Current Lover: Double "pop" on some settings

[UnclePsychosis]

Hi guys.

I have a Current Lover (2015) that someone else built (bought it on ebay). I've built three or four pedals in the past but nothing as complex as this.

The pedal sounds really good, but on some settings there is a loud double "pop" . It repeats when the LFO gets to the end of its sweep, but sometimes the popping goes away. The problem seems to appear if I max out the controls (particularly the Range pot). Its not always repeatable and sometimes it goes away. It sounds like the kind of pop you get when plugging a cable in or from a DC offset/footswitch problem.

The seller advised me to "Try turning T1 anticlockwise a quarter turn. That may help."

Does this sound sensible? Reading the build manual suggests to me that its the Clock trimpot I want to adjust.

Any tips? I don't want to radically alter the sound because fundamentally it sounds good, just this pop is annoying as anything!

[Orbis_Ignis]

T1 trimmer just sets the maximum feedback. Does the pop go away with the feedback  knob set lower? If not, I wouldn't think doing anything to T1 would help.

[LaceSensor]

Hi
I cant remember exactly  what addresses this but I do know that it is a trimmer / biasing issue

Good luck have fun

[Orbis_Ignis]

Hi
I cant remember exactly  what addresses this but I do know that it is a trimmer / biasing issue

Good luck have fun

Yeah, I'd probably rebias it using Madbean's instructions in the build doc

[UnclePsychosis]

Thanks guys

Playing with the bias and the clock trimpots makes the popping go away, so its obviously a biasing issue.

I've decided the DEM sound isn't really for me anyway so I'm going to move it on in favour of something more swooshy!

[Mcentee2]

I also am having this trouble with my 2015 version; also an ebay buy so I did not put it together myself.

Range pot on max clockwise, Rate at slowest, I get a double pop at the top of the sweep.

If I increase the Rate (turn CW) or narrow the range (turn CCW) sufficiently, eventually it will go away, but I do not get the full range of control then.

Feedback T1 does not affect this, and it does not matter when the Bias trimmer is; the Clock trimmer either speeds up the sweep or slows it down (ie the two pops are closer or farther apart) but they don't go away at max or min Clock trim.

Tried on 9v and 12v, tried many variations of the pdf instructions


Help.....

[Mcentee2]

Ok, done some more testing.

Bias resistor swapping made no difference to the pops, except that a 20k R10 (2015 build) means i now get 3007 cutoff at low and high pot settings, that seems "better" to me so will keep it.

Voltages on IC2, 3007, pins 2 and 6 both cut out to 0v as the pops occur, ie something cuts out going up to the top of the sweep and cuts back in off the top of the sweep.


If I bias the 3007 off, then the LFO is still working and the pops are still there, so to me this isn't a bias buy something in the LFO not being able push out the sweep signal correctly.

As I say, if the rate gets faster and/or the range decreases then it is fine and sweep works through its cycle.

Any clues?  LFO cap values or something?

[Mcentee2]

OK, more investigation today:

IC4: all voltages are fine, but Pin 1 moves to 0v between the pops, Pin 2 moves to 8.7 between the pops.

Pin 3 (input from the clock/LFO) varies between 0.66-7.7v when rate min and range Max.

Pin 3, again, with range min and rate shorter only varies between 3.1-6v with no pops

Best guess position for Pin 3 min voltage with no pops is 2.3v

So I reckon the feed from IC3 into IC4 is varying too much, lowering the low end too much below the value needed to keep IC4 "alive".

Tracing back to the Rate pot (1MOhm reverse taper C) it is in series with R27 which must sets a Minimum r in that path.

The 2015 PDF schematic shows this as 3k9, but my board has  3k3 in.

Doesn't look as though this could make much difference though.

Haven't traced any more yet

[Mcentee2]

Update - I posted this on diystompboxes, and got some great info from DrAlx, all fixed now.

http://www.diystompboxes.com/smfforum/index.php?topic=114014.0

R30 in the 2015 build is in line with the Range pot and sets the lower limit, the Orig EM has 22k-39k.

I now have mine at 37k , and with the bias and clock correctly set there is now no cutout at the top of the sweep