StratoBlasterBooster: problem with noise...

[marione]

   
I just assembled a booster (StratoBlasterBooster) following the project are on GeneralGuitarGadgets.
The pedaler works correctly except for two problems:

- One is a constant hum when the pedal is powered with DC adapter (no problem with batteries).

- The other is a "popping noise" when the effect is switched on or switched off.

I do not understand a lot of electronics and I do not know where to intervene to solve the problem ...

Any advice? Opinion?

Help!

P.S. I use a Tube Guitar Amplifier

[newfish]

Hi!

Quick couple of answers to your queries you may wish to try...

Switch pop can usually be cured by adding a large value of resistor (say 1M Ohms or bigger) between the input lead and the ground *before* the first capacitor of the Booster.  What can happen is that the first capacitor stores charge (as caps do), and then they release it all in go when you switch the effect *on*.  Using a large cap helps this built-up charge leak silently to ground - so no popping!

As regards the DC noise, what sort of adapter are you using?  I've found quite recently that the better the quality the mains adapter, the less background noise.
Look for anything labelled as 'Regulated' for starters.  They're a little more expensive, but the difference in quality is more than worth it.

Pictures being worth a thousand words, these traces show an excellent comparison of what a DC supply can look like - the straighter the line, the cleaner the supply. 

http://www.diystompboxes.com/smfforum/index.php?topic=78641.0

A regulated adapter will give out the stated voltage (9v or 12v etc) 99.9% of the time.

An unregulated supply will give your 9 or 12 volts under certain conditions, lunar phases or whenever it feels like it - they are, as the title suggests, completely unregulated.

Bitter experience has taught me never to use an *unregulated* adaptor on shiny new digital delay pedals. 

Hope this helps...

[marione]

I do not know if you saw the project on the site of GeneralGuitarGadgets.

I have performed work in tandem with the project and I believe the advice I have about the fate popping is already applied ... right???

Regarding the hum I do not think the question of adapter since I tried two ... but I do not know!

Please help me!

[Talon5051]

Did you measure the voltage on the adapters?  If the voltage is too high, it can produce the hum.  I have had this happen with a couple of adapters.
There are a lot of posts on this forum about switch popping and the ones that I have read recommend the cap as newfish comments.  Give it a try and see what happens.  The worst that can happen is that it does not work and you can say "I told you so".

[marione]

   
Sorry but I can not understand some things because I do not speak good English and some words I can not translate ..........

Can you help me better with the "SBB Parts Layout" which you can find here?

http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=64&Itemid=26

Sorry but I need to understand better what to do!

[RDV]

Make sure C3's polarity is correct, and use a Boss Adapter which is regulated at around 9.7v IFAIK.

RDV

[marione]

Thanks...

I verified but the C3's polarity is correct...

[newfish]

I've just had a quick look at the GGG Schematic - am I right in thinking that there is no input cap?
It's a FET boost - so strictly speaking, one isn't required.

Marione - if you have a spare capacitor - round about 0.1uF, or a small 'disc' shaped one with something like '473', or '104' on (for the purposes of the test, it's not too important what value).  Try placing this between your switch and the input wire. 

Are you using this pedal wth other equipment, or is it just "Guitar - Boost Pedal - Amplifier" ?

If you're able, please try to post photographs of your board so far - that may help.

[marione]

ok, I do the test with the capacitor between the switch and the input wire and hopefully good ...

I try the pedal without other effects...only "Guitar - Boost Pedal - Amplifier"

Then came the pictures and certainly will help you better...

[marione]

I try with the capacitor as indicated but nothing.........

[marione]

The hole indicated with the letter "G"?

Why in the scheme (parts layout) is not plugged? May be due to that problem? I have left it unplugged!

Sorry but I am a beginner........

http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=64&Itemid=26

[marione]

This is what I do...can help you this photo?

[Talon5051]

The hole labeled G is just another hole for grounding.  It should be OK to leave empty. 
Did you get a chance to measure the voltage on your adapter?

[Pat Mustard]

Do you have an input signal?  I.e. do you have a guitar plugged in?  Mine pops with the switch only when no guitar is plugged in, plug in a guitar and it's very quiet...