WebEE

Diagrams

• Circuit Diagram Page 1
• Circuit Diagram Page 2
• Circuit Diagram Page 3
• PCB Artwork
• PCB Component Layout
• Interwiring Diagram
• Front Panel
• Filter Frequency Response

Zip Files

• PCB Gerber Files

Tips
Bjoern Wieck has kindly provided details of how to use a ZN427 in place of the ZN448 . He says:

I checked the datasheets and the only difference between ZN448 and ZN427 is the clock-generation. The ZN448 has internal clock-generation and is adjustable by an capacitor to ground (in your design 47p for approx 1MHz). The ZN427 has no clock generation and must be clocked externally. I have assembled a small adapter board for the ZN448 socket which contains the ZN427 and a 74LS132 as 1MHz oscillator.

• Diagram for using ZN427 in place of ZN448

He also supplied sound samples demonstrating a tone without and with echo.

• Sound sample - tone without echo
• Sound sample - tone with echo

Steven Dumon suggests the use of a TL074 dual op-amp in place of the LF347 (which is apparently now difficult to obtain).

Parts

PCB, Knobs, Case, Wire, 2 Core Mains Flex, 13A Plug with 3A Fuse, IC Sockets, M3 Screws and Nuts

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.