CURRENT LOVER 2015 ISSUE

[JMPearlman]

EDIT: Please see my updated voltage readings and description of the issue lower in the thread. The pictures are still in this original post. Thanks!

Hello All,

I'm having issues with my Current Lover build. I think I have all the proper components, I've checked the orientation of electrolytics, diodes and ICs, I've re-flowed the solder and I'm fairly certain my wiring is okay. So, I've taken voltage ratings of all the ICs and there are definitely problems. Unfortunately, I'm not too capable of telling exactly what is causing the problems. I'd appreciate some brighter minds than mine taking a look. Thanks!

https://www.madbeanpedals.com/projects/_folders/FilterMod/pdf/CurrentLover_2015.pdf

https://imgur.com/a/63xcEfB

I'll list the proposed measurements and my measurements to the side.

IC 1
1. 4.5 -- 5.2
2. 4.5 -- 5.2
3. 4.1 -- 0
4. 0 -- 0
5. 4.5 -- 0
6. 4.5 -- 1.1
7. 4.5 -- 4.9
8. 9.1 -- 10.2

IC 2
1. 9.1 -- 10.2
2. ~ 4.4 -- 4.2
3.~ 4.8 -- 0
4. 41mV -- 0
5. 0 -- 0
6. ~ 4.4 -- 4.2
7. ~4.2 -- .07
8. ~4.2 -- .07

IC 3
1. 9 -- 9.9
2. 4.5 -- 4.3
3. 4.5 -- 3.6
4. 4.5 -- 3.6
5. 4.5 -- 3.4
6. 4.5 -- 3.6
7. 4.5 -- 3.37
8. 0 -- 0
9. 4.5 -- 3.6
10. 4.5 -- 4.3
11. 4.5 -- 3.6
12. 4.5 -- 4.3
13. ignore
14. 4.5 -- 3.6
15. 4.5 -- 4.3
16. ignore

IC 4
1. 4.5 -- 3.4
2. 4.5 -- 3.4
3. varies
4. 0 -- 0
5. 4.5 -- 3.4
6. 0 -- 0
7. 0 -- 0
8. 0 -- 0
9. 0 -- 0
10. 0 -- 0
11. 0 -- 0
12. 9 -- 0
13. 0 -- 6.7
14. 9 -- 9.8

IC 5
1. varies
2. ~ 4.2 -- .11
3. varies
4. 9 -- 9.9
5. 0 -- 0
6. 0 -- 0
7. 7.8 -- 0
8. varies
9. varies
10. varies
11. 0 -- 0
12. ~ 4.2 -- .11
13. ~ 4.2 -- 0
14. varies

IC 6
1. 0 -- 0
2. varies
3. varies
4. 0 -- 0
5. 9.1 -- 10.4
6. 9.1 -- 10.4
7. varies
8. 9.1 -- 10.4

IC 7
1. 4.5 -- 5.2
2. 4.5 -- 0.17
3. 4.5 -- 1.7
4. 0 -- 0
5. 4.5 -- 0
6. 4.5 -- 5.2
7. 4.5 -- 5.2
8. 9 -- 10.4

When the effect is bypassed I can hear the high pitched "airplane taking off" sound, and when the effect is engaged there's a terrible high pitched squeal. Any help is greatly appreciated!

[Zerro]

Lowpass around Q1 is suspicious at first. Clock freq is penetrating your output. C9, C6 and R17 - try controll. And power supply - how strong it is? All caps in power branch try controll too.

[JMPearlman]

The reading at the power jack was reading around 10v. I'm not sure I understand the rest though.

[Zerro]

When power supply is weak, not matter what voltage it shows at VU meter, it cannot hold clear power without to be modulated some processes inside of your project. At oscilloscope you would see that power line is "waved" by HF modulation of clock freq, and/or another trigger rates, and this you can finally hear at the output. So the capacitors are important in power branch and power strenght of your supply. Try for a moment feed it from heavy duty baterry with that voltage. So, this is the question of power.

That second issue is more suspicious - that low pass filter around Q1. I mentioned before. Maybe some grounded detail is hanging off at real.

[thomasha]

The voltages are all over the place.
Are you powering it with a 12v or a 10v supply? Is that 10V reading without load?

The 5.2 makes sense if you are powering it with 10.4v.

First try to get the voltage at the voltage dividers right. That means the correct VR, VB, VC and VD.
If you are using 10.4v they all are going to be a little higher than the readings.

IC7B Should have 4.5V at pin 5, without that VB will not work. It is weird that you have 5.2v at pin 6 and 7, but not at pin 5. VB is 0 at every other pin that you measure. But IC7 B, pin 7 is at 5.2v. That is weird.

It is probably a could joint near IC7b, which results in the weird voltages.

Without powering the pedal, test the continuity of every component in that region (use the schematic for the resistor numbers, lower right corner of the schematic has the different supplies).

If you get the voltages there right, the voltages at the chips should be right, and the chips correctly biased.

Let us know if you find something.

[JMPearlman]

Welp. I don't know what happened, but I retook measurements and everything is pretty close to what it should be with the exception of pin 7 on IC5. Mine is at 0. The rating of my power supply read 10.35. Here are the voltage readings now:

IC 1
1. 4.5 -- 5.2
2. 4.5 -- 5.2
3. 4.1 -- 4.7
4. 0 -- 0
5. 4.5 -- 5.04
6. 4.5 -- 5.09
7. 4.5 -- 4.9
8. 9.1 -- 10.06

IC 2
1. 9.1 -- 10.06
2. ~ 4.4 -- ~ 5
3.~ 4.8 -- 4.7
4. 41mV -- .22
5. 0 -- 0
6. ~ 4.4 -- ~ 5
7. ~4.2 -- ~ 4.2
8. ~4.2 -- ~ 4.2

IC 3
1. 9 -- 10.05
2. 4.5 -- ~ 5
3. 4.5 -- ~ 5
4. 4.5 -- ~ 5
5. 4.5 -- ~ 5
6. 4.5 -- ~ 5
7. 4.5 -- ~ 5
8. 0 -- 0
9. 4.5 -- ~ 5
10. 4.5 -- ~ 5
11. 4.5 -- ~ 5
12. 4.5 -- ~ 5
13. ignore
14. 4.5 -- ~ 5
15. 4.5 -- ~ 5
16. ignore

IC 4
1. 4.5 -- ~ 5
2. 4.5 -- ~ 5
3. varies
4. 0 -- 0
5. 4.5 -- ~ 5
6. 0 -- 0
7. 0 -- 0
8. 0 -- 0
9. 0 -- 0
10. 0 -- 0
11. 0 -- 0
12. 9 -- 10.05
13. 0 -- 0
14. 9 -- 10.05

IC 5
1. varies
2. ~ 4.2 -- ~ 4.6
3. varies
4. 9 -- 10.03
5. 0 -- 0
6. 0 -- 0
7. 7.8 -- 0
8. varies
9. varies
10. varies
11. 0 -- 0
12. ~ 4.2 -- ~ 4.7
13. ~ 4.2 -- ~ 4.7
14. varies

IC 6
1. 0 -- 0
2. varies
3. varies
4. 0 -- 0
5. 9.1 -- 10.06
6. 9.1 -- 10.06
7. varies
8. 9.1 -- 10.06

IC 7
1. 4.5 -- 5.02
2. 4.5 -- 5.02
3. 4.5 -- 5.02
4. 0 -- 0
5. 4.5 -- 4.98
6. 4.5 -- 5.02
7. 4.5 -- 5.02
8. 9 -- 10.06

When the effect is bypassed I get a clean guitar signal, but when it's engaged I get lots of white noise / whooshing. However, I also get my guitar signal and can achieve some flanging when turning trimpots. Just need to get rid of the noise and I might actually have this thing ready to go. Any ideas? And thanks for the help so far.

[Zerro]

That is that Q1 and lowpass filter around it. Capacities and Q1. Tro to replace.

[JMPearlman]

I replaced Q1 several times with no change in noise. I should try replacing C9 and C6 now? Thanks for the help.

[thomasha]

Looking at the schematic shows that pin 7 of IC5 is disconnected, with both inputs grounded. It will not make a difference. So the circuit should be OK.

Can you also measure the transistor pins?

Something I just realized is: You are powering it at 10v. BBDs are very sensitive to bias. When I say very sensitive, I mean less than 1V can make a huge difference.

First: The Bias of the BBD is still at 4.8V (pin 3 IC2) and the output is at 4.2v (pins 7 and . What does the document say about using other voltages? There is at least one change that is necessary (R13). I only ever seen this pedal powered with 9v or 12v, never 10v. You may have to change R13 to something between.

Second: The bias of 4.8v is probably for 9.4v (as stated in the document). That means: 10.3/9.4*4.8 = 5.3v.  I would start there. If you cannot get there, try reducing 82k. Some people even suggest that it is not necessary and may only reduce the ability to change the bias.

Do you have an oscilloscope?
If you do not have one, turn the bias trimmer until there is no flanging on one side, and then turn it the other way around until there is no flanging. Mark this two points, there is a high chance that the ideal bias is exactly in the middle. You can then fine tune with your ears.

Flanging is more pronounced with the feedback on max., but then you cannot hear the original repeat clearly. Try with the feedback at min. too.

Trimmer T1 also changes the feedback. See how it sound when it is at the lowest setting. You don't want the loud oscillations now. 

Is the filter matrix position working? I think it is easier to test everything with the LFO setting, and with the rate pot at half way, where the flanging occurs slowly. 

The clock trimmer should be adjusted so that you have a weird chorus like sound at half of the way and a normal sound on the other. In one direction it will go deeper into chorus territory and have lots of hiss, too much to the other side and you end up not having the flanging, because the clock is too fast and you are into that territory where it sounds kind of dry.

I think in filter matrix mode there is no LFO, so you are at a fixed clock setting. Try measuring pin 3 of IC4 or pin 7 of IC6.
By the way, do not use the voltages in the document as a reference for setting the trimmers (you can multiply them by the same factor 10.3/9.4 I used, to see how they should look like)

Last but not least, BBDs can be noisy. Hiss is normal at some settings.

PS: I was writing this, when I saw your update. I think the noise is incorrect bias+wrong adjustment of the trimmers and not a bad transistor or leaking cap.

[Zerro]

Hi, optimal would be the measure those transistors and capacities. Most of standard or even low-end VU meters have this functionalities. It is good investition to future. By a way :@)

Put out and measure details I mentioned before. It is first. Second, control and measure all tracks if they are consistent and without crackles. They can be very tinny to see. Clear all points around with needle from tin dust. That is good start and maybe will help. And then, if problem is going on, try that trick with power from heavy duty battery. And finally, those caps in power branch. They are here to clear power from HF penetration.

[JMPearlman]

Looking at the schematic shows that pin 7 of IC5 is disconnected, with both inputs grounded. It will not make a difference. So the circuit should be OK.

Can you also measure the transistor pins?

Something I just realized is: You are powering it at 10v. BBDs are very sensitive to bias. When I say very sensitive, I mean less than 1V can make a huge difference.

First: The Bias of the BBD is still at 4.8V (pin 3 IC2) and the output is at 4.2v (pins 7 and . What does the document say about using other voltages? There is at least one change that is necessary (R13). I only ever seen this pedal powered with 9v or 12v, never 10v. You may have to change R13 to something between.

Second: The bias of 4.8v is probably for 9.4v (as stated in the document). That means: 10.3/9.4*4.8 = 5.3v.  I would start there. If you cannot get there, try reducing 82k. Some people even suggest that it is not necessary and may only reduce the ability to change the bias.

Do you have an oscilloscope?
If you do not have one, turn the bias trimmer until there is no flanging on one side, and then turn it the other way around until there is no flanging. Mark this two points, there is a high chance that the ideal bias is exactly in the middle. You can then fine tune with your ears.

Flanging is more pronounced with the feedback on max., but then you cannot hear the original repeat clearly. Try with the feedback at min. too.

Trimmer T1 also changes the feedback. See how it sound when it is at the lowest setting. You don't want the loud oscillations now. 

Is the filter matrix position working? I think it is easier to test everything with the LFO setting, and with the rate pot at half way, where the flanging occurs slowly. 

The clock trimmer should be adjusted so that you have a weird chorus like sound at half of the way and a normal sound on the other. In one direction it will go deeper into chorus territory and have lots of hiss, too much to the other side and you end up not having the flanging, because the clock is too fast and you are into that territory where it sounds kind of dry.

I think in filter matrix mode there is no LFO, so you are at a fixed clock setting. Try measuring pin 3 of IC4 or pin 7 of IC6.
By the way, do not use the voltages in the document as a reference for setting the trimmers (you can multiply them by the same factor 10.3/9.4 I used, to see how they should look like)

Last but not least, BBDs can be noisy. Hiss is normal at some settings.

PS: I was writing this, when I saw your update. I think the noise is incorrect bias+wrong adjustment of the trimmers and not a bad transistor or leaking cap.

Hey Thomasha,

I can take transistor voltages and report back when I get home this evening.

Regarding my 10v of power, I'm really not sure why that's happening seeing as how I'm using a 9v power supply (a standard boss style power supply and then a 9v port of a truetone one spot power supply with the same result).

I forgot to mention earlier in the thread that I took madbean's note about R10 and replaced 82k with a 1k. I've since removed and soldered a jumper, however it made no discernable difference.

The issue doesn't seem to be improper biasing (at least not only that) as there is no setting with the trimmers that results in no noise. If the effect is engaged there is noise/hiss/wooshing/distortion no matter where the trims are set or the combinations of the trims. The noise intensifies when the bias trim is set in what would likely be the "right" spot, but there is always noise.

I think zerro's mention of the low pass filter needing some attention is a good road to go down next. However, as I'm new to reading schematics, I'm not entirely sure where to find the low pass filter or which particular components are making it up. Any help with that would be greatly appreciated. I hate that I need someone to walk me through that at such a granular level, but that's the way it's got to be right now haha. I also have some new transistors and a couple new 3007s on the way to try out just in case. Thanks again! Sorry it took me so long to reply.

[Zerro]

Hi, I attached schematic with emphased details around Low pass filter (red color) which are important to measure, including PCB tracks, if there are not cracks which would disconnect some branches of circuit. Low pass filter takes away from signal HF part, which remained here from previous processes. Thus, signal is not poluted by HF modulation. Especially notice those capacitors I mentioned before. I think that it will be some of it, and repairment will be easy.

And don't forget for that power supply - experiment with outer heavy duty baterry. I am wonder for results ;@)

And last thing - VB output is blocked in power supply with cap C25 10uF. I emphased it with blue color. Try to attach paralelly with it another cap - film cap 100nF the same type like C22. Honestly, I would add this cap 100nF to VC output too.

p. s . By a way, I realized, that HF freq are generally very "problematic" to shield it away from output tracks only by those means. So, try to get rid all problematic wiring - play around power and signal wires placement in box.

[JMPearlman]

Thanks so much! The hFe on the 2N3904 (Q1) is 282. Voltages are E ~4.2 B ~4.9 C ~10.3. The hFe on 2N5087 (Q2) is 400. Voltages are E - 10.3 B - 6.1 C ~ 1.2.

[JMPearlman]

Going through the circuit with an audio probe showed all the noise originating from R5 to R6 and onward. I double checked the values and I have the right components in the right place. Seems kind of strange. I figured I'd go through with the probe before doing anything else, but I didn't expect to find the noise that early in the circuit.

[Zerro]

IC1_a at a very start of input circuit is the first detail (op amp) connected to power supply. So, that noise (I mean HF noise, not normal one) is originated from power supply. It is clear now. Nothig can give it here from another way. So aim at this. I sent before picture with colored branches. That blue enhanced part needs the controll. Some caps will be bad or tracks damaged. But this cap 100nF I recomended to add is usefull. I would add it to all power terminals, not only VB, but VR and VD too. See my new attachment.