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jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 300
Registered: 11-2009
Posted on Monday, January 27, 2014 - 7:06 am:   Edit Post

Greetings, everyone!. Well, after some years of immensely enjoying my Epic 5, I decided to move things in the house a little, and ended setting up my Gallien-Krueger MB200 (bass), an external 1x0 Eden-loaded cab, and my GK ML-250 (guitar) besides the living room couch, for playing and enjoying while watching tv or listening to music in the living rom. Well, everything seems to be fine, EXCEPT when I take the Epic. There is this directional hum that I can remember I had in the late 80s with a sound system I had back then installed in this same wall (in some spots can get VERY nasty). With that sound system, the solution was to swap equipments, put another system in the living room, and get the "noisy" one to another room, where it was quiet and nice. Same with my Epic, no noise anywhere else, nasty hum when playing in the couch or its surroundings. This does not happen with any other of my basses, nor is a faulty cable.

I opened the control cavity of my Epic, and found I have no ferrite bead on it. I am attaching a pic I took. Any help on this will be greatly thanked for!

epic 5 control cavity
jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 301
Registered: 11-2009
Posted on Monday, January 27, 2014 - 7:11 am:   Edit Post

I should have specified before, I am aware of the need for the ferrite bead. My real question is.. Would ANY ferrite bead do? Can I shop for one at any electronic supplies store and would work well? Do I have to install it right in the wires coming FROM the pickups TO the balance pot? Then Ill have to desolder the wires, pass them through the bead, an solder them again, right? Would TWO ferrite beads (one per pickup wire) be more effective than one for the two wires? Does size matters? (Im talking about ferrite beads!). Thank you so very much!
bsee
Senior Member
Username: bsee

Post Number: 2680
Registered: 3-2004
Posted on Monday, January 27, 2014 - 11:27 am:   Edit Post

I am troubleshooting such an issue with my Excel and the thinking is that it could be a defective pickup. If you fully balance your bass to one pickup or the other, is the amount of hum affected? Hard to believe that both pickups went bad, if that's what's going on. If that isn't the cause with yours, then maybe it isn't what's bad with mine.

-bob
mica
Moderator
Username: mica

Post Number: 8107
Registered: 6-2000
Posted on Monday, January 27, 2014 - 12:56 pm:   Edit Post

Your pickups are soldered to the pan board, so testing if they are connected backwards is going to be more difficult since you would need to desolder.

Let me mark up a picture so you can visually inspect where the signal and ground wires are connected on the pan board and see if they match.
mica
Moderator
Username: mica

Post Number: 8108
Registered: 6-2000
Posted on Monday, January 27, 2014 - 12:59 pm:   Edit Post

Also, you state the hum is directional, but do any directions you face produce a null in the hum? Ans what Bob said... is it the same in both pickups?
jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 302
Registered: 11-2009
Posted on Monday, January 27, 2014 - 3:30 pm:   Edit Post

I cant be thankful enough for all the help and support I find in this community :-).

Well, there are certain angles I can turn to, where the hum diminishes a little, but doesnt go away as such. Also, panning to either one of the pickups seems to diminish it, but VERY slightly.

Again, this only happens when on the couch in the living room, nowhere else (and thankfully not in the room I have set as my home studio!). The few tiimes Ive used this gem on stage Ive had no similar problems either.

Could it be that the previous owner had tampered with the pickups as to solder them improperly to the pan board? Ive never touched them myself in the 4 years and so Ive had it. The only thing Ive had to do (and I would love to have some guidance on this, too) was to replace one of the... what to call those? Sliding parts? Pins? on the jack, since when I bought it one of them (the one which makes contact with the plastic-tip switch one) was broken. I had around another jack which was kinda similar, from some preamp (which ended up being a waste of money) that I had bought for another bass, and took off the corresponding piece and replaced the bad one on the bass one. However, it does NOT work alright with all plugs, only certain plugs seem to work properly, and Ive kept using only the "reliable" ones on my Epic. Is this a common behaviour for this kind of jack? Ive tried to find a replacement one at electronics store around, but here in Venezuela nobody seems to carry those.. :-(

Ill be awaiting (on the couch in the living room, of course!) for that picture, with the solder in one hand!.

Again, thank you very, very much!
jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 304
Registered: 11-2009
Posted on Tuesday, January 28, 2014 - 6:19 pm:   Edit Post

UPDTAE: Ive found around the house one of those "clip-on" ferrite squares (not exactly a "bead" bu its shape) and put it around the couple cables coming from the pickups to the balance pot, to very little avail. Due to the length of these cables and the size of the ferrite square, I only could clamp it around the cables, cold not pass the cables through it more tan once. Then I found a ferrite ring from some old power supply or else, and tried passing the cable which goes FROM the balance pot TO the preamp board, and could do a couple passes through it. Again, just a little change, still some directional hum (although not as heavy as it was without any ferrite around). Then I noticed, juggling the plug (the jack problem seems to have worsened a little) that, if I touch the body (chassis) of the plug, the noise goes away...

Could it be the "improperly soldered pickups" case then? Any other ideas?
mica
Moderator
Username: mica

Post Number: 8110
Registered: 6-2000
Posted on Tuesday, January 28, 2014 - 7:13 pm:   Edit Post

Sorry! I didn't get to this picture today and now I'm setting up the Northbday PERL Mongers meeting with dad, so it will have to be tomorrow.
jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 305
Registered: 11-2009
Posted on Tuesday, January 28, 2014 - 7:56 pm:   Edit Post

Oh, no problem at all, Mica! I was just fiddling around with it since Ive found those ferrite things around the house (I knew I had seen them when looking for something else not too long ago!). As I said, theres no hurry, since Im not having any issue with it on the recording studio, which is the real crucial area for me. :-)
mica
Moderator
Username: mica

Post Number: 8113
Registered: 6-2000
Posted on Wednesday, January 29, 2014 - 4:36 pm:   Edit Post

Since the problem goes away when you touch the plug, we don't think this is a direction hum situation in the end. We need to check those soldered connections of the pickups first:

pickup signal


We need to make sure the signal from the pan board to the filter is also connected properly, since both pickups are affected. Please check both ends of the 2-pin connector:

Pan signal

to Filter

Confirm the shield and signal are connected as these pictures show.

Also, email me your mailing address so I can send you the ferrite bead.
slawie
Senior Member
Username: slawie

Post Number: 584
Registered: 8-2002
Posted on Wednesday, January 29, 2014 - 6:50 pm:   Edit Post

It looks as if the shielding at the where Mica writes "these loops may not be helping things" is making a connection with only one or two strands of wire.
I would be stripping back the sheathing and re-soldering that cable.

(Message edited by slawie on January 29, 2014)
slawie
Senior Member
Username: slawie

Post Number: 585
Registered: 8-2002
Posted on Wednesday, January 29, 2014 - 6:58 pm:   Edit Post

Forgot to include the picture
jcdlc72
Advanced Member
Username: jcdlc72

Post Number: 307
Registered: 11-2009
Posted on Saturday, February 01, 2014 - 12:51 pm:   Edit Post

Well, first of all I must solemnly declare I am nothing to the skillful master electronic tech at Alembic. How do you guys do to solder these things? I decided to follow everyones advice, and tried to redo the soldering on both pickups wires. I found a small ferrite ring around the house, and decided to give it a try (again: Does size matters in ferrite beads?). Also tried to tidy the cabling a little bit just to make sure. There I was, desoldered both pickup cables, passed both through the ferrite ring a couple turns, and went to the soldering phase. Oh boy, was it hard to resolder! There was NO way I could pass the ground wire through such small circuit holes, and (assuming I have very poor soldering skills when compared to the Alembic techs), had to resort to solder the signal wires as shown, but the shield wires in the other side of the board. I managed to do so, as you can see in the pics, and assembled everything back together, to go back to the living room to give it a test drive. The noise, although diminished, is still there, sometimes almost inaudible, but there nonetheless. Would the difference in the ferrite bead (size, shape) make a significant change on this? epicpost1 epicpost2 epicpost3

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