Geofex Low Fidelity / Telephone / Noise Pedal - Layout proof

[chi_boy]

Hi all,

I was hoping I might trouble some of you to proof a layout for me? 

This is my first attempt at a layout and would appreciate a critical review before I try etching a board.

The pedal is the Low Fidelity / Telephone / Noise Pedal posted at http://www.geofex.com/FX_images/lofi.gif

The schematic with resistor numbers and two views of the layout are shown below.  The layouts are the same, only the components are darker or lighter for viewing the traces.  I used DIY Layout Creator, but it's new for me, so I may not be using all the best tools.  Sorry if this isn't the best way to view the layout.

Also, the schematic is posted with R.G.'s permission.

Thanks for any help.

George












 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Group	Name	Value	Quantity
Capacitors	C1	100uF	1
Capacitors	C2	47uF	1
Capacitors	C3, C10	0.1uF	2
Capacitors	C4, C5, C7, C6	0.01uF	4
Capacitors	C8	0.01, 0.1, or 1.0uF	1
Capacitors	C9	1uF	1
Diodes	D1	1N4001	1
IC's	IC1, IC2	TL072	2
Potentiometers	VR1	100K	1
Resistors	R11, R19, R17, R13, R9	100K	5
Resistors	R12, R10, R8	56K	3
Resistors	R16, R14, R18, R15	51K	4
Resistors	R2, R1	47K	2
Resistors	R20, R5	10K	2
Resistors	R21	22K	1
Resistors	R22, R3, R4, R24	1M	4
Resistors	R23	100R	1
Resistors	R7, R6	5.6K	2
Transistors	Q1, Q2	2N5088	2

[chi_boy]

Well, I've checked this several times and it looks good to me. Time to etch, I guess. The only thing left is a board for a rotary switch to add some versatility to the filters.

[sevenisthenumber]

Did this work? I would love to build!

[Skruffyhound]

Also interested. Nice work George.

[chi_boy]

Did this work? I would love to build!

It worked as advertised, but there was a minor issue with the noise section.  I'll look everything up and post the changes tonight.  The problem was a resistor value, not with the layout itself.

This is the thread about the noise problem: http://www.diystompboxes.com/smfforum/index.php?topic=81197.msg672208#msg672208

I also have a version on my breadboard right now that works even better.  I used Mark Hammer's suggestions from this post and it made the thing a lot more versitile: http://www.diystompboxes.com/smfforum/index.php?topic=25185.msg164559#msg164559

I'm also trying to add some different noise options.  Like white, pink, brown, and some crackle noise.  The white noise varients were easy.  Now I'm looking for something that will gererate a nice whine.  I also wanted to add a mixer to replace the panner so that the new noise sources could be mixed as desired.  The panner works as it should, but I don't like how it cuts the guitar volume as it adds the noise.  Haven't got to that part yet though.

George

[bancika]

<pride>
cool, that's one of the prettiest layouts drawn with my DIYLC, nice work man!
</pride>

[chi_boy]

<pride>
cool, that's one of the prettiest layouts drawn with my DIYLC, nice work man!
</pride>

Wow.  That's means a lot coming from "The Man."  Thanks for the kind words.  That was actually my first attempt at a layout.

For the others asking about verification, the circuit worked for me as shown.  The final changes are wrapped up in this post:
http://www.diystompboxes.com/smfforum/index.php?topic=81197.msg673042#msg673042

The DIYLC file is available here: http://home.comcast.net/~gprause/Telephone_4.diy

You may have to right click and save. 

The DIYLC file has all of my final changes. 

Cheers,
George

[knutolai]

I know this thread has been inactive for quite some time. The schematic has 404ed. Could you possibly repost the drawings somewhere? Im very interested in this circuit!

[runmikeyrun]

worked for me... maybe an issue on your end?

[chi_boy]

Should be good to go now.

[knutolai]

Now its working! Thank you very much

[timd]

Any soundclips?

[chi_boy]

Any soundclips?

Sort of, but not quite.  I didn't like the original, so I added some of Mark Hammer's ideas and came up with this:

http://home.comcast.net/~gprause/LOFO_MOD.gif


This is a clip of the modified pedal:

http://home.comcast.net/~gprause/LOFI_Sound.mp3


This is still testing, so it's not in a box and I don't have a switch on it.  The clips is as follows:

  Treble and bass set to max - No cut
  Treble cut at MAX
  Bass cut at MAX
  Treble and Bass cut at MAX
  Bass cut at max, treble cut at 50%


The problems with it right now are:

  1) I made a different noise section and haven't fully tested the mixing part.
  2) There is a volume drop as the controls are maxed.


I think the volume drop can be fixed by making R16 a pot, but again haven't tried it yet.  I like the noise section on the breadboard, but just need to test that mixing part.

[timd]

Great job - this sounds really good. I love how it adds extra flavor.

[chi_boy]

Thanks, the flavor was intentional.  I used all ceramic caps and 1458 op-amps.  I tried it with better caps and TL072's and it worked fine too, just not the sound I was after.

[timd]

I think I may attempt a sound that's in the same ballpark via circuit-bending then making a guitar pedal out of that mess. I post back if I have success. I'm really looking for a white/pink noise generator...