Noise coming from right channel post speedball [Resolved]

[AndrewinNV]

Hello all,
     I recently completed building my crack and a week later installed the speedball. All the voltages and resistances seemed to check out on the original crack, and the speedball voltages were either in spec, or slightly higher. The voltages are as follows:

Terminal      Specified     Measured
       OA                 75-100V               109V
       OB                 75-100V               113.7V
       G                   0V                        0V
       B+                 170-195V              186V

It sounds good, minus the interference/noise coming from the right channel. It seems to be volume independent. It is still there without any input to the amp, and I moved it away from the computer to a different power source just to check if it persisted. Additionally, I tried leaving it on all night to see if that helped, it did not. I did try poking around blindly at joints with a chopstick, but was hoping I could narrow down where to look. I also saw other threads, but wanted to make one tailored to my issue. Thanks for any help.

[Paul Birkeland]

What does the noise sound like?  Is it periodic in nature (like a hum or something resembling Morse code) or more like static?

[AndrewinNV]

Hello Paul, thank you for the reply.
      Id say it is more a static white noise type sound. As for if its periodic or not, I'd say its periodic. I went through each wire and tried touching each with a chop stick. There seemed to be no change to the static sound coming from the right channel.

[Paul Birkeland]

You could try pressing on the PC boards as well to see if a little flex in one of the PC boards changes the nature of the noise. 

[AndrewinNV]

Hi Paul,
    In addition to checking the wires, I pushed on the boards as well as most if not all other connection (resistors, transistors, etc.).
 
    I also would like to amend what I said previously about the static being periodic. I have the headphone on my head currently and the static sound is constant, though there can be slight variations in how it actually sounds.

[AndrewinNV]

I'd like to confirm if some of these readings I am getting is correct. ON page 29 of the speedball manual, it says to check resistances at OB and OA on the large board. It says the resistances "should read very high, in the hundreds of Kohm." I'm getting 19-22 Mohm at these points.

[Paul Birkeland]

19,000,000-22,000,000 ohms is very high.

[AndrewinNV]

Any idea what this may suggest?

[Paul Joppa]

It suggests that  your reading is OK.

The manual might have said "...in the hundreds of Kohm or more." but that construction seems a bit clumsy. Technical writing is always a choice between precision and clarity.

[AndrewinNV]

I've read some posts where a bad tube was causing a static noise in a channel, so I ordered a replacement tube to rule that out. I do hope it solves the issue, however I don't recall the noise pre speedball. I also went and reflowed connections that could be questionable, the noise still persists. If there are any specific areas to look at or tests to run, please let me know.

[AndrewinNV]

I ordered a new tube to rule out tube issues with the 6AS7G. Turns out the noise issue was with the provided tube, no noise issues with the replacement that I ordered. Resolved.

[Paul Birkeland]

You may find that a tube which presents noise like that will quiet down if you let it run for 3-4 days straight.