Summary of Contents for Synthesis Technology MOTM-850
- Page 1 MOTM-850 Pedal Interface Assembly Instructions & Owner’s Manual Synthesis Technology 6625 Quail Ridge Dr. Fort Worth, TX 76180 (817) 281-7776 www.synthtech.com Oct. 25, 2001...
- Page 2 MOTM-850 PARTS LIST Please carefully check that all parts are in your kit. If you have a suspected shortage, please call or email. If you get free extra stuff, keep it for next time. Capacitor bag, containing the following 10 parts:...
-
Page 3: Front Panel
4ea 1/4 inch aluminum spacers 6ea #6 KEPS nuts (2 for attaching bracket to front panel, 4 for pc board) 2ea small heat-shrink tubing 4ea small tie-wraps Organic Solder No-clean Solder PC Board, MOTM-850 SYNTHESIS TECHNOLOGY PAGE 3 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM... -
Page 4: General Information
GENERAL INFORMATION Thank you for purchasing the MOTM-850 Pedal Interface. If you have any issues concerning the building or use of the kit, please contact us at (817) 281-7776 or by email: syntht@yahoo.com This kit should take the average builder between 2 to 3 hours. The kit contains many different resistors and special parts. - Page 5 You will start by soldering in ALL of the resistors. Find the RESISTOR bag. Find the MOTM-850 blank pc board. There is a copy (larger than actual size) of the silkscreen which shows where the parts go at the end of this document. It will be useful if you locate the part on the print first, put the part in the board, then ‘check off’...
- Page 6 Verify all the resistors are flat on the board. Correct if needed. Check solder joints. Wash the board in warm water, gently scrubbing both sides. DO NOT USE ANY SOAP! Just water! SYNTHESIS TECHNOLOGY PAGE 6 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 7 The IC will have a ‘notch’ or indentation in the top by Pin #1. Locate the LM311 comparator. Solder into U1. Locate the 2N3904 transistor. DO NOT GET IT CONFUSED WITH THE 2 VOLTAGE REGULATORS!! Solder into Q1. SYNTHESIS TECHNOLOGY PAGE 7 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 8 (lower pad) and a smaller pad (top hole). The braided wire is soldered into the larger hole. The smaller, inner conductor goes in the top hole. BE SURE THE SHORTER BRAIDED END GOES INTO THE PC BOARD. SYNTHESIS TECHNOLOGY PAGE 8 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 9 The #6 KEPS nut attaches on the bottom of the bracket. Note the bracket has 2 long mounting flanges with a hole SYNTHESIS TECHNOLOGY PAGE 9 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 10 Red wire in D1. The other lead is the Cathode, and is soldered to the Black wire. Insert the LED through the panel, with the longer Anode lead towards the top panel edge (looking from the rear, this is towards the “left”). SYNTHESIS TECHNOLOGY PAGE 10 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 11 Gently rub with your fingernail across it and it will peel off. Use the extra wire tie to “bundle” the coax wires ************************************************************************************ CONGRATULATIONS! YOU HAVE FINISHED BUILDING THE MOTM-850! ************************************************************************************ All that’s left to do is test it! But before we do, please read the following Theory of Operation.
-
Page 12: Theory Of Operation
The MOTM-851 consists of 2 separate circuits: the voltage drive to the pedal and the scaling/offset, and the Gate extractor. The MOTM-850 can interface to 2 basic types of pedals: resistive and voltage-out. Resistive pedals use a 3-conductor (stereo) plug, because 3 signals are needed: ground, voltage IN and voltage OUT. - Page 13 Vout = 15 * (Rdown)/(Rdown+16500 +10000) Where 16500 is the value of R18 and 10000 is the value of the pedal pot. Rdown is the fractional resistance of the 10K pot as you press down. SYNTHESIS TECHNOLOGY PAGE 13 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 14 AND to the RANGE pot VR1. This adds it’s own ‘series resistance’ to the wiper of VR1. Since the voltage output from the pedal is not buffered, and has a large SYNTHESIS TECHNOLOGY PAGE 14 MOTM-850 ASSEMBLY 10/25/01 WWW.SYNTHTECH.COM...
- Page 15 5K - 15K OHMS 15K – 75K OHMS 75K – 150K OHMS OPEN/PARKED It doesn’t matter if the Tip is the wiper of the pedal pot or not, the MOTM-850 circuitry will compensate. SYNTHESIS TECHNOLOGY PAGE 15 MOTM-850 ASSEMBLY 10/25/01...
- Page 16 RANGE and OFFSET. IMPORTANT NOTE! The expected DC output of the MOTM-850 is based on setting the jumper JP3 to generate a 0 to +5V voltage into R24 as the pedal is pressed from up to down. This may not be the case if the pedal pot is not 10K, 50K or 100K, or if your CV out pedal has a different range (say, 0 to +6V out).
- Page 17 MIX is a simple attenuator, so there is no gain associated with this signal. An example is to insert the CV out of a keyboard, and the MOTM-850 can add ‘pedal portamento’ effects or even theremin-type glides to VCOs. Remember, this is just a DC offset to the MIX signal, it’s not a volume control function (VCA).
-
Page 18: Troubleshooting
STRIG is Moog-specific! When GATE is INACTIVE, the GATE output is +12V. When GATE is ACTIVE, the GATE output is 0V. If you are using the MOTM-850 to control a Moog modular, Rogue, Source, MiniMoog or other Moog synth, be sure JP2 is set on STRIG. -
Page 19: Specifications
SPECIFICATIONS MOTM-850 Pedal Interface Pedal resistances 10K, 50K, 100K nominal (jumper selectable) DC output range -7.5V to +7.5V nominal GATE voltage +12V max, 0V min. MIX input range -7V to +7V nominal CONTROLS RANGE Sets the over pedal response range...
Need help?
Do you have a question about the MOTM-850 and is the answer not in the manual?
Questions and answers