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Numark PT-01 modding thread


Guest rasteri

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Guest rasteri

Thought I'd start a new thread for this.

 

First step is to jot down a rough schematic for my PT01 so planning mods will be easier. Note that not all the components have the correct names yet.


Some things to note :

  • This is for the PT01USB version, which has an extra connector (TE13) on the main board that sends the signal to the USB board, and the motor control circuit uses a different IC. The circuit looks broadly similar to the regular PT-01 however and the components have the same names.
  • The top section of the schematic is the main audio/motor board, the bottom section is the power supply/IO board.
  • Connector TE11 connects to TE12 via the black ribbon cable.
  • The phono preamps are a common-emitter class A transistor design with no proper RIAA equalisation. This might actually be a good thing as most of us turn the bass down when cutting anyway.
  • The L/R connectors on the black ribbon cable are actually AFTER the power amp. Wiring a fader in at this point probably isn't a great idea as they aren't really meant to handle that kind of power, but I guess if it works it works.
  • A better place to put faders would probably be after the DC-blocking caps C8/C18, or perhaps after connector TE8 (the tone/volume knobs).
  • For an AUX IN port, putting a couple of resistors in series with the AUX and connecting it to TE8 pins 1 and 3 (or 4 and 6 if you don't want it to be affected by the volume/tone knobs) would probably work.

Next step is to reverse-engineer the motor control section, hopefully ultrapitch will be doable.

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Guest petesasqwax

I neither have nor plan to get a portable scratch setup but I still absolutely love that this thread exists

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I don't mod stuff myself and I'm glad you guys are embarking on this.

 

There are only two things I really want on this thing.....

 

Ultrapitch

Proper adapter for Carts (M447)

 

If there is anyway you guys figure this out.... I'm going to do it!

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Guest rasteri

Are M447s really necessary? I figure most people are using skipless vinyl anyway, and I'm getting pretty good tracking from the stock needle just by putting a couple of 5ps on it.

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Are M447s really necessary? I figure most people are using skipless vinyl anyway, and I'm getting pretty good tracking from the stock needle just by putting a couple of 5ps on it.

lol... I have a coin on my stylus as well. Its decent.... just not optimal for stabs imo. but its probably my heavy ass hand.

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Guest Symatic

HashtagRasteriIsABadman

 

the different carts thing is valid i tihnk - because the red sylus totally mashes up your vinyl.

i suspect in 6 months there are gonna be a lot of ruined 7" scratch recs.....

 

ultrapitch would be the golden grail though......

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Guest rasteri

Figured out ultrapitch. Replace VR1 with a 2K resistor and that lowers the 33RPM speed to about 20RPM.

 

Bigger resistor values will make it even slower if you want.

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Awesome Rasteri! I did a VCA fader mod for friend in the PT. I would have had great help if you reversed it in april :)

I took the phono signal (after RIIA) and hijacked the line in and made a new preamp more or less. Used a VCA because I was suposed to have a Mini-Innofader. But in the end didn't have any at the moment so ended up with a old vestax 05 fader. Used a ADC on micro from the fader to control the cutin and just outputted 1 or 0 to the VCA. It worked just fine. It could have been done so much better but it worked. Fun project and got to try the PCB machine at work.
Im making one for my self in the future and Im gonna study your schematic to make a better circuit. Thanks man!


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Guest rasteri

That's sick! Does it work good without popping noises etc? VCA cut circuits are hard to get right without pops and clicks.

 

I'm prob gonna use a vestax fader too (I have like 15 of them lying around, mostly thanks to rockwell/dubbadutch), but I'm hoping I can get away with using an analog switch IC (like a 4066) triggered by an opamp comparator to cut the signal. Perhaps with a D-type flipflop to delay the cut until the next zero crossing.

 

Although I reckon if you used an innofader pro you wouldn't need any extra circuitry, just wire it up like this : http://www.innofader.com/installations.php?id=5&pid=2- and set the cut to sharp.

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You can hear a slight pop if you have nothing on. But nothing that is bothering when cutting.
I did try different op amp solutions as input to the VCA.

 

Here is one before I used a microcontroller.
the graph is over the fader movement from one side to the next
http://i1292.photobucket.com/albums/b576/Backtrack82/ops_zpsllmxvkql.png


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Guest rasteri

Amazing.

 

I was just going to use a comparator (or maybe schmitt trigger) to set a threshold close to the edge of the fader and use that as the input for the analog switch. Hopefully it works.

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Guest rasteri

Tested the 4013/4066 cut circuitry with a Vestax PCV fader, it works like a charm. Razor sharp with no pops/clicks and cuts on both sides of the fader (U-shaped curve).

 

Also got AUX IN working. It just involves putting 1K resistors after C8/C18 and the AUX signal, then connecting them together. I'll post a guide when I get a chance.

 

Now to figure out the best place to attach the fader...

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Guest rasteri

In the spirit of open source, here's the schematic for the fader and AUX IN circuit I'm using :

 

 

Unfortunately this won't work with an Innofader mini or PNP without disabling the 2-sided-cut functionality :(

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You guys are on fire with this...

Do any of you have experience using a Photomos? I was looking for a way to keep the parts count to as minimal as posible and they seem promising...

I just ordered a few but if any of you have an old pc soundcard of fax card they usually have a photmos chip in there somewhere...It be ideal if we could add a few parts, add power, audio input and connect fader...As usual the Clicks/Popping is the issue...

 

These Raiden/Frisk Faders are coo to keep the momentum going for Scratching but they bring it back to the old days of not having high end faders in mixers since they are entry level alpha/nobel faders imo...

 

Focus Fader V1.0 was just a IR Transmitter/Receiver since the 05 already had the VCA Circuitry everything fell into place and the timing was right...This could be the same thing with these Portable Cut Machines, a Photmos plus battery, modified Vestax or other fader Mechanism with IR Pair and done...

 

Adding a Variable Potetiometer would be cool for the Ultra Pitch Adjustment...This gives room to make some Ultra Pitched 7" Records...

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Guest Symatic

 

Adding a Variable Potetiometer would be cool for the Ultra Pitch Adjustment...This gives room to make some Ultra Pitched 7" Records...

 

hmmmmm, funny you should say that.....

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Guest rasteri

Yeah I did consider using a photoMOS before I settled on the analog switch. There are a lot of advantages to the photoMOS - total isolation between the control circuit and the audio, the ability to pass an AC signal so you don't need to use a negative voltage rail or bias the signal - but as you say it'll click and pop since there's no real way to do zero-crossing detection.

 

 

 


hmmmmm, funny you should say that.....

 

You filthy little tease

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Guest Symatic

i didn't invent sheeit, the scratch science 7" is ultrapitch..... :)

 

but ultrapitch on a 7" deck would be effin sweeeeeet

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Guest rasteri

Yeah like I said for now a crude ultrapitch can be got by replacing VR1 with a 2K resistor and that gives you about 20RPM. I'll try and figure out a better/more flexible way of doing ultrapitch.

 

I wonder if it would just be worth making a whole new mainboard that had all the features we need - decent phono preamp (the stock one sucks), decent speed/torque control (the stock one sucks), decent speaker amp (the stock one sucks), decent EQ (the stock one sucks), fader cut circuit (the stock one doesn't even exist).

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http://scratchdj.de/include.php?path=forumsthread&threadid=917

 

German mod with new speaker and a exler fader

 

thats fucking ill....

 

 

Now I want to mod my PT01.... maybe something simple like putting in a recess/hole in the area where I would put the Raidenfader so I it sits flush with the PT's body. Oh shit... forgot about all the dam wires..... scratch that

Edited by Acts_One
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Guest Symatic

yeah on an old thread i showed how i installed a fader that was flush with the body. but a velcro'd on raiden / frisk fader is way more useful.....

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Yeah like I said for now a crude ultrapitch can be got by replacing VR1 with a 2K resistor and that gives you about 20RPM. I'll try and figure out a better/more flexible way of doing ultrapitch.

 

I wonder if it would just be worth making a whole new mainboard that had all the features we need - decent phono preamp (the stock one sucks), decent speed/torque control (the stock one sucks), decent speaker amp (the stock one sucks), decent EQ (the stock one sucks), fader cut circuit (the stock one doesn't even exist).

 

 

Is the speed selector just a switch that switches between different value Resistors and the VR1 does the additional speed adjustment?

 

If so then maybe getting rid of the 78 rpm speed and converting that to use the 16 RPM...

 

Most of these portable turntables use the same parts from the same manufacturer, there was a Ebay seller selling all the parts minus the casing awhile back, I was looking into adding the parts to re-introduce my Scratch Practice Pads with Audio, definitely good for any of you do it yourselfers to make your own design.

 

I'm waiting for things to mature some more and I would really love a CNC Router too...

 

I think if you do those upgrades you mentioned and sold the upgrade kit they would sell good and help the Scratch Arts.

 

For On the Go Cuts the Audiophile quality might be overkill but the Speed/Torque Control and Fader Circuit would be excellent...

 

I'm going to try your Circuit with the 4066 when I get a chance if you don't mind, I do have a bag of them somewhere...I was never a fan of gutting those Vestax 06 / 05 and pros to make the Scratch boxes but it does work and they look good...

 

This Fader Cut Circuit would be a good kit to make by itself, that way it would be easy for anyone to add a Fader and make their own basic Scratch box or External Fader...

 

I never released an external fader because the High End Faders were expensive and the low end ones weren't quality enough, now here we are with these Frisk and Raiden Faders using those low end $2 Alpha/Noble faders and selling...blew my mind but I do like that it's Artists within the Scratch Arts releasing these...

 

Scratch Ninjas just want to Scratch and it's the only options right now and that's why they are selling...It's not the faders it's the un-tethering but just wait another month or two when the faders start to get staticky and bleeding and you'll see the importance of these Fader Cut Circuits...There will be riots :-)

 

With a Fader Cut Circuit VCA or Analog Switch...A battery powered External Fader can be made...That's what the Photomos was for and to add Contact-less Fader to a One Direction Portable Turntable...It's all free territory so anyone one of you readers can get to work on some of this ish too...

 

 

Would you mind sharing the PCB layout? Are you the Rasteri that's my facebook friend? I have some stuff I can share with you too...

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Adding a Variable Potetiometer would be cool for the Ultra Pitch Adjustment...This gives room to make some Ultra Pitched 7" Records...

hmmmmm, funny you should say that.....

 

 

Well, I predicted it too...:-)....

 

Let me tell you a story...In one of my books I have a list of different Scratch / Breaks Records that I wanted to either try to get licensed or at least motivate the Artists into releasing them on a 7" Inch Format to kick start this ish back in the late 90's...One of those records on the list was "Super Duck Breaks"...

Licensing a Scratch Record" Who ever heard of such a thing :-)...

 

My label partner at the time called StonesThrow /Peanut Butter Wolf and asked to license Super Duck Breaks..Peanut Butter said he would talk it out with Babu to see if it was possible...The answer came back and it was a NO :-)...Next thing you know they dropped a Super Duper Duck Breaks 7" inch teaser and Stones Throw has been dropping 7" inch records ever since :-) Check the time line on their releases...

 

Let me tell you another story, at NAMM I was giving away "Precision Incisions" my first 7 inch Scratch Record and Serato loved the idea...Next thing you know, the next NAMM Serato 7" Inch Limited Records being given out at the show...I hear it's a collectors item now...:-)

 

So in my note book there is a list of Break Records I wanted to license for 7 Inch Releases and it's pretty interesting...

 

The idea was to condense them by using the most recognizable Beats and Sentences, end result would be 2 things....1. You have a Fresh 7 Inch Record and 2. The Scratch Training Part....You could go from 7 Inch to 12 inch record which already existed...Here you get into muscle memory ish...

 

It would be coo if some of you went back check some of my sentences and sounds...All the Ultra Pitching is there and Reverse Sounds and it's all in my notes too...for the time most of it was too experimental and overlooked...and this is before turntables had a 50% pitch range...and come to think of it.At the time of my first 7 Inch,There were No Vestax or Numark Portable Turntables...check the timelines..

 

Anyhow...I was going to message you because my game plan is to release "Precision Incisions" 2.5 or 2.6 :-) but you kinda beat me to the punch with your center label and alignment waveforms...

I was going to do that, with some artwork or markings but on the underside of the Record itself...

Part of the game plan is to press a Clear 7 Inch Vinyl to be able to do some Custom Artwork...

There are more features, since I gotta make it extra special, it will be my first release since 2001 :-)

The point is that If you're dropping a 7 Inch record soon, I'd like to convince you to press some clear Vinyl so we can Frankenstein that sucker...I'm down to share some of the other secrets for the cause...

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