Topics

As the title says, I've got bad hum, my LFO led is not lighting up, and my LM13700s are all really hot. I've done the usual component and solder bridge check and don't see anything wrong.

I'm afraid I'll damage IC 3, 4, and 5 so I haven't left power connected for long enough to measure their voltages. So, I pulled them out, and here's my voltages on IC 1 and 2:
IC1:
1: 2.85   2: 2.85  3: 2.62  4: 6.3  5: 3.14  6: 2.85  7: 2.86
8: 3.4  9: 2.85  10: 2.81  11: 9.1  12: 2.86  13: 2.86  14: 2.85

IC2:
1: 5.7  2: 2.83  3: 5.7  4: 10.2 (seems high?)  5: 6.4  6: 0.9 (should be 0?)  7: 5.6  8: 2.86

Mine keeps slipping and sticking. Is there a way to fix these, or do they just wear out after a while? They seem simple enough, but no matter how many times I take it apart, I can't find the problem.

Finally getting to some pcbs I've had for a looong time. Working on a Superjudge now...
Sheet calls for a 1N4739 (9.1V 1 watt), but I don't have one. I do have a 9.1v 0.5 watt, will that work, or is it necessary to have a 1 watt diode?

I need a preamp for my turntable and was considering building a vero layout because... why not? Do any of you have experience with prhono preamps? I was wondering if you had any thoughts or advice on whether it is worthwhile to build one vs just buying a decent one. Like pedals, they seem overpriced for what they are.

I. Love. This. Pedal.
Really enjoying playing with this. A big thank you to David for helping me get it running, after hunting down a couple of incorrect resistor values.
I had a hard time finding a graphic for this. I spent days looking for a cool graphic with two mountains or peaks, but gave up after a while and decided on a water related motif. After I applied and envirotexed this, I realized I could have very easily copied the mountain on this and made it have two peaks in the background. I really wish I had now.
Anyway, here it is.

Edited after realizing I shouldn't use IN/OUT in the typical wiring.

I am using the "SND" as the input and the "RET" as the output.

I have no output signal. After probing, with tone at 50%, I have dry signal at both octocouplers, but nothing at C7 or C8, or anything after that in signal path.

My tap switch and LED are functioning and LED1 is lit.

My voltages look fine to me, but please feel free to check these:
TL074
1- 4.5
2- 4.5
3- 4.5
4- 0
5- 4.5
6- 4.5
7- 4.5
8- 4.5
9- 4.5
10- 4.5
11- 0
12- 4.5
13- 4.5
14- 4.5

LM356
1- varies
2- 3.3
3- 3.3
4- 0
5- 3.3
6- 3.3
7- varies
8- 5.0

TAPFLO
1- 4.95
2- 2.3
3- 2
4- 5
5- varies
6- 1.5
7- varies
8- 4.95
9- 2.5
10- 2.8
11- 2.2
12- 4
13- 2
14- 0

T1: O= 5, G= 0, I= 9.3
T2: O= 4.9, G= 0, I= 9.2

Edited after realizing I shouldn't use IN/OUT in the typical wiring.

My Mastech meter lights up the LED, but gives no reading on the voltage. It always reads "OL".
It may not work on this function, or it my be a crappy meter. If anyone could try with their Mastech Meter and post up, I'd appreciate it.

Please only post regarding the Mastech Meters, that is all that will help me. Thank you!

I'm not sure I understand how to wire the tap switch and tap LED. See the attach image for reference. Correct me if I am wrong...

1. The two lugs of the tap switch go to tap LED cathode and the "tap switch" pad?
2. The tap LED annode goes to the "Tap Led +" pad and the cathode goes to the tap switch?
3. The "ret" and "snd" pads are for an optional loop, or are they meant for some other purpose?
4. This image IC2 (U2) is labeled as NE5532, but the build doc parts list calls for LM358. I didn't think it mattered, but wanted to check.
5. The build doc calls for an LED with 2v forward voltage. How do you measure this?

It was mentioned in another thread that MN3007s are harvested from old karaoke machines, and it got me wondering what kind of stuff to keep an eye out for. If anyone knows which non-pedal related electronics have BBD chips in them, please chime in.

After deciding to just go with 9v operation, here's my finished Pork Barrel. I used one of the new stomps with the led washer. Looks really cool and the switch feels like it is of good quality. I went with off board pots so I could space them to look better on this enclosure and so I could use large knobs. I love how it turned out and how it sounds. I compared it to my MIJ CE-2, and it is 99% spot on. The knob settings even match up almost perfectly. I'll be using this a lot!

Try to ignore the little bit of velcro fuzz below the input label. It's not a blemish. 

I've done some searching, and can't find a straight answer. There seems to be some back and forth regarding whether the MN3007 version can handle the 15v or not. More specifically, I found where Brian mentioned that the IC can technically handle 15v, but the LFO portion can not. In another thread he also mentions that he may have had an issue with his charge pump that caused this. Elsewhere, it seems like some have built it this way and works fine.

I'd just like to know for sure: Can the 2015 rev.1 Pork Barrel run at 15v with the MN3007?

To continue, is the LT1054 recommended for the charge pump for this effect, or will one of the others (ICL7660SCPA, TC1044SCPA, etc.) work fine on this? I don't know how much current this circuit will draw, so I'm not sure if it matters which pump should be used.

Here's my vero 4 knob comp. I scored some nos 3080 chips a while back and am just getting around to using one of them. Mojo, baby, yeah! My drill got away from me and made a nasty hole in the vero, by the diode, but its still usable. It bothered me almost enough to start over, but not quite.

I figured some of you have enough experience with the pork barrel to help me out with my old Boss. I have an original MIJ CE-2 and its acting funny. Occasionally, and randomly, when I turn it on, the LED barely comes on and the sound is not quite normal. It seems like its not getting enough power. If anyone can give me any pointers, it would be appreciated.

Here's my voltages:
MN3007:
1 9.7
2 6.7
3 6.6
4 3.7
5 3.3
6 6.7
7 6.5
8 6.5

MN3101:
1 9.7
2 6.7
3 3.3
4 6.7
5 3.7
6 8.8
7 5.1
8 3.7

JRC4558:
1 7.4
2 7.4
3 7.4
4 3.3
5 7.4
6 7.4
7 7.4
8 9.7

TL0220P:
1 varies 5.1 to 8.8
2 6.4
3 6.4
4 3.3
5 varies
6 6.7
7 jumps back and forth from 4.0 to 9.0
8 9.7

I have an MXR Smart Gate, and according to the manual, its maximum input and output level is +7dBV. Assuming my Marshall JVM's line level power amp serial loop is the typical +4dBu, (the manual doesn't specify the level), does that mean I can use my gate pedal safely in the power amp serial loop?

Using an an online converter, +4dBu equals +1.78dBV, so I should be safe, right?

I am working on a vero build that requires 150k pots. Using the Analog Alchemy page, I calculated what value resistors to put across the lugs of my pots. My vero build only requires soldering wires to lugs 2 and 3. Do I need to solder a resistor between lugs 1 and 2 AND lug 2 and 3, or can I get away with only soldering a resistor between the lugs I am using (2 and 3)?

(FYI, I am using 200k pots with 270k resistors to achieve 146k pot, according to the calculator, which is close enough for me.)

I was working on a build today that called for a 320k resistor, which is not very common, so I didn't have one. I decided I would measure through my 330k resistors and see if one came close, only to discover they all would not register at all on my meter. Well, they would register around half of 330 for a split second, then go to 1, indicating no measurement. I tested other resistors (from mouser) and they were fine, ruling out a bad meter. So, once again, you get what you pay for, kids. Now I will test every blasted one of them before I use them until theyre gone, then no more Tayda resistors for me.

Update: It turns out it was my cheapo multimeter. Into the bin with it!

I saw this in a local craigslist ad. Anyone heard of it? It looks like a fairly simple pt2399 circuit. Just thought I'd see what you all think. I got the seller to send me a gut shot.

I can't seem to find anything larger than the typical 20mm (approx.) size chicken head. Does anyone make/have them?
Thanks!

I haven't built many delays, but I've seen multiple mentions of some sounding better than others. I've been lucky I guess, that none have sounded "bad", or maybe I just don't know what a bad chip sounds like. So, my question is... What does a bad chip sound like? Conversely, what does a good chip sound like? What sound do you listen for?

This makes two in a row from Jon Patton.

I love how this came out. I didn't want the footswitches to be too close together, so I opted for a larger enclosure. While I was at it, decided to make one row of knobs to fill out the space better. My only minor complaint about this circuit, and correct me if its just mine, is that the tap light doesn't immediately follow your foot. It stays solid for a moment, then reacts to the tapped tempo. Not a big deal at all, the pedal does exactly what I needed it to.