Low staticky crackle on right channel (solved)

[Paul Birkeland]

Went over the soldering, IB and IA got up to 175 now but OB and OA are the same as before.

IB and IA voltages function independently of that board.  If they have changed significantly over the course of your work, that indicates a loose or broken wire that is acting as a bottleneck to the circuit. 

There's also still a small possibility that there's still a grounding issue in your amp.  Try measuring the OA and OB voltages with terminal 3 as your ground reference (or B-A/B on the small board if that's easier).

-PB

[Julyan9]

It got up to 175 from 138.

OB 159 and OA 148 from terminal 3. Same results from B-A/B

These are with the small tube only

[Paul Birkeland]

Small Board OA 33.8 OB 37.5

OB 159 and OA 148 from terminal 3. Same results from B-A/B

Which terminal were you using for ground before 3?  For the second set of results, you have the 12AU7 in the socket hopefully (like the first set of measurements).

[Julyan9]

Which terminal were you using for ground before 3?  For the second set of results, you have the 12AU7 in the socket hopefully (like the first set of measurements).

"OA 28, OB 31" This was the result using the 12AU7 only

"
Large Board OA 63.7 OB 60.7 G 0 B+ 137.7
Small Board OA 33.8 IA 138 B-A/B 0 to 1 IB 137.7 OB 37.5"

These were taken with both tubes on like the manual suggested.

I was using 12U as ground before 3.

[Paul Birkeland]

If your OA/OB voltages on the small board with just the 12AU7 installed are different depending on whether you are grounded at 3 or terminal 12, then terminals 3 and 12 are not well connected and you need to reflow all of the solder joints on the ground path (black wires from the RCA jacks to the volume pot, volume pot to terminal 3, terminal 3 to headphone jack/9 pin center pin, headphone jack back to the power supply, and black wires in the power supply back to the diode bridge).

[Julyan9]

They are the same from terminal 12 and 3

[Paul Birkeland]

I would reflow all of the solder joints on the small PC board.  Having that super low voltage indicates that nearly no current is flowing through the tube.

[Julyan9]

I would reflow all of the solder joints on the small PC board.  Having that super low voltage indicates that nearly no current is flowing through the tube.

Nvm the numbers are actually different, ill reflow the ground path now.
so from terminal 12 and terminal 3 to OB on small board 159 and 147.6 to OA

The problem is I confused the 12U to the transformer 12 pin and not to the 12 on terminal strip.

The numbers from terminal strip 12 are way higher.

both tubes on

small board: OB 162 OA 150.2 IB 425 IA 425 B-A/B 0
big board:    OB 232 OA 241    B+423 G 0 

I did the check to A2/A7 and both sit at 0 with all LED's lit

If the heater (AC) supply ground is tested from E to B7/B8 all ground resistance path checks passed.
Is there a path that should end to T22?
Edit://
What could cause the high voltages?
Pics of the small PCB, I can't get the solder to go nice and smooth and shiny on the top side of the board. I've tried warming it more and more but nothing seems to happen. The solder is moving on both sides of the board.

[Julyan9]

Ok so I got a meter I actually know how to use and that works 100%.
Numbers are with both tubes attached.

Small board:

OA 70
IA 193
B-A/B 0
IB 193
OB 75

Big board:

OA 110
OB 106
G 0
B+ 193

[Paul Birkeland]

OK, those are working voltages!

[Julyan9]

OK, those are working voltages!

The intermittent sound is still there though on right channel

Is there anything else than reflowing all joints for the 30th time that could help?
I think I will reheat and desolder the joints and warm and apply new solder. The first soldering iron I was using was super bad and didn't keep the heat well enough. I have heated all joints numerous times but that just doesn't help

Edit:/ So I changed the wire from potentiometer to 9pin middle again ja made sure the connection is good. Also resoldered T3. 0 change.

I took the solder out of the joints with wick, reheated and added smaller amout of solder cos I thought maybe I used a bit much on the first times. Still the same sound is there even after not just reheating but resoldering all the joints. I also improved some of the subpar physical connections
Voltages changed ever so slighty after this overhaul. At some point during this there was all sorts of weird hisses ja sounds from both the channels at different points but now left channel is dead quiet again ja right still has the same crackle .
Only thing I haven't done is roll another 6as7g in.

[Julyan9]

If I had a wire broken from the inside near a solder, wouldnt I be able to detect that with the chopstick test?

[Paul Birkeland]

The chopstick test is great for finding broken wires.

You might have environmental noise that is only being picked up in the right channel.  Can you pack your Crack up and take it to work with you for the day?  That would give an alternate data point in terms of noise performance.

[Julyan9]

The chopstick test is great for finding broken wires.

You might have environmental noise that is only being picked up in the right channel.  Can you pack your Crack up and take it to work with you for the day?  That would give an alternate data point in terms of noise performance.

Sure I can test that on Monday. That's what I thought. 'Im just running ideas since I resoldered the whole circuit, changed a couple of wires and the issue still persists. I'm mostly testing without RCA's connected but that doesnt change the sound at all.

[Julyan9]

I went to the basement where the bomb shelter / storage room is and its the same.
I was wondering if maybe the fact that I live in an older apartment where only the kitchen and bathroom has to have grounded Schuko sockets matter, but seems like it doesnt.

Should I still go the circuit over one more time? It would be nice if there was even the slightest of change after all that soldering and stuff, but there been no improvements

Only wires that maybe could have an issue and that I haven't changed are the ones connected at T3 but no matter how much I try and yank or poke the wires there is change.