Parts and Construction Information

FrontPanelExpress Templates

I have created templates using HPGL graphics to reduce the cost of panels from FrontPanelExpress.

1U basic panel template

2U basic panel template

This is a template for small 0.75" knobs.  I modify this design depending on the spacing of the controls.  I used this full design on my PSIM, without numeric legends on my Fixed Filter Bank, and without minor tic marks or numeric legends on my ComputerVoltageSource.

Small knob template


Module Power Consumption

Here is my spreadsheet with the power consumption of many purchased modules.  This information is either from the module specifications or was measured.

Module power consumption spreadsheet


Patch Cables

I bought many of my patch cables through the custom orders that the late Larry Hendry organized.  I have found some others that I like.  Peavey makes a set of 6 molded color cables in 1' and 3' lengths.  I have only had a couple ever fail.  Calrad makes a set of 8 colored cables in 1', 2', 3', and 6' lengths.  The connectors are gold plated and I have only had one fail although they are difficult to find.  Recently I needed longer cables and bought the Orange County Speaker 12' 6 pack of colored patch cables.  They are quite nice although the strain relief is simply the connector crimp.  I bought multiple colors of 1/2" heat shrink and covered the plug and cable with 4" at each end.

1/4" Molded Patch Cables Supplier Part Number
Peavey set of 6 molded color cables - 1 foot Peavey 00054550
Peavey set of 6 molded color cables - 3 foot Peavey 00054570
Calrad  set of 8  molded color cables -1 foot* Arcade Electronics 55-720G-1
Calrad  set of 8  molded color cables -2 foot* Arcade Electronics 55-720G-2
Calrad  set of 8  molded color cables -3 foot* Arcade Electronics 55-720G-3
Calrad  set of 8 molded color cables -6 foot* Arcade Electronics 55-720G-6
  * The Calrad cables are now black with colored plugs so they are not as useful
Orange County Speakers set of 6 color cables - 2 foot GLS Audio 37-308
Orange County Speakers set of 6 color cables - 3 foot GLS Audio 37-310
Orange County Speakers set of 6 color cables - 6 foot GLS Audio 37-312
Orange County Speakers set of 6 color cables - 12 foot GLS Audio 37-314


Hook- Up Wire

I use NTE 24 AWG stranded wire for all front panel controls and jacks.  It comes in 25' and 100' spools and 10 colors.  I used to buy this from Mouser but they no longer carry NTE products but you can buy it from NTE.

NTE Hook-Up Wire Supplier Part Number
24 AWG stranded hook-up wire NTE Parts Direct WH24-AA-BB
  where AA designates color; 00 = black, 01 = brown, ... 09 = white (follows the resistor color code)
  where BB designates length; 25 = 25 feet, 100 = 100 feet
so WH24-02-25 is a 25 foot spool of red wire, and WH24-00-100 is a 100 foot spool of black wire

Momentary and Toggle Switches

I do not use momentary pushbuttons as I find them awkward to use in the top and bottom cabinets.  I instead use momentary flatted-handle toggle switches to match the look and feel with all the other switches.

NKK Flat Handle Switches Supplier Part Number
SPDT On-None-On Mouser 633-M201202
SPDT On-Off-On e.g. center off Mouser 633-M201302
SPDT (On)-None-On  e.g. momentary Mouser 633-M201502
SPDT (On)-Off-On e.g. center off momentary Mouser 633-M201902
DPDT On-None-On Mouser 633-M202202
DPDT On-Off-On e.g. center off Mouser 633-M202302
DPDT (On)-None-On  e.g. momentary Mouser 633-M202502
DPDT (On)-Off-On e.g. center off momentary Mouser 633-M2029ES1W01

These flat handle Mountain switches have no life specifications and the threaded bushing is a bit shorter than the NKK.

Mountain Flat Handle Switches Supplier Part Number
SPDT On-On Mouser 108-1MS1T6B1M1QE-EVX
SPDT On-(On)  e.g. momentary Mouser 108-1MS2T6B1M1QE-EVX
SPDT On-Off-On  e.g. center off Mouser 108-1MS3T6B1M1QE-EVX
DPDT On-On Mouser 108-1MD1T6B1M1QE-EVX
DPDT On-(On) e.g. momentary Mouser 108-1MD2T6B1M1QE-EVX
DPDT On-Off-On e.g. center off Mouser 108-1MD3T6B1M1QE-EVX
DPDT (On)-Off-(On) e.g. center off both momentary Mouser 108-1MD4T6B1M1QE-EVX

These colored push button switches with metal bushings seem to be the ones used by several synth vendors.

E-Switch RP Series with metal bushing Supplier Part Number
SPST-NO Red Mouser 612-RP3502MA-RED
SPST-NO Green Mouser 612-RP3502MA-GRN
SPST-NO Yellow Mouser 612-RP3502MA-YEL
SPST-NO Black Mouser 612-RP3502MA-BLK

I do like these C&K momentary push buttons with caps.  Only the black cap is available at Mouser.

E-Switch RP Series with metal bushing Supplier Part Number
SPDT On-(On) Mouser 611-U811SYZGE
Black cap Mouser 611-752705000

I like the Lorlin rotary switch because of the variable positions and 30 indexing.  The bushing however isn't long enough to go through a 3mm panel and a bracket.

Rotary Switch Supplier Part Number
Lorlin 1 pole x up to 12 positions, 30 indexing Mouser 105-13571



Lumix LEDs

I purchase a number of the Lumex LEDs and change them on most of my modules to match this color scheme.
    Green as general indicators and status such as the LFO rate on the MOTM-390
    Red for warning such as clipping on the Blacet TimeMachine
    Bi-color for indicating polarity such as on the MOTM-320
    Blue for MIDI status such as on my DJB-011 Ribbon Interface

The green, yellow, and red Lumix LEDs are available from Digikey.  The bi-color Lumix LEDs are available from Mouser.

Lumix Panel Mount LED Supplier Part Number















Red/Green bi-color Mouser 696-SSI-LXH387HGW

I make my own MOTM-style blue LEDs by grinding the top of a LED flat and fitting it into the Lumex plastic holder.


BI Technologies P260P Series Potentiometers

I originally used the Vishay/Spectrol 148/ 149 series potentiometers.  When the cost on these skyrocketed I switched to the 248 series.  As the cost of these skyrocketed I switched to BI Technologies P260P series potentiometers.  I couldn't find them in distribution in the USA so I purchased a minimum order quantity of 240 direct through Arrow Advantage.

Here's a visual comparison of the three different types of potentiometers.  The shaft on the P260P is a bit shorter so the knob is closer to the panel.  This is an advantage when using the smaller 3/4" knobs which have a shorter depth.  There is sufficient shaft length to space the knob out to match the 148/248 as shown on the far right.  The P260P has a good solid quality feel but is less stiff than the 148/248 controls.

1/4" Shaft BI Technologies Supplier Part Number
100K linear; min order qty 240; 8+ week leadtime BI Technologies P260P-D1BS3CB100K
100K linear Digikey 987-1331-ND  New
10K log Digikey 987-1332-ND  New
100K log Digikey 987-1330-ND  New
1M log and dual ganged log Oakley Sound email
10K, 50K and 100K linear and log Oakley Sound email
1/4" Shaft Piher (low cost all-plastic construction)
100K solder lug, 7mm hole, cut shaft to fit Mouser 531-PC16SC-100K

I use chiclet PCBs from John Loffink to wire my panel mount potentiometers.  They're great.


I used to use the Tyco PKES90B1/4 for my standard knobs but they are now very expensive.  Bridechamber sold a very close Alco knoff-off knob that I bought a quantity of.  Mammoth Electronics sells inexpensive knobs that are very close as the aluminum center has a circular ridge texture but looks the same from a distance.  Radio Shack makes a considerably less expensive molded heptagon knob.  It is slightly larger in diameter, has slightly wider flutes, and uses a slotted instead of allen setscrew.  They also make this same knob in a 3/4"" size that I use for all my smaller 1/4" shaft knobs.

Knobs Supplier Part Number
Standard MOTM style knob Mouser 506-PKES90B1/4
Small MOTM style knob Mouser 506-PKES60B1/4
Large BOSS style black knob with silver top Mammoth Electronics 4SKLGFLBK
Small BOSS style black knob with silver top Mammoth Electronics 4SKSMFLBK
Small flatted knob (for rotary switches) Mouser 5164-1510AH
Tiny knobs Mouser 506-PKG40B1/8



I use thin plastic washers to protect the panels for mounting and the additional thickness is an issue when using 1/4" screws to mounting rails.  I bought 5/16" screws which work perfect with the washers but they only come in quantity of 1000.

Panel Screws and Washers Supplier Part Number
#8 plastic washers Mouser  561-D832B
#8-32 x 5/16 phillips black screws Aarons General Store 1701SN1296
PCB Standoffs
4-40 plastic standoffs Mouser 561-K4.25  144-13SP040
6-32 plastic standoffs Mouser 561-K6.25  144-13SP041
6-32 aluminum standoffs Mouser 534-3464
Control Hardware
3/8-32 Nickel hex control nut Mouser 534-1456
3/8 ID Switchcraft flat washer Mouser 502-S10221


Other MOTM-Style Parts

Here are a variety of miscellaneous MOTM-style parts that I use.

Ferrite Beads Supplier Part Number
Short ferrite beads Mouser 623-2743001112LF
Long ferrite beads Mouser 623-2743002112LF
22 F 35V low leakage electrolytic capacitor Mouser 647-UKL1V220KEDANA
10 F 35V low leakage electrolytic capacitor Mouser 647-UKL1V100MDDANA
0.1 F ceramic decoupling capacitor (discontinued) Mouser 147-72-104-RC

I now use these 0.1F ceramic decoupling capacitors

Mouser 581-SA105E104M
DIP Sockets
8 pin DIP Mouser 517-4808-3000-CP
14 pin DIP Mouser 517-4814-3000-CP
16 pin DIP Mouser 517-4816-3000-CP
Panel connectors
MIDI connectors (silver) Mouser 16HR655
MIDI connectors (black) Mouser 164-2522
MTA power connectors
4 pin 0.156 MTA header (PCB) Mouser 571-6404454
4 pin 0.156 MTA connector (cable) Mouser 571-3-640426-4
4 pin 0.156 MTA dust cap  Mouser 571-6405514

Note: these next two parts are for daisy-chain feed-through power cables

4 pin 0.156 MTA thru connector (cable) Mouser 571-3-640599-4
4 pin 0.156 MTA thru dust cap Mouser 571-6406434
MTA signal connectors

Note: the last digit specifies the number of pins

2 pin 0.1 MTA header Mouser 571-6404542
2 pin 0.1 MTA connector Mouser 571-3-640441-2
2 pin 0.1 MTA dust cap Mouser 571-6405502
FCI signal connectors (e.g. Berg) Mouser
Note: use where limited space for MTA connectors
0.1" female receptacle (connectors) Mouser 649-48235-000LF
2 pin connector housing Mouser 649-65039-035LF
3 pin connector housing Mouser 649-65039-034LF


Tempco Resistors

Digikey used to sell the Panalsonic 3300PPM 5% 0805 SMD tempco resistors for about $0.55 each.  They had a variety of values from 27R to 1K8.  I used these to make my own through-hole tempco resistors by soldering them to leads and encapsulating them in epoxy. Unfortunately the Panasonic parts have gone obsolete. The closest available is the 3600PPM 5% KOA Speer. While not ideal it is available at Mouser.

Tempco SMT Resistors Supplier Part Number
1K 3600PPM 5% 0805 resistor Mouser 660-LT732ATTD102J360
1K 3300PPM 5% 0805 resistor Digikey P1.0KCDCT-ND

This is a flatted style for mounting between differential pairs.

I also made a round axial style for mounting on a PCB.  

I also used epoxy to directly mount the SMT resistors on the top of an IC. 



CMOS Logic

Some synthesizer modules use CMOS logic parts.  There are multiple families of CMOS logic parts but they fall into two main groups: 15 volt compatible and 5 volt compatible.  Vendors sometimes use unique nomenclature for their CMOS families.  You need to check the data sheet to verify the operating voltage range.

Go to my Modular Synth Tips page for a more complete description and examples.



PCB Brackets

I created a separate page for PCB brackets and moved the information here.