming from only one pickup or both.  Pan fully one way or another and see if one pickup is cleaner than the other.  Put the switches into the center or "flat" position, then try boost or cut... etc...  Maybe you can isolate which part of the circuit is causing issues.

Let us know!
Jimmy J

[rv_bass]

Just an added comment to Jimmy’s suggestions, I recently had to exercise pots and switches fully a couple hundred times each to clean them all out on an instrument that was not used for quite some time prior to that.

[rickstevenson]

Thanks for all your help, JimmyJ, rv and gtrguy.


Looking under the bridge pickup, the black twin cable does indeed head down in the direction of the bridge so, as suggested, it does appear to be a retrofitted attempt at earthing using a random cable.  I have taped over the exposed copper on the loose wire for now.


I worked all the pots and switches and the noises (which sounded a bit different today) have almost all gone away.  For a while there was still a little hum that was attenuated if I touched the metal surround of the input jack but that has stopped now.  I also had a couple of bursts of crackling but after playing for a while that seems to be gone too.  I'll see how it goes over the next few days but the results seem promising so far!


One other data point: while the noises were present they didn't appear to be affected by the position of any of the pots or switches.


Thanks,
Rick.

[lbpesq]

I would remove the unnecessary DIY grounding wire.

Bill, tgo

[rickstevenson]

I would remove the unnecessary DIY grounding wire.

Thanks, will do that in a day or two.  I didn't want to mess with too many things simultaneously and not know which ones made a difference.

[pauldo]

Thanks, will do that in a day or two.  I didn't want to mess with too many things simultaneously and not know which ones made a difference.

Wisdom.  👍🏼

Just tossing this out there… how is your instrument cable?   I have a 3’ Monster cable that I use when I hunker down in the basement.  Recently it exhibits nasty noises if it is turned in certain directions (no more dancing and playing until I get a new cord).