Build Your Own Clone Message Board

Hey all, I just finished my parametric EQ. This is my first BYOC project. Frankly, the build was longer and harder (small parts) than I figured. Everything powers up, and all the knobs function, but I have noise issues and I wanted to compare notes...

First - I already did the resistor removal, place at lead 2&7 fix for the rev1.0 error. This did help, but the noise is still very significant. (I sure wish BYOC would have include a notice in the packaging ALERTING me to this....)

Second, when I use a 9 volt adapter I get a very noticeable low hum making the adapter unusable.

Third, I get a lot of noise in strange settings. Sometimes if I crank the master to 100% noise is so bad I can't use the device. Sound is still there and all works, but the "hisssss" is just too much. However, if I play with various other knobs, its seems like I can "tune" the hiss out. Conversely, sometimes things are not cranked up, but when I tune things, the "hissss" comes back. It feels like I am hunting for a radio station and sometime the signal comes in, and with some slight changes, the signal goes out.

Fourth, the high freq gain almost acts like a master gain. (I'm using on a gtr). This might be normal (because a lot of guitar freq are between 1k to 11k) but it seems a bit much.

Finally, all my op amps are upgraded to Burr Browns, and I expect this would make the things very quite.

I can play with things an make the noise almost go away - and the device sound good. But turn the Q here, or turn the Freq there, and I tune in the noise and the device is not worth using...

Ok - so is this "normal - are these things really just very noisy and the tune noise like a radio station? Does anyone else use DC and do you have a problems with hum?

If this is not normal (I sure hope not) any ideas on where to start to get he hiss out?

Thanks in advance.

Is this noise present when you power the pedal with a battery? If not it’s the power supply adding the noise.

_________________
"It’s your soldering."

First - I'm a huge Schenker fan, love the icon. Saw the Built to Destroy tour as a kid....

The "hummmmm" is only there with the power supply, so I likely need a regulated supply. The bigger problem is the "hisssss" - it is the same with battery or power supply. Like I said, the "hisss" tunes in and out, so I don't think I did anything wrong in the build. In by-pass, there is zero noise.

I read another review that indicated the pots were so close to the board they act like capacitors and create all sorts of weirdness. This would help explain the "radio tuning" issues I'm having. The hisssss isn't just when the gain is cranked. In fact, I can crank the gain and tune almost all the "hisssss" out by playing with freq and Qs.

The only think that makes me think it is a build issue is the dramatic effect the gain/bost of the high freqs has. It is almost a master volume, but not entirely, the low and mid still make it through a bit. It this normal?


I plan on putting some form or insulator/dielectric below and beside all the pots to see what this does. But, please let me know how much of this sounds like a "build issue", and how much is "it is just a noisy pedal with weirdness." I wish there were a good demo of a properly completed pedal so I could properly set my expectations.

Thanks for the reply.

Well I added dielectric between the pots and the board, and there was marginal (a very small) improvement. So at this point I'm stuck.

A few more clues, is seems like the hissssss increases when the low Freq is set a 0dB boost, and again, the High gain still works almost like a master volume. I'm hoping I did something wrong (like bleed solder over two connections) and the clues can help track it down. I've looked several times and I don't see anything wrong.

Unless there are ideas (or again if this is just a noisy strange pedal) I guess I can post pics.

Thanks in advance for ideas.

Hi - sorry to hear about your troubles! Doesn't sound normal to me. I don't have my build anymore, but I don't remember it as particularly noisy, and I also don't remember the treble knobs being so dramatic.

Here is a good post with some tips that can help us help you: viewtopic.php?f=52&t=34439

One thing in particular is to go back over your solder joints and reflow them. There are a ton of connections in there and one bad one can throw the whole thing off. And it happens all the time - by far the most common build issue is a bad solder joint somewhere that otherwise looks fine.

Another must is photos of the build as described in that post. While you have the pcb out of the enclosure, go ahead and snap some candids.

Letting us know your level experience can help too. If you've dne any soldering before, if you know how to take voltage readings, etc.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

No offense to anyone, but that is just silly. The pot casings are grounded to the enclosure by virtue of how they bolt on. This makes the internals shielded against RFI. They are not perfectly shielded - there is small gap near the lugs and the top wafer - but the theory does not play out in this or any of the other BYOC builds. And this one is not particularly high gain.

EDIT - I stand corrected. I forgot that this build uses those dual ganged pots and they are not shielded on the back. Hmmm...

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

I'm an EE but not really a circuit guy. Put it this way, I'm trying to understand the circuit from the schematic to figure out what might be causing this.

I'm very good with a multi-meter, and I've done a good amount of soldering. However I have NEVER done so many very small parts like this. In some ways, this is the most ambitious project I have ever tackled - there are soooo many small parts!

(P.S. capacitors are strange things and they are everywhere. Even if the pot cases are grounded, that just means you have a capacitor tied to ground. Like cross-talk, this can be a real problem especially when there are so many components so close together like on this build.)

Again, if I heard a good demo, I would be able to set my expectations more reasonably.

Thanks.

So I found the pics of the board layout/component numbers, and I found a high-res schematic. With these in hand, I started tracing everything (working backwards from the output) and so far I have found one issue with a high resistance from pin 1 of the high-freq opamp. I will have to re solider pin 1 of the chip holder for starters.

I plan on tracing back every component to see if I find any other anomalies. Once I'm done tracing the entire thing, I will take the board out of the box (again), and fix the pin 1 issues and anything else I find.

Wish me luck.

Apologies - I've been out of the area lately and checking in on my phone. I should have pointed you to that stuff earlier. Here is the pcb map and a link to a high rez schematic if that helps anything at this point.



http://byocelectronics.com/schematics/byocPEQscheme.pdf

When you get the pcb out of the enclosure again, I encourage you to take the shotgun approach and reflow as many of the solder joints as you can get to (remove all the ICs from the sockets before you do that). And follow that up scrubbing the solder side of the pcb with alcohol and an old toothbrush to clean away flux residue (can be conductive). I know it might sound silly, but by far the #1 cayuse of all sorts of weird issues with these kits is the soldering. And it happens to all of us (well...maybe not Stephen). Actually, when I built my PEQ, the mid Q control was sort of 'working' but not really. One reflow and one alcohol cleaning later, all was working.

Also voltage readings can sometimes help pin point a suspect area. The 3 quad op amps are all run on a bipolar supply, so you should have around 9vdc on pin 4, -9vdc on pin 11, and close to 0vdc at all other pins. Unfortunately, I can't tell from the schematic of the dual op amp is run bipolar or not, but you can easily tell that by determining if pin 4 connects to ground or if it has -9vdc on it. Pin 8 should be at supply, and the remaining pins should be in between the voltages on pins 4 and 8 (either zero or 4.5v depending on if its run bipolar or not).

If none of this helps, I encourage you to snap some decent photos of the top and bottom of the pcb, and the jack and switch wiring. Stephen and I have been helping guys trouble shoot builds for around 8 years now - photos almost always help highlight potential trouble spots.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

That's cuz I'm da man.


Has it really been that long? We should qualify for our pension any time now.

_________________
"It’s your soldering."

A few more things just to make sure we address everything...


I think this relates to your issue with the high freq band. The circuit has around 30dB of gain on tap, so when you crank that master, it is amplifying any noise that is already present in the signal path. The 'in between radio stations' hiss you are describing is not normal - assuming you are using the device with a 'typical' guitar and amplifier. (Every now and then we get a troubleshooting thread where it finally comes out the guy is using the device on a trumpet into a PA system or something).


This does not sound right, and this is what is making me think you have an issue in the build. Yes, if you boost the high freg, a lot of the guitar signal lives there, and it will probably sound like there is more signal boost on tap for the treble boost/cut knob when compared to the low and mid boost/cut knobs. But like you said, what you are describing seems a bit much.

Another thing to check out is swap the quad op amps around to different positions (IC2 controls lows, IC3 controls mids, & IC4 controls treble) to see if the problem follows the op amp currently in the IC4 position. That would indicate a chip issue.


Well...while that is true - they should provide a lower noise floor compared to lesser op amps - what I've found is that nice op amps like that have more fidelity than the typical 4558 or TL072 op amps usually used in stompboxes. Most of the extra fidelity you'll hear is in the high frequencies. So they could actually be accentuating your high freq issues a little bit. But in a properly working build, you should be able to use them without any issues. If you have the original op amps that came with the kit, it's best to get it working with those before you move on the BBs.


That's encouraging - it sounds like most of the circuit works well.


No, I don't think you have a properly working build there. With my build (I wish I held on to it), I only used it with a DC adapter, and it did not produce any excess noise or hum. In fact, if you set all the boost/cut knobs at noon (so no freqs are being boosted or cut), you should just get a real nice sounding clean/flat boost or buffer, depending on where you set the master volume.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

I know, right? The new board (this one) went live around Feb 2006, IIRC! And you were already a mod before that. Where's the gray-haired old men emoticon?

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Thanks for the reply guys. It's good to know that I have a build issue and it will be worth the time in trying to fix it. Given the large resistance in the negative feedback loop of the High Filter, I can see why the high was acting like a volume.

I like the idea of the alcohol toothbrush rub down. I think I have an old bottle of Tequila I can use.

I already swapped the IC's around, and its didn't change the behavior. I also played with BB and the TL. You are correct, TLs did cuts some of the hisssss (not much) but sound very "tinny" compared to the BB's. I'd rather have a bit extra hiss with a nice round, full sound (BBs), than a tinny-thin signal with no hiss.

And I am running it through a PA, not a guitar amp. All my gear goes direct to the PA - including the mic'd trombones. (no trumpets, my lips are too big).

Once I get this working, if it sound good enough, I will likely mod it to have a balanced output...but first things first.

Thanks again and I will update as I make progress.

Are you seriously

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

yep. Rock & Roll the R&B.

http://www.musiciansfriend.com/brass-in ... c-trombone

I get the occasional request for pedals from horn players. I always assume there will be a horrible impedance load, or something, with running guitar effects from something like a clip on mic. I'd love to hear any tips you might have!

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Run the efx as an insert in the mixing board. I never go direct from mic-impedance matcher - efx box.

Build Update:
Material progress last night. I traced the entire device and didn't find any other problems (except for being an idiot on R1 before I realized the stomp switch grounds both ends of R1...).
It turns out I simply forgot to solder Pin 1 of the IC4 holder. I also scrubbed the board with rubbing alcohol and a tooth brush as suggested.

Good news: Once I soldered, my High band worked properly. The High band no longer acts as a "master volume", but does just what is is supposed to do. The "hisss" noise level was also reduced.

Not so good news: I still have a lot more hiss than I think is proper. In particular, it seems I can get the hiss level to drop materially by touching the base of the Low band cut/boost pot. Also if I just touch the circuit board the hiss goes down, and if I touch the back of some of the capacitors (particularly C7) the hiss level goes down.
Also, my adapter still introduces hum (I will blame the adapter for now). But overall, I still have the radio-tuning issue going on, and can get most of the hiss out by tuning or touching, but it not as bad as before.

Tonight I plan on reflowing the solder on all the parts that seem to reduce hiss when touched and see if this helps.

Right now everything works, but since I can get hiss reduction via touching things, I think its worth the effort to try resolve this noise. I am very happy with the sound when it operates in "low hiss" mode (it still has some minor background hiss but at levels I expected and find acceptable.)

Sounds good, and thanks for the tip on the mixing board patch.

If you are testing the circuit outside of the enclosure, you can expect some lowering of the noise floor once everything is properly installed, secured, and sealed up.


That suggests a grounding issue (though not 100%). The circuit board is grounded to the chassis via the sleeve tabs on both the input and output jacks. Make sure the jacks are seated well on the enclosure and that there is not paint getting in the way of a good ground contact.

Also, something I've seen in the past, especially on builds with lots of pots (this one has the most by far), is that sometimes when re-mounting the pcb in the enclosure, a pot or some of the pots will 'catch' and not quite seat right. When the builder tightens the nut on the pot, it can put a bunch of pressure on the solder joints where the pot connects to the pcb, and a bunch of torsional pressure on the pcb in general. Pressure like this = lots of stress on solder joints = iffy connections. If you get the feeling that some of the pots might be not quite seating right, or slightly twisted, uneven vertically, or otherwise cattywompus, usually reflowing the solder joints on the pot connections will remedy that by allowing the solder tabs to move and relieve any pressure (I've had some snap pretty violently once the solder melted).

Also, pictures can only help! We've seen a lot of kit builds and are pretty good at pointing out potential trouble spots.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Update:
Well, not very good news. I went an re-flowed all the joints for all the pots. I also re-flowed most of the joints on the caps, and various other easy to get components. I then put the entire box back together, made sure everything was nice and snug, and even put all four screws on the bottom plate for a good ground and shield.

Everything works but I still have the radio-tuning issue. In some settings I get hardly any hisss, in other settings, it is way too much. Now I noted that my 9V battery was down to 8V, but I don't think that will explain much.

Next step - take everything apart, take a lot of pictures and post them.

The build has some cryptic instructions for installing the pots "Lift the PCB up off the pots and toggle switch about 2mm just to make sure that the back of the PCB does not short out against that pots." I didn't do this, but the pots (at least before they go in to the enclosure) are not shorting out. I previously had some insulating dielectic on the back of all to pots to make sure they were not shorting, but I took this out (because in theory it magnify the stray capacitance issues.) I don't think the problem is pots resting on the board...

Pictures should post tonight...starting to get a bit weary at this stage.

Pic, pics, pics, I re-ran all joints, and tried to clean everything. Still too much hiss and radio-tuning for me to be happy.
Let's see if these pics post... (2,3,11)

More pics (4,5,6)

more pics (7,8,9)

More pics (10,12,14)

Final pics (15,17,18). All these close-ups make it look like I destroyed the board. More flux than I expected at this zoom...