Technics remote pitch control

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-=JK=-

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I've been checking out this board for a while, but this is my first post. There's a lot of good info here, so I thought I'd toss out a question.

I have a fairly large console, and its a bit of a stretch from the mixer to the farthest two decks. I've always wanted to wire up a remote pitch control module that I could mount above the mixer to allow for +/- 1% (or less)to each of the three decks. This would allow me to ride the pitch during a mix while still keeping my hands close to the mixer.

I't seems that you could just put a good quality (Alps?) pot in series with the main pitch control (which I believe is just a variable resistor). If you properly sized the pot, you could have really precise, fine control. Of course it would be cut or boost only unless you recalibrated the main pitch to account for the extra resistance at the pot center point, but you could work around this.

I actually took apart one of my turntables once to have a look and see if it could be done. I saw the circuit board that the pitch control is connected to, and was fairly intimidated, so I put it back together. Maybe schematics would help, but I don't know where to find them. Anybody ever tried this? Anybody ever thought of this and thought it would be cool? If I did want to have it done, are there reputable people that do mods to 1200's?

-Jason
 
Jason - way cool idea man! it is certainly doable. the fact that you only want a 2% range should allow the standard pitch range to remain the same (with adjustment inside the deck). i'd have to play with values and actually Peasant Nikon on here has more experience with pitch resistance values than i do. all you will need to do is to put a variable resitor between the pitch pcb and the main pcb (red and brown wires i believe). i would also recommend getting rid of the quartz lock circuitry at the same time (remove the orange wire). another thought would be to remotely mount the entire pitch control. what do you think? i have detailed pics of the pitch control if you need them. check out the MK5G mod by Peasant Nikon, this may give you some ideas https://www.futureproducers.com/forums/showthread/threadid/33516 - jeff h
 
Thanks for the reply Jeff - I read the thread about Peasant Nikon's mod, and I just may have to give it a try. I just needed a few specifics like which wire was the pitch circuit.

Your post brought up another question though. You mentioned removing the quartz lock, and I want to clarify what you mean because I've seen people refer to two different things as the quartz lock, and I'm a little confused as to what it actually is.

What I think you mean is remove the "click" at the zero point, and the circuitry that overrides the actual pitch control resistor value, and makes it spin at EXACTLY 33 1/3 RPM's. I've been wanting to do this for a long time!!

I've also heard some people over on the Wave forum refer to the circuitry that keeps the platter from "freewheeling" when pushed faster, or "fighting" when dragged as quartz lock. Apparently if you spin older disco music that was played with a live drummer, its necessary to do some sort of mod to remove this feature so that you can make adjustments by hand (push or drag the platter) to correct for the abrupt tempo change or bad splice, etc. This is not I mod I would really want to do because I've heard that it makes a major difference, and once you get used to it, its hard to play on unmodded tables.

So which of these is the quartz lock mod, and if you know, what is the other mod called?
 
What you are talking about could certainly be done. I have to rip open a deck when finals are over anyway, and I will see what I can do. You would need to find a pot with a small range, like 0-50 Ohms or something. I will be happy to mess around with one of mine when tests are over.

The quartz lock is what causes the platter 'fighting'. The Zero click (second zero point) is a different thing, but usually people like to get rid of both.
-Peasant Nikon
 
JK, when i said remove the quartz lock, i meant disabling the quartz lock circuit and not necessarily the click removal. you can certainly remove the "click" while you are in there though. the quartz lock comes on engages at 0% independant of the click. the click was designed to keep the fader locked in at this point on the circuit board. by disabling the circuit, it never comes into play so there is no possiblity of 2 zero points. the mod you are referring to from the wave forum affects how fast the platter snaps back to the actual pitch the pitch control is set at when pushing or pulling the platter. this involves disconnecting one resistor from the main PCB. i have never been shown or had the desire to research how this mod exactly works. i'm sure whoever came up with it had a good understanding of what they were doing, but all i've seen on how to do the work is "cut this resistor" without any expanation of what it does electronically. it sounded to me like the mod was making the 12 more like a belt driven deck.

anyway, if you want to remove the quartz lock from the pitch control, desolder the orange wire from the pitch PCB and shrink insulate it and you're done. the yellow wire is for the LED that indicates 0% it will still light up at 0%, but the quartz lock is indeed gone. if you don't want the LED remove the yellow wire as well. - jeff h
 
you can certainly remove the "click" while you are in there though. - jeff h
Click to expand...
Where can I find out more detailed info on how to remove the "click" from a 1200mk2 pitch contol? Thanks
 
JRue, here is a link with info on click removal and quartz lock removal. http://music.hyperreal.org/dj/pitch_slider/ i do not desolder the pitch fader from the board (as directed) - there just is no need if you are careful. if you are going to remove the quartz lock, i would not remove the yellow wire (as directed) - unless you really don't want the LED to light up (it serves no other purpose) and i would not use electrical tape to isolate components - i would only use quality shrink insulation.

here is a writeup i did for my LED kits and is how i do this exactly (let me know if you need pics). oh yea, one revision to my writeup - you only need to bend back 5 of the tabs on one side. 10 tabs is overkill and more of a PITA. enjoy - jeff h



There are 2 modifications I want to cover here, removing that annoying click at zero for those of you with MK2 decks and removing the zero lock entirely. The first time I had a pitch fader apart, I started thinking of why I needed the 33.3333 quartz lock at exactly zero % pitch. I decided that I have absolutely no need for an exact zero lock and the benefit of never ever having potentially 2 zero points again was more than enough reason for me to go ahead with this. M3D owners will have no need for this since their lock doesn't come on unless the button is depressed.

a. Click removal

Remove the pitch control PCB as detailed above. De-solder the pitch LED and set it aside. Remove the 3 screws that mounts the upper plate to the pitch fader and set these parts aside. The next bit of work can be frustrating, so take your time and don't force anything. The write-up I originally went by from a search on the net instructed me to de-solder the connections that hold the pitch fader to the PCB. I found it much easier to pull the 10 tabs back while the fader was still connected to the board. Carefully use a jeweler's screwdriver and a small set of needle nose pliers to pry all 10 tabs back enough so that the metal cover can be pulled straight up and off. Before pulling the metal cover off, you'll want to be in an enclosed area if you care to save the small ball bearing and spring that may pop out. Once the ball bearing and spring are out, you'll want to clean and lubricate the fader. I wipe the fader clean with a soft cloth and lightly grease the upper case where the plastic guide rides. I suppose you could lubricate the actual tracks of the fader with Caig MCL but I have never seen the need. Place the plastic guide back in the metal cover and keep it pulled at the top while you place the cover back on the fader. Once the cover is back on, keep the two halves pushed together while you push the metal tabs back into position. Install the metal plate on top of the fader cover with the 3 screws and reinstall the pitch LED or new LED. If this as far as you're going to go reinstall the pitch control as described above.

b. Quartz lock removal

This part is really easy and I've loved the results. Find the orange wire and de-solder it where it connects to the pitch control PCB. My 1210s were built right before the M3D was introduced and actually have the M3D board which is set up to accept the M3D quartz lock switch, they are just not wired the same way. If you have this type of board, you will notice that the last large connection at the end of the 4 wires is marked black and actually goes no where electrically. If this is your board, re-solder the orange wire in it this location. It will be out of the way and goes no where. If you have the older style PCB, you will not have this extra connection. Cover the exposed connector on the end of the orange wire with a piece of shrink tubing and shrink it down. Reinstall the pitch control board ensuring the orange wire isn't pinched if it is loose. The yellow wire attached to the control board powers the pitch LED. Even with the orange wire removed and quartz lock defeated, the pitch LED will still light up when the control is at zero % pitch which made me happy since the blue rectangular LEDs were a pain to find. If you don't want the LED to light, remove and insulate the yellow wire as well.
 
Well, I finally got around to trying the remote pitch mod, and I'm not sure it can be accomplished as I'd hoped. My intent was to add a remotely located pot in series with the pitch control to allow for +/- 1% adjustments without having to reach all the way over to the turntable.

As luck would have it though, the pitch control is a 20K logarithmic pot - not linear as I would have guessed. This means +/- 1% is about 100 ohms at one end, but more like 1000 ohms at the other.

I did however remove the center click and the quartz lock while I was in there, so at least it wasn't a complete waste of time.

If anyone has any ideas or suggestions, I'd love to hear 'em.
 
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