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Kingslayer 2 gain control issue?

Started by zilla, May 26, 2014, 06:18:03 AM

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zilla

Damnit. I went to pull the 274 out of the socket and it was being difficult and I had to apply some brute force to get it out and I think I broke something because the circuit passes no sound now.

Going to have to troubleshoot tomorrow night.

zilla

Can someone post the voltages on their quad for reference?

I assume this is the proper pinout?


madbean

Well, the KS is a split rail design so the bias voltage is actually 0vDC. This means you should have +9 on pin4, -9 on pin11 and 0v on the other pins. There isn't much to break on an IC other than the solder pins.

blearyeyes

I'm just starting to build a Sunking II and a Kingslayer into dual pedals with optical comps. Before I get going is there an answer here regarding this issue? Which opamps should I get, use order etc.

Thanks!

zilla

what i thought was me breaking the pedal was an embarrassing mistake that we shall never speak of again ;)

anyway, swapped out the 274 with the 074 and the weird RFI noise disappeared.

I might have had a bad 274, but i don't have any other 274 chips kicking around to verify. I tried a few 074 chips and the noise didn't come back.

Maybe the 274 isn't suitable for this circuit anymore?


zilla

has anyone been able to confirm this?

jalmonsalmon

Is there a sound improvement using the 274 over the 074? May be a dumb question but I was about to order some 074s and since I read this thread about noise issues, I will stick with the 074s lol
I made an original kingslayer with the 074 and I love that pedal! 8)
Information is not knowledge
Knowledge is not wisdom
Wisdom is not truth
Truth is not beauty
Beauty is not love
Love is not music
Music is THE BEST . .

sdlogan9

I am having this same issue.

I used     -  TLC274CN From Mouser

And        -   TC1044SCPA     Mouser

I think the pedal sound F*cking Fantastic!!  Other than most people use it as a clean boost and run the gain all the way off.  This could make a person feel there is something wrong with the pedal if they encounter this.

I would like to try other options to get rid of the unwanted noise,  but I dont want to sacrifice the awesome sound.

Any suggestions?

-Shane

madbean

Okay, I'll check into this further tomorrow, for sure.

zilla

Quote from: sdlogan9 on June 24, 2014, 01:37:14 AM
I am having this same issue.

I used     -  TLC274CN From Mouser

And        -   TC1044SCPA     Mouser

I think the pedal sound F*cking Fantastic!!  Other than most people use it as a clean boost and run the gain all the way off.  This could make a person feel there is something wrong with the pedal if they encounter this.

I would like to try other options to get rid of the unwanted noise,  but I dont want to sacrifice the awesome sound.

Any suggestions?

-Shane

I guess the only thing is to add a resistor in parallel with the gain pot to keep a minimum value when the pot us set to zero?

midwayfair

Quote from: zilla on June 24, 2014, 03:57:11 AM
I guess the only thing is to add a resistor in parallel with the gain pot to keep a minimum value when the pot us set to zero?

It has a minimum value. That's what the little resistor hanging off the wiper is for in the first Kingslayer.

A resistor across the pot will just shrink the pot's value, it won't do what you're looking to do.

sdlogan9

Quote from: madbean on June 24, 2014, 02:34:10 AM
Okay, I'll check into this further tomorrow, for sure.


Any up dates should I order a 072 or should I assume my 274 is messed up?

-Shane

Droogie

I got the same thing at the clean end of the gain knob—only affects the first 5% or so of the control, then the whine stops.
True bypass btw.
Chief Executive Officer in Charge of Burrito Redistribution at Hytone Electric

madbean

I am pretty sure I know what's causing the problem. I'll check in here in a couple of hours with more info.

madbean

#29
I was wrong on what I thought the cause was. In fact, my prototype had no noise problem with the gain pot as described. After looking a bit further, I found the culprit: I did not test a TLC274 in this build but a TL074. With the TLC274-same result as you guys. So, I can confirm that I am an idiot.

Sorry guys, I should have figured this out sooner. Use a TL074 for now. I'm going to do some part swapping and see if I can get the noise to go away. Somehow, grounding the input of the gain stage is causing the IC to go into oscillation. Previously, I had a 2k stopper resistor between the wiper and ground (on KSv1), but I switched it to be more like the Klon way which is to put it between the outside lug and the wiper. I don't remember if I did it this way because I found the same problem back when I worked out KS1, or not.

The good news is it still sounds great with the TL074. I just thought the TLC274 sounded a little bit better on KS1. I'll see what solution I come up with to make it work again.