headbanger amp

You can also keep trying on the perfboard method. One trick I learned at work is the "wirelist". You put the components on the board and name them. You take the schematic, make a copy, and trace the wire circuits with a colored pencil, writing down each node (connection to a component) in a list as you go. Each entry has a source, and a destination name. Where there are two wires, the destination of the first entry repeats as the source of the next line. Each line is one wire. Where the end wire is not repeated, you have all the connections in the net, and start of on a new net on the next line. Leave space on the paper if you made a mistake, to add another wire. Then you mindlessly execute the wirelist wire by wire on the board, coloring off the wires on the wirelist as you go to keep track of where you are. This keeps your mind focused on one thing at a time, and reduces the confusion of too many things at once. There is art to arranging the wire runs for minimum length, and no parallel runs of inputs (high impedance) and outputs (high power) for example. There should be no parallel runs of mains AC wire and input signal wires, either. Then you check your work against the schematic with the buzzer function of a DVM. This confirms both the wirelist, and the quality of your solder or wirewrap joints.
Where there are a lot of connections to one thing like the power supply or analog ground, I tend to hook a bare buss wire between two holes on the board and hook all the supply wires over it like coat hangers on a rod.
I'm still building with insulated wire on perfboard. It is hard to get layout or simulation software obsolete enough to match this Linix op system and 400 MHz computer I use without overloading the memory capability. And besides if you want to make a little change on PWB you have to write off again to the etch service and buy another iteration. With soldered wires, you just unhook and move a wire or two.
Soldering trick- bend the wires where they hold without the solder, before you solder them. Takes two needle nose pliers, sometimes. Wirewrap was a lot of fun once but the support for it has broken down, and wrapped connections were never very long lived on low energy audio signals. My 1966 design Hammond organ has several wirewrap connections on low energy inputs soldered to the pin by dealer service to fix ittermittant sound problems.
 
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Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
right so i bought a couple of freds cmoys, empty boards and i am going to do one with standard components and the other with more high end parts like mundorf, but the instructions says to use a b47k pot, i cant seem to find one for pcb mount or in my price range, is it worth using a 50k???
This a matter of marketing tradition. High-end, boutique parts and pretenders use traditional round figures and avoid newb questions about why 47 and not 50. Commercial components are ranked in a mathematical progression of values that provides better coverage of design requirements with low inventory so you get 1, 2.2, 4.7, 10 instead of 1, 2, 5, 10.

As a volume pot, it will make 3/5 of a gnats whisker difference, if anything, due to parts tolerances.
 
yeah perf board got a tad annoying for me, got it to work fine after a few attempts :), and build a cmoy on my perf board aswell, and thanks ian i just wanted to know if it made a slight difference and it looks like it dont to much, and i know hi end hi-fi parts like mundorf and dueland from owning some very nice amps and speakers, and i am a newb to building my own stuff, hence starting off small at headphone amps and progressing after some time (years) to making my own tube amp, expect tons of n00b questions for some time to come haha