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Pin 8 is waaay cool.

I wanted to mention R5 is a series of 2k and 390 ohm resistors, and the pot I first referred to is the external pot. The wiring on that checked out.

Here's a link to the squealing sounds, if you're interested. I was wondering what is causing this effect in case it could be harnessed in some way for another project.
**Please make sure to keep your volume low!**
http://youtu.be/tP2IlPtKNFA

Here are the voltages:
1) 5.12
2) 5.09
3) 4.98
4) 0
5) 0
6) 8.76
7) 8.76
9.33

So something is amiss with pins 6&7 but according to my understanding of the schematic (IC1B) don't they simply connect to each other?

Pics

I just built the Cupcake. Everything works but I have a few questions:

1. Is the 10K pot supposed to be at 0 volume at it's lowest setting, then peak midway, then return to 0 volume when at its highest setting?
2. I am getting wild squeals with the trimpot in most settings (persistent, throughout notes being played) that change pitch and intensity if you roll the guitar volume/tone up or down. What is going on?

Now I admit - I ordered my IC from Tayda and they did not have something called JRC4558, but "NJM4558" (which has 4558D / JRC / 0058T). That is the IC I am using and getting these weird results. There is a setting I can reach where there is no squealing, but it seems to not be doing much as a compressing effect. Again, the volume is at 0 when the level pot is at 0 and returns to 0 when the level pot is maxed.

I also bought another "4558" IC from Tayda - the TJM4558CN - do not know what kind of difference this will make. It's tough to desolder ICs. Any pointers on that, while we're at it!?

Josha

Well, further testing has shown one more issue -  I am getting a high squealing when the tone knob on my bass is rolled up to the treble side and the distortion is past about 12. Also this happens in conjunction with the "Cut" on the pedal between 7 and, say, 10 or 11. I realize the Cut is very similar to the tone knob on my bass, but don't know what this means, or why more treble through those pots would cause this squealing. The pitch of the squeal changes as I move either the pedal Cut or guitar tone pots.

Anyone have experience with something like this?

Thanks everyone. Unboxed it, grounded the output jack and resoldered a few suspect joints. It was a good opportunity to get some use out of my DMM I just got. Cap had correct orientation, and I was getting continuity tones all over.

In the end it was indeed shorting out because the back of the board was contacting the enclosure. I put a piece of canvas over the back of the PCB and that was it.

Cool! First build! Looks kinda Sputnik and beat up, but I like it.

You don't have to ground the jack sleeve but if you can it will help with reliability in the case the jack gets loose.

Do I ground to the switch, the DC jack, or the input sleeve?

I couldn't tell from your post, but did you "rock it before you boxed it?" 

This build was working in a temporary enclosure previously, which is why I suspect it is something to do with the wiring - did I get the DC lug wiring correct? That is something I reworked when boxing In the 1590A.

Seeing as you got everything to fit...you already did the most difficult part! 

...and now I'm terribly afraid if I remove it, it will never go back in!

But I will do that, makes the most sense for troubleshooting. Any worth in continuity check while still in the box from IN to OUT jacks?


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I built the Runt previously and housed it in a temporary enclosure. Now I decided to finally try and get it into the 1590A and have run into a few issues. I basically followed the baby build guide step by step. I got it to all fit. I checked the bypass which seemed to work. I installed the pots and connected up IN/G/OUT at the bottom of the board to the 3PDT switch, 9V and G at the top to the DC jack and fired it up to no great success...

I switched out C1 with a 2u2 electrolytic, and I believe I have the polarity correct (can this be tested with DMM?) - currently negative lead is connected to R1. I had it the other way around originally and was getting no signal.

I am fuzzy on the resistor that completes the LED circuit, but have attached a photo to show my interpretation of the baby build procedure.

I am getting a loud buzz when I turn up the volume, so I'm assuming this is a grounding issue, but I don't know where I went off.

Well that's great to hear. It was not so much that I was turned off by the noise, but I wanted to see if perhaps I did something wrong. So far my builds have been fun and trouble free! Now, fitting everything into a 1590A is another story. I think I like wire sculpture too much...

OK, second build, Cave Dweller, super fun build, I got it all to fit into a maybe 4" diameter can. It looks like a spaceship!

My problem is with the echo function. The echo, or slapback sound is not a direct echo of the input sound. That is to say, when I play a note, the note is colored with this "pfft" or "pptthh" kind of fuzzy sound. This only takes effect in the last 1/3 of the echo pot. The first 2/3 of the sweep are clean.

I replaced socket C3 with a 3n3 cap, and also have a 1uF tantalum cap in C10. Polarity on C10 is correct.

I have not tried any problem solving yet, as I am quite new, and am more so "assembling" pedals at this point than "building" them. Anybody have any ideas?

Cool, I ended up with 200n on the input cap and 2u2 on the output and it sounds to my liking. A noticeable amount of bass increase. WOO BOY this is fun stuff!

JL

If you use it for bass you might want to change the input capacitor to 220n or so.

Could you explain why, exactly, that is? I put 2 100n caps in series in C1 since I did not have a 220n, and do not notice much difference. What is the added capacitance doing?

Yes I did. I see now that I used a 47 Ohm resistor instead of 47k... Thanks for the quick reply. I'll make sure to keep my values straight next time! Have you built this pedal? It sounds great through both my bass and guitar, when I play through a Bass VI there's a terrible hiss and it seems like there is some sort of phasing going on. Ever experience that with this pedal?

Built the Runt. Sounds great. First build ever (still unboxed). Had a blast. BUT...

I originally used a 3mm blue LED for a power indicator. I noticed when I touched one of the LED leads when it was powered, it glowed slightly, although the pedal was off. I then turned the pedal on, and after a minute or two of playing through it the LED apparently died. I replaced it with 3mm green. It began blinking when I turned it on and played, and died very quickly.

I am using a CA3130EZ instead of the LM308. Also, I am using an electrolytic capacitor for C9, however the polarity is correct.

Any idea what's frying my LEDs? This was really fun for me and I'm eager to get it into a box!

OK so I finally got all my parts in the mail... I am trying my hand at a Runt and accidentally got electrolytic 1uF caps (C9 on the Runt). My heart is telling me the positive should come from R9 and the rest of the circuit. The negative goes straight to Volume, so the other side coming in would have more voltage. Does that logic make sense? It happens to be in an "ending point" so I am not running in to other voltage sources, is that right? Is it a rule that there's always more voltage on the side closest to power?

Either way I am having a lot of fun populating the board! I will definitely order some film caps, as right now I just have electro and ceramic (should sound fun...)

Thanks!