Speedball 1 & 7 channel high voltage

[Paul Birkeland]

How about A3?

[BrettMatthews]

A3 is 0 Vac as well.

Edit:interesting enough it seems that the voltage at pin 1 is sitting at about 101V today which puts it right about in spec. Pin 7 is still a bit high at 119V though.

One other thing I did notice is that when the amp is upside down I didn't hear any noise if I taped on the baseplate, but once I flipped it back over tube side up it came back. Also when listening I can hear small electric noise bursts everyonce and a while.

I also heard a pop when I turned on the amp with headphones connected (luckily no damage done to the headphones), I then checked the voltage on the jack at the ring and it started slowly started climbing and then jumped to 25v for a second then back down to 0v.

[Paul Birkeland]

A3 is 0 Vac as well.

These need to be DC voltage measurements.

One other thing I did notice is that when the amp is upside down I didn't hear any noise if I taped on the baseplate, but once I flipped it back over tube side up it came back. Also when listening I can hear small electric noise bursts everyonce and a while.

The not about having the plate flipped over suggests a bad solder joint.  The electric noise bursts indicate that you own a cell phone.

I also heard a pop when I turned on the amp with headphones connected (luckily no damage done to the headphones), I then checked the voltage on the jack at the ring and it started slowly started climbing and then jumped to 25v for a second then back down to 0v.

The amp will thump audibly when you turn it on and headphones are connected, there isn't anything unusual or alarming here.

[BrettMatthews]

These need to be DC voltage measurements.The not about having the plate flipped over suggests a bad solder joint.  The electric noise bursts indicate that you own a cell phone.The amp will thump audibly when you turn it on and headphones are connected, there isn't anything unusual or alarming here.

I will grab the DC measurements tomorrow morning, any others to check right now?

Phone noise makes sense as it was being driven off my phone. The sound I heard when I turn it on isn't a thump, I'm used to heading a quiet thump with my o2 amp, this is a plus pop,loud enough that I was worried it damaged my headphone, was more than one pop and just from one side (left I think).

I will double check some of the grounds, can you think of any in particular to check?

[BrettMatthews]

A3 and A8 are both about 1.6 Vdc

[Paul Birkeland]

Can you remove the small PC board on the offending side and put the 22K resistor back in, then recheck your terminal 1 voltage?

-PB

[BrettMatthews]

I will give that a try this weekend when I should have some time to work on things.

I'm starting to think that maybe a ground came loose while transporting the amp from my home to my work (have nice pace soldering gear at work). I'll retouch all the grounds this weekend too.

[BrettMatthews]

Okay so good news! Looks like I found the bad ground (sounds the same upside down or right side up), not sure exactly where it was I was just touching up a few spots then tested things out and it seems to be good! A1 and A7 are still higher than the other side but are within spec now at least.

It's still recommended to connect the non used pins on the 1/4" Jack to ground correct?

[Paul Birkeland]

It's still recommended to connect the non used pins on the 1/4" Jack to ground correct?

There's certainly nothing wrong with doing this to a stock Crack or Speedballed Crack.