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Turntable buzz question

mannybolonemannybolone Los Angeles, CA 15,025 Posts
edited July 2010 in Strut Central
Lately, I've been getting a buzz from my turntable - sounds a lot like an ungrounded wire though about 1/4th as loud.

Sometimes, it's in the right channel, sometimes the left (right now, it's in the left). The distinct impression I get is that it's being caused by a faulty contact between my cart head and the tone arm junction - if I flick the tone arm, this often with "fix" the problem but only temporarily. Sometimes, all I need to do is pick up the tone arm again and the buzz comes back.

i've tried Detoxit on both the cart contacts and the tone arm contacts but this hasn't seemed to had much of an impact. I've had the same problem with multiple carts so it's not the cartridge.

What is confusing me is that besides flicking the tone arm, the other "solution" is that I can unplug the turntable RCA cord from my pre-amp and then reinsert it. When reinserted, the buzz is usually gone (until it comes back again).

One explanation offered to me was this: "some contact within the tonearm is probably ungrounded. This means some electrical charge can build up and generate currents that run into your preamp, which causes the buzz. If you isolate the TT from the preamp, these parasites currents can't run into the preamp anymore, which will suppress the buzz."

He described this solution: http://www.radioshack.com/product/index.jsp?productId=2062214

I wanted to get a quick second opinion from the Strut cloud wisdom to see if all this sounds about right.

  Comments

  • GrandfatherGrandfather 2,303 Posts
    first thing i was gonna say, get a ground loop eliminator.
  • dj_cityboydj_cityboy 1,478 Posts
    i have had this issue a few times, usually i clean the contacts on the carthead 4 lil dots, and dip a q-tip in some alcohol and clean the contacts in the tonearm....

    i've only had to do this twice but it fixed my issue...
  • mannybolonemannybolone Los Angeles, CA 15,025 Posts
    What would Soul Strut Do?

    I bought this Pioneer turntable for about $100 back in Jan and have been using it as my primary digitizing TT. Up until recently, it was working pretty well but then this buzz shit started happening and it definitely seems to be some kind of contact problem along the tonearm. You tap it enough times and it'll fix the problem but only temporarily.

    Few questions:

    1) I tried Deoxit on the contact heads but seemingly, to no effect. Other suggestions?

    2) Would a ground loop eliminator make a difference if the problem is a loose contact somewhere in the chain?

    3) Worth taking it in for a turntable specialist to fuss around with it?

    Thanks.
  • JimBeamJimBeam Seattle. 2,012 Posts
    if you've got a ohm meter, check for continuity between the 4 terminals inside your tonearm where the cartridge connects (the "socket) and the tips and grounds of your RCAs. There should be zero resistance. It sounds like a ground is the problem, not the positive terminal since you're getting buzz and not sound cuts. If jostling the tonearm around changes the resistance, you're problem is probably in the tonearm.

    the cartridge socket on the tonearm can work itself loose over time from changing carts and the twist clamp being repeatedly screwed and unscrewed. without seeing your setup though, it's hard to say... if it's similar to the 1200:
    when the cart is locked in the tonearm, it should not have any play at all (ie: you shouldn't be able to jiggle it side to side or in/out at all while the cartridge is locked in)
    because of the way the contacts are sprung inside the tonearm socket, any looseness will translate to weak connections/ground buzz.

    If there is play in the cartridge socket, you'll have to unscrew the needle seat at the base of the tonearm to remove the entire arm (wires still connected inside, so don't yank it too hard), flip it over and tighten whatever screws or connectors the cartridge socket is connected to the tonearm with.

    hope that helps.
  • mannybolonemannybolone Los Angeles, CA 15,025 Posts
    Jim: Thanks for the thorough response. I went back and spent half an hour testing things out. Here's how things stand:

    1) Left channel works perfectly. No buzz or anything. No matter what happens with the right channel, the left stays working.

    2) Right channel vacillates between:
    A) Working with no buzz (but only for a split second)
    B) Barely working (very low volume), with buzz.

    If I tap the tonearm, I hear that ZZZZ! sound, as if something electrical is making contact in that instant. Sometimes, the tap will restore sound to the right channel w/ no buzz, most of the time, it doesn't do shit.

    The fit between the tone socket and the cart is very snug. No "play" there at all and I've tried this with three different carts. One thing worth noting is that a Shure White Label, when my hand gets near the head of the cart, the buzz increases in volume. Strangely, this doesn't happen with the two other carts I tried (a Pickering and a Shure 44-7). Don't know what that means but it seems like significant information.

    One other notable piece of information: when I had my turntable plugged into a solo pre-amp, unplugging the RCA and replugging it would temporarily fix the problem. But now, with the turntable run through a DJ mixer, unplugging doesn't do shit. Problem persists regardless of how the turntable is plugged. Don't know what that means but it seems hella odd.
  • JimBeamJimBeam Seattle. 2,012 Posts
    you're getting crossed pos and neg signals-- meaning that at some point on the line from the headshell to the rca male on the right channel, you've either got:
    a) a signal short grounding to your turntable
    b) the pos and neg leads are contacting one another, causing cross interference

    based on your description, (unplugging it and plugging back in temporarily fixes it) it sounds more like a, which is a normal thing for turntables in really "small doses"-- (it's the reason for a ground wire, which eliminates most small interference/ground to the body and static electricity related buzz). I imagine you've checked the ground and it's solid, your cables aren't pinched in any way, etc., so I'm assuming it's a bad wiring issue-- the reason you get buzz w/ the whitelabel is that it's got more exposed metal parts on it than a 447 (that little polished lip), and the signal that is being grounded to your turntable is grounded to your hand when you get close to touching the headshell.

    The two major parts that have these buzzing issues are the RCA cable (90% of the time) and the tonearm. The most cost effective way to handle it is to replace the RCA, and see if it goes away (if you've got a soldering iron and a pair of wire strippers, it should be a painless 30 minute job, it's way simpler than repair techs would have you believe). If that doesn't solve it, a new tonearm is in order.

    Other things to note: have you moved the turntable recently? no leads are pinched by anything? (really common in flight cases) when you disconnected the turntable from the phono preamp did one of the little plastic isolators fall out of your male RCA plug? ground wire is securely connected (it didn't get yanked at any point recently?) you've tried bending the RCAs at different points to see if the buzz comes and goes? you've hooked it up backwards and the problem comes on the left channel (so you know it's not a mixer issue)

    i know what a pain in the ass the buzz issue can be, i've fixed it for a ton of people-- but it sounds like you're on the right track. just do anything you can think of working from the headshell back to the RCA leads to try and isolate the problem, and replace the offending part.
  • mannybolonemannybolone Los Angeles, CA 15,025 Posts
    Jim: Thanks again. This is all tremendously useful.

    Question: if the problem is with the RCAs though, why would tapping the tonearm make a difference?
  • JimBeamJimBeam Seattle. 2,012 Posts
    if you're getting a short in the RCA's-- some sort of cross interference between pos and neg signal, it's looking to ground itself to anything-- including the turntable. Since the tonearm is exposed, conducive metal, it's grounding to it, causing a ton of interference/buzz.
    touching it or tapping it temporarily grounds the signal to you or something else, the problem goes away, and then comes back again. (anything interfering w/ the tonearm can be interfering w/ the pickups in your cartridge, etc)

    If you're hesitant to replace your RCA as a process of elimination step, just play a record, start at where the RCA connects to the TT (in you're case, you may just want to leave the right channel hooked up), bend, kink pull and twist the RCA inch by inch all the way to the male plug end at the mixer. If at any point, the sound cuts, the interference changes or stops and starts (ie: you can isolate the problem to the cable) the cable should be replaced.
  • mannybolonemannybolone Los Angeles, CA 15,025 Posts
    Jim: I tested the RCA cable and voila - the problem seemed to be based somewhere around the male lead. Looks like your intuition was completely on point and now I have a pretty simple solution to a not-so-complicated problem as first I thought. I'm just glad it wasn't the tonearm; that would have been a pain to replace, just in terms of locating parts.

    Thanks again for your help and more importantly, for explaining the science at work here.
  • mannybolonemannybolone Los Angeles, CA 15,025 Posts
    Jim: I tested the RCA cable and voila - the problem seemed to be based somewhere around the male lead. Looks like your intuition was completely on point and now I have a pretty simple solution to a not-so-complicated problem as first I thought. I'm just glad it wasn't the tonearm; that would have been a pain to replace, just in terms of locating parts.

    Thanks again for your help and more importantly, for explaining the science at work here.
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