Constant buzzing in both channels after installing speedball

[Zia Warrior Princess]

Hey Guys,

I finished building my crack about 2 months ago with no issues. A couple of weeks ago, I moved on and installed the Speedball Upgrade. When I finished it and fired her up, I noticed a constant buzzing sound in both channels that gets louder as I increase the volume. It is completely unnoticeable at low volumes but incredibly loud at higher ones. I tried swapping tubes (both the input and output) to no avail. Then I resoldered the speedball entirely but that didn't affect the buzzing either.

After this I began to investigate the components using the "Chop Stick" method and found that when I touched the red and white wires of the braid that connects the RCA inputs to the volume pot it caused the buzzing to intensify. I also found that touching the red and white wires that lead from the volume pot to the Nine Pin Socket A similarly caused an intensification in buzzing. Additionally, touching the black wire that leads from the headphone jack to the 12L terminal also caused the same intensification.

So, after discovery this, I resoldered all the suspect joints and those in close proximity to them which only made the buzzing worse. This is literally the worst thing that has ever happened to me. Any help would greatly appreciated.

Thank you and Good Day

[Paul Birkeland]

Generally a loose ground wire will do this.

Are your voltages within specifications?

[Zia Warrior Princess]

Hey,
Thanks for the reply. I actually have yet to do a voltage test because there was an issue with the one I had. I assume this is my next course of action.
 

[Paul Birkeland]

Yup. (love the moniker by the way)

[Doc B.]

This is literally the worst thing that has ever happened to me.

Well, I gotta say if that's the worst thing that ever happened to you life must be pretty tolerable. It sounds like something came loose in the process of modding the amp. Since the buzzing seems to be affected by touching wires at the input section and follows the volume control as it is turned up and down, it is probable that the issue is at the RCA jacks. Check to see if the solder connections at the jacks are good and after that check to see if you still hear a buzz if you disconnect source component cables and leave the RCA inputs unconnected.

[Zia Warrior Princess]

Hey Doc,

Thanks for the reply! It's interesting that you brought up the RCA inputs. The ones that originally came with my crack were a little warped so I went out to The Source (Canadian Circuit City) and got some new ones. Will definitely look into this. I'm super excited to open it up tomorrow and investigate further. Despite all the issues, I've had a blast building this kit.

Take her especially easy,

Zia Warrior Princess

[Mike B]

The RCA's were "warped"?

Dunno.  Mine are solid metal "bolts"

You have them insulated "floating" off the plate right?

[Zia Warrior Princess]

Good News Everybody!

My buddy and I ended up doing a voltage test which I've attached.

We then removed the other RCA jacks I bought to replace the original ones which were warped (for some reason the RCA inputs from my source wouldn't fit into the RCA jack because the silicon was encroaching in the jack) and we reinstalled the original ones.  This completely removed the buzzing in the left channel and made the buzzing much less noticeable in the right (I don't think we soldered the right input very well which might explain why there was still a little buzzing). Doc, I think you were absolutely right. The other RCA jacks we bought in store were causing the issue. Would it be possible for me to order the same RCA jacks you use when you ship the crack?

Thanks so much to everybody for the help. I really appreciate it.