Diagrams
- Circuit Diagram
- Stripboard Component Layout
- Interwiring Diagram
- Sega MegaDrive Connector
- Super Nintendo Connector
Zip Files
Parts List
| Resistors (all 0.25W 5% or better) | |
| R1,10,101,110 | 22K |
| R2,3,102,103 | 10K |
| R4,7,104,107 | 4K7 |
| R5,6,105,106 | 220R |
| R8,9,108,109 | 15R |
| VR1+101 | 50K Log PCB Mounting Pot (1 off) |
| VR2+102 | 10K Log PCB Mounting Pot (1 off) |
| Capacitors | |
| C1,101 | 22nF Polyester |
| C2,102 | 100nF Polyester |
| C3,103 | 47pF Polystyrene |
| C4,104 | 100pF Polystyrene |
| C201,202 | 470uF 16V Axial Elect |
| Semiconductors | |
| IC1,101 | LF351 Op-Amp |
| TR1,101 | ZTX300 NPN Transistor |
| TR2,102 | ZTX500 PNP Transistor |
| D201,202,203,204 | 1N4002 Rectifier Diode |
Miscellaneous
X1 9-0-9V 100mA Mains Transformer, 0.25" Stereo Jack Socket, 9 pin Mini-DIN Plug, 9 pin Mini-DIN Socket, Choc-Block Connector, 3 Core Mains Flex, Thin 9 Core Screened Cable (1 Metre), Stripboard, Case, 2 Knobs, Hook-Up Wire, Thin 2 Core Screened Cable, Tinned Copper Wire (about 24SWG), 13A Plug with 3A Fuse
Use with Super Nintendo
Since the article was prepared, I have had the opportunity to try the unit with a Super Nintendo Entertainment System (SNES). The results are superb.
The SNES has the RF modulator built-in, and has a separate Audio/Video output socket. This simplifies the connections somewhat, since the loop-in arrangement is not needed. The amplifier is simply connected to the appropriate connections on Audio/Video output socket.
This socket is not a standard type, but a suitable plug can be fabricated. The connector resembles the edge of a PCB, with six connection tongues on each side. This is recessed in a cut-out that is basically rectangular in shape, but with the corners cut. A locating recess is at the top. This socket is difficult to describe, the general shape is shown in the illustration.
Making a Suitable Plug
A small piece of 0.1" PCB edge connector can be filed down to fit into the socket. It may be worth buying a large connector, such as a 36 way type, as you will probably need to have two or three goes at it! Having got it the right shape, solder a length of two core screened cable to the pins shown in the illustration.
There is no obvious method of protecting these connections. I potted the connections in epoxy resin (Araldite), using a mold made from cardboard lined with Sellotape. This could then be painted black to make it look more professional. The result is a reasonable sized lump that supports the connections, and enables the plug to be gripped when being inserted or removed.
The other end of the cable is connected directly to the appropriate points on the amplifier PCB.
In Use
The first thing I noticed when testing the amplifier with the SNES, was that the sound quality is much better than that from the Sega Megadrive. The digitising noise that was evident on the Sega audio output is completely absent on the SNES. Consequently the Tone control may be left fully clockwise (maximum treble), or even omitted altogether.
It is possible that I may have the Left and Right connections transposed since I do not have the official information from Nintendo. I have not yet encountered any games where the connections are obviously wrong (or right), but it would be a simple matter to swap the connections at the amplifier end if necessary.
This project, including all text, images and diagrams, is copyright 1991 - 2003 Paul Stenning. No part of this article may be reproduced in any form without prior written permission from Paul Stenning and WallyWare, inc. All details are believed to be accurate, but no liability can be accepted for any errors.
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