ARIES System 300 Music Synthesizer,. 22 Sept 75Module AR 316 y *■'-/?'"/ • \;■. •'.•■
Voltage Control Amplifier Assembly Instructions
The previous pages were written as a general guide, to familiarize thebuilder with the components. Here, now, are the specific assemblyinstruct ions for bui ld ing yourIt is recommended that you do the following before you proceed:
Find a place where you can work through completion, withoutdisturbing your set-up.Use adequate lighting.Wash your hands before starting. This removes contaminating oilsand perspiration and makes assembly more comfortable.As you proceed, check off each step with a pencil.
( ) 1 . P r e p a r a t i o nLay the circuit board down on a sheet of white paper.. PLACE METALSIDE DOWN! Turn boaed so that connector strip is to the left.
Lay the assembly drawing down near the boaed.
Unpack the parts carefully and place in a large box or tray so theywon't set lost .
Have the following tools nearbysPencil tip soldering iron, hot and tinned (solder coated)Solder—Use only thin rosin core solder!Small diagonal wire cuttersSmall wire strippersSmall long-nose pliersRegular pliers-Flat blade screw driver
( ) 2 . J u m p e r sFind jumper Jl on the drawing. Measure Jl on the PCboard. Cut apiece of insulated wire one inch longer than Jl measures on the PCboard. Strip 1/2 inch of insulation from each end being careful notto damage the wire itself. Bend the bare ends to a right angle andinsert into the holes on the boaed, according to the drawing. Whileholding the ends down against the board to hold the wire in place.Solder and cut off the excess. (Refer to the introduction on partsinstal lat ion.) Instal l al l k jumpers in the same manner.
( ) 3 " R e s i s t o r s . . ,Careful ly instal l a l l 29 resistors on the circui t board. R 10, l j ,
..and 31 are trim pots. ,.R l,3,l?.,and 23 are potentiometers and willlater be mounted on the panel.To avoid breaking the resistors leads, bend the leads at least 1/16of an inch away from the body of the resistor.For examples
C o r r e c t I n c o r r e c t
AR316 VGAAssembly p2 of 5
( ) 4 . C a p a c i t o r sInstall all four capacitors on th board. (Cl through C4)
( ) 5 « T r a n s i s t o r sInstall all transistors on the board. (Ql and 0,2)
( ) 6 . ' I n teg ra ted C i r cu i t Amp l i fie rsInstall all Integrated Circuit Amplifiers. Ul is a CA3080.U2 and 3 are LM 301.
ALL BOARD COMPONENTS ARE NOW MOUNTEDMODULE ASSEMBLY~~Please refer to Module Assembly Drawing
( ) 1. Unpack the frame, bag of hardware, and front panel.( ) 2. Snap the two plastic card guides into the holes in the- frame. . ■;. ;. .
Be sure that the pairs of tabs in the guides which hold the boardpoint toward the rear of the frame. (The bottom one is showninstalled in the drawing.)
( ) 3. Slide the circuit board Into the frame, holding the top and bottomof the frame together against the bcnrd so that the board fitssnugly in the card guides-, Be sure that the pairs of plastic tabs
■.; '. ' pinch the edge of the circuit board properly. . .';., ,( ) '4. :: Using 4-40X3/3" screws and nuts, mounkthe.tw» angle brackets
to the frame as shown in the drawing. The brackets should be :\e n t i r e l y o n t h e c o m p o n e n t s i d e o f t h e b o a r d . \ y .
() 5. Now screw the board to the brackets. Insert the 4-40 X 3/8"screw from the foil side of the board. DOUBLE CHECK THAT;THE HEAD OF THE SCREW DOES NOT TOUCH ANY FOIL! U ■
( ) '6. ■•: Unpack the front panel carefully.: Avoid scratching its surface.':;■; .:;'•:•" AT THIS POINT you may i! you wish skip steps ?-8, and proceed through
the first few steps in the panel wiring (those in which wiring ia;v ■: _.done between components on the panel, but net to the board) ;; v'"■■/!•before finishing the module assembly.
( ) 8. ■ . Attach the bottom of the panel to the frame using the remaining ; ,4-40 screws and nuts.
() 8.. Install the other pota on to the panel* 4( ) 10. Install all 3,2 mini-phone jjaeks as shown in the panel drawing.( ) 11„ . Turn, all pot, shafts fully counterclockwise and mount the knobs >.
; /- ; . ' point ing to the leftmost number. Tighten knob screws. . ■ -THIS COMPLETES MODULE ASSEMBLY
PANEL WIRING-- Please refer to panel wiring diagram and layout diagram.( ) 1. Run a wire connecting thn grounds of all 13} mini-jacks, as shown,
and from there to the ground point on. the circuit board near point?'M" of the edge connector.
( ) ,2. Wire the 3 pins of each pot as shown in feh® panel diagram. Wiresindicated with arrow heads connect to the appropriate points on thecircuit board, as shown on the layout diagram. Wire one pot at ■a time to avoid confusion. .' .
( ) 3. Wire all jacks with arrows and a letter designation to the appropriatepoints at the rear edge of the board, as. shown in the layout diagram.
^ } «•, Wire SI to the appropriate points on the board as laoexxea on theassembly drawing.
THIS COMPLETES ASSEMBLY OF YOUR AH 316 VOLTAGE CONTROL AMPLIFIER
, u A R 3 1 6 V C A A s s e m b l y p . 4 o f 5AR 316 VOLTAGE CONTROL AMPLIFIER PANEL WIRINGJKAGRAM—rear view
Arrows indicate awire to the PC board.All wires with arrowsand ground bus mustbe insulated.
MODULE AR316VGA TRIM PROCEDURE
AR316 VGAAssembly p 5 of 5
NOTE: The VCA may be trimmed by ear, however, the following test procedureis recommended if the test Instruments are available.
1. A regulated + and - 15 volt power lupply2. Oscil loscope with DC coupled vert ical input.3. EnvelopeGenerator or LFO.4. LFO or VCO.
Trim as follows!1 Monitor the output wi th the osci l loscope.2. With no audio inputs to the VCA and audio level pots at 0, apply a
10 volt square wave to the control input.Adjust RIO for minimum signal at the output, (increase the gain on theoscilloscope for more precise trimming.)Apply a 10 volt sawtooth to audio input 1 and set the pot to 10.Applv a 10 volt square wave to control input 1 and set the pot to 10.The envelope generator can be used to produce the square wave.Turn the initial gain to 0 and the control mode switch to LIN.Adjust R 13 for a 10 volt sawtooth at the output.
8. Change the control mode switch to EXP.9. Adjust R 31 for a 10 volt sawtooth at the output.
3.
4 .5-
6.7.
Your AR 316 is now ready to use.
THEORY OF OPERATION- AR-316VOLTAGE CONTROLLED AMPLIFIER
A u d i o I n p u t s a r e s u m m e d i n b y R 2 , 4 , 5 , a n d i n t o t h e i n v e r t i n gi n p u t o f U l , w h i c h i s a c u r r e n t - c o n t r o l l e d g a i n c i r c u i t . T h ei n p u t s , a f t e r m i x i n g a t t h e i n p u t , a p p e a r a s a n o u t p u t c u r r e n t .T h i s i s c o n v e r t e d t o a v o l t a g e b y U 2 , a c o n v e n t i o n a l i n v e r t i n go p a m p . T h e o u t p u t i s o f t h e s a m e p o l a r i t y a s t h e i n p u t , b e c a u s et h e t w o i n v e r s i o n s c a n c e l .
C o n t r o l s i g n a l s a r e s u m mIn the LINEAR mode, theT h i s i s c o u p l e d t h r o u g hb a s e - e m i t t e r d r o p s c a n c eu s e d . S o , t h e e m i t t e r v oT h i s v o l t a g e a c r o s s R 3 3 ,c o l l e c t o r o f Q 2 , a n d i n tg a i n c i r c u i t . W h e n R 2 3 ,i t s o u t p u t o f - 1 5 v o l t ss o U 3 o u t p u t i s 0 , a s i s(Off ) . Turning up R23, orcauses U3 ou tpu t to becoa c r o s s U 2 , t r i m s t h e m a xo f + 1 0 v o l t s .
e d t h r o u g h R 1 8 , 1 9 2 0 , 2 1o u t p u t o f U 3 v a r i e s f r o m 0e m i t t e r f o l l o w e r Q l i n t o Q1 , s i n c e o p p o s i t e p o l a r i t yl t a g e o f Q 2 v a r i e s b e t w e e n
d e t e r m i n e s t h e c u r r e n t f ro t h e c o n t r o l t e r m i n a l o fthe INITIAL GAIN CONTROL,i s b a l a n c e d b y t h e + 1 5 v o l
t h e c u r r e n t i n t o U l . T h e na p p l y i n g a p o s i t i v e c o n t r
m e n e g a t i v e , w h i c h t u r n s oi m u m g a i n t o b e u n i t y a t f
, and 22, and U3.t o + 5 v o l t s .
2 . The twot r a n s i s t o r s a r e0 a n d - 5 v o l t s .
o m e m i t t e r t oU l , t h e v a r i a b l ei s t o t h e l e f t ,t s a c r o s s R 2 5 ,, t h e g a i n i s o .o l i n p u t v o l t a g e ,n Q2 and Ul. R13,u l l c o n t r o l i n p u t
In the EXPONENTIAL mode,w h i c h m a k e s t h e c u r r e n t( e x p o n e n t i a l l y ) a s i t s bacross U3 a re changed tonow var ies between 0 andc u r r e n t t h r o u g h Q l , t h e no f 0 . 0 5 v o l t s . T h i s i s nin the EXPONENTIAL mode,g a i n , a l s o t o u n i t y .
T h u s , i n b o t h m o d e s , t h eI N I T I A L . G A I N c o n t r o l i sL INEAR mode, the ga in i sv o l t c o n t r o l s i g n a l . I np o i n t i s o n l y 0 . 0 0 3 ( - 5 0
F i n a l l y , R 1 0 i n t r o d u c e so u t i t s o w n i n t e r n a l o f fC rom ca r r y i ng a chang ing
a c t i o n i s s i m i l a r e x c e p t ( 1 ) R 3 3 i s s h o r t e d ,th rough Q2 change much more rap id lya s e v o l t a g e c h a n g e s , a n d ( 2 ) t h e r e s i s t o r s
p r o v i d e a s m a l l e r d r i v e v o l t a g e . U 3 o u t p u t- 0 . 3 3 v o l t s . R 3 1 v a r i e s t h e e m i t t e rc h a n g i n g i t s b a s e - e m i t t e r d r o p b y a t o t a l
o t s i g n i fi c a n t i n t h e L I N E A R m o d e , b u t i sw h e r e i t i s u s e d t o t r i m t h e m a x i m u m
t h et h ea +5
g a i n v a r i e s f r o m e s s e n t i a l l y 0 t o . 1 a sv a r i e d o v e r i t s f u l l r a n g e . H o w e v e r , i n
. 5 ( - 6 d b ) a t t h e m i d - p o s i t i o n , o r w i t hthe EXPONENTIAL mode, the gain at : th is
d b ) .
a v a r i a b l e D C o f f s e t i n t o U l , w h i c h b a l a n c e ss e t . T h i s p r e v e n t s v a r y i n g c o n t r o l s i g n a l s
