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As per my previous post, are there any issues with the component placement for this simple LM 386 amp?





Or that matter, any issues at all?
TIA

For those who take schematics and design their own PCB's. What concerns should I have when placing the components. I believe that I should try to keep power away from signal, and to always pay attention to polarity. Beyond that, does placement impact the sound? Should certain parts be placed closer or farther from each other. Maybe I'm over thinking this.

Would there be a problem using an MP3 player plugged into the input of a pedal I'm trouble shooting, as to not have keep plucking a string? Impedance mis-match or something that damage the pedal circuit further?
TIA

I mill my own PCB's on a 3018 CNC. I've been toying with the idea of of cutting odd shaped boards for a little while now. This morning I think I may have solved it. Disclaimer: No curves lines, just straights and angles. One also needs to know some VERY basic gcode commands. And yes, it is a little bit of a PITA, but I feel it is worth it.
I use four different programs to achieve this: Eagle as my PCB design software (gerber files), Flatcam to generate gcode, ncviewer.com (online) to simulate what my mill will cut, and CAMotics to edit  the gcode (this is the snarky bit). One could use other such programs I guess, these are just what I know how to use (mostly).
I'll be brief, not a "full" tutorial, but will answer any questions I can.

In Eagle draw the shape you need with the line tool on the top layer, using a thin line, ~.5 mm. Under the Cam Processor pick Profile. Add the top layer to the Profile's layer list. Unfortunately you can't delete the board shape layer (you'll do that via gcode editing). Under advance setting mirror it. Process job.
In Flatcam open the profile gerber. You'll notice your cutout shape, and a square board shape. Go through the regular process of isolation routing using only one pass. Tool dia, depth, feedrate and spindle speed all set to what you use to cut out boards. Go through all the steps to generate the gcode.
At ncviewer.com open your gcode, and find the lines that cut the inner shape (there will be two) of your custom board, hightlight and copy.
In CAMotics make a short gcode file of just the generic opening and closing lines (I'll post what I use if wanted), paste the lines from the veiwer between them. Save and then open your new gcode file in the web veiwer. Cross your fingers, and if you had all the right lines copied that will be it.
I hope this all wasn't too boring, but if only one other member mills their own boards, and needs to wrap the front edge of their board around the dc jack, then I feel this is worth the trouble

Do WS blank sheets go bad after time? Back when I first bought these, they went on for me wrinkle(ish) free. Now they end up looking antiqued. Maybe I've gotten worse at applying them?

Consider this schematic:


The section highlighted in pink is what I usually use when I only need 9vdc. Now I need both 9vdc and 4.5vdc. I searched for voltage dividers and they all looked pretty much the same. R2 and R3 always matched (I know why), and usually were 47K. C3 differed also.
My questions are; Should C1 and C3 match? How does changing their values effect the circuit? What should C2's value be?
TIA

Consider this schematic:

I have seen the same PS, but only R1 is placed after D1. Is there a difference?
TIA

The schematic I have calls for a 100pf in parallel with a 1M resistor across pins 9 and 10 of the CD4049. All I have on hand is 120pf. Is that close enough?
TIA 

I've just been chasing my tail with this, and I'm going nuts.  I've conquered (so far), the act of milling PCB's on my little CNC machine. I find the resulting pads are just a little too small for my limited skills to get an iron on after I  apply the solder mask, and would like to enlarge the pads on a component by component basis. All I need to change from the parts I'm using are the pads.
I tried to use the minimum size thing in the DRC which enlarges all the pads, but then the transistors, and IC's pads touch. I can enlarge those pads by hand, by just leading a thicker trace, then using a Sharpie to enlarge the mask printed on transparency paper to block the UV curing. Of course I don't want to have to do this for all components, but a hand full of pads are no biggie. Just a nudge in the right direction will help.
TIA

Does anyone here do this? I bought a 3018 two months ago, and I'm having a devil of a time.
TIA

I'm fairly new to eagle and I'm trying to draw a schematic using a DIL16 (CD4049UBE). I found one in a library, but when I add it, there are pins missing (1 and 8, the other missing pins are NC). Is there a way to modify a part? Or would I have to create one from scratch? mostly interested in "adding" pins 1 and 8.
TIA

Does anyone do this? I'm just starting to look into this, and it seems that everyone does it different with different cnc's and software. Ive just started to learn Eagle and Inkscape, I'm lost (sorta). I'm not sure the steps, or their order.
I've made a schematic and board layout in Eagle (simple Fuzz Face because I know the circuit well). I don't know what I have to do next. It seems the process uses different file formats at different stages, and I just don't know what I need.
As far as hardware, I'm looking at 3018's, but don't know which company to trust.
Any help, or a gentle nudge in the right direction will help.
I'm just tired of the toner xfer/ acid etch approach, for several reasons.
TIA

I'm taking a shot at modding a FF for Bass. Here is the schematic I'm working off of:


I increased both input and output caps, and tied the E of Q1 to GRD via a 330 ohm, I'm guessing, to decrease the gain, insuring Q1 has less gain than Q2.
I have no idea what the 100pf strapped across both trans does, but to my ear it kinda mellows the harsh.
For the most part, I really dig the sound on the low E and A strings, no mud at all. The D and G, especially pass the 5th fret, is kinda harsh, getting worse as one goes up.
Is there a known mod for this?
TIA
 

This is probably a newbie question, but the only stupid question is the one you don't ask
Consider this out stage of a blender:

(my apologies if I have violated CR)
My issues with it is this:
I used a 50kB pot, wired backwards in reference of the schematic, pin 1 is now to the right, effects in side, with pin 3 to the left, so as to add blend to the effect, instead of taking it away.
The physical range of motion for the knob is from 7'o clock to 5'o clock.
From 7'o to 1'o, adding clean signal appears to have no effect, at least to my ears.
From 1'o to 3'o is where all the blending of clean signal occurs.
From 3'o to 5'o, its sounds just like pure clean signal, for the most part.
I have two schools of thought at this point. Raise the value of the 560 ohm is series with pot, thinking it will it hit the threshold earlier in the pot's swing. 
Change to taper to an audio, and wiring it backwards may make the taper act sorta reverse audio
(shrugs shoulders) I have pulled all of this this out of thin air. I have no science to support this, that's why I'm asking  
TIA

I have just bread boarded a Red Llama, and there is this piercing high squeal, kinda strobing, riding over what otherwise is a great sound. If I adjust the pots, it kinda goes away, but only if the knobs are in a "sweet spot". Ive checked my connections and values. And usual suspects?
TIA

May one replace a 50pf cerm cap with a 51pf?. The only 50pf I can find are 1KV and physically wont fit in my build.
TIA 

As far as audio goes, what is the difference between carbon film and metal film. I have noticed that some carbon films are smaller than metal at the same wattage, and that the size of carbons differ. I am trying to squeeze as many components in as small a space as I can so size is a factor. Also, what are the good companies?  I mean like who is cheap, who is middle of the road, and who is the premo?
TIA

Hey Guys, I've got a question about the power supply section of a circuit. Here is the whole schematic:



and the section in question:



I realize that this section is providing two different voltages. Is it also providing polarity protection? And if so, which components are doing that? I've seen it done with a diode before so I'm wondering.
Knowledge for knowledge's sake.
TIA   

Many schematics show non-polarized caps, but do not tell which kind to use. Consider this Schematic;



Which of the non-polarized caps are which? What is the criteria for the selection?
TIA

I'm having a hard time getting the transistors (2N5457) used in the blending portion of my pedal, so I spent most the afternoon looking for an alternative circuit. I believe I may have found it, but it doesn't name the IC.



I would guess a TL072, but I'm wouldn't know.
I also tried to get a schematic of S. MacCellen's B Blender, but I closest I could get was a PCB layout with no values. I would be willing to try either one.
TIA