Technics SL-1200 Internal Grounding

This is video explaining the process of replacing the RCA's and and an explanation of what "internal grounding" is and how to do it. This applies to any turntable, not just Technics 1200's.
Find my repair service at: / commonbeatmusic

[@djrichiet]

As an engineer I must say the chassis and audio ground must remain separate until it reaches the device with the RIAA pre-amplifier (mixer or hi-fi pre-amp) Unfortunately quite a few technicians do this modification without understanding the electrical principles behind why the chassis and audio grounds must be kept separate. please see the following documentation which explains in a little more detail: www.technics-service.co.uk/app/download/15133899/Internal+Grounding+Info.pdf

[@commonbeatmusic1290]

I understand what you are speaking of and I now make this decision based on what my customers are comfortable with because I will often replace the ground wire if they choose to keep it and not internally ground their table. I made the video to explain the process of "internal grounding" to people, not necessarily as a recommendation. I advise my customers to make a decision. Another alternative would be to have the chassis ground go through a grounding AC plug and have the tonearm use internal grounding alone which is something I may pursue in the future.

[@arizonaguy7574]

@@commonbeatmusic1290 The problem there is your customers probably are not electrical engineers. If they were they probably would do it themselves. I would also recommend a solder sucker on your solder joints.

[@Mazeisaspace]

agreed.

[@BjorgenEatinger]

Purchase the pair of RCAs with the PCB board to resolve this "don't internal ground" issue.

[@dooksan]

Best video on the subject. Thanks!

[@rightbrainlefty2275]

Super helpful, I’ve got my turntable running back to the receiver from a distance and the ground is too far easy to connect to the receiver so this will work great

[@dj4our5ive]

Great Job Buddy!!

[@Xmaximaz]

Thanks a lot you save my life every minute worth it

[@EmilyGrayFow]

Great vid.

[@RickyGoodwood]

great video!!!!!!!!!

[@EdOlikeme]

I've tried to soldering this way, but didn't work, it make noise. Instead it works soldering the grounding on a single rca ground (right or left, not both). Is it ok?

[@VideoArchiveGuy]

Don't internally ground it, it's why it has separate signal and chassis grounds and is going to induce hum at some point.

[@dipulator]

Thank you for creating this. When I opened my 1200 up I found that there was already a single wire bridging the 2 ground points but that wire wasn't connected to anything else. any idea what that might be for?

[@derrickarthur2295]

i guess it is quite off topic but do anybody know of a good place to watch new tv shows online ?

[@piercechance1085]

@Derrick Arthur I dunno I'd suggest Flixportal. just google for it :P -pierce

[@derrickarthur2295]

@Pierce Chance Thank you, signed up and it seems to work :D I really appreciate it!!

[@piercechance1085]

@Derrick Arthur Glad I could help :)

[@DnB.Therapy]

Excellent video👍 small Q hope u can help with? On the pcb nxt to the tiny blue,yellow,red,green wires is a tiny black one. What is that connected to? Cheers for any help👍

[@commonbeatmusic1290]

That black wire runs from inside the tonearm to ground it on this board. If you follow the circuit trace it connects to the metal tab that the original external ground wire is attached to.

[@djlancematthew]

So is that what people mean when you’ll hear of people internally grounding a turntable incorrectly for Serato? Do you have to actually have the ground wire to both left and right grounds so that the program will receive the signal correctly?

[@commonbeatmusic1290]

We are explaining the method of how it is done since the phrase "internal grounding" is thrown around a lot and some don't have an understanding of how it actually looks. We recommend if internal grounding is done to strap the shortened ground wire across both sides of the RCA audio cables for best results.

[@WhisperLeo]

Where on the table does the second part of the gound wire attach to

[@commonbeatmusic1290]

The ground wire connects to a brass tab on that PCB. This is where the black "earth" wire connects the tonearm tube to the chassis of the turntable.

[@derreire]

Thanks :D

[@marciom909]

This is WRONG. Technics has released a document that states you should never do this. RIAA curve is destroyed, adds hum at 70hz, transforms your deck in a giant RF receiver, capacitance and inductance problems.. and so it goes. Dont do this! Most problems about grounding are dirty or bad connections at the headshell or damaged rca/ground cables.

[@alelondon23]

you explained some things twice and many other are missing. Have you consider replacing this viddeo?

[@toomanyprojectstx]

so i have a really important question. Why solder it on Both ground traces than just using the right or the left? please explain great work btw.

[@commonbeatmusic1290]

There's not really a big reason for this other than that it just couples those grounds together. You could achieve the same result by just soldering the grounding to either the Right or Left ground plane, but if for some reason you only hooked up the side that didn't have this ground strapped across it, the tonearm would hum very loudly.

[@EdOlikeme]

I've tried to soldering both ways, but the only one it worked is soldering the grounding wire coming from the pitch to rca ground (right or left, not both). All the other ways make some noise.

[@dingleberry9341]

Why didn't the manufacture or designer do this in the first place? Why are field repairs better than the the as-built?

[@DjTecniq]

Good stuff. I have internally grounded my decks however I wrapped the ground wire and kept it inside my deck from another tutorial (which I later found out is a bad idea) noticed I get a slight humming noise when the rca's are connected to mixer (vinyl only) however when they are connected to Serato box I get no hum at all and perfect tracking. So I think I grounded it to the wrong area. Looking for your suggestion. Thanks for the tutorial.

[@commonbeatmusic1290]

You always want to keep your grounds short. I have opened up tables and seen people do this and there is really no point to have the wire long at it. I cut it so there's enough length to get from the EARTH solder point on the little board to solder to both RCA ground points. It should attach the black thin wire (which is connected to the tonearm itself and you just that ground wire to strap it across the shield grounds of the RCA cables.

[@DjTecniq]

Interesting a have a Pioneer DJM-S9 mixer now and there is no hum whatsoever with vinyl with the same tables but my DJM-700 there is. Which has to be the old djm700 is the culprit as there is complete silence and perfect audio with my S9 mixer.

[@seanbarr1966]

i in need of ground wires for the 1210s so looking for advice on good brands high ends or even original and length need any help be great thanks

[@raffaelemaione2651]

I had this work done when i replaced my RCA cables but now its making a buzzing sound again. What could it be ? the solder broke inside?

[@RockNRollHouseFilms]

A lot of people go and swap their RCA cables on these and forget to check the headpins in the tone arm first. The gold plated pins in the headshell receptacle get dirt and oxidation on them and it's good to swab them out with a solvent like isopropyl alcohol or even WD40 on a Q-tip. Often clears up signal and grounding issues and costs nothing to do yourself.

[@raffaelemaione2651]

@@RockNRollHouseFilms so you recommend just to clean the headpin where you put the cartridge with alcool and a qtip. I guess I’ll try then. I’m asking because a lot of technics engineers say to refuse this modification and keep it original

[@RockNRollHouseFilms]

@@raffaelemaione2651 yeah I’m also @commonbeatmusic on KZbin. What I am saying is to check the headpins before opening the table up. Generally when people bring these in to our shop for cable changes, I ask the customer if they want a new ground wire or internal grounding and also clean the headpins as part of the process. I like to eliminate all variables before just swapping cables for no reason.

[@user-eu5fg3pn8d]

There is another black cable - i think is grounding the pitch -. If you grounding on RCA, where will you ground the black cable from the pitch ?

[@commonbeatmusic1290]

That black ground on the pitch routes under the black sub platter and connects to the same tab as the external ground wire so it all grounds at the same point.

[@user-eu5fg3pn8d]

@@commonbeatmusic1290 Last question . Maybe its better for clearest sound, ground separate the black cable from pitch fader? I mean one ground for tonearm in rca and second ground for pitch to the amp. I need you opinion and thank you

[@grpsmartgrpsmart5285]

If you are doing regular stuff... You can use this method. But you are doing " Recording " or " DJ's " or " Video Dubs, etc... " than the " Ground Wire " should always be separate.

[@commonbeatmusic1290]

I've explored the possibility of a ground spike in a 1200 based on some of the comments I've gotten on this video and the likeliness of having serious electronic damage done because of internal grounding are slim to none. Not saying it's not possible. The tonearm ground wire is connected to the plinth as well as the main board inside these tables. If that was a concern to Technics when these were made, I feel they would have gone with a 3 prong power cable which in that case would negate the intent to internally ground. I made this video to explain what it is more than anything else. It's really up to the user to decide what they feel is a method suitable to their application.

[@ernieg]

yo.. can you use digital RCA's ? Is It Better ?

[@commonbeatmusic1290]

It doesn't have anything to do with anything. It's just the branding they use. It's still shielded 24 gauge wire inside with gold connectors. I chose this cable because it fits the 1200 like stock ones and it also had the best signal to noise ratio of variety of cables I installed in a guinea pig 1200 years ago for a shootout to find the best one.

[@lawze4409]

Thanks for doing the video now i can save some by not getting someone to do it

[@ernieg]

so why didnt they do that in the first place ??

[@commonbeatmusic1290]

It's not what was done at the time.

[@marciom909]

Because it is WRONG. Technics has released a document that states you should never do this. RIAA curve is destroyed, adds hum at 70hz, transforms your deck in a giant RF receiver, capacitance and inductance problems.. and so it goes. Dont do this!