discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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Hey folks, I've had this issue for a long time and would love to get to the bottom of it.
It's actually a couple of issues. 
I have a yamaha active bass guitar which I bought second hand
at the end of 2007 (DX-5 or similar, I forget the exact model) running with a NiMH (not
sure if this is important, thought I'd mention it) 9v battery.
When plugged
into my EMU 1616, it was very buzzy, unless I had a finger on a metal part of the guitar,
including the metal housing at the end of the cable. To enable me to get a half decent
recording I found that connecting a wire between the end of a string (at the bridge) and
the guitar end of the cable (looping it round the coil bit) removed the bulk of the buzz,
and seemed to do the same job as me having a finger on a string. This is I'm sure not a
great idea but was the only solution I could get that worked.
The 1616 has a
ground connector on the back for use with the phono input, i tried wiring this to a
radiator in the room (I figured this is pretty much ground) but it had no effect on the
buzz coming from the guitar. I tried different guitar cables, even though the cable was
brand new, and this didn't help.
The second issue is that if I then connect a
SM58 into the other mic/line input on the 1616 (with a XLR cable), I get an electric shock
from the mic on my lips (ouch) when playing the bass. I'm pretty sure this only happens
when I have my little anti-buzz wire going from the guitar bridge to the cable
connected.
So I'm between a rock and a hard place really, either I get a noisy
guitar signal, or I get an electric shock.
When doing all this, all kit is
coming out of the same Belkin 8-way adaptor, and the house has just been re-wired. I had
similar issues in my old flat and had assumed it was down to the building but since I have
the same issues in a freshly wired house this is unlikely.
I note that the 1616
power in is only a 2 pin connection, there is no third 'earth' connection, but I find it
hard to believe that a semi-pro audio interface has such a major design flaw that it's
incapable of doing what I'm trying to do - run a guitar and mic together, essentially.
I have a few ideas on what could be the problem but am not sure how to check or
fix them, so I'm hoping for some help!
In no particular order:
1)
The bass is dodgy in some way, there are wiring issues causing the buzzing.
2)
the fact that the bass is active is causing the problems.
3) the 1616 is not
properly grounded.
4) The wiring in my house is dodgy.
5) There is
a problem with the mic (SM58) or its cable (pricey XLR cable from sound control). I think
this is pretty unlikely, I don't get any noise issues with these.
Can you offer
advice on how I can check the 5 points above? I have a basic multi-meter to check voltages
etc...
Any suggestions on things I should do to test/check stuff would be
great, or any referrals to other posts...
Many thanks in advance.
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so, how does this make you feel?
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Hewesy
Joined: 19/10/04
Posts: 1437
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First of all DESIST using the gear until you can prove the earth for the house is OK.
1) Buy a socket tester in Maplins (or DIY store) and check your sockets to ensure
they are earthed. If you find any issues take them back to whoever rewired the property
ASAP. This will also be invaluble for gigs.
2) You need to ensure the 4 way
is working OK. Plug the EMU into the wall direct and check with the SM58. Any issues
then raise with EMU. Any splits, fraying cables etc on the 4way then recycle and
replace.
3) The bass. Do not use your earth loop any more. Check the wiring
to the jack socket is OK (no broken connections). Check the wiring for the battery is OK,
e.g. no broken connections etc). I would also replace the rechargeable battery with a new
9v battery - some rechargeable batteries don't kick out the full 9v which could be letting
noise into the circuit. Also check the cable is OK, no broken/damaged connections
etc.
It sounds to me like the bass is the culprit, and it may seem heavy
handed, but you need to be sure the house wiring is OK first. The fact you had the same
issue in the flat could be a red herring - for less then a £10 it pays to be sure with a
plug tester.
Hewesy
Edited by Hewesy (03/11/09 02:34 PM)
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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Thanks Hewesy, I'll be stopping off at Maplin on the way home.
I will conduct
some tests to clarify everything above.
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so, how does this make you feel?
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Rockrooms
Joined: 06/12/05
Posts: 160
Loc: Oxford
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Quote discomb:
The 1616 has a ground connector on the back for use with the phono input, i tried wiring
this to a radiator in the room (I figured this is pretty much ground) but it had no effect
on the buzz coming from the guitar.
As mentioned, you really should stop using the equipment for the time being.
Long shot, but it might be worth checking the potential difference between the radiatior
and the earth supply of the socket as well as the PC case.
I once was on the
wrong end of a 40V difference when fitting an external TV ariel which was connected to an
pre amp, supplied via the mains and the external earth point I had naively assumed was the
same one used for the house. A quick multimeter check confirmed the worst.
- Joe -
Rockrooms Studio
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eggle5
Joined: 15/10/07
Posts: 18
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Try having a look in the Forum Index under Live Sound top of the list. There's lot's of
info & discussions there.
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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I should've mentioned I'm using a laptop with the 1616 and it's corresponding PCMCIA card.
That is another potential source of grounding issues. bugger.
The radiator
trick was in my old flat but I will investigate the ground connection on the 1616 in the
new place. I always meant to make a mains plug with solely an earth connection and attach
this to the 1616 ground socket, I'll try this tonight too.
I will also check
out the buzz from the bass when plugged directly into a Laney bass amp - it is kinda noisy
but I always figured it was the amp.
I'm hoping it's the bass, should be the
easiest to fix.
Many thanks guys.
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so, how does this make you feel?
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dubbmann
member
Joined: 17/03/04
Posts: 985
Loc: 3rd stone from the sun.
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Quote Rockrooms:
Quote discomb:
The 1616 has a ground connector on the back for use with the phono input, i tried wiring
this to a radiator in the room (I figured this is pretty much ground) but it had no effect
on the buzz coming from the guitar.
As mentioned, you really should stop using the equipment for the time being.
Long shot, but it might be worth checking the potential difference between the radiatior
and the earth supply of the socket as well as the PC case.
I once was on the
wrong end of a 40V difference when fitting an external TV ariel which was connected to an
pre amp, supplied via the mains and the external earth point I had naively assumed was the
same one used for the house. A quick multimeter check confirmed the worst.
- Joe -
Rockrooms Studio
Major +1 on this advice. i once lived in a house where i got
shocks when i touched my gear rack and the nearby metal window frame. got out my volt
meter and found a many-volt (i forget the amount, more than 20V) potential difference.
somewhere i had a floating ground in the house. a lot of older houses used to tie the
house ground to the plumbing pipes, then years go by, the house settles and no ground.
likewise, the nastiest ground problem i've ever heard of was in a mainframe
computer shop back in the 80s: whenever someone flushed a certain toilet in the men's
room the mainframe went tits-up. turned out that a piece of metal pipe had been replaced
by PVC, as long as there was water in the pipe the ground connection was still fine but
when the toilet flushed there was a moment when the ground was disconnected.
as others have suggested, get it fixed and avoid joining jimi, janis, and jim in god's
waiting room ;-)
cheers,
d
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"If you've been playing poker for half an hour and you don't know who the patsy at the table is, you're the patsy." - Warren Buffett
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eggle5
Joined: 15/10/07
Posts: 18
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Socket tester at Maplins - £5.99 - bargain when it will deffo save yer life!!!!
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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Hey guys, I've got me a circuit tester and all is fine both in the wall socket and when
the tester in in the belkin 8-way, plugged into the wall. so the ground stuff seems
alright.
I have played a bit and determined the buzzing is due to the bass,
which is a RBX-374 btw. I've determined that the knob furthest from the neck is causing
the buzzing, in that if I turn it to 0%, the buzzing disappears, but rises in volume as I
turn this knob to 100%. I think this knob is the fader between the two pickups, but
without a manual (which doesn't seem to exist) I can't be sure.
It's not due to
the 1616 because I get the exact same buzzing problem plugging into my little tapco
mix120, and also into my Laney L30, although it's less noticable in the bass amp.
presumably this is because it's a bass amp - the buzzing is quite high pitched.
So the buzzing issue now becomes one of how do I stop a pickup buzzing. I'll do some
more digging and take it to the shop I bought it from, hopefully they can help.
weirdly, and this is what always puzzled me, is that i can stop the buzzing by touching
any of the four knobs, or the metal jacketing of the guitar cable. touching a string helps
but doesn't eliminate the buzz completely.
Regarding the electric shock thing,
I wasn't able to recreate it. I disconnected the wire connecting the bridge and the guitar
lead, and the buzzing returned, but had no issues with a small shock from the SM58, with
any combo of playing, not playing, connecting or disconnecting the bridge->cable wire.
Not sure why!
I did find a review of this bass saying "When you turn one of the
knobs it buzzes uncontrolibly". maybe it's just a dodgy pot.
On the plus side,
the problem seems to have fixed itself, on the minus side, I might have wasted your time.
Many thanks for the advice peeps. much appreciated. 
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so, how does this make you feel?
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Hewesy
Joined: 19/10/04
Posts: 1437
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Good work discomb, it does indeed sound like the bass is at fault.
I would
check with the shop as to any warranty etc you may have on the product, then consider your
next steps.
An email to Yamaha may also help, I'm sure they would be keen to
stop a player being shocked when using their products!
It could be a duff pot,
though if it is a blender it may need to have a specific pot value - again Yamaha can
confirm.
I'd also try a regular, new 9v battery. At least you can replicate
the noise without worrying about shocking yourself, so it should be easy enough to trace
and resolve.
Hewesy
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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I'll have a shot at contacting Yamaha, I'm not fancying my chances though, all the stuff I
read about customer service indicated it's very poor. One guy said he'd fired off several
emails over a year ago and still hadn't got a reply. pretty shocking. no pun intended 
I forgot to get a regular battery, will do so. I did check the
voltage on the NiMH and it was 9.06V when plugged in and being used, so I think it's
unlikely to be the root cause of the issues. My gut feeling is there's something wrong
with the wiring inside the bass, maybe a loose contact or this dodgy pot. I'll get some
de-ox stuff, always needed it anyway.
cheers guys, will update this post with
any new developments...
--------------------
so, how does this make you feel?
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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I sent an email to yamaha, just before finding a page on their website saying what the 4
knobs do. the buzzy knob is the treble EQ.
Yamaha website - RBX374
Potentially the buzz could be generated constantly and is only inaudible because the
treble is cut completely. I'll have a play with recording the buzzing and examining
frequencies...
I can at least be sure it's not a pickup now I know which knob
is the pickup crossfader (the knob closest to the neck).
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so, how does this make you feel?
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Ian Savage
Joined: 16/12/07
Posts: 475
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You're almost certainly right, the buzz appears to disappear because you've rolled off all
the treble and got rid of it.
What's happening with the guitar buzzing is it's
picking up external interference, either due to a dodgy connection somewhere within the
bass or poor shielding. When you touch a metal part you introduce yourself as a 'shield',
and get rid of a good amount of it. It'd be worth taking the bass to a tech who knows
their stuff, they'll check the wiring and possibly put in some conductive tape around the
control cavity which should help to screen out the noise. Might be worth trying the setup
with another instrument before you spend your money to check it'll make a difference, but
I'd bet on that being the problem.
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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I'm pleased to say Yamaha got right back to me and referred me to to Yamaha Service UK,
and I just spoke to one of their guitar technicians.
Unfortunately, he said
it's just a property of the guitar, particularly because it's active. And that active
basses don't like computers. This is a bit of a bugger! His suggested solution was just to
roll off the treble until the buzzing disappears. This would mean I'd have to record with
absolutely no treble which isn't very satisfactory.
Thanks Ian for the tip,
I'll try a bit of testing with positioning it and try and determine the source of the
interference. I'm also going to take it down the shop I got it from this weekend to see
what they can suggest. I'll try and resist the temptation to take it apart
I guess ultimately it is actually alright at the moment: I can
make the buzz disappear with the bridge to cable connection, and am not getting shocked at
the moment, but this seems a bit of a half assed fix!
cheers guys.
--------------------
so, how does this make you feel?
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Ramirez
Joined: 24/10/06
Posts: 197
Loc: Pwllheli, Cymru
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Quote discomb:
Unfortunately, he
said it's just a property of the guitar, particularly because it's active. And that active
basses don't like computers.
That sounds like load of cr*p and a complete cop-out on their behalf. As Ian Savage
said, it's probably either a dodgy connection or poor shielding. Neither of which is that
big a deal - you could do it yourself if you're confident enough with a soldering iron
and/or sticking foil to wood. If you're not keen on that, it shouldn't take much for a
guitar tech to sort it.
Aled
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Bill Withers while Tom Waits, and Stan Getz
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Dynamic Mike
Joined: 31/12/06
Posts: 610
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Quote discomb:
I have played a
bit and determined the buzzing is due to the bass, which is a RBX-374 btw.
I sent 2 of these back to iMuso for exactly
the same reason having searched in vain for an earth problem. The buzz was unbearably
irritating, as were the clicks whenever I touched the strings/bridge. I have an old
Washburn G15V signature series & an Ibanez BTB (which are the only active guitars/bass
I own) which have never suffered any of these problems, so I presumed the 374 was the
culprit.
I bought passive RBX-170, admittedly not as pretty or as versatile as
the 374, but at least it's fit for purpose.
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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So it seems it is some inherent design flaw in the RBX374, or one or more poor quality
components.
I took the back cover off last night, just to have a look, and
noted that the cover had a layer of foil on the inside, to shield the components - I guess
this is standard practice. Without sticking tinfoil to the outside of the bass there
didn't seem much more potential for shielding.
I did some testing where I
plugged in the bass and SM58 into a zoom H4, to get a recording on the buzzing and see if
it was other electrical equipment causing the problems. There was no noticeable difference
(maybe 5% fluctuation in the volume) in the buzzing between having my desktop, laptop, TFT
monitors, EMU, mixer, (audio) monitors etc etc on, and turning them all off. one
interesting thing was that the tone of the buzzing changed when i switched off the power
to the belkin 8-way at the wall. If I remember rightly, the volume of the buzzing actually
increased a bit when i turned the mains power off! Lighting had no effect.
What
really puzzled me, was I had everything off apart from the zoom H4, bass, mic and some
headphones so I could listen, no other electrical equipment in the room, and depending on
where i stood in relation to the bass, the buzzing changed volume. The bass was on a stand
on the floor, and if I stood in front of the bass the buzzing was 'loud', and if I walked
behind the bass the buzzing decreased notably in volume, say about 25%. I put all the kit
behind the bass and just had me standing in front of the bass, and the buzzing was still
loud. It really seemed like if the majority of my body was behind the plane of the guitar
body, the buzzing dropped, and then if I moved just a tiny bit, to the front side of the
guitar, the buzzing came back.
This seemed really weird, it seemed like I was
contributing to the buzzing. I didn't have anything in my pockets. Ho hum, the mysteries
of electromagentic radiation...
Listening to the buzzing on the headphones, it reminded me of
the buzzing that dimmer switches make. Maybe it is just a poor quality pot. I couldn't
find anything on the net about people replacing this in their RBX374s, just a few
complaints about buzzing. Funnily enough, a guy on talkbass.com (hi squishy) posted
something this week about his new RBX374 making noises.
I've come to the
conclusion that I'm probably going to have to live with this buzzing unless I get a pro to
sort it out, I don't want to try myself and risk making it worse. Using the H4 has shown
that if I roll off the treble EQ it's VERY quiet, which is good to know. And it is a bass
guitar after all, not a treble guitar
One last thing to do is closely examine the recording of the
buzzing. I wonder if it will be based around 50Hz, surely it must be.
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so, how does this make you feel?
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Hewesy
Joined: 19/10/04
Posts: 1437
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Reading the other posts it sounds like an inherant design issue, which I find very odd for
a Yamaha (unless they are using an off the shelf preamp?).
You could try
shielding the whole cavity, then resoldering each connection incase of dry joint or break.
If you can, replace the pots or use the de-oxit to ensure they are clean.
Failing that, and if it is inherant, then perhaps either replace the preamp - or the
bass?
Sounds like a right pain but worth it if the bass is a keeper.
Hewesy
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Dynamic Mike
Joined: 31/12/06
Posts: 610
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Quote Hewesy:
Reading the other
posts it sounds like an inherant design issue, which I find very odd for a Yamaha.
I actually bought a Yamaha
because I thought it would be a safe (if a little boring & predictable) bet as I knew
very little about basses. It was new out when I bought it, so I figured maybe it was a
problem with the first batch, but it appears not. It's a pity because otherwise I really
liked it & wanted to use it, but I know it would have wound me up no end if I'd kept
it. It was also no better through a known good bass amp, but I have to say I didn't get
the shocks that Discomb has experienced.
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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went to the guitar shop on saturday with the bass, and when I mentioned the wire I used to
stop the buzzing the guy twigged straight away that the ground wire in the bass must be
loose. He opened the back and it turns out the ground wire running from the pots to the
bridge was loose. It's not a great design, the ground wire comes out of the body
underneath the bridge and is simply squashed under it, no designed connector or solder. I
tried soldering it but it was actually easier to just squash the wire against the bridge.
The buzzing has stopped! There is still some high freq noise that gets louder as I turn up
the treble EQ, but I can live with it. I know prefer the treble rolled off Funny that I had ended up making my own ground cable, kind of vindicating
This week I will mostly be trying to give myself an electric
shock 
It might be caused by me using a FCB1010 midi footpedal at the same time as using
the mic and bass with the 1616. I know I got a shock then, and perhaps the reason I didn't
get one the other day when testing was because I wasn't using the footpedal.
--------------------
so, how does this make you feel?
Edited by discomb (09/11/09 09:30 AM)
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Hewesy
Joined: 19/10/04
Posts: 1437
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Nice one, a full check of the wiring was recommended, so good to hear this was the
culprit!
Its interesting that the bass has a ground, I always presumed that
active pickups didn't (though I am used to EMG's, which don't need a ground).
Good to hear it is sorted, perhaps you could advise Yamaha of the fix? 
Does the FC1010 run off a PSU? Do you use the remote switching facility of does
it just control via MIDI?
Hewesy
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discomb
Joined: 16/09/09
Posts: 40
Loc: Cambridge, UK
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I'm sure yamaha would be overjoyed for me to educate their guitar technicians
The FCB1010 uses a kettle lead for power, it has a transformer
inside. Hmm, Behringer, could you be the cause of my electric shocks? I would not be
surprised!
I'm only using it for midi control, so the likely path for any stray
voltages would be the power connection. Time to get the multi meter out...
--------------------
so, how does this make you feel?
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Hewesy
Joined: 19/10/04
Posts: 1437
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I bet 
The kettle lead could be at fault - and possibly the
Behringer...! Check it out and see.
Careful with the multimeter chap! Good
luck.
Hewesy
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zenguitar
active member
Joined: 05/12/02
Posts: 3389
Loc: Devon
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I ought to have spotted that.
I recently set-up an old Yamaha for my brother
and the string ground had never been connected to the bridge.
It had a similar
problem (which was one of the reasons the previous owner sold it, it had always buzzed),
and that fixed it instantly.
Andy 
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When the going gets weird, the Weird turn Pro.
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