Looking for tiny layouts

Heemis · February 01, 2011, 06:20:21 PM

Just finished up some PCB etching and I am left with a piece of copper blank which is roughly 1" by .75" and I don't want it to go to waste! Can anyone think of any tiny layouts I can fit on this piece, I'm thinking something in the realm of a single transistor boost or even simple buffer. Let's see those tiny layouts!

FunkyGibbon · February 01, 2011, 07:21:15 PM

Yes, buffer or boost. Also charge pump, or SMD CMOS switching. I used a couple of off-cuts to make name tags for my kids' school bags. Just lacquer after scrubbing with scotchbrite to keep the copper shiny, and perhaps bevel the edges with a file.

Christopher

stezza · February 02, 2011, 06:11:24 AM

Search for tiny tremeloooooooooooo

by this stage you should be able to build a couple with that size board!

snakey · February 02, 2011, 06:13:13 AM

SHO

Joecool85 · February 02, 2011, 08:21:06 AM

I don't have a PCB layout, but my 5th gear overdrive is a really simple single transistor overdrive. Sounds great, pretty high gain, excellent for that "white stripes" sound.

Here's the schematic:

And a vero layout dragonfly did:

**edit**
If you end up doing a PCB for it I'd love to see pictures!

Heemis · February 02, 2011, 04:43:25 PM

And the winner is.....

The 5th gear! I breadboarded it up and really liked the sound from such a simple circuit. Only changes I made were to add a 1Meg pull down resistor, and I did away with the gain control, instead opting for max gain all the time.

Here's the finished PCB:

Not so pretty but...

IT WORKS! I'm pretty excited actually since this is only my second PCB etch, and it's the first time I've ever done my own layout! Thanks a bunch Joe for the circuit, I really like it. Planning on sticking with the tiny theme and putting this into a pretty small enclosure (not a 1590A though). Will post more pics as it progresses!

jasperoosthoek · February 02, 2011, 05:34:13 PM

I would like to point out that the schematic and vero layout do not match. The orientation of D1 and D2 is reversed.

My educated guess is that the schematic is wrong and layout correct. There is no sense in having the LED with a large forward voltage connected from the base to the collector as in the schematic. The collector can never go below the emitter (0.5 / 0.6 below the base) and the LED will therefore not reach its forward voltage. So it's useless.

I'd say EXPERIMENT

.

Heemis · February 02, 2011, 05:50:39 PM

Oh yeah, I didn't notice that... It still sounds good though!

jasperoosthoek · February 02, 2011, 06:21:15 PM

It's a nice little circuit. Reversing the diodes shouldn't make it sound bad, only a tad different and not intended by the designer

.

Which way around did you solder them?

Heemis · February 02, 2011, 06:40:20 PM

I have them arranged the same way as the vero layout, although it was completely by chance. I never thought about the difference being in the feedback loop makes as opposed to going to ground. Thanks for bringing it up! Something to think about...

Joecool85 · February 02, 2011, 07:19:58 PM

Heemis - I was planning on adding a 1 Meg drop down resistor next time I play with the circuit, it's like you read my mind! Glad you like it. It was my first successful design when I got into the hobby. And somehow it's still my favorite. Post up a sound clip if you have a minute, I'd love to hear what it sounds like with someone other than me playing it on my gear.

Jasper - Holy crap! I didn't realize I put that in there like that. Version 1.2 was right...I must have typed the D1 and D2 labels wrong when I went over to v2.0 (I didn't change anything other than gain pot value for v2.1).

I suppose I'll need to make a v2.2 with 1 Meg drop down (finally) and flip D1 and D2.

jasperoosthoek · February 02, 2011, 09:20:36 PM

Just wondering, why did you put D1 in the circuit? It seems like the collector can never go low enough below the base to make it really effective. Or is the tranny a darlinton? (I write this on my Nokia). If it's a normal one then it's almost redundant. A germanium diode as D1 should make it effective, probably not better but it'll give it a function.

It seems that because you didn't include a cap between the diodes and the collector that the LED takes the bias current. So the LED voltage will be somewhere below the forward voltage as the bias current is low. This is somewhat unconventional (don't remember seeing that before) and will give you more of the natural characteristics of the components used. Very interesting design!

Do you have some sound clips?

Heemis · February 03, 2011, 01:28:11 AM

The transistor is indeed a darlington.

Joecool85 · February 03, 2011, 05:37:24 AM

The MPSA13 is a high gain darlington tranny. To tell you the truth, I did this design mostly by "knowing very little" and "playing a lot" lol. I don't remember why I laid it out the way I did other than it sounded really nice to my ears.

I do know that the 5th gear OD that I play is built on vero using Dragon Fly's layout, corrected diode orientation and all.

**edit**
Also, I remember trying it without the LED and it just didn't have the same grunt to my ears. It may have been in my head, but I figured that the cost of a single LED is no biggie, so I left it in.

Joecool85 · February 03, 2011, 05:47:05 AM

Soundclips circa 2006.

Full Gain: http://www.thatraymond.com/downloads/5OD1.mp3
1/3 Gain: http://www.thatraymond.com/downloads/5OD2.mp3
Full Gain power chords and single notes to show dynamic response: http://www.thatraymond.com/downloads/5OD3.mp3

All clips were recorded using a crappy microphone into a powerbook using Garageband, no added effects or tonal adjustment. The amplifier I was using is a Dean Markley K20-X and the guitar was a humbucker equipped Lyon LG-1 (looks sorta like a Les Paul).

deadastronaut · February 03, 2011, 07:10:59 AM

Quote from: stezza on February 02, 2011, 06:11:24 AM
Search for tiny tremeloooooooooooo

by this stage you should be able to build a couple with that size board!

almost....

jefe · February 03, 2011, 07:19:34 AM

Quote from: Joecool85 on February 03, 2011, 05:47:05 AM
Soundclips circa 2006.

Full Gain: http://www.thatraymond.com/downloads/5OD1.mp3
1/3 Gain: http://www.thatraymond.com/downloads/5OD2.mp3
Full Gain power chords and single notes to show dynamic response: http://www.thatraymond.com/downloads/5OD3.mp3

All clips were recorded using a crappy microphone into a powerbook using Garageband, no added effects or tonal adjustment. The amplifier I was using is a Dean Markley K20-X and the guitar was a humbucker equipped Lyon LG-1 (looks sorta like a Les Paul).

Joe, this sounds great! I'm going to try and find time to breadboard it this weekend. I have no way to record myself, but I'll try to report back with my findings.

jasperoosthoek · February 03, 2011, 10:41:58 AM

That's a very nice little dirt box

. It's a very elegant little circuit and makes great sense electrically. I must applaud you for your design! I doesn't look like it was designed by someone that "knew very little"

.

Joecool85 · February 03, 2011, 11:57:00 AM

Quote from: jasperoosthoek on February 03, 2011, 10:41:58 AM
That's a very nice little dirt box . It's a very elegant little circuit and makes great sense electrically. I must applaud you for your design! I doesn't look like it was designed by someone that "knew very little" .

Ah ha! So I've fooled you!

Thanks for the compliment. I know more than I sometimes give myself credit for I guess. I've built a handful of effects, designed this one and I'm working on another right now actually. I've also built about a dozen amplifiers ranging from a 1/4w tube amp to a 100w 2x LM3886 chip amp. Solidstate is more my thing though, hence why I started SSGuitars.com

Heemis · February 03, 2011, 01:54:20 PM

I'd be glad to share the PCB layout I did for this circuit if you're ok with that Joe... It's pretty basic being my first go at PCB layout, but it works! Just gotta figure out how to correctly export it from Eagle....

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Looking for tiny layouts