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Ultrapitch (simplified) Mod for Numark PT01

 

This is a Simplified Ultrapitch Modification for the Numark PT01

Parts needed:
Resistor between 1k ohm and 2k ohm

notes:
-when the platter speed switch is set the 33rpm, the platter will spin at ~22rpm
-when the platter speed is set to 45rpm, the platter will spin at 33rpm
-this mod can only be done on newer (example 2014) PT01 turntables
-older models, such as circa 2006, have a different motor control circuit and require a different mod
-the new models have the orange potentiometer shown below, where the older models have a blue potentiometer
-download the “RPM – the turntable speed accuracy checker” iPhone app to test platter speed
-this mod came from a forum comment by Rasteri, which said “Replace VR1 with a 2K resistor and that lowers the 33RPM speed to about 20RPM”
-buy Dj Focus’ ultrapitch mod for full control, and to support the skratch community
-works with ultrapitch 7” records, such as skiratcha breaks from DJ A1

-Remove and Replace VR1
1. Unsolder the potentiometer in VR1

2a. Solder a resistor across the 2 pins shown in pic_1_replace_VR1. This picture shows a 2.2k ohm resistor in place of VR1. This results in a platter speed of ~20rpm, when the platter speed switch is set to 33rpm, and ~32rpm when set to 45rpm (varies between turntables).

pic_1_replace_VR
pic_1_replace_VR

-Alternate VR1 values
2b. It was found through test that a 960 ohm resistance across VR1 results in a clean 33rpm, when the platter speed switch was set to 45rpm. This resistance results in 22rpm, when the platter speed switch is at 33rpm. A 820 ohm and 150 ohm resistor were connected in series to achieve ~970 ohms. The resulting speed vs. resistance value depends a lot on the friction between the spindle and the platter. A value between 1k and 2k ohm should work great. see pic_2_replace_VR1_series

pic_2_replace_VR1_series
pic_2_replace_VR1_series

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3D Printed Tonearm Clip Install for Numark PT01

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Adds 3D Printed Tonearm Clip to the Numark PT01

Parts needed:
3D printed tonearm clip

notes:
-only for use with 3D printed tonearms

-Install 3D Printed Tonearm Clip
1. Remove white backing paper from tonearm clip
2. Stick 3D printed tonearm clip onto existing PT01 tonearm clip. Make sure the orientation of the 3D printed clip base matches the existing PT01 tonearm clip, before sticking (one side is round, one side is square)

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Faceplate Removal for Numark PT01

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How to Remove the Numark PT01’s Metal Faceplate

Parts needed:
plastic pick, such as a guitar pick
plastic putty knife (any plastic putty knife from your local hardware store will work. Preferably, not more than a couple inches wide)

notes:
-always use plastic tools for the procedure to avoid faceplate and plastic housing does not get scratched
-the metal faceplate is applied to the plastic turntable housing with heavy double sided tape
-the adhesive sticks to the faceplate better than the housing, so there is little damage to the housing, when removed
-the plastic housing below the faceplate is black
-there is no need to paint or replace the faceplate, if a black faceplate is desired
-removing the faceplate exposes a spring and a hole for the spring, which is a good place to add a switch or knob
-the spring is attached to the housing with a single screw (no solder). Remove the screw to remove the spring.

-Remove the tonearm
1. See tonearm removal guide

-Start at the 45 Adapter
2. Starting at the 45 adapter hole, use a plastic pick and gently pry up the faceplate. The 45 adapter hole is a good place to start, because it doesn’t have a beveled edge to protect the faceplate.
3. Lift the corner of the faceplate from the 45 adapter hole enough to fit a second plastic pick or putty knife along the outer edge of the faceplate (see pic_1_45_adapter)

pic_1_45_adapter
pic_1_45_adapter

-Pry Outer Edge
4. Work around the outer edge of the faceplate. Be careful not to pry too far up, or the faceplate will bend (see pic_2_outer_edge)

pic_2_outer_edge
pic_2_outer_edge

-Pry Inner Faceplate
5. Use a plastic putty knife to pry the deeper sections of the faceplate, such as between the platter and the EQ controls (see pic_3_putty_knife)

pic_3_putty_knife
pic_3_putty_knife

-Lift Faceplate Off
5. Use your hands to lift/pry the faceplate the rest of the way off. Be careful not to cut your hands on the edge of the metal faceplate.

-Mount a Start/Stop switch in the Spring Hole (optional)
6. See start/stop switch guide

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Start/Stop Switch Install for Numark PT01

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Adds start/stop switch to the Numark PT01

Parts needed:
SPST (Push 0n – Push off) Switch

notes:
-any push on – push off or latching switch with a greater than ~300mA rating will work for this
-the switch listed above was used for this install
-if you remove the PT01 faceplate, this switch fits in the existing spring hole without drilling (remove the spring, which is attached internally with one screw)

-Remove the Existing Switch
1. Unsolder and remove the existing start/stop switch (see pic_1_remove_switch)

pic_1_remove_switch
pic_1_remove_switch

-Mount the New Switch
2. Mount the new switch in a preferred location (see pic_2_mounted switch). For this guide, the switch is mounted in the existing spring hole with the faceplate removed (see faceplate removal guide for instructions on removing the faceplate).

pic_2_mounted switch

-Solder Wires
3. Solder 2 wires to the existing switch PCB (see pic_3_add_wires)

pic_3_add_wires
pic_3_add_wires

4. Solder these wires to the new switch (see pic_4_connect_switch)

pic_4_connect_switch

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Platter Bar Install and Comparison

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How to Install Platter Bars for the Numark PT01

Parts needed:
platter bars
needle nose pliers

Optional Parts:
silicone grease

notes:
-there are at least 2 different platter heights for the PT01
-the older model, circa 2006, has a low platter height
-the newer model, circa 2014, has a high platter height
-one clear difference between models is that the belt holder attached to the motor is plastic on the 2006 model, and metal on the 2014 model

-Remove Platter
1. Use a pair of pliers to push off the spindle clip (see pic_1_remove_spindle_clip)

pic_1_remove_spindle_clip
pic_1_remove_spindle_clip

2. Push on one edge of the platter to raise the opposite edge

3. Lift the platter using the raised edge, and remove platter (see pic_2_remove platter)

pic_1_remove_spindle_clip
pic_1_remove_spindle_clip

-Install Platter bar
4. Remove white adhesive backing from platter bar (see pic_3_platter_bar_backing)

pic_3_platter_bar_backing
pic_3_platter_bar_backing

5. Place the wide edge of the platter bar flush against the turntable wall (see pic_4_place_platter_bar)

pic_4_place_platter_bar
pic_4_place_platter_bar

6. Cut or break off the 2 nubs on the bottom side of the platter (they have no functionality). This will stop the nubs from potentially hitting the platter bars. See pic_6_cut_nub

pic_6_cut_nub
pic_6_cut_nub

7. Reinstall the platter and platter clip.
a. wrap the turntable belt around the inner edge of the platter first
b. place the platter on the spindle, while pulling on the belt with one finger to keep tension
c. wrap the belt, which is being held with one finger, around the motor spindle
d. reinstall platter clip using pliers

8. Turn on the motor and let the platter spin. If the platter rubs on the the platter bars, push down hard on the platter and move it back and forth in a baby scratch motion. This will grind down the platter bar’s plastic housing. Turn on the motor again to see if the platter still rubs on the platter bars. Repeat until the platter stops rubbing on the platter bar during playback. See “How to Grind Down Platter Bars Video”, below:

How to Grind Down Platter Bars Video:

Platter Bar Comparison Video:

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3D Printed Tonearm Counterweight Adjustment

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How to Adjust the Counterweight for a 3D Printed Tonearm

Parts needed:
3D printed tonearm

notes:
-the scale used for test is a 5g (maximum) stylus scale, with 0.01g precision
-the sure m44-7 needle expects 3-5g of weight for optimal tracking and audio performance

-Check Weight of Needle
1. Check the weight of the needle using a stylus scale (first measured weight is at 3.48g, see video)

-Adjust Counterweight
2a. Increase the counterweight by removing tension from the counterweight rubber band. In this case, the rubber band moves from the inside position to the outside position to reduce tension (second weight is at 4.26g, see video).

2b. Tension can also be adjusted by using a rubber band of a different thickness, and also by stretching or releasing tension in the section of the rubber band between the base of the tonearm and the back of the tonearm

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Rechargeable Battery Install

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Adds 12V rechargeable Lithium Ion battery to the Numark PT01

Parts needed:
12V rechargeable battery
DC plug (2.1mm x 5.1mm)
Picture hanging Strips (optional, or can be substituted):

notes:
-Disconnect the rechargeable battery from the PT01, when powering the PT01 from a wall supply.
-Charge the battery by disconnecting the DC plug from the battery, and charge it using it’s supplied charging wall supply.
-The battery power switch must be on, while charging the battery (explained in the battery instructions, but are in Chinese)
-Turn the battery power switch off, when not in use to save charge (not required).
-see LM7805 data sheet for more info on the PT01 regulator (actual part number is LM7809)

-Connect Wires to the PT01 Power Supply Input
For PT01 or PT01USB (see step 1b for PT01-Scratch):
1a. On the PT01 or PT01USB power supply PCB (not PT01-Scratch), solder a GND wire (black) to the center pin (pin 2) of the LM7809 regulator (see pic_1_PT01_regulator)
2a. On the PT01 or PT01USB power supply PCB, solder a power wire (red) to pin 1 of the LM7809 regulator (see pic_1_PT01_regulator)

pic1_PT01_regulator
pic1_PT01_regulator

For PT01-Scratch:
1b. On the PT01-Scratch power supply PCB, solder the GND and Power wires to the bottom side of the DC input connector (see pic_1_PT01_regulator)

pic_1b_PT01_Scratch
pic_1b_PT01_Scratch

-Connect DC Plug
3. Confirm whether the center pin of the DC plug needs to be + or – by reading the label on your rechargeable battery. The center pin is + for the battery listed above.
4. If using the battery listed above, solder the red wire to the center pin of the DC plug (see pic_2_DC_plug)

pic2_DC_plug
pic2_DC_plug

5. If using the battery listed above, solder the black wire to the outer ring of the DC plug (see pic_2_DC_plug)

-Mount Battery
6. The battery can be mounted however you like. I like the using the picture hanging strips listed above. One strip is mounted on the wall of the PT01 within the battery compartment (sticky side against wall), and one strip gets mounted on the battery (sticky side against battery). I put a set of strips on 2 sides of the battery (example: side and top). This is rock solid, and allows the battery to be removed, if necessary (see pic3_Battery_placement).

pic3_Battery_placement
pic3_Battery_placement
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Supercollider MIDI Synth for Flesh MIDI Mod

Screenshot

This post describes a MIDI controlled software synthesizer intended for use with a scratch mixer having a Flesh MIDI Mod. The synth is built entirely in the programming language Supercollider 3. Sounds, which are generated using Supercollider’s unit generators, can be controlled externally via MIDI. The software synthesizer allows for simultaneous playback of sound loops and the software synthesizer. Example sound files are given to illustrate the functions of the synth.

Details on the next page…

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Orban 111b Spring Reverb Model

orban_face

The goal of this project is to learn a bit about modeling spring reverbs. The goal of this project is not to model an entire spring reverb unit through circuit analysis, but to take a look at it’s response by testing it with audio signals. The unit under test is the Orban 111b spring reverb. Details on how the springs affect audio, and how the springs look in the Orban 111b will be discussed. The tests will be presented and results will be posted.

Details on the next page…