Hamlet+ problems

[jkokura]

It's possible too that there's an issue in the power section. It is very strange that you'd get this twice in a row, but I would once again double and triple check your soldering, your part values, your part orientation, and even use something to scratch between the individual solder pads. If you can use some rubbing alcohol to clean the back of the board, that might be worth doing as well.

Jacob

[Dawnofzion]

I dug around in my box of random guitar things and found a couple different power supplies.  Both were 9v - 400ma. I thought I would hook them up and check for the same noise.

The pedal made noise with all 3 power supples.  Each one made a different noise.  All at the same volume, just with a different tone. 
It's Crazy how this thing makes so much noise with any power supply, and attached but not with a battery. 

[midwayfair]

It does look like it's a power section issue.

A battery has no switching noise for a start. I don't know if all the power supplies are switched mode but it's fairly likely. If they're all making noise even with the charge pump pulled then you'll have to start poking around the components in the power section.

First, a little explanation. The filter capacitors in a DC supply are primarily to filter out a very high-pitched noise that switching supplies make (basically the frequency of the switching). They're not for filtering hum in that case and they could actually be lower values than we tend to use and still do their job. In some other types of power supplies, the capacitors are there to hold a reserve of voltage in between the power supply swings every 120Hz (because rectified 60Hz AC is doubled). When filtering high frequencies, the internal resistance of the power supply and the capacitors form an RC filter.

IIRC, as the filtering improves, the pitch goes up.

So you've got a *fairly* low-pitched noise, which I suppose could indicate a filtering issue.

I'm going to try to simplify some things here while we search for the issue.

1) Remove the Zener. If you're never at risk for plugging in anything except a 9V supply, this isn't needed. Plus when they fail they can cause all sorts of issues, like shorting your power supply to ground. Sometimes they also cause noises. Etc.

2) If the 5V regulator is socketed, try removing it. This will leave the charge pump and the transistors as the only things running. (We've already established that the circuit can run with the charge pump. You can leave that in or remove it as you like.)

3) Check your caps. I know you probably already did this, but check to be sure.

4) I just noticed a typo in Jacob's schematic, where C18, the main filter capacitor, is only 10uF. There are actually a lot of power supplies where this would be fine (remember how I said above that we're just filtering very high switching noise?), but it was a 100uF in my original design. Go ahead and increase that. Maybe this should be #1 on this list, but I'd still remove the Zener.

[Dawnofzion]

I will try changing out the 10uf cap for the 100uf first.  The two additional power supplies that I tried out did produce a really pitched low noise....much lower than the 1spot. So what you said above makes sense.

In regards to the zener....if it is ok to remove it, what was its purpose?  Can it remain out? 
Also,  could you share a link to a proper zener for this project?  I used one I had laying around and if I purchase another one, I want to make sure I am getting something that is appropriate.  You can see in my images it is the small red one. Maybe this is the wrong Zener?

I am away from Home for a couple days but will try the 100uF cap exchange when I get back.

[jkokura]

A 12V Zener is there to prevent more than 12V from hitting the LT1054, because that would blow the chip and it's more expensive than the Zener. Essentially, this part is just insurance, but if you're sure you're only feeding the pedal 9V, than removing it should be fine.

If you're just using a random Zener, it's possible that's the issue. I don't know for sure, because I don't know the part you're using.

Here's the option from Mouser that I recommend.

http://ca.mouser.com/ProductDetail/Fairchild-Semiconductor/1N4742A/?qs=sGAEpiMZZMtQ8nqTKtFS%2fD313Kx94AdFJGMlPg6CdPg%3d

Here's one from Smaller that I recommend,

http://smallbear-electronics.mybigcommerce.com/diode-zener-1n4742a/

Jacob

[Dawnofzion]

I removed the Zener and replaced the 10uf with a 100uf as discussed.  Still have a noise.  I then replaced the d4 for safe measure....still noise.  After each thing done above I checked and the noise would change pitch.  I did notice the pitch changes as I rotate the bias pot. 

Still dead quiet with a battery. 

[jkokura]

Have you tried using the 5088 on a breadboard to see if that's the issue?

Jacob

[Dawnofzion]

I don't have a bread board.  I need to get one. 

[Dawnofzion]

I am picking up a breadboard today....however, I have never used one.  I know is may be an elementary question, but I am still kind of new to pedal building.  How would I go about building the power section of the pedal on the bread board to try and find the problem? 

[midwayfair]

I am picking up a breadboard today....however, I have never used one.  I know is may be an elementary question, but I am still kind of new to pedal building.  How would I go about building the power section of the pedal on the bread board to try and find the problem?

A breadboard will have two rails, one for ground (-) and one for the positive voltage. Most breadboards have two sets of rails, one on each side. Since the whole row on one side will be connected, make sure you keep the +9V rail separate from the +18V rail. Alternatively, if you have a road rage board, you can use that for your +18V connection point. (I keep one around for breadboarding.)

As far as basic breadboarding goes, Smallbear has a series with some basic tips starting here:

http://diy.smallbearelec.com/HowTos/Breadboarding/BreadboardIntro.htm

I know it's kind of a pain to run through some stuff unrelated to your project, but the tutorial really is great and it's way more thorough than what I can type out in a forum post.

Unfortunately, his tutorial for ICs involves an in-line 8-pin op amp. To get you started there, you want to have the IC "straddle" the center division of the breadboard, so that each pin has its own separate column.

Start simple -- get the basic power section stuff and a single transistor stage working first, to make sure you've grasped how the breadboard works. Keep your multimeter handy so you can check continuity.

Breadboarding is a fun way to mod effects and it's also a good way to eliminate some frustrations while troubleshooting, so it's worth some extra time up front to develop some good habits.

[jkokura]

Just to echo what Jon is talking about, the real key issue here is isolating that Q1 transistor. It seems to me that we need to verify that it can work without causing you any noise. If the source of the noise is that transistor, we can simply swap it out for one that's working properly.

If it's not the issue, and we know that it will work without making noise, then we know that it's another issue. It's part of the reason we recommend testing PCBs before installing them into an enclosure (rock before box) so that we know it's not the PCB, and can check through switch and wiring system to find the problem if it doesn't work when boxed.

Eliminating and verifying independant sections is the key to debugging.

Jacob

[Dawnofzion]

I picked up a few different LEDs when I got my breadboard.  This evening I thought I would replace the tempo LEDs to see what that would do.  To my surprise the new LEDs worked just fine.  Both flashing as they should.  However, it is still making some really crazy noises.  Check out the video below.

https://youtu.be/FK5Vlzr73d8



On another note, I have read through some basic bread boarding instructions.  After watching a couple of bread boarding how-to's on YouTube, I thought I was ready to do the power section of this pedal...
I pulled the schematics out and immediately was overwhelmed. Haha.
I guess I was a tad overconfident. Then I thought, even if I knew how to lay out the power section on the breadboard....how do I connect it to the PCB and where?  This is how I would check for the noise. Correct?

[midwayfair]

The way I would do it is to pull the charge pump from the PCB and insert a wire from the 18V output from the breadboarded supply at the pin8 connection on the PCB. You'll lose a quarter of a volt from the extra 1N5817, but that's not that big of a deal. Or you can solder a wire to one of the 18V points (i.e., on the trimpot or on the top of the 4k7 connecting to Q1).

You might have an easier time breadboarding the charge pump section if you use the Road Rage schematic. There's a lot less going on in that!

[Dawnofzion]

Ok I finally got the noise gone. I bought a new power supply in combination with replacing a couple power section parts and the noise is gone.  I boxed it up into the enclosure and now I only get the dry signal. Zero delay coming through.  If I turn the repeats all the way up I get oscillation sounds but no delay sound from the guitar.   It's as if the pedal is bypassed at all times?  It was working perfectly prior to boxing it up into the enclosure.

I thoroughly checked everything over and cannot see anything that looks suspicious. 

Any ideas?


Sent from my iPhone using Tapatalk

[midwayfair]

Ok I finally got the noise gone. I bought a new power supply in combination with replacing a couple power section parts and the noise is gone.  I boxed it up into the enclosure and now I only get the dry signal. Zero delay coming through.  If I turn the repeats all the way up I get oscillation sounds but no delay sound from the guitar.   It's as if the pedal is bypassed at all times?  It was working perfectly prior to boxing it up into the enclosure.

I thoroughly checked everything over and cannot see anything that looks suspicious. 

Any ideas?


Sent from my iPhone using Tapatalk

Backs of the pots isolated? If you unbolt the pots and pull the board up, does it come back? Basically, try one by one pulling things away from the enclosure until the sound comes back. Just to narrow down the problem.