Sparkle Boost - First time build questions

[monkmiles]

Hello all...

I'm about to start on my first build, a Sparkle Boost. I'm creating this thread to post my questions that hopefully you will be kind enough to help with! I'm putting it into a 1290 enclosure that I bought pre-drilled.

I'm going to start with one or two questions for now, but I'm sure I'll be adding more question posts here once I get into it.

For reference, I'm using this layout below. Well technically I have an etched layout for the NTE458, but I'm using a J201 (and insulating/twisting the legs to the correct formation):


Let's start with a few questions...

1) For the 1uf and 10uf capacitors... I bought Electrolytic, Axial 16 ones from Small Bear (1mf and 10mf). Firstly, hopefully those are correct for this circuit! Secondly, I believe these have a positive and negative side, right? So, which way do I attach them to the board then for this layout?

2) I need a resistor for my LED. What size resitor should I go with? This is the LED I bought, it's a orange 5mm 5000mcd one here: http://www.pedalpartsplus.com/mm5/merchant.mvc?Screen=PROD&Store_Code=PPP&Product_Code=5003&Category_Code=LO5

3) I need to pick up some more wire. I have some red 22awg. What is the recommended wire gauge? 22, 24, etc? I'll grab a couple colors (black for ground is standard I suppose).

4) I plan on picking up this inexpensive radio shack DMM to use for biasing, measuring my resistors (to figure which is which), etc. Let me know if this wouldn't be good. http://www.radioshack.com/product/index.jsp?productId=2103176

[PRR]

> So, which way do I attach them to the board then for this layout?

+ to the square pad. (Many caps mark the - end, which of course goes to the not-square pad).

> What is the recommended wire gauge?

Whatever feels good and won't break on the road. Your #22 is fine. #28 may be too fragile for hard touring.

> this inexpensive radio shack DMM

Twenty Nine Bucks ? ? ? And that's nearly the cheapest thing RS stocks.

You can get an adequate DMM on eBay for $2.99. It won't be as well-made as the ones RS is so proud of, better get two. You might also look in WalMart Auto or Electrical section, there's often a $9.97 DMM.

[monkmiles]

Thanks for the info...especially about the right pad for the caps!

Any recomendations for the resistor for the led?

[stringsthings]

do you have a copy of the schematic? .... the electrolytics will have a + sign near one leg of the cap .... 10uF caps are usually electrolytic .... the 1uF is prolly electrolytic, but i would need to see the schematic to be sure

as far as wire goes, it's your choice ..... having a few different colours is nice for debugging .....

not sure about the LED resistor ...

the DMM looks just fine ....

good luck with the build ! 

[PRR]

> Any recomendations for the resistor for the led?

There's no LED on the plan you show. So you are asking for wild speculation.

ASS-uming the path is a 9V power source, resistor, LED, and switch, all in series (any order), and assuming fairly-bright or 5mA-10mA:

The LED voltage is probably "small" compared to 9V. Maybe 1.5V, maybe 3V. So you end up with 7.5V to 6V across the resistor. If you want "several mA" and have "several Volts", that's about 1K resistance.

Check: 6V across 1K is 6mA. 7.5V across 1K is 7.5mA. The maximum for most LEDs is 20mA, so we are safe from burn-out. The brightness goes down with current, but even 1mA makes a good glow. So a 1K resistor giving 6mA-7.5mA is sure to work.

BUT: if this effect is battery-powered.... the actual effect uses less than 1mA. A 1K resistor for the LED will pass around 7mA. The battery will run-down 8 times faster with the LED.

If that matters, run the LED with lower current. 5K (or 4.7K nearest stock value) will give 6V/5K to 7.5V/5K which is 1.2mA to 1.5mA. The LED still eats more than the effect (shooting light through space is harder work than ticking a guitar-amp through a cable), but battery life is much better than with 1K.

You can go further. 10K, 22K.... just try it. There's no real minimum current (maximum resistor) except how much light you need to see to know it is "on".

[PRR]

I met a guy who has bought dozens of Harbor Freight's $2.79 DMMs for classes, going back several years. He says the only "flaw" is that if a clumsy student yanks the lead, it breaks. Which for him (or for you) just segues into "The Soldering Lesson".

[monkmiles]

> Any recomendations for the resistor for the led?

There's no LED on the plan you show. So you are asking for wild speculation.

Oh, didn't realize that. But your further response was exactly what I was looking for, so I guess it wasn't too wild.

As a newbie, my thought was that there was a typical way of wiring in the LED to the circuit. I already mentioned the specific LED I'm using in my initial post. I will be using a 3pdt switch and using the wiring diagram here (which does mention a 1k resistor):



I'll go and pickup a couple resistors today in between 1k and 22k so I can have a couple options and not drain too much battery. My plan is to have both a power jack and a battery snap to be able to use either.

Thanks for your replies.

[monkmiles]

Well, I just spent alot of time today and tonight building this. I just finished (minus the battery snap). I go to test it and....nothing.

The bypass works. But that's it. The led doesn't even light up and no sound.

Don't even know where to start to debug. Anything I can do with the multimeter to test where the issue is? Any pointers are MUCH appreciated!!

I can post pics tomorrow if that's helpful?

Trying to think of anything I could have done wrong...
- I have both a lug of the footswitch and a lug of the power jack going into the +9v node with two separate wires.
- The trimmer...there's 4 possible nodes to attach it to but only 3 legs on the trimmer. If you look at the layout in my first post, I put the trimmer in the top 2 and middle 1, but not the lowest node.

[monkmiles]

Well, I just spent alot of time today and tonight building this. I just finished (minus the battery snap). I go to test it and....nothing.

The bypass works. But that's it. The led doesn't even light up and no sound.

Don't even know where to start to debug. Anything I can do with the multimeter to test where the issue is? Any pointers are MUCH appreciated!!

I can post pics tomorrow if that's helpful?

Trying to think of anything I could have done wrong...
- I have both a lug of the footswitch and a lug of the power jack going into the +9v node with two separate wires.
- The trimmer...there's 4 possible nodes to attach it to but only 3 legs on the trimmer. If you look at the layout in my first post, I put the trimmer in the top 2 and middle 1, but not the lowest node.

[PRR]

> Don't even know where to start to debug.

Stuck near the top of the forum: DEBUGGING - What to do when it doesn't work