Summary of Contents for Slightly Nasty 1411
- Page 1 M O D E L 1 4 1 1 D U A L D I S C R E T E M I X E R L I N D I S T L I N D I S T D u a l D i s c r e t e M i x e r Co nstru ctio n &...
- Page 2 D u a l D i s c r e t e M i x e r PHYSICAL FORM FACTOR: Loudest Warning / 4U WIDTH: 3NMW / 75.5mm HEIGHT: 175mm DEPTH: ~25mm from panel front inc. components PCB: 70 x 75mm, Double Sided CONNECTORS: 4mm Banana IDC power connector pinout.
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Page 3: Table Of Contents
Output Amplifier CHOOSING COMPONENTS Bill Of Materials (BOM) Choosing Components CONSTRUCTION Construction Overview Physical Assembly CALIBRATION Calibrating the 1411 CONTROLS Controls REFERENCE PCB Guide This document is best viewed in dual-page mode. C i rcui t Ove r v i ew... -
Page 4: Introduction
L I N The circuitry in each half of the 1411 is based around a pair of discrete opamp- D I S T type circuits that operate as summing amplifiers - providing signal isolation between the inputs. -
Page 5: Circuit Overview
For full schematics, please download the separate schematics PDF. Excerpts shown in this manual may be outdated and are provided for reference only. Unsurprisingly for a mixer, the 1411 is an incredibly simple module consisting of essentially three small elements: 1. - Page 6 C i rcui t Over v i ew...
- Page 7 D u a l D i s c r e t e M i x e r The 1411's input amplifier is a classic three-transistor opamp circuit consisting of a differential pair (Q101 and Q102) that control an output transistor (Q105). The best way to understand the operation of the differential pair is to consider the...
- Page 8 D u a l D i s c r e t e M i x e r resistor at the point where the amplitude is relatively close to the usual diode drop voltage of ~0.7V. This is done by splitting the one resistor into two, and ensuring their combined resistance is lower than the summing amp's feedback resistor in order to supply makeup gain at the output.
- Page 9 (Quantities listed are for one PCB) R101, R102 240R R114, R122 R121 R123 R109, R110, R116, R119 R113 R112 R108, R118 100K R103, R104, R105, R106, R107, R111, R115, R120 R117 10pF C103, C104 4.7nF C105 100uF C101, C102 100K RV101, RV102, RV103 100K trim...
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Page 10: Choosing Components
D u a l D i s c r e t e M i x e r Like all Slightly Nasty modules, the 1411 is designed to use common "jellybean" components wherever possible, so getting hold of parts is relatively straightforward. - Page 11 I personally like to clean up any remaining protrusions with a few passes of a needle file as well. The DPDT mode switch in the 1411 is probably the component that requires the most attention during construction . As mentioned in the "Component Selection"...
- Page 12 D u a l D i s c r e t e M i x e r Assembling the finished PCBs and front panel is very simple. Begin by fitting the banana sockets into their respective holes on the front panel - making sure to align the flat terminals vertically (if using the Cinch-style sockets).
- Page 13 PCB. Calibration of the 1411 is very simple, and consists of nulling out any small voltage offset that shows up on the output jack. then setting the correct gain for the A and B inputs at full scale.
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Page 14: Controls
D I S T INPUT ATTENUATORS Control how much of the input signal is sent to the output. S L I G H T LY N A S T Y SLIGHTLY NASTY JACK COLOURS Bipolar signal output BLUE Bipolar signal input YELLOW... -
Page 15: Pcb Guide
D u a l D i s c r e t e M i x e r LOWER BOARD - TOP LOWER BOARD - BOTTOM P C B Gui de... - Page 16 w w w . s l i g h t l y n a s t y . c o m...
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