Charge pump

[danwojaz]

I recently made a skeptical buffer and it works fine. I started messing with my strymon timeline and when I switched to any delay type other than analog and tape delay, I notice some form of oscillation. I have had issues with charge pumps and the timeline in the past.So, I just avoid pedals with them.

After trouble shooting for a while, ( used a one spot for the skeptical buffer, and left the timeline on the strymon power supply, took multiple pedals out of signal chain , etc) I found that if I turn the grit knob on the timeline all of the way down and the noise went away. After playing with everything for a while, I decided to change the charge pump IC and when the noise kept happening, I changed the ic to a tc1054 or 45 (I forget the number) and noise went away.

Anyways, does anyone know why a charge pump would cause the grit knob on the timeline to make noise when turning it up?

And why would changing the ic get rid of the noise?

 

[DeadAirMD]

I don't know why, but I ALWAYS have problems with charge pump ic's........unless it's a LT1054. I stopped buying anything else a long time ago.

The TC1044 datasheet has information on how to correct oscillation that may occur with that charge pump ic.

 

[jwin615]

I recently made a skeptical buffer and it works fine. I started messing with my strymon timeline and when I switched to any delay type other than analog and tape delay, I notice some form of oscillation. I have had issues with charge pumps and the timeline in the past.So, I just avoid pedals with them.

After trouble shooting for a while, ( used a one spot for the skeptical buffer, and left the timeline on the strymon power supply, took multiple pedals out of signal chain , etc) I found that if I turn the grit knob on the timeline all of the way down and the noise went away. After playing with everything for a while, I decided to change the charge pump IC and when the noise kept happening, I changed the ic to a tc1054 or 45 (I forget the number) and noise went away.

Anyways, does anyone know why a charge pump would cause the grit knob on the timeline to make noise when turning it up?

And why would changing the ic get rid of the noise?

Oscillating can be the pumps heterodyning. Two things on the same circuit oscillating at a similar high frequency....
Isolated power *should* help.
The timeline probably has a pump in it to run dual rails.
Not saying this is the issue. But it could be.
I've wondered if a ferite on the power lines could help...

 

[jwin615]

I don't know why, but I ALWAYS have problems with charge pump ic's........unless it's a LT1054. I stopped buying anything else a long time ago.

The TC1044 datasheet has information on how to correct oscillation that may occur with that charge pump ic.

I'm risk adverse to them at this point. I'll just build with npn germanium...

 

[danwojaz]

Yes, I have been experimenting with it further. I have 4 pedals with charge pumps and added them one at a time to my board. I was able to get the noise from the timeline to stop after swapping the ICs on a few of them. Currently i have two pedals with LT1054 and two with TC1044. If i change the TC1044 to LT1054, the timeline makes the noise.

So I guess the lesson is, have a few different ICs for the charge pump and change it out until you don't get noise from your timeline.

 

[Paradox916]

The 1044s can be replaced with a Tc7660HCPA which operates at a higher freq out of our hearing range In some cases this can get rid of audible “charge pump whine/ squeal.” But not always if you have other pedals with CPs in there, it doesn’t necessarily fix the problem but it can mask it in a fair amount of situations.

 

[danwojaz]

The 1044s can be replaced with a Tc7660HCPA which operates at a higher freq out of our hearing range In some cases this can get rid of audible “charge pump whine/ squeal.” But not always if you have other pedals with CPs in there, it doesn’t necessarily fix the problem but it can mask it in a fair amount of situations.

Can the 1044s be replaced with the 1054s? I also tried it with the Tc7660 and got noise.

 

[Paradox916]

I believe the 1044 and 1054 are NOT interchangeable if I remember correctly someone else maybe can chime in on that specifically, the 7660cpa and the “H”CPA are different H being for high frequency once again if I remember correctly , take a look at the datasheets and you can find the rock solid answers to these questions.

 

[danwojaz]

Can the 1044s be replaced with the 1054s?

I believe the 1044 and 1054 are NOT interchangeable if I remember correctly someone else maybe can chime in on that specifically, the 7660cpa and the “H”CPA are different H being for high frequency once again if I remember correctly , take a look at the datasheets and you can find the rock solid answers to these questions.

I have been reading into it, and it sounds like they are, I could be wrong though.

 

[tegendemuur]

Oscillating can be the pumps heterodyning. Two things on the same circuit oscillating at a similar high frequency....
Isolated power *should* help.
The timeline probably has a pump in it to run dual rails.
Not saying this is the issue. But it could be.
I've wondered if a ferite on the power lines could help...

Thinking of one circuit exciting the other, could it be a form of resonance that produces the whine?

 

[jwin615]

Thinking of one circuit exciting the other, could it be a form of resonance that produces the whine?

Essentially. Charge pumps are oscillators themselves.
Heterodyning is the single frequency result of 2 separate frequencies.
Strymon pedals are well known to have issues with pedals with charge pumps in them. It's not just a diy issue. Turkey isolated power can help.