CMOS nyquist aliaser perf lay-out (not yet verified)

[birt]

here ya go:


i've built it myself but i did that in a hurry and it didn't work, didn't have the time to debug it yet... but i think the lay-out is ok.
if someone wants to throw this together before i have the time to debug mine, please do so!

thanks to Bioroids for the schem.

[zpyder]

sweet, I'll definately try this one out sometime soon...

thanks!!!

zpyder

[zpyder]

Questions-

1) What the hell is up with that potentiometer?

2) Why do you space several resistors at only 2 holes ... ? with no spacing in between.  I see other ways to do this without having to place those resistors vertically...??


thanks,
zpyder

[birt]

the pot has two lugs (2 and 3) soldered together to the circuit and the other lug to ground.
i do place resistors vertically to keep lay-outs compact.

oh and i'd like to know what all of you think of the way i make perf lay-outs.. i mean the notation, colours, shapes...

thanks,
bert

[zpyder]

the pot has two lugs (2 and 3) soldered together to the circuit and the other lug to ground.

Okay gotcha...  I'd suggest noting this on the layout - it is not initially clear.  Somehow you need to indicate GR on lug 1 of that pot.  Also, you did not indicate if the pot was linear or log.

i do place resistors vertically to keep lay-outs compact.

whatever floats your boat   In this case, I would have used R1 to get across the lead between IC2 pin9 & C2, and bring C1 and the IN terminal down toward the bottom right.  I don't know enough about twisted pairs, so I may be overlooking some utility there if you intended to twist IN with GR.  I'd really like to know if this is what you intended as twisting stuff is something I would really like to figure out before I build too many pedals without it.  It seems to me that by moving R1 to where I indicated, and using a top-left-to-bottom-right diagonal lead off of IC1 pin5, that R2 and R3 could be layed out to 4 spaces each.  That's just me I spose, but if you did intend to twist IN with GR, there is another ground terminal right where IN would end up if replaced how I suggested...

oh and i'd like to know what all of you think of the way i make perf lay-outs.. i mean the notation, colours, shapes...

:: I find the writing hard to read in many cases - particularly the white fonts and the D1 over the diode, but in general the value labels are hard for me to read.  Maybe just some bold fonts...?
:: Although I can quickly figure it out by following the circuit, the "X" on the electro cap does not indicate anything to me.  Instead, I would indiate the negative side with a "-" symbol, since electros are marked on the negative side.
:: I like the use of red for traces/leads.  It makes them very easy to see through components, which is often an issue without other layout color templates.
:: Why not use white or some much lighter color for the background?  Would create more contrast.
:: Reading "GR" over the pink is exceedingly difficult.


cheers - to DIY!,
zpyder

[birt]

normally i don't use the white component values since i always have the schematic with me when i build a pedal. i never use the lay-out on its own (the same goes for other peoples lay-outs).

the X on the caps should actually be a + since a - gets lost in the lines of the traces and components. this si also clear when you have the schematic with you as you build it

i seem to have enough contrast on my screen :s

i know, but i used it to have an easier job wiring the board. i know all pink are ground connections and all white are 9V. on a board with a lot of wires this makes things easier since i always start the wiring with ground and 9V

[zpyder]

Right on...

Yea, I kinda figured the "X" was a 45-degree-off "+", it's just not obvious.

Maybe a parts list below the schematic with the values for each component listed, rather than putting them right next to the component.
I too also always have the schematic right there when I build from a layout...

Did you intend to twist IN & GND?

zpyder

[Austin73]

interesting conversationn but does it actually work yet! I hope so as I really want this one!

Cheers

Aus

[birt]

interesting conversationn but does it actually work yet! I hope so as I really want this one!

Cheers

Aus

build it and you'll know



oh and i didn't inted to twist in and ground, i've never tried that

[Austin73]

ok will order the chips next week.

what does everyone mean by twisting in and ground?

Aus

[Gilles C]

Instead of using a shielded wire for the input, you can twist the ground and the input wire together to help in reducing the noise picked-up by the input.



Gilles

[bryantabuteau]

hey, I read the MC14066B (4066) is a pin for pin replacement for the 4016.  I can get these locally, but as I'm unsure how the aliaser actually works, does it rely on the limitations of the 4016 or can I do a substitution...?

[birt]

my pedal works but there is a loud hum (louder than the guitar).
its a plain hum until the frequency knob is about a quarter up, then the effect kicks in and the hum is modulated.
with the frequency knob below that point there is also no signal coming trough.

[birt]

in the first lay-out R10 was connected to pin 3 of IC2 instead of the junction of C5 and C6. i corrected the lay-out and i hope there will be no problems anymore once i fix this in my pedal.

[birt]

i just changed it. now the frequency pot is fully functional and the hum is gone. but it's still self oscillating. or maybe thats just the modulated hum thats left?

[birt]

*BUMP*
i'm a bit lost with this one. i'm pretty sure the lay-out is correct altough the pedal still doens't work like it's supposed too.

help me out plz!

[birt]

i found out some weird stuff after replacing all the wiring and reheating every solderpoint.
the noise volume changes when i hold the board in different directions. also when i touch the junction of C7 to pin 5 and ground at the same time the noise goes away but the effect too and my guitar sounds a more like its bypassed. C7 as well as C6 make a lot of noise when i touch them.
there is also a little bit of this noise in bypass (from ground i guess) but only when the frequency pot is set to high resistance. in about one fourth of the pots taper it suddenly dissapears.