Sunking + Harbinger One = annoying whine when both are ON

[Cortexturizer]

https://drive.google.com/file/d/0B--6F_4JB7SYZTlCcU93MmhtT1k/view?usp=sharing

You can here how it sounds. It's in the rate of the rate of my Harbinger's LFO.

Now, this only happens when I am in the normal component values of the Klon (Sunking). I have a switch that takes me to a component change, the 390pf from the feedback loop gets changed with a 47pf. I've stumbled at this by accident and I can't live without that sound, it makes so much difference to me. Brian explained it best:



So, when in this mode (C8 = 47pF) I get oscilations and whine like on the soundclip. When not (c8=390pf) - I get no whine.

What I want is to somehow remedy this. Any ideas? I gotta resolve this, I just love using them together and I can't get away from the C8=47pf sound.

Help!

[madbean]

How are you powering the HB One? Is it a charge pump...are you using the same 9v supply as the Sunking?

[Cortexturizer]

The Harbinger is powered by the charge pump, and I've tried putting the pedals at separate power supplies and it was the same thing. The Harbinger is in a 2in1 which also has RobA's Hyperbolic fuzz in there. Just sayin. Shouldn't matter though, I think.

[madbean]

Last questions before making a suggestion: does the noise happen regardless of your gain setting on the SK or is it present no matter what? Lastly, does the noise happen if the HBOne is off and just the SK on?

[Cortexturizer]

Yes, regardless of the gain level, and it doesn't help that I max the gain...
No, it happens only when both are on, when only one of them is on all is fine and no noise is heard no matter the settings on each pedal.

[Cortexturizer]

Just bumping this :-D

I also get a weird behavior with my Sunking when there is a germanium diode in there, it starts chopping the sound like a tremolo but only on the fattest notes, I'll do a sound sample of that as well, it's pretty crazy, almost cool haha.

[Cortexturizer]

[drolo]

If you are going Harbinger -> Sunking, it sounds like the Harbinger is carrying some of its charge pump's switching frequency in the audio (it is also using a charge pump, right?)

I guess you could try to tame the high frequencies somehow.
Perhaps try adding some lowpass filtering after the Harbinger or at the input stage of the Sunking.

Charge pumps sometimes are the devil ...

[Cortexturizer]

Thanks drolo! Yeah, it has to be something like that. I was hoping Brian could try and answer because he had designed both boards and probably would have some ideas on what could be done here. I'll wait as much as it's needed, but guys please don't mind the occasional topic bump

In the Harbinger I think I have LT1054 and an ICL7660SCPA in the Sunking.

[drolo]

Perhaps you can try strapping a cap in parallel with the Harbinger's volume pot. Try a few different values and see if it makes a difference (and also if it does not affect the treble in the audio too much). Basing the calculation on the 47k coming from the effected signal, 470pF should give you a cutoff of about 7kHz. There is a (good) chance I am calculating this wrong  but you can always start from there and see what happens :-)

[midwayfair]

Put a 1054 in the Sunking. See if it makes a difference at all. Also try running the Harbinger on 9V or on an 18V adapter (REMOVE THE PUMP FIRST. Then jumper the appropriate pins in the socket). (Yes, the bulb won't work at 9V. The object is to figure out if the charge pump is the problem.)

You can increase the filter caps in the power supply for both pedals if you suspect it's power supply noise. Better than filtering the audio path, which isn't what's causing the issue.

It's also hypothetically possible that the audio path IS the problem. You say this happens when you change something in the Sunking, which alters some gain characteristics. I think you should audio probe to see where it's introduced. After you determine whether the power supply is the issue, of course.

[Cortexturizer]

Only had time to try out lt1054 in the sunking - no change.
I'll try the other stuff tomorrow.

[Cortexturizer]

Tried the no charge pump aproach and running the harbinger on 9v - no whine. So it has to be the pump somehow or my power supply right? I use the one spot and it is uber silent with EVERY pedal. What to try next?

[midwayfair]

Tried the no charge pump aproach and running the harbinger on 9v - no whine. So it has to be the pump somehow or my power supply right? I use the one spot and it is uber silent with EVERY pedal. What to try next?

First thing I would try is an LT1054 in the Sunking -- put another LT back in the Harbinger.

You can also try increasing the power supply filtering before and after the charge pumps.

[Cortexturizer]

Yeah I did try LT in the Sunking so there was two LTs in the equaion at that time, no change. I guess I'm gonna try the caps increase next.
Bummer.