Alembic Guitars Club
Connecting => Miscellaneous => Topic started by: olieoliver on January 27, 2009, 06:14:21 AM
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I posted this in the trouble shooting area then though maybe it may fit here better...
This is not really a trouble shooting question as much as an advice request.
I was switching from my 4 string S-2 to my 5 string S-2, and while unplugging the 5 pin cable I must have gotten my thumb wrapped aroung too far and got a pretty good shock.
2 questions; Has this happened to anyone else here and which is the recommended way to unplug a Series instrument cable, from the DS-5 first(which does not have a power switch like my DS-5R or bass first or does it not really matter?
OO
(buzzed but OK) LOL
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Wow; that's never happened to me, and it never even occurred to me as something to think about.
I'm wondering if the phenomena varies among different makes of plugs; whether some plugs have the contacts further from the surface of the plug.
At home, when I'm done practicing, I bring the volume pedal down, unplug from the bass, put the plug on the rack handle, bring the power amp volumes down, and turn off the rack.
It seems to me that you shouldn't have to turn your rig off every time you switch instruments. But it's an interesting question.
At least I now know not to touch the surface of the plug when the power is on. Thanks Olie!
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The cable should only be passing +9 volts and -9 volts at relatively low-current (not like licking a 9-volt battery with a wet tongue, for instance), so you shouldn't be able to feel much (if any) shock. I would check for a ground loop somewhere in your rig and look into other factors in your environment (barefoot on a steel stage? :D)
John
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I don't know whay I thought the voltage was more like 32 volts on a Series instrument. Felt like more than 9 volts. LOL
I beleive what happened was my thumb touched the ground on the cord and the bass as I was disconnecting and it became the loop.
On a side note the drummer said I was rushing a tad after that.
OO
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I'm only on my second cup of coffee, but unless you have your hand inside the control cavity I don't think you can touch ground on the bass. And ground on the cord would be one of the five pins.
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I asked my dad bout this yesterday. He suggested first sending in the power supply, but then as he thought about it more, he has a new theory. You wouldn't need to wait to hit a pin to get shocked if the source was the bass, cable or power supply. Once you touched the metal housing on the 5-pin cable that would have been enough.
He said that sometimes when you touch something with a small surface area (like the tip of one of the 5-pin connector pins) suddenly, it can really feel like an electrical shock if you hit your finger just right. He's done it before, but not with a 5-pin connector.
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Well, I think that negates what I said during my second cup of coffee. Will I have to start on a third?
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It's only happened once and my hands were pretty sweaty. No big deal I was just curious.
Is it only 9 volts running through the cable from the DS-5?
OO
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To clarify, the electric shock feeling can happen on anything, even something that's non-conductive. It only feels like a shock, it's actually a nerve response.
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NO... I wasn't nervous... just kiddin'.
I una-stan!. That's entirely possible.
(((O)) (((0)))
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just a small point..any moisture will reduce the resistance of any surface whether it be metal or skin.
The fingers do contain a huge number of pain receptor nerve endings.
Although 9V is small and I guess the current is around 300mA but maybe a little more it may still give a tingle if the resistenace is reduced due to sweat.
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OO,
The DS-5 generates closer to +18 and -18 so about a 36 vote potential from + to -. That would be enough to give you a pretty good zap but I can't imagine how you might be able to touch any of the pins while plugging in or unplugging. Contact is not made until the body of the plug is about 1/4 into the jack... UNLESS you have lost the set screw on the bass's male jack and the insert with the pins is being pulled out as you unplug... (I can't remember if Switchcraft plugs do that but I think Neutrik can.) Check to make sure your pins aren't moving!
This is one of the great things about the Series design - as long as you have the pickup selector OFF you can plug and unplug the basses at will without sending transients down the audio line. I've seen many engineers quickly reach for the mute switch when they see I'm changing instruments. Ha!
Jimmy J
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All is tight in the connector, I'm pretty confident it had to do with my hands being extremely wet do to sweat and that is what made contact between my thumb and the connector.
OO
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Jimmy,
The pickup selector *off* bit was a piece of information that was escaping me: I have unplugged completely silently, but occasionally it makes noise!
I'll remember the proper detent in the future.
Bradley
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Bradley - Having almost blown speakers unplugging, I feel it should be compulsory for amp manufacturers to include a mute button (sorry Mica)
graeme
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Isn't that what the standby switch on the amp is for?
Bill, tgo
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OK, I figured it out. (I think).
Not being one to enjoy getting a good shock, having 3 near death experiences with electricity but that?s another story, I had to convince myself to reproduce the whole shocking experience.
SOoooo to do this I had to convince myself that it wasn?t going to hurt. (I can?t find my multi tester so my thumb needed to do.) I kept telling myself all day at work, it won?t hurt, it?s going to uh ...tickle, yea that?s the ticket, it will tickle.
So I get home and decide to try a couple of test tickles, and you know what I found out? My test tickles HURT. ZZZZZappp.
But seriously I got out my little test light and found the culprit. In the photo below the arrows point to the 2 outer pins (I assume are ground??) anyway when I pulled the cable out from the bass, the inner 5 pins of the bass were still making contact with the female pins in the cable. But my thumb made contact with these ?outer? pins and the outer case of the 5 pin socket on the bass, I assume my thumb completed the circuit, and ZZzzzaaa-aaap. No big deal I just need to switch basses a little slower nest time and watch my thumb.
OO
(http://club.alembic.com/Images/449/60595.jpg)
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Thank you for sacrificing yourself in the interest of science.
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My grandpa use to test 110V with his thumb and forefinger ( he was a line man in the 40's)...I'm glad they've made progress in electrical testers.
I'm glad you figured out the mystery Olie.
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OO,
Well done and very brave! When I was a kid I built a variable power supply out of a wire-wound rheostat, a volt meter, an AC receptacle and an extension cord. Amazing I didn't kill myself...
There is still something amiss here. What your painful test implies is that pin-1 (ground) is not making the proper contact between plug and jack. The female side of our plugs and jacks are designed so that pin-1 is the first to connect when inserting and the last to disconnect when unplugging. So at no time should the + and - voltage be live when the ground circuit is disconnected. By your decription the ground circuit is being completed only through the physical shells of the plug and jack making contact - or through your thumb. Ow!
Open both the plug and the bass and make sure pin-1 connections are sound. If all looks proper it could just be a worn out female plug and time to invest in a new cable.
Good luck!
Jimmy J
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Great diagnosis Jimmy! Olie; have you tried another cable?
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Where you are touching should not shock you at all.
Let's test the DS-5R rackmounted power supply. Set it up like usual and plug the 5-pin cable in your DS-5R. Find your voltmeter (or get a cheap one at Radio Shack) and put one probe at the contact shown at the red arrow in your picture, and hold the other probe in your hand with the multimeter set on AC volts and you shouldn't see very much.
You can safely do the same thing with the DS-5. Are the readings different? If so, send that DS-5 back here pronto - you are getting shocked from the wall current, not from the DC that normally powers the bass.
If the reading are similarly low, there's potentially a problem somewhere else (power amp, outlet strip, wiring in the wall) that is serious. Please be careful and report back to me.
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olieoliver..I would take mica's advice strongly and get a multimeter and send the PS back to them for analysis.
As a part time electrician I have seen & felt far too many faults and we have 240V AC here in the UK so we are extra careful...110V pah! a walk in the park!
Seriously though get it sorted for your own & family's sake
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OK, first off I DID NOT use my thumb, I may have been born at night but NOT last night. LOL
Since I couldn't find my multi-tester I used a automotive 12 volt test light. I plugged the cable into the DS-5 and connected my test light to the terminals shown. I do get current there and it is not much for it illuminated the light but did not blow it. SO if it where anything more than 20 volts it would have blown the blub.
And Jimmy pin 1 on my cable is the last thing to make contact. I can pull the plug slightly out of the bass and see pins 1 and the others (pin 2....)are making contact.
When I get home tonight I'll post a photo that should clear this up.
I guess now my question is should there be NOthing at pin1? Is it NOT the ground or...?
Honestly I don't think there is anything wrong with the bass, DS-5 or cable. Just one of those condition things. My hand was wet from sweat, my thumb came into contact in a place it should not and there ya go.
I will try what you suggested Mica tonight.
NO Worries
OO(http://club.alembic.com/Images/449/60609.jpg)
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Just to change the subject(and show my ignorance) since I only own a MK which takes a single 9V battery.
Do you have to plug the bass into your amp via the 1/4 socket as well as have this power cable plugged in or is this cable split with a separate line to the amp...I have never seen this at all.
Mark King used batteries I believe on his S2 as he used a radio system.
Pics would be useful..anyone!
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Nope. One cable for the power and stereo signal but it has to go into the DS-5. From there, you can either use 2 1/4 leads into a stereo amp/ two amps or a single 1/4 from the ds-5 passing full range into a single amp (the DS-5 works out what you've done).
As an alternative, you can use a 1/4 inch cable from the instrument to get a mono signal as per the signature etc electronics although I believe earlier series instruments only had one of the pickups signals into the 1/4 socket.
graeme
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Thank you jacko for putting me right on that one.
Seems like a good system although I read that the Ox got right pissed off with it and stopped using Alembics, it was at the Live Aid gig 20 odd years ago.
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Double O,
The mystery continues! Sorry I wasn't totally clear... You wrote:
...pin 1 on my cable is the last thing to make contact. I can pull the plug slightly out of the bass and see pins 1 and the others (pin 2....)are making contact.
But here's the thing... The points on the plug which you have red arrows pointing to are not pins. Those points ARE meant to make an electrical connection between plug and jack, but only really to extend the shield or screen as the cable enters the instrument. There is not meant to be any voltage potential there. As you observe, the shells of the jack and plug are the last to connect.
Take a look at the attached pic below. (I know, it's a panel jack but the pin configuration is the same as on your female plug.) If the face of this jack was a clock, at um, 2:30 you will find pin-1. In our instruments THAT is meant to be the primary ground connection. Also notice on this pic that this is the only hole that you can see a little of the metal contact showing. That is how the plug is built to connect pin-1 first! Cool, huh?
Now the next problem... You said you lit up a 12v bulb between the two points you've marked. Are you SURE you weren't testing between the shell and the other side of your plug? You see, pin-2 (about 4 o'cock on the pic) is not one of the power conductors. Power is running on pin-4 and pin-5, the other side of the plug face (8 o'clock and ... 9:30). Again, the voltage here should be about +18 to ground on pin-4 and -18 ground on pin-5. Your 12 volt bulb would have lit quite brightly when attached to the shell of the plug (red arrows) and either pin-4 or pin-5. But not pin-2...
I'm still voting for a disconnected pin-1 on the plug or the bass causing any current going to ground to travel through the shells of the two connectors. Not what's supposed to happen! Take some more readings - can you take a photo of the inside of the plug? Be careful not to short out things when it's powered up!
Double J(http://club.alembic.com/Images/449/60619.jpg)
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Thanks JJ, I will try that tonight. You are probably correct about which pins I got current thru.
After I look tonight I will check back in.
Thanks,
OO
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I didn't realize that DS-5 peak to peak was 36V.... I always assumed that it was +9V / -9V, and corresponded directly to the 2 batteries in the cavity....
unless of course Ron built Jimmy an extra special SII....
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Maybe that's why I always thought my rig has more headroom using the power supply then on batteries.
I may be old, but it seems that I can still hear things.
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Double J, you are spot on! Pins 4 & 5 do give me a low current and not the others.
I've tried everything and could not replicate the experience.
When the shock occured I was playing at a hotel and we were provided power via a portable power station that look REAL old. Anyway I dp remember touching my amp while I was unplugging the bass.....yadadada. Anyway I am confident the problems lies within hotels concern not mine.
I appreciate all the suggestions and concerns, Jimmy and Mica ya'll are great.
Thanks,
OO (7)