Darkside problem. Highs are attenuated!

[engineelite]

So this is the second darkside I've built. I had no problems with the first one and on this second one the high frequencies are attenuated when the effect is "bypassed" or active. All of the controls work as they should but the high frequencies are pretty much gone. It is VERY muffled sounding.

Any suggestions/insights are appreciated. Thanks.

[stecykmi]

sounds like you've got a cap shorted to ground in the input buffer stage... easiest way is to trace it out with a probe. keep checking nodes until you loose all the high end. C1 or C2 seem like likely culprits.

[engineelite]

sounds like you've got a cap shorted to ground in the input buffer stage... easiest way is to trace it out with a probe. keep checking nodes until you loose all the high end. C1 or C2 seem like likely culprits.

Thanks for the quick reply. I'll give it a shot and see what happens.

[Analog Design Audio]

have you used the same type of diodes?

[engineelite]

Yes, I used the same 1n60p diodes in the first darkside I built and it worked perfectly. So I prodded around and triple checked all of my connections and couldn't come up with anything. I actually had another darkside board to finish building for a friend of mine. I populated all of the components for both boards at the same time so I figured I'll just see if this other one works. Low and behold... it has the exact same problem as the first board! I must have installed the wrong value of component. I checked all the caps, transistors, diodes, polarities.. Everything was right. The only thing I didn't check was the resistor values. Is it possible that a wrong value resistor could affect the high frequencies so much?

[bigmufffuzzwizz]

Yes, I used the same 1n60p diodes in the first darkside I built and it worked perfectly. So I prodded around and triple checked all of my connections and couldn't come up with anything. I actually had another darkside board to finish building for a friend of mine. I populated all of the components for both boards at the same time so I figured I'll just see if this other one works. Low and behold... it has the exact same problem as the first board! I must have installed the wrong value of component. I checked all the caps, transistors, diodes, polarities.. Everything was right. The only thing I didn't check was the resistor values. Is it possible that a wrong value resistor could affect the high frequencies so much?

Of course it could. If it calls for a 100 ohm and you mistakenly put a 10k, 100k, 1M then I could see that causing problems. Especially if it's a resistor that needs to be an exact value for what it does.

[engineelite]

Oh man, this is going to take a while to check all them colors. 

I'll report back soon. Thanks.





Of course it could. If it calls for a 100 ohm and you mistakenly put a 10k, 100k, 1M then I could see that causing problems. Especially if it's a resistor that needs to be an exact value for what it does.
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[bigmufffuzzwizz]

its good practice. It will get easier I promise.

[engineelite]

I just got finished checking all of the resistors and they are all correct! This is mad! I can't figure this puzzle out. Is there anyone who would be willing to check this pedal out? I've checked every possible thing on this circuit and maybe I'm just blind to it but I'm ready to just pay someone to fix it.

I've also got lots to trade as payment for the service as I've got very little cash on hand...

Tubes, other pedals and guitar accessories. I guess it will all depend on how long it takes to fix also :/

Thanks.

[mgwhit]

Seriously, build yourself a probe and debug it with that.  Tremendous learning experience. 

[engineelite]

I appreciate your passion for this but I've got no time now that summer is coming to an end. I'm about to get crazy busy and won't stop until around christmas time for a break. I'm probably not going to make pedals any longer either as I've made several and have just gotten burned out with electronics tinkering. I need to spend more time with family and friends instead of investing more time into electronics. If I already had a probe and knew what I was doing with it then it would be no problem. Thanks.

Seriously, build yourself a probe and debug it with that.  Tremendous learning experience. 

[bigmufffuzzwizz]

I'll take a look at it, but I'm gonna be busy until about September. If that's cool then you can sure send it to me! 

[engineelite]

I'll take a look at it, but I'm gonna be busy until about September. If that's cool then you can sure send it to me! 

You da man! I sent you a pm. Thanks a million!

[engineelite]

So it looks like I built the circuits correctly and I'm extremely sensitive/particular about how much high freqencies that I like. Any suggestions on changing values of one (or more) of the components in the buffer to make the pedal brighter sounding?

Thanks!