Simple Booster

[madstayen]

Nope. The boogie is giving a squealing(like a sharp whistle that shifts pitch the closer the pot's wiper gets to ground) sound when I turn the guitars volume knob only, other than that, it's working perfectly. The Booster is making a buzzzzzing sound that truly makes me irate.

[nocentelli]

Is the power negative definitely connected to both input and output signal grounds (i.e. Shield)? If you have a DMM, I'd check continuity between all points that should be grounded.

Also, as mentioned already, those leads connecting the input jack, output jack, and volume pot to the board look awfully long, like 1 metre of cable or something. Outside a box, the input cable is going to act as an antennae, and the boost will amplify any RF noise at all nearby. I'm not saying it will be silent inside a box, but shortening those leads now may rule out some things now if it does or does not make a difference.

[madstayen]

I understand, and will shorten them quickly. About the power negative, it's connected directly from the sleeve of the input and output jack, straight to the board ground. Should I rather connect it straight to the ground terminal of the dc jack?

[madstayen]

Update. Shortened wiring to about 50mm (2"), kept grounds connected where they were, but added extra ground from input jack to dc ground, from output jack to dc ground, from pot ground lug to dc ground. So basically I "over-grounded" the setup. But, still, heavy buzzz. Then, I decided to use my Boss PSA-230S Switching Adapter.... ....NO BUZZZ!!!!!!!!! Now I'm wondering what could be wrong with my GGG-power supply? Guess that's something for a new thread. But alas, the bloody pedal is working smoothly, and it packs quite a bit of a punch, taking the volume to a point where a little grit comes through, and I also found it saturates the sound quite a bit, especially  when used with distortion. HOOAH!!!!!!

[peterg]

Congrats! Are you going to box it up?

[duck_arse]

how many hooah!'s is that now?

now show us your ggg power supply. sounds like less than clean dc.

[madstayen]

Finished product! Thanks guys

Here's the update and correct pcb print for anybody interested

[madstayen]

This is the pcb layout i used, only difference is I didn't use a small bear tranny, couldn't get one, so I used a 12V 1000mA CB radio charger tranny. Other than that, no difference. Is it possible to take a 12V a switching adapter down to 9V? I have one, and would like to use it for this.

[duck_arse]

just out of interest, what is the dc voltage across that 220uF in the power supply?

Is it possible to take a 12V a switching adapter down to 9V? I have one, and would like to use it for this.

if you mean "can I put a 9V regulator on the output of a 12V dc switchmode supply", then, yes you can.

[madstayen]

Thanx, will check the voltage tonight. keep you informed. do i still have to use the whole ggg circuit eg. diodes and caps with the swichmode supply, or just a 7809 rec?

[duck_arse]

if you don't have one, look up the datasheet for the regulators, then just follow the recommended cap values at input and output, and probably a backwards protection diode, just in case.

[madstayen]

just out of interest, what is the dc voltage across that 220uF in the power supply?

Voltage at 220uF is 21V5. ......Come to think of it, I used a 220uF 16V cap I'll swop it tonight and see if there's a difference

if you mean "can I put a 9V regulator on the output of a 12V dc switchmode supply", then, yes you can.

Problem is the switchmode doesn't have a ground from the main power source, so I recon it uses some kind of "artificial ground". The GGG circuit requires a ground to function. How do I do this then? I mean, is it possible to do this?

[madstayen]

Brilliant. Swopped the 16V 100uF with a 25V 100uF (cause it's the highest Voltage rating I could find in my drawer). Runs silky smooth. Even more quiet than my Boss switchmode! I like! I recon a 50-100V cap would serve better, so I'll do that tomorrow. Just thankful for all of your help

[head_spaz]

I suggest you reconfigure R6 and the 100uF cap.
B+ needs to pass thru the diode into R6 BEFORE connecting to the (+) of the 100uF cap.
And the negative side of the 100uF cap should then be connected to the negative side
of the battery (gtound).
Then R2 and R3 should connect to the junction between R6 and the 100uF cap.

Like this...

[madstayen]

could you explain why please. look, i'm not dissing you, but it would be a good learning curve for me to know the difference it would make to the circuit if i swop and reroute some of the parts, mostly because i don't really have an idea what each part do in the circuit.

[Pojo]

I'll attempt a quick & dirty.

You cannot put the 100uf in series between the voltage supply and components that need the juice because it will simply block any DC from getting through, that's one of the attributes of capacitors....they block DC. Also, there's two reasons it was suggested to move the 100uf so that it is after R6 and having the (-) terminal connecting to ground:

1.) There very existence of the 100uf across the (+) and (-) of the supply will lower any ripples coming from unregulated supplies, etc.

2.) R6 and the 100uf form an RC filter which helps prevent any AC signals that may be superimposed in the voltage supply from making its way into the circuit.

[duck_arse]

how hot does your regulator run? it might be possible torun a half-wave rectifier instead of the full-wave bridge, which would cut your 21V down to about 15V or so, which would less-stress the regulator and produce less heat. you'd have to look up rectifier configurations though.

the switchmode will have a "V+" and a "0V" as its output terminals. the 0V becomes "ground" if you use a positive supply.

[madstayen]

Okay so I discarded my psu, and built this one, plus I added "the humonator" as well! That fixed my problems! runs smooth with no ground loops!

[duck_arse]

if your transformer secondary is outputting 24V AC into your full-wave bridge rectifier, you will have 24V * 1.414 = 33V9 DC at the 1000uF cap. you would need a cap rated at 50V here, just for safety sake. but, as you are dropping your 33V down to 9V with yr regulator, it will probably be running STINKING HOT! is it? you might want to find a lower voltage transformer, if that one doesn't have a centre tap on the secondary.

[madstayen]

  Oh, yes, I forgot to mention that. It is running a bit hot. I will change it and let you know. Thanks.

b.t.w, is there any reason why my overdrive and distortion effects work great, until I hook them up to a 3pdt switch (true bypass, A. Nelson's method) (well, any method for that matter, I've tried input ground as well). Anyway, as soon as I hook it up, I makes this funny type of crackling noise mixed with what sounds like volts going to the speaker(a type of buzz), it goes away a little bit, but not completely, then comes back again. A friend of mine said it's because of the switch's internal capacitance. What does that mean? Is it just the poor quality of the switch (no-name-brand;Fong-Kong ), or something else? And then, as soon as I hook up an LED to it, the noise is amplified 10-15 times!!!! Makes me nuts!! I ordered a different kind from ebay, as in South Africa we only get the Fong-Kong type. Hope their of a better quality than this black ones.