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Internally Gounded TT mess up mixer?

dELfONiK 7:14 PM - 27 March, 2009
Quick question... I haven't had any problems with my internally modded Technics 1200 turntables and my TTM-57, but I had a question.

I did the mod per online instruction, TT ground cable to one of the RCA's signal grounds.

So each RCA cable has a signal wire and signal ground. I tied the turntables chassis ground into the rca's signal ground, which grounds at the mixer's rca input.

Does this have any negative effect on the mixer? As I said, it works perfectly, but I don't want to do any harm to my mixer.

Thanks.
DJ Dill Pickle 3:40 PM - 28 March, 2009
Shit mate, that aint a quick question.

I dont fully understand what you've done here, but any ground problems will make themselves noticeable straight away. If not, should be fine.

you have a link for this procedure you have done??
dELfONiK 5:25 PM - 28 March, 2009
Sorry for any confusion. Check out this link.
www.gigacrate.com

You'll notice that each RCA wire has 2 connections to the board, making a total of 4 connections.
The red wire has a signal wire and signal ground, same with the white. I basically tied into one of those grounds.
keilamym 3:12 AM - 30 March, 2009
the mixer works fine with the internal ground..

i did my tables and it works with no problem... a club i dj in has one table grounded internally and the other one is still external.. mixer still works fine...
westell54 7:56 AM - 20 April, 2009
I started doing this back in 1993 and from what I remember about this mod is that, as long as the device you have the turntable connected to has a universal/centralized ground, then you should be fine. I discovered this by accident one night by trying to hook up my 1200 directly to my Mackie mixer and I couldn't figure out how to ground it properly. I accidently let the ground wire touch the ring on the 1/4" input jack and noticed that the buzzing stopped. I ended up slipping the ground wire underneath the insulation on the rca connector while connected to the mixer and it worked. I didn't know anything about preamps (equalization) back then. I called Mackie and asked them about it and the tech I spoke to on the phone told me back then that although he didn't advise doing that (and explained RIAA phono preamps), the reason that it worked in their mixer is because the mixer had a common ground (all the grounds throughout the mixer are connected). He also told me that it should work in any other device that shares a common ground (I haven't seen a mixer yet that doesn't).

This doesn't mean that you won't EVER have a problem, but most gear that you'll be connecting your turntable to will have a common ground.
westell54 8:00 AM - 20 April, 2009
I was so confident when I did mine, I cut my ground wires off my tables and never looked back. Besides, you can always redo them if need be. You really don't even need to do them both, but if you ever have your cables go bad on you (common on frequently mobile turntables) then that's when you'll be glad that both of them were grounded.
keilamym 3:21 PM - 20 April, 2009
i grounded one channel, but also left the ground wire on my tables just in case i had a problem.. i read a while ago that this didn't work on 1 specific mixer but i haven't come across it.. i dont remember what mixer it was either...
westell54 6:18 PM - 20 April, 2009
Yeah I remember hearing of rare products back in the day. I doubt that mixer is even in use anymore. The only thing that kept me skeptical at first was, why didn't the manufacturer ground them internally from the factory? Then when I thought about all of the different preamps and home receivers that were used over the years, it made sense because some of the more exotic stuff had separate grounding points. I have a Carver preamp that has a ground lift installed on it but I've never connected my 1200 directly to it to see if it matters. Maybe I'll do it today just to see.

I'll let you know...
tomatoslice 1:26 AM - 22 April, 2009
dELfONiK

in my area the majority of djs use TTs and most of them at this point, especially in the clubs, have been internally grounded. also, most places i play have their own 57. so far in the 2 years i have been playing on them i have come across no issue with internally grounded TTs or the 57...

i haven't pulled a 57 apart to see what the grounds are attached tho.
simply grounding thru an rca to the mixer shouldn't do anything.
personally i have NEVER seen an issue with this in any the decks/mixers i have played on.

you will proabably do more damage thru wear and tear than in the long run than anything an internal ground will possibly do.
nik39 7:54 AM - 24 April, 2009
Internally grounding, grounding the ground-cable to the audio ground is not a good idea I was told...!
westell54 9:42 AM - 24 April, 2009
nik39 I think it depends on the circumstances. The whole reason that this ground mod became so popular is that countless DJ's were either tired of always having to fool with the ground cable, or they were tired of trying to connect ones that were worn out/damaged from constant use. Then of course there are those times that you use another DJ's setup only to find that either that terminal at the end is damaged and just barely holding on, then it slips off during a set and you end up with a sound effect that you didn't want. :) When this mod became know to the DJ community, a lot of people weighed out the pros and cons of doing such a permanent fix to their tables and I know for me it was worth the risk. Each situation is different but, I always use my own tables and mixer so I know what works and what doesn't. At first I very nervous about doing it because I figured that there had to be a reason why this wasn't done by the designers or a the factory when it was built. What really kind of gave me peace of mind is when I got some insight a tech support rep at Mackie about WHY it works, and situations when it won't. After that for me, I had no reservations whatsoever about doing it and I even started converting my all my RCA cables over with heavier duty gold cable ends. I started doing it on other DJ's tables who were known to really known to abuse a pair of 1200's. Like I said earlier I started doing this back in 1993 and I'm still using those same decks and none of the tables I modded have ever had problems (at least that I know of).

The main downside to doing this mod was because there may be some devices without a common ground. I test a piece of gear for this by using my multimeter to test a device for a common ground if I'm unsure, and I haven't run into a mixer or preamp yet that doesn't have this configuration. I'm not saying that my method is the best, but it had served me well all these years so, I keep using it. Now keep in mind that I'm not hooking my 1200's up to $2000 audiophile phono preamps or anything so if there's anyone who can speak to that, I'd be curious to know if anyone has found a situation where this would be a problem.

For all of my applications (so far) it has worked...
nobspangle 11:17 AM - 24 April, 2009
Quote:
Internally grounding, grounding the ground-cable to the audio ground is not a good idea I was told...!

I don't think it's a problem, if it were I don't think the SL 3 would work properly.
With the SL 3 you have the choice of grounding either to the box or to your mixer and both work, I pretty sure the reason both work is because the grounding posts are also internally grounded with the RCAs.
nik39 1:14 PM - 24 April, 2009
Quote:
the grounding posts are also internally grounded with the RCAs.

Are you talking about the SL3 now or turntables?

I'll let you know what I find out.
nobspangle 3:45 PM - 24 April, 2009
Quote:
Quote:
the grounding posts are also internally grounded with the RCAs.

Are you talking about the SL3 now or turntables?

the SL 3
nobspangle 9:00 PM - 24 April, 2009
Steve,
I've never quite understood turntable ground wires. Why are they not simply connected to an electrical ground?
westell54 5:26 AM - 25 April, 2009
Alright. I THINK I understood all that. They must pay you a lot. No wonder Rane's gear is so expensive. Thanks for the info Steve, but I'm gonna ride it out for now since my stuff stays in the house and for the streets I use either my CD players or the VCI-300 that I ordered today. That does answer the question that I used to have as to why turntables were wire like that. What about the ones that have line level outputs on them. Do they have ground wires or is it all done inside the unit.
I think as long as I'm using Rane's gear, then I shouldn't run into any problems (fingers crossed).
tomatoslice 4:10 AM - 27 April, 2009
oooo k, wait a second...

so steve, if i read that correctly you are saying that the ground wire is somehow associated with the (motor). assuming we are talking about the industry standard technics turntable that typically connects to a mixer, it is in no way associated with the motor.

"The TT ground wire connects the motor control board in the turntable"... that is not true with what we are talking about. the tone arm and ground wire are COMPLETELY separate than from the motor system in a 1200. they work completely separate from each other and in no way are ever connected to each other.


the ground wire associated with the tone arm is not connected to anything electrical within the technics 1200.
tomatoslice 4:14 AM - 27 April, 2009
and btw westell54, if done properly the internally grounded mod for a 1200 is not permanent.
westell54 6:19 AM - 27 April, 2009
The way I do mine they are, unless I open them back up. I cut and remove the original and do 2 short jumpers on the tone arm board. To reverse that I'd have to open them back up, cut the jumpers and reattach/solder the ground wire back in. That's the only reason I say "permanent".
djdragon 11:13 PM - 27 April, 2009
Quote:
I've never quite understood turntable ground wires. Why are they not simply connected to an electrical ground?


The turntable ground cable prevents the magic smoke from being released from the electronic circuits, you must have them connected to the DJ mixer or SL3 box (SL3 box has a USB 2.0 magic smoke inhibitor that's why the USB port is organge, the SL1 didn't have a magic smoke inhibitor because it wasn't supported in the USB 1.0 protocol) .

That's all you need to know and that's what you tell others.
J-Fresh 6:58 PM - 29 April, 2009
A lot of people like magic smoke like puff the djdragon....

Okay but seriously I've had my tables internally grounded for YEARS and I play on multiple systems 4-5 days a week. What are the circumstances that something could go wrong? In plain mans terms? Using a certain kind of mixer or something?
westell54 7:47 PM - 29 April, 2009
My point exactly J-Fresh. Mine have been grounded since 1993 and I've never had issues either, so I'm sticking with it. I've heard it depends on the component that the turntable is hooked up to. Steve M gave a much more technical explanation of it, but for my purposes, all I need to know is that it works for me and anyone considering doing the mod needs to be aware of the pros and cons of doing it. As with anything you buy, if it's something that the manufacturer did not design the product to do, you attempt it at your own risk.
J-Fresh 7:57 PM - 29 April, 2009
Honestly, I've had a lot less issues with mine than I have with messed up ground wires at clubs.....
westell54 4:21 AM - 30 April, 2009
Mine have been ZERO! How about you?
djdragon 3:33 AM - 2 May, 2009
Quote:
A lot of people like magic smoke like puff the djdragon....


Boooooo, like i've never heard that one before LOL
tomatoslice 8:17 PM - 15 August, 2010
i don't have too read much further than this line in Steve M's post to know he is COMPLETELY WRONG.
Quote:
... The TT ground wire connects the motor control board in the turntable to an earth ground ...


the 1200 ground wire and the motor control or anything electrical in a technics are totally and completely independent.
they work totally separately and not connected by any wires at all.

they are in no way connected
the ground hum you get is NOT electrical.


i don't even know why this post is still here.
Steve M is very misinformed.
research the subject, take a TT apart or work on them, you will see.

i have personally internally grounded many turntables and repaired well over 300.
unless the work was shotty, i have never had an issue or heard of anyone having an issue with an internal ground ever.
djpuma_gemini 9:23 PM - 15 September, 2010
Have you actually taken a DMM and measured the resistance between the 1200 ground wire and the ground on the pcb of the techs?
tehBEN 9:53 PM - 15 September, 2010
Quote:
Have you actually taken a DMM and measured the resistance between the 1200 ground wire and the ground on the pcb of the techs?

yep
djpuma_gemini 10:09 PM - 15 September, 2010
So, if they are completely isolated you wouldn't want to connect the two grounds together.
tomatoslice 3:24 AM - 28 September, 2010
what 2 grounds??

you definitely do NOT want to ground the tonearm internally to anything electrical or the motor or any other ground not associated with the arm.
there's no reason to do that. the electronics and the tonearm are independent units. don't connect them.
SiRocket 12:57 PM - 28 September, 2010
i've been internally grounded for 7 years.... never have had an issue.
nik39 1:28 PM - 28 September, 2010
Quote:
what 2 grounds??

you definitely do NOT want to ground the tonearm internally to anything electrical or the motor or any other ground not associated with the arm.
there's no reason to do that. the electronics and the tonearm are independent units. don't connect them.

Now you're confusing me. :-/
tomatoslice 12:54 AM - 29 September, 2010
Quote:
Quote:
what 2 grounds??

you definitely do NOT want to ground the tonearm internally to anything electrical or the motor or any other ground not associated with the arm.
there's no reason to do that. the electronics and the tonearm are independent units. don't connect them.

Now you're confusing me. :-/


oh, just take a 1200 apart and you will see.

it's easier than you think, just do it.
nik39 6:24 AM - 30 September, 2010
Ha! I have opened a few 1210s in the past ;)
DJ BOJAN 8:30 PM - 31 March, 2012
After Steve's breakdown, what is the consensus among the group because i am on the cusp of doing it vs not doing it.... I am taking apart my 1200 this week for RCA cables..and was thinking of going ahead and doing the ground mod too?
Rane, Support
Shaun W 6:11 PM - 2 April, 2012
Don't do it! The last place you want noise/interference and etc is in your audio signal path.
DJMark 7:51 PM - 2 April, 2012
Whoever started the "no ground wire" thing has about as little technical sense as the person who started the "put the counterweight on backward, track at 12 grams, and strip the tonearm threads" thing.

Both are really bad ideas.
DJ BOJAN 7:57 PM - 2 April, 2012
So many different opinions! lol I really want to see examples of people that did the internal ground and had issues or problems..
DJMark 8:19 PM - 2 April, 2012
I'll give you one example of the "no ground wire" thing creating a mess.

DJ using a laptop with power-supply having only a two-prong power plug (no ground).

SL-1 powered from USB.

"No Ground Wire" turntables connected to SL-1.

Mixer was some piece of crap old Vestax that ran from a "Wall Wart" power supply (again, no ground).

Result: lots of noise seen on Scratch Live scopes. Hum and buzz in speakers (not at a constant level). "Real Records" not playable, Scratch Live tracking messed up to the point of general unusability. They ended up playing CD's.

Keep in mind that the Technics turntables themselves have only a 2-prong power cord, and the reasoning is legitimate: when dealing with very low-level signals, a "Central Grounding Point" scheme becomes important. That's why the ground wire is there.
DJ BOJAN 8:25 PM - 2 April, 2012
Thank you for the kind explanation. My set up is going to be two MK2 with 57SL of course running scratch live. Originally i was seeing a lot of good feedback from people internally grounding, essentially cleaning up the turntables a little bit. So while i was going to replace my lights and my RCA cable in my 1200s, i figured I would do that. But i just changed my mind and order originally techincs ground wires and just going to replace them to new and keep it externally grounded. Hope this was a good choice ha :)
DJMark 12:04 AM - 3 April, 2012
Glad to have helped.

The people at Rane should generally be taken at their word :-).
SiRocket 6:40 AM - 3 April, 2012
if you are in doubt leave the ground wire there tucked into the rubber cover under the techs if you need to use it....
AKIEM 6:46 AM - 3 April, 2012
did mine years ago without any problems.

I do rip from a deck without it done - just in case.
still dont hear a difference tho

whatever the risk of an issue I easily accept compared to the slight hassle saved fiddling with the ground all the time
JMO