Upgrades for Pioneer plx-500kw/Audio Technica lp120XUSB (BK)

[darkspr1te]

So long story short 25+ years ago I was a DJ and loved my SL1200 MK2's , my wheels of steel and sadly had to sell them in order to travel to Africa where I now live.
Recently i wanted to scratch that itch again so to speak (I have some numark NV2's and VDJ license , a real one not a crack) but wanted the feel of a record but i dont have Technics money to throw at it so got some Audio Technica lp-120xusb bk's and well they are actually pioneer plx-500kw table made by another company i've not bothered to look up.

Well it turns out they not 1200 clones, they the inbred son of the clones.
Some of the issue can be fixed but require major mods, irons and a prayer so I've decided to see what i can fix to bring them close to the technics 1200's  in feel and sound ( cant fix all the functions as the 120's dont have height adjust and more)

I also want these mods to be easy swap outs, where possible
so first two things that lack is torque on the decks and audio response. A quick google on the lp120 will tell you why but i will attach the schematic for better visuals,
i intend to remap the torque controls and remap the audio routing while still keeping as stock as possible, sadly some parts need to be attacked with a iron, that's the way of the world.

So First to remove R109,R110 and use JR5 as a branch off to a switchable resistor array
I've yet to disassemble mine but there are plenty of videos online so am using them to design the basic replacement pcb and VR/Dip Switch in much the same way the SL1200 mk4/5 have the hole at 3'clock with a adjuster for brake & torque and like mk7 have dips for other functions (all from the BA6868FM controller)

Second is to remove the inline 'crap' that is parts of audio system. I personally dont understand that part so am reading up on it but i can tell you from get go that Dolly parton records and Meat loaf dont sound right, the sound is muted and lacking in bass tones. I have tried all 3 outputs (USB, PHONO,RCA ) and only rca produced a semi close to original signal , i checked this on my other system which is Sony PS-9 via the same speakers and it's way richer in bass and mid tones.
anyway, wish me luck, Time to take it apart


darkspr1te
 *edit , attached the files this time*

[themadhippy]

unless its got some sorta auto cue id bypass the built in pre amp and have the pickup going direct to the output connector and use an external riaa preamp

[darkspr1te]

from the needle/cable to board it's normal but once on the board they stuck some caps onto the feed to give it a ref level i guess? dunno but yes i will route PHONO as direct on my new board , it has no auto stuff, it's a "common 3 phase motor driver" + usual USB audio criminals ,
bypassing audio on these models is well known , i mention the video's on youtube you can find, but what I "want" 'ahem' to do is make a couple of upgrades, one is new audio board with a 48v preamp section driven by my mixer , not many if any dj's would want this but in my case it's a benefit, i was given two by a A/V tech  a few years back and they are great for pushing low signal far without digital lag and ground noise. Sadly i dont have those unit anymore as they were taken in a theft of my work van/vanette - cd's, records, amps, lights, stands etc- ,
never got paid out on that as they used the excuse "place of alcohol" so i must be drunk. ha ha, sigh, "DJ equipment " cannot be really insured here.


Anyway
my actual first mod will be the power, i already tried it and it's lame, I have a very light touch and a 3 gram needle and the motor wont keep up, somewhere i read the lp120 has more torque (and pop up head lights sigh) so i looked into it. it's all set by R109/R110


darkspr1te