MOTM 830 Mixer
- Patrick Joericke
Projecttitel: MOTM 830 Mixer
STATUS finished
Startdate: 25.11.2013
Duedate: 15.12.2013
Manufacture link: http://www.synthtech.com/motm830.html
further links:http://www.dragonflyalley.com/constructionMOTM830.htm
About the module ( copy from synthtech)
The MOTM-830 is a dual mode (audio and/or control voltage) mixer. Using a clever switching scheme, the mixer can configure itself into either 6:1 or dual 3:1 mixers. The mixer is "split" when a patchcord is inserted into the OUT 2 jack.
The MOTM-830 is unique in the modular world: it is optimized for both audio signal quality and DC stability. Other mixers are generic, TL072-type mixers which are OK for audio but suffer from input offset voltage drift over temperature. The MOTM-830 uses special circuitry to provide superior audio specs (less than 0.005% THD, greater than 90dB SNR) while having superior DC specs (less than 1uV/C drift). Other features include:
Shielded cables on ALL signals
DC Bias generator: module can act as DC source!
Mixer #1 (IN1 - 3) uses linear pots, while Mixer #2 (IN4 - 6) uses audio taper pots
All pots are sealed, conductive plastic for long life and low noise
Easy to build, the MOTM-830 is a valuable addition to your MOTM system.
Userguide - Buildingguide
Modifications
http://www.tellun.com/motm/mods/motm830/motm830.html
Increase Gain
Changed some resistors to get unity gain from any input to any output.
Changed R8 and R17 from 44.2K to 100K (1%).
Changed R18 from 100K to 49.9K (1%).
Gallery |
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BOM:
RARE Parts:
the Op285 was ordered from littlediode
pots from bridechamber and mouser
PCB, Panel, Bracket, pots from Bridechamber
Capacitors |
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Radial Electrolytic - tol:+/- 20% |
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10μF,50V (this has poles) | 2 | Mouser | Xicon | 140-XRL50V10-RC | 1 | 1 | $0,06 | 2 | $0,12 |
Axial Ceramic Caps |
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.000022uF (= .022nF = 22pF) | 1 | Mouser | Xicon | 147-75-220-RC | 1 | 1 | $0,27 | 1 | $0,27 |
.1uF (= 100nF = 100,000pF) | 7 | Mouser | Xicon | 147-72-104-RC | 1 | 1 | $0,16 | 7 | $1,12 |
Caps Subtotal |
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| $1,51 |
Project Subtotal |
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| $1,51 |
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Resistors - 1/4 W - 5% (unless resistors are specified as otherwise, assume they're 5% - Paul lists them as 5% - extra clear!) note: there is a price breakpoint on the 5% Rs that makes it super-cheap to buy 10 of them. I always do and put the extras away for when we need them. | |||||||||
1K ohm (2K2) | 2 | Mouser | Xicon | 291-1K-RC | 1 | 1 | $0,10 | 1 | $0,10 |
10 K ohm | 3 | Mouser | Xicon | 291-10K-RC | 1 | 1 | $0,10 | 4 | $0,40 |
44.2 K ohm (44K2) 1% | 2 | Mouser | Xicon | 271-44.2K-RC | 1 | 1 | $0,13 | 1 | $0,13 |
49.9 K ohm (49K9) 1% | 2 | Mouser | Xicon | 271-49.9K-RC | 1 | 1 | $0,13 | 1 | $0,13 |
51K ohm | 1 | Mouser | Xicon | 291-51K-RC | 1 | 1 | $0,10 | 1 | $0,10 |
100 K ohm 1% | 13 | Mouser | Xicon | 271-100K-RC | 1 | 1 | $0,13 | 3 | $0,39 |
150 K ohm 1% | 1 | Mouser | Xicon | 271-150K-RC | 1 | 1 | $0,13 | 3 | $0,39 |
Resistor Subtotal |
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| $1,64 |
Project Subtotal |
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| $3,15 |
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Semiconductors |
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TL072 dual op amp | 1 | Mouser | STMicroelectronics | 595-TL072ACN | 1 | 1 | $0,95 | 1 | $0,95 |
OP285GP | 2 | Synth Tech |
| these are very hard to find | 1 | 1 | $8,00 | 1 | $8,00 |
you may have to sustitute a OP275 |
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IC Subtotal |
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| $8,95 |
Project Subtotal |
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| $12,10 |
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Misc |
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Axial Ferrite Beads | 2 | Mouser | Fair-Rite | 623-2743002112 | 1 | 1 | $0,12 | 3 | $0,36 |
MTA .156" Connectors FRCTN LK HDR STR 4P Square post, tin | 1 | Mouser | Tyco | 571-6404454 | 1 | 1 | $0,30 | 1 | $0,30 |
Toggle Switches SPDT on-none-on | 1 | Mouser | NKK | 633-M201202-RO | 1 | 1 | $4,50 | 1 | $4,50 |
Misc Subtotal |
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| $0,66 |
Project Subtotal |
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| $12,76 |
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Pots / Trimmers |
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Set of 100K log taper Spectrol 148 pot - this has 4 pots - these pots are very diffcult to find | 1 | Synth Tech |
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| 1 | 1 | $30,00 | 1 | $30,00 |
100K conductive plastic Spectrol 148 log pot | 3 | Mouser | Vishay/Spectrol | very very hard to find | 1 | 1 |
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Set of 100K cermet Spectrol 149 pot - this has 2 pots and ends up being much less expensive than getting them from Mouser | 1 | Synth Tech |
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| 1 | 1 | $15,00 | 1 | $15,00 |
100K cermet Spectrol 149 pot | 1 | Mouser | Vishay/Spectrol | 594-149-7104 | 1 | 1 | $12,97 | do the math! If you're doing another module, it pays to buy the set from Paul | |
Bourns 100K panel mount 95A pots | 3 | Mouser | Bourns | 652-95A1A-B28-A20 use: 91A1A-B28-A20L | 1 | 1 | $8,08 | 3 | $24,24 |
Pots Subtotal |
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| $69,24 |
Project Subtotal |
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| $82,00 |
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Jacks |
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2 Conductor Closed Tip 1/4" jack (112A type) | 7 | Mouser | Switchcraft | 1 | 1 | $1,89 | 7 | $13,23 | |
Closed tip Closed ring jack (114B type) | 1 | Mouser | Switchcraft | 1 | 1 | $3,35 | 1 | $3,35 | |
lock washer | 8 | Mouser | Vishay/Spectrol | 594-512-0008 | 1 | 1 | $0,13 | 8 | $1,00 |
Jacks Subtotal |
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| $17,58 |
Project Subtotal |
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| $99,58 |
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Wire |
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Power Cable - 20" | 1 | Synth Tech |
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| 1 | 1 | $7,00 | 1 | $7,00 |
Wire Assortment | 1 | Synth Tech |
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| 1 | 1 | $8,00 | 1 | $8,00 |
Coax assortment | 1 | Synth Tech |
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| 1 | 1 | $9,00 | 1 | $9,00 |
OR you could buy a bunch of wire and do it yourself. |
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Belden Hook-Up Wire - 22AWG, box of five 100foot spools, different colors |
| Mouser | Belden CDT | 566-9531 | 1 | 1 | $134,68 |
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Belden Co-Axial Cable 100 foot spool - RG174/U 26AWG BLACK |
| Mouser | Belden CDT | 566-8216-100 | 1 | 1 | $51,70 |
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Wire Subtotal |
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| $24,00 |
Project Subtotal |
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| $123,58 |
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Hardware |
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Large BR-1 mounting bracket | 1 | Synth Tech |
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| 1 | 1 | $8,00 | 1 | $8,00 |
#6-32 x 1/2 screws | 4 | Mouser | Keystone | 534-9409 | 1 | 1 | $0,08 | 4 | $0,32 |
1/4" al spacers | 4 | Mouser | Keystone | 534-398 | 1 | 1 | $0,14 | 4 | $0,56 |
#6 KEPS nuts - these come in a bag of 100 | 6 | Pointe-Products.com |
| 10607-P | 1 | 100 | $6,70 |
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count them individaully - here' how they add up: |
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| $0,07 | 6 | $0,40 |
Tie Wraps | 9 | Mouser | 3M Electronic Specialty | 517-41932 | 1 | 1 | $0,04 | 4 | $0,16 |
8 ALCO knobs - so look, if you'r only building this module, you can buy these guys at Mouser… but otherwise think about buying them from Paul - much less expensive | 1 | Synth Tech |
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| 1 | 1 | $16,00 | 1 | $16,00 |
knob - Alcoswitch | 7 | Mouser | Tyco Electronics / Alcoswitch | 506-PKES90B1/4 | 1 | 1 | $3,33 |
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Hardware Subtotal |
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| $25,44 |
Project Subtotal |
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| $123,58 |
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PCB / Panel |
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MOTM-830 Mixer pc board | 1 | Synth Tech |
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| 1 | 1 | $39,00 | 1 | $39,00 |
MOTM-830 front panel | 1 | Synth Tech |
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| 1 | 1 | $39,00 | 1 | $39,00 |
PCB/Panel Subtotal |
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| $78,00 |
Project Subtotal |
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| $201,58 |
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Solder |
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heat-shrink 1/8" - four foot length - you need this |
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| 602-221018-4BK | 1 | 1 | $1,50 |
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how to bugfix: https://diysynth.wiki.dsl-man.de/wiki/spaces/SKM/pages/336101402/How+to+bugfix
non commercial pages, all infos are best can do without warranty, without liability.