watt, volt, degrees, preset, linear, log??????? WHAT????

[madstayen]

  Okay, so I biased the pedal, works great! Totally love the sound. Except I would appreciate a bit more bass, and more overall volume (I get volume drop when I chain it with my other pedals and the effect is on). Still squealing when bypassed, but I didn't get chance to do the "input ground" wiring method. Will do that sometime this weekend!!! The 1M-A pots were wired correctly, but I re-wired the mid and volume ground straight to the input jack ground, and now my volume is actually working as it should. Doesn't make sense how that can make a difference, but apparently it did. When I use my normal dc power supply "Fong-Kong" import (this is the one where I have to set it at 4V5 to actually measure 10V ) I get major feedback. When I use my Boss PSA-230S, it runs like dream. I wanted to open it up and see how it looks on the inside so I can build one, but it's a sealed unit, so I'll have to break it open, which I don't want to. Do you guys know of anybody who has the schematic/pcb lay-out for this power supply, or something similar? I would greatly appreciate your help on this matter. And again, thanks for helping me through this build, lotsa tears and cursing, but I learned a great many new things, and I absolutely look forward to my next build, HOOAH!!!

[Jdansti]

>Still squealing when bypassed, but I didn't get chance to do the "input ground" wiring method.

You can test this without residing your stomp switch. Just run a temporary jumper from the input of the board to ground.

>When I use my normal dc power supply "Fong-Kong" import (this is the one where I have to set it at 4V5 to actually measure 10V ) I get major feedback. When I use my Boss PSA-230S, it runs like dream. I wanted to open it up and see how it looks on the inside so I can build one, but it's a sealed unit, so I'll have to break it open, which I don't want to. Do you guys know of anybody who has the schematic/pcb lay-out for this power supply, or something similar?

Your "Fong-Kong" PS appears to be unregulated. Make sure you check the output voltage while it is connected to your pedal  I recommend not building your own PSU unless you really really really know what you're doing. It would be better to either buy one that's regulated or to take an unregulated PSU and build a small regulator circuit that also cleans up the power.

Sounds like you're possibly in Europe, so here are some options for regulated power:

Electro Harmonix EU96 DC-200 BI Power Supply ~10€ + Shipping
1 Spot Power Supply ~17€ + Shipping
9V Danelectro DA-1 ~8€ + Shipping

If you decide to tame an unregulated supply, your Kong might work if you can select an output > 11V. Or you can use any other unregulated PSU, including a laptop supply.

[madstayen]

I'm in South Africa. I think I'll go with the regulating circuit using a 7809 to bring it 9V. Now guess what happened last night, I was still testing the pedal, gain was maxed, sounded very good, then all of a sudden the gain starts to fade, up to a point where the pedal now sounds like a booster, WTF Anyway, I tested the resistors, all is fine, except for the 2M2 one at the bottom left of


It should be reading somewhere around 550k, but it is actually reading the full 2M2. So I recon something has popped either before, or after it, but don't know what exactly. Can't measure the capacitance of the caps because my meter gives me a hundred different readings on each cap. So where do I start to look for/diagnose problems. Just some basics will do. I will figure this out, because it wont help my learning curve if I build another, and another if it keeps happening!

[Jdansti]

Why do you think the 2M2 resistor should read 550K?

[madstayen]

because in my struggle to do this build, i built 3 boards, thinking something on the board isn't right, then at the end it was the pots that was the problem, and i checked every board and remembered that the 2M2 resistors measured 550k +- after i soldered it in. And the circuit worked ofcourse, until i lost all gain, when i rechecked it, it was a solid 2M2. so i knew it shouldnt be like that.

[Jdansti]

It's unusual for a resistor to be changing its value. I guess it might be possible if a lead or the resistor itself were partially broken. It could also be possible for it to appear to change values if you have a bad solder joint and you're measuring the resistor from points on the board instead of from the resistor's leads.

The other thing I wonder is what the reading across the 2M2 resistor should be when it's in the circuit. The resistor is part of a parallel circuit as shown below. I'm not sure how the 2n2 cap affects the resistance, but I think the resistor, when in the circuit, might read close to 1M. Maybe the cap would cause it to go close to 500K.

Hopefully someone more knowledgeable than I can chime in on this.

[madstayen]

yes, the 2M2 measures the correct value when not in the circuit. when it is soldered in, and i grab its leads with my aligator clamps, it measures about 560k. all 3 boards were like this, until saturday night.

[Jdansti]

Without fully understanding how the circuit affects the 2M2 resistor, it appears to me that 560K is probably the correct reading when it's in the circuit. If that's true, then a reading of 2M2 when it's on the board would indicate that one of the three resistors is not connected (2M2, 680K, or 1M pot), i.e., a bad solder joint, broken trace, or a solder bridge.

[madstayen]

I checked that, they are good. All points re-soldered, in fact, I replaced all resistors and caps of the gain circuit, and about 90% of the rest. Replaced all 4 trim-pots, changed Q4 and Q5 as well, so all 5 j-fets are BF245B's(new ones). Still nothing. Then I took the other two boards, replaced the 1KA pots with 1MA. They are wired exactly the same, but with only 1 LED. Also, nothing. I think I've come to some sort of conclusion: One of the 3 J201's, or all 3, were fried, and the board doesn't work with BF245B's. If I had more J201's I could've verified my theory, but for now this is pure speculation.

[PRR]

> I'm not sure how the 2n2 cap affects the resistance,

Put your ohm-meter across a (film) capacitor. It should read infinite. (In practrice it is hundred of Megs, but most meters just say "OL", and hundreds-Meg is infinite-enough for our work.)

If the gain-pot is shorted, the reading is 680K||2200K= 540K. Also no sound should come through.

[Jdansti]

Thanks, PRR.

[madstayen]

hmmm, makes me ponder! i did change the gain pot though, but i didnt replace the wiring. i will strip it tonight and do that, thanx. worth a try. where can i download a book/Pdf that explains the relation of resistors in a circuit combined with caps, ex, what the values change to, what formulas etc?

[Thecomedian]

Wikipedia has a lot of correct information about formulas. I believe a resistor is a non-frequency dependent impedance (it's the same resistance for all freqs) while a cap is a frequency dependent impedance (changes with frequency, impedance itself implies frequency dependent resistance). You might want to use norton or thevenin reduction theroms to simplify the circuit until only two or three parts remain, which would make solving easier. Those formula are a lot less scary than they look, just time consuming. Math is the original Plug and Play media

[madstayen]

Okay, so I re-wired like this: http://www.generalguitargadgets.com/diagrams/switch_lo_3pdt_ig_dcjack.gif?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
No difference at all, except I got sound (clean) when effect is on, and off. So, I replaced Q1 with one of the J201's I removed previously, and suddenly I have a little bit of DS, then did the same with Q2, even more DS, then Q3, even more DS. So it must've been a wiring problem, but I changed the fets and resistors and caps before I redid the wiring. So to make it short, the circuit is most definately designed for J201's, not BF245B's. I recon if I can get more of them to replace Q4 and Q5, I would get more DS from it. I don't know if the BF245A's might work, but that is just as difficult to get here in South Africa. But at least the bloody thing is working now, I'll change the last 2 fets when I get more. Thanx for all your help. How difficult is it to build the "little angel" chorus http://www.diystompboxes.com/smfforum/index.php?topic=86297.0
Just wondering if it could make a better 2nd project.

[madstayen]

I got the J201's today. Soldered it in. Very good distortion, pleased with it, but I find when I turn the volume knob on my cort x6, I get a squealing sound. It can only be on max, or min. Anything in between squeals. If I use my Les Paul, It squeals all the way, no matter where the volume knobs are. Any help with this maybe?

[Dysfunction]

I got the J201's today. Soldered it in. Very good distortion, pleased with it, but I find when I turn the volume knob on my cort x6, I get a squealing sound. It can only be on max, or min. Anything in between squeals. If I use my Les Paul, It squeals all the way, no matter where the volume knobs are. Any help with this maybe?

Just a quick thought as i saw you building a dr boogey , did you remember to bias your j201's to around 4.5v - 5v ??

[madstayen]

Yes I did. All of them is biased at 4V5. Don't know if this is related, but if I adjust Q1 (Gain trimmer), it makes scratching noises, and it kinda acts like a pickup of some sort when you touch it, the thumping sound of your finger hitting the trimmer can be heard through the amp.

[duck_arse]

the squealing means we now need new photos of yr input and output and bypass wiring. we might get lucky.

[madstayen]

Will do so, thanks for the help guys!!!

[madstayen]

So I finally fixed the boogie. I changed most of the caps to box caps, and the rest to quality disc caps. Except for the radial ones. Played around with the tonestack a bit, with minor improvements(not much). I then changed to star grounding as described in some post elsewhere on this forum, which by the way, solved 90% of the problems, I think!! I made sure each section has its own ground, and that it does not interfere with the next, and then connected that directly to the dc jack. Problem solved. Now I can turn the volume knob on my axe with no squealing, hissing, biting, growling, or farting! All sorted!  

The short of it: 1) ALWAYS use good quality caps and resistors, ALWAYS!!!
                     2) Over grounding can cause oscillation!
                     3) Use star grounding with high gain pedals, in my opinion!
                     4) NEVER PICK THE BOOGIE AS A FIRST PROJECT!!!!!!!!!!!!!      NEVER!!!!!!!!!!! It will cause you months of agony, cursing, and breaking things unnecessarily!
@ deadastronaut -

as a noob, the dr boogey isn't a wise choice...but not impossible, but .i would try something else first to dip your toe into...

- absolutely true!
@ Mark Hammer -

Just know that you may have instant success or you may be faced with a couple of months of exasperation and asking questions here.

Yep, if you're just learning to swim, always best not to jump into the deep end of the pool wearing lead-lined boots!

- Spot on!
For the rest of you guys who helped me, I SALUTE YOU!!!!! Thanks for keeping up with my crap, it shows great character, I respect that very much!