So I just finished building my Ping. All components in place, wires hooked up. Plugged it in and it passes a clear signal to the amp. Once I turn on the switch, the LED lights up but it makes what I would call a sputtering static sound and the guitar signal is cut off completely. I'm going through and checking all the wires, solder bridges that I can see, basically everything I can get at without taking off the reverb brick.
Does anyone have any ideas as to what this sound could be indicating?
Can we see a pic of the build and wiring?
(https://farm2.staticflickr.com/1592/25966486632_6565c8c16b_z.jpg)
(https://farm2.staticflickr.com/1547/25786163430_d7013dfb15_z.jpg)
(https://farm2.staticflickr.com/1641/25454244194_a048455109_z.jpg)
What's the solder side look like and have you reflowed everything yet?
Sent from my iPhone using Tapatalk
Quote from: jimilee on March 27, 2016, 01:45:57 PM
What's the solder side look like and have you reflowed everything yet?
Mainly everything is covered with the reverb brick. Contemplating how to heat and remove tin pins at once... ???
Desoldering iron or braid. Take some voltage Readings before that though.
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Are you sure you have that DC Jack wired correctly? I can't tell from the angle of the pic. You won't be able to use that jack anyway - it will cause a short with the enclosure. Use plastic/insulated jacks for DC.
Quote from: madbean on March 27, 2016, 02:45:18 PM
Are you sure you have that DC Jack wired correctly? I can't tell from the angle of the pic. You won't be able to use that jack anyway - it will cause a short with the enclosure. Use plastic/insulated jacks for DC.
Ah, good to know. I'll swap it out and try it again.
Is it possible I could have ruined something by not having the DC leads hooked up right and powering it on?
I think you have the opamp flipped.
Quote from: Leevibe on March 28, 2016, 05:18:05 AM
I think you have the opamp flipped.
I'll try that next. Is there a possibility i will (or have) burned something out or ruined any components by having this flipped and sending power to it?
Yeah good call - IC is wrong way in. It's possible it could have been damaged but in my experience it's probably fine. Flip it around, check your voltages on pin8 and 4 to make sure they are right.
I think you also wired the stereo pot in the wrong way. I think you swapped rows and columns there, though it's hard to see on the picture.
Ok, the IC was definitely in backwards. Now, when I switch it on I get no signal, but also no static. Whats interesting is that I accidentally bumped one of the #1 pins in the Room pot against the metal end of the guitar cable and it gave off a high pitch squeel but with reverb, so something is definitely working. I can also turn up and down the pots and they seem to be changing the sound as well.
Here's how i have the Room pot hooked up.
(https://farm2.staticflickr.com/1479/26077101306_7b3d68a485.jpg)
I did also notice that when the switch is on and I unplug the power, there is no bypass signal. It completely cuts out. Is that the way its supposed to be? Might i have the IN/OUT jacks wired wrong somehow?
If the pot is indeed wired like this, it should be ok :)
Post your voltages on all active device pins.
Use a fresh op amp. Putting them in backwards is a good way to kill them.
Audio probe. See if you get any signal at R2 /C1, pins 1 and 7 of the op amp (you won't get signal elsewhere on the chip because it's an inverting op amp), the base and emitter of Q1, and pins 2 and 3 of the verb pot. You can check the pins of the brick if you lose it between the last two areas.
Folks, can we PLEASE remember to at least ask for voltages and audio probe results before speculating and potentially sending people on wild goose chases?
Volt meter. No idea what I'm doing... What setting do I need to have this on? I'm getting quick flashes of numbers, and when HOLD is on, nothing.
https://flic.kr/p/FSnTN1
The blue ones on the left are DC. The number is the maximum voltage you can measure with that setting. So, since this is a 9V pedal you should use the blue 20 on top left. Attach the black common cable to ground (such as sleeve of either jacks) and measure the voltages with the red cable. :)
Here's a great tutorial video about measuring voltages: https://www.youtube.com/watch?v=idWhtCU7xw0
Thanks a ton!
Here are my readings:
IC 1
1-4.18
2-3.76
3-2.24
4-0.00
5-2.24
6-4.17
7-4.19
8-4.49
IC2
1-2.51
2-0
3-----
4-0
5-0
6-0
7-1.27
8-1.25
9-1.27
10-1.25
Q1 (right to left, flat spot facing downward)
3.87
4.09
4.5
Reg (right to left, flat spot facing down)
2.51
0
4.49
I should also note, tried two other TL072's and got similar readings
From the looks of it, it seems like my voltages are about half what they should be across the board.
what power supply are you using and what is the voltage reading on the +9V input? You are definitely having a problem somewhere in your power supply. the regulator needs more than 5V to put out steady 5V, and without that the reverb brick won't do anything..
On the same note as Felix above.. check your pinout on your regulator. I have had some that the pins were flipped 180 degrees from the mask on the board.
Hope this helps
Cody
Quote from: m-Kresol on April 06, 2016, 07:32:08 PM
what power supply are you using and what is the voltage reading on the +9V input? You are definitely having a problem somewhere in your power supply. the regulator needs more than 5V to put out steady 5V, and without that the reverb brick won't do anything..
I'm using one of those One Spot adapters with a daisy chain powering several other pedals. They all power up and work just fine. I've plugged it into a at least one other adapter with the same result.
Quote from: selfdestroyer on April 06, 2016, 08:01:43 PM
On the same note as Felix above.. check your pinout on your regulator. I have had some that the pins were flipped 180 degrees from the mask on the board.
Hope this helps
Cody
Thanks, i'll give that a shot too
hmm. I can't be the regulator alone. You've also got low voltages on IC1, which should get 9V supply voltage on pin8! Check the voltage on the supply pin and on the cathode (-) of D1. Hope you get it sorted, good luck
Completely different readings today, >:( and all I've done was put the project away for a few days. The input wire did come disconnected at some point, so I re-attached that. But still no signal:
IC 1
1-8.41
2-6.91
3-4.50
4-0.00
5-4.51
6-8.37
7-8.43
8-9.03
IC2
1-5.05
2-0
3-----
4-0
5-0
6-0
7-2.56
8-2.52
9-2.55
10-2.52
Q1 (left to right, flat spot facing downward)
7.81
8.14
9.05
Reg (left to right, flat spot facing down)
5.05
0
9.05
Cathode end of D1 is 9.05
Power input is 9.33
In my last readings I mistakenly said right to left when i meant left to right on the REG and Q1 readings. I haven't flipped the REG yet.
ok, readings look better now! Don't switch the regulator, it's fine like that (puts out 5V).
You seem to have a problem at IC1 though, all voltages are higher than what it says in the doc.
your Vb (pin 3 and 5) are good, so the voltage divider and the cap are ok too.
I actually don't know what's causing your increased voltages as my knwledge about opamps is really limited. One possibility would be a solder bridge?
I checked out all the solder joints... Not seeing any bridges any where. Now I'm starting to think I may possibly have it wired incorrectly. Here's a sketch of the tracing of the wires:
(https://farm2.staticflickr.com/1566/25776471324_52351f3e57_z.jpg)
You've got power wired to the wrong lug of your DC jack. You want the middle lug, not the outside one -- that's the battery disconnect terminal.
I made this mistake on two builds in a row before learning not to do it a third time.
I tried that. It didn't work at all, didn't even power on. Maybe my drawing was wrong.
I flipped the regulator and got almost the exact same readings. Still did not pass a signal when switched on. Only a very faint one that I could hear once I cranked up the volume on the amp. I could even hear some self-oscillation when the pots were both at max. In the process I broke a leg on the REG, so I might as well socket a new one in this time. :-\
Got a new transistor and a new IC and it works! I needed up trying 4 different TL072's before I found one that worked. Now to finish the enclosure and box this up... Thank god the problem wasn't some other hard to remove component.
Congrats! Good job sticking with it. How does it sound??? I have to say, it seems a little suspect to have that many TL072s be bad. Curious where you sourced them. Hopefully it's just a bad run of parts and not an intermittent problem that will resurface. Anyway, at least you know it works. That's awesome. I need to put in a SB order so I can start rocking some of these 1590g's.
I'm not 100% sure it wasn't a bad or damaged transistor either. It sounds good! There is a little self oscillation when both pots are cranked, and i kind of wish there was more. But its good the way it is. crossing my fingers nothing breaks after I box it up...