Random*Source SERGE DUSG User manual
RANDOM*SOURCE
RANDOMSOURCE.NET 1
Serge DUSG
SERGE Dual Universal
Slope Generator (DSG)
The Serge Dual Universal Slope Generator consists of a main pcb that already contains most of the parts in
surface-mount technology (SMT) and a component pcb serving as an interface to the front panel.
Main pcb:
Please note:
• TheRandom*Sourceversionfeaturesindependent VC control over RISE and FALL,
super-matched THAT transistor arraysandBurr-Brown op-amps.
Also:adjustableBIPOLARsymmetryandLEDbrightness.
• Orientationofthemainpcb:power header is at the bottom(whenlookingatthemoduleup-
right,e.g.inarack).
• UseantistaticprecautionwhenhandlingtheDSGpcb-don’ttouchthesmallSMDpartsandICs
withyourhands.
• Onlythesepartshavetobesolderedin:trimpots,polystyrenetimingcaps,jumpers,pinstripesto
connectthemainpcbtothecomponentpcb,MTApowerheader(seepictureabove).
• LED:Thetrimpots(“LED”/20k)(togetherwithanon-boardresistorof1k)determinethebright-
nessoftheLED.Itisessential to use low current (max 2mA) LEDs-otherwise the LED
action might affect the operation of the module(dependingonbrightnessandcolor).Use
atleast100-130mcdorultrabrightLEDs(60°)plusatrimpot of (only) 2k for (fairly) bright
LEDs (100-150mcd).Ifyouuseultra-brightLEDs,a5ktrimmermightmakesense,higherval-
uesforthetrimpotareprobablynotneeded(butworkalso).WhenusingaredLED,makesure
thetrimpotissettoatleast(another)1k(whichaddsuptoatotalof2kwiththe1kresistoron
board),whenusingblueorwhitethisislessrelevant.
RANDOM*SOURCE
RANDOMSOURCE.NET 2
Serge DUSG
Bill of Materials
Trimmers
4 100k T1, T5 (Offset)
T4, T8 (bi-polar output)
Trimpot (Bourns 3362P, Vishay T73YP104KT20 or
anything that matches the footprint) to adjust the uni-
polar output and the symmetry of the bi-polar output.
2 50k T2, T6 (1V/Oct) Trimpot (Bourns 3362P, Vishay T73YP503KT20 or
anything that matches the footprint) to adjust the
tracking of the 1V/Oct input. Single turn is sufcient.
2 2K or more T3, T7 (LED) Trimpot (Bourns 3362P or Vishay T73YP202KT20 or
anything that matches the footprint) to adjust the LED
brightness. Pick value depending on LED (see text).
Capacitors
2 10n* Timing Cap - use Styrene / Styroex.
Sets the frequency range covered in Cycle mode.
* Use a lower value (e.g. 6.8n) to increase the
maximum frequency (but also the slowest frequency).
Misc
1 MTA-156 MTA-156 power connector
1 SIL header 8pol 8-pin connector, links main pcb to component pcb
4 SIL header 10pol 10-pin connector, links main pcb to component pcb
4 Banana Jacks TRIG IN, GATE OUT (red) Emerson-Johnson
Mouser: 530-108-0902-1 (red) or Thonk
4 Banana Jacks IN, BIPOLAR (black) Emerson-Johnson
Thonk / Mouser: 530-108-0903-1 (black)
8
(+4*)
Banana Jacks CV / unipolar (blue or white)
(* for the CV Processor depen-
ding on module)
Emerson-Johnson
Thonk / Mouser: 530-108-0910-1 (blue),
530-108-0901-1 (white)
1 LED 5mm low current (max) 2mA pick color to suit LED lens
1 LED lens 5mm VCC, Mouser 593-3000R (red), 593-3000A (amber) ...
8
(+4*)
Potentionmeter
50k or 100k
linear (B50K or B100K) Alpha 9mm vertical pcb mount
available from Thonk, Tayda
RANDOM*SOURCE
RANDOMSOURCE.NET 3
Serge DUSG
Building
This is simply a suggestion - you might nd a different workow more practical:
1. MounttheBananajacks,theLEDlensandtheswitchontothefrontpanel.Ifyouusearetention
ringfortheLEDlens,attachtheringtothelens.
2. Mountthepotsontothecomponentpcb.Potsshouldsitontheprintedside-thissidefacesthe
frontpanel.Don‘tsoldertheminyet.SticktheLEDintothecomponentpcb-thelonglegmustbe
atthe+side.
3. Carefullymountcomponentpcb(withthepotsandLEDinserted)ontothefrontpanel.Firstslide
/pushtheLEDintotheLEDlens-alltheway,thismaytakeabitofforce.Youmaythenhaveto
wiggleeachpotabittogetthepotsthrough.Makesurethethreadsofthepotsgothroughcom-
pletelyandthepotssitrightatthefrontpanel.Youcanevenscrewthepotstothepaneltomake
sureofthat,butyouhavetounscrewthemagainlater(forStep5).
4. Onceeverythingisnicelyinplace,especiallytheLEDsittinginside(andnotontop)oftheLED
lens,soldertheLEDandthepotsontothecomponentpcb(whilethefrontpanelisattached).DO
NOTSOLDERTHEBANANAJACKSYET!
5. Solderthethrough-holepartsontothemainboard.For the 3“ DUSG module, connect
Jumpers 1 and 3 on each side(seepictureonpage1)-fora2“DTGmodule,adifferent
jumpersettingisrequired!
6. MainpcbandcomponentpcbaretobeconnectedthroughprecisionDIPsocketandpins.Itis
recommendedtousethepinsonthemainpcb(facingdown,solderedfromabove)andthepin
socketsonthecomponentpcb(standingup,solderedfromthefrontpanelside).Breakorcutoff
thepiecesyouneedandstickthemtogethersothatmainpcbandcomponentpcbformanice
sandwich(don‘tsolderyet).Checkthatyoudidn‘tleaveoutanypins/holesandthatthesockets
areallonthesameside(componentpcb).Solderallthepinsinwhilekeepingthesandwichto-
gether-thisavoidsanymisalignments.
7. Carefullyseparatethesandwich-ifyouusedprecisionsockets,thismaynottotooeasy-they
sticktogethernicely(givingagoodconnection).
8. Mountthecomponentpcbontothefrontpanelagainandscrewonthepotsfromthefrontside.
RANDOM*SOURCE
RANDOMSOURCE.NET 4
Serge DUSG
9. Makesureeverythingisinplace.
10. Solderthebananajacksin.Youcaneithersolderthemdirectlytothesurroundingvias(ring
round)or-whichmakesremovingeasiershouldyoueverneedtodothat-byinsertingastiff
(bare)wireintothelittlehole(via)andsolderthatwiretothetopofthebananajack:
11. Attachanyscrews/spacersifdesiredandmountthemainpcbontothecomponentpcb.
12. Connectapowercordsupplying+12V,GND,GND,-12VtotheMTA-headeronthemainboardand
youshouldbereadytogo:-)
Calibration
Patch GATE OUT into TRIG IN on each side of the module. This should put the module in CYCLE mode (acting
like an oscillator). From the original kit instructions:
Turn the RISE and FALL knobs fully CW. Patch the OUT(put) into an audio mixer or Output Module to moni-
tor the output. There should be a 5000 Hz triangle wave present which can be changed to a sawtooth wave
of lower frequency by turning down either the RISE or FALL knob. The frequency and timbre will depend
upon the settings and the shape as set by the relationship between the Rise and Fall times.
Starting from a middle position, adjust the OFFSET trimmer so that the OUTput is in the range of 0V to 5V.
The module will most likely stop cycling towards either end of the trimmer - if this happens, move the trimmer a
bit back towards the center, unplug the patch cord between GATE OUT and TRIG IN and plug it in again - that
should bring the cycle back.
Use T4 and T8 to center the BIPOLAR output - this depends on the OFFSET setting, so if you change OFFSET,
the symmetry of the BIPOLAR wave will be affected.
Adjust LED brightness with T3, T7 according to taste - make sure you don’t turn the brightness up too much
(i.e. trimmer setting shoud be at least 1k unless you use white or blue LEDs).
Using T2, T6 the 1V/Oct tracking can be adjusted. However, be aware that by design the tracking of this
module is not very good compared to dedicated oscillators.
(Version 2 June 2015)
SERGE Modular by Random*Source. Module and circuit under license from Serge Tcherepnin. All rights reserved.
Table of contents
