Showing posts with label Two. Show all posts
Showing posts with label Two. Show all posts

Thursday, November 13, 2014

Cross Linking With Two Patch Cables

In networks, the supremacy of coax cable is a thing of the past. Nowadays, Ethernet connections are made using UTP cables. The BNC plug has yielded to the 8-way RJ45 plug. Previously, coax cables were daisy-chained from computer to computer and terminated at the two ends using 50-_ resistors, but modern networks use central ‘socket boxes’ (switches and/or hubs) to interconnect everything. The connections between the hubs and the computers are made using patch cables having the same sequence of leads in the RJ45 connectors at each end. For making a direct connection between two computers without using a hub or switch, a ‘crossover cable’ is used.Cross-Linking
Cross-Linking
Cross-Linking
Cross-LinkingSuch a cable has the leads cross-linked in order to allow the two computers to directly communicate with each other. If there are problems with the network, it can be handy to be able to directly interconnect twocomputers, or directly connect a computer to a cable or ADSL modem without using a hub or switch. A long crossover cable is not always available, and shoving around computers is not an attractive alternative. Consequently, we can use a dual RJ45 wall outlet box to construct an adapter, which can be used to interconnect the two patch cables coming from the equipment in question. This outlet box must be wired to create a cross-linked connection. This is done by making the following internal connections:
  • 1 → 3
  • 2 → 6
  • 3 → 1
  • 4 → 4
  • 5 → 5
  • 6 → 2
  • 7 → 7
  • 8 → 8
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Monday, September 22, 2014

Modular Phono Preamplifier High Quality Moving Magnet Pick up module Two stage

Circuit diagram:

Modular

Parts:

R1_____________270R 1/4W Resistor
R2_____________100K 1/4W Resistor
R3_______________2K2 1/4W Resistor
R4______________39K 1/4W Resistor
R5_______________3K9 1/4W Resistor
R6_____________390K 1/4W Resistor
R7______________33K 1/4W Resistor
R8______________75K 1/4W Resistor (or two 150K resistors wired in parallel)
R9_____________560R 1/4W Resistor

C1_____________220pF 63V Polystyrene or Ceramic Capacitor
C2_______________1µF 63V Polyester Capacitor
C3______________47µF 25V Electrolytic Capacitor
C4______________10nF 63V Polyester Capacitor 5% tolerance or better
C5_______________1nF 63V Polyester Capacitor 5% tolerance or better
C6,C9__________100nF 63V Polyester Capacitors
C7,C10__________22µF 25V Electrolytic Capacitors
C8,C11________2200µF 25V Electrolytic Capacitors

IC1___________LM833 or NE5532 Low noise Dual Op-amp
IC2___________TL072 Dual BIFET Op-Amp
IC3___________78L15 15V 100mA Positive Regulator IC
IC4___________79L15 15V 100mA Negative Regulator IC

D1,D2________1N4002 200V 1A Diodes

J1,J2___________RCA audio input sockets
J3______________Mini DC Power Socket

Comments:

Any electronics amateur still in possess of a collection of vinyl recordings and aiming at a high quality reproduction should build this preamp and add it to the Modular Preamplifier chain.

This circuit features a very high input overload capability, very low distortion and accurate reproduction of the RIAA equalization curve, thanks to a two-stage op-amp circuitry in which the RIAA equalization network was split in two halves: an input stage (IC1A) wired in a series feedback configuration, implementing the bass-boost part of the RIAA equalization curve and a second stage, implementing the treble-cut part of the curve by means of a second op-amp (IC2A) wired in the shunt feedback configuration.

This module comprises also an independent dual rail power supply identical to that described in the Modular Preamplifier Control Center.

As with the other modules of this series, each electronic board can be fitted into a standard enclosure: Hammond extruded aluminum cases are well suited to host the boards of this preamp. In particular, the cases sized 16 x 10.3 x 5.3 cm or 22 x 10.3 x 5.3 cm have a very good look when stacked. See below an example of the possible arrangement of the rear panel of this module.

Notes:

  • The circuit diagram shows the Left channel only and the power supply
  • Some parts are in common to both channels and must not be doubled. These parts are: IC3, IC4, C6, C7, C8, C9, C10, C11, D1, D2 and J3.
  • IC1 and IC2 are dual Op-Amps, therefore the second half of these devices will be used for the Right channel
  • This module requires an external 15 - 18V ac (50mA minimum) Power Supply Adaptor.

Technical data:

Sensitivity @ 1KHz: 4.3mV RMS input for 200mV RMS output

Max. input voltage @ 100Hz: 53mV RMS

Max. input voltage @ 1KHz: 212mV RMS

Max. input voltage @ 10KHz: 477mV RMS

Frequency response @ 200mV RMS output: flat from 30Hz to 23KHz; -0.5dB @ 20Hz

Total harmonic distortion @ 1KHz and up to 8.8V RMS output: 0.0028%

Total harmonic distortion @10KHz and up to 4.4V RMS output: 0.008%

A possible arrangement of the rear panel of this Module
Phono

from: http://redcircuits.com/Page154.htm
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