Weird random distortion

[Nightloyd]

Hello everyone!
I got a really weird distortion that sounds like when you connect an audio cable but you miss and it creates a high distortion sound.
This distortion problem is completely random, because sometimes it won't appear for weeks and sometimes it continues for days.
First i though it was some distortion created by the RCA output on my ASUS STX, but after unplugging the rca cables from the crack it still continues.
So next i tried turning the power cord 180 degrees and it worked for a while.
Now nothing works, it can stay for hours and then dissapear for 10min and then it comes back again.

This is how i connect my crack: Asus STX (RCA output) -> RCA cable (ARGON 5056) -> Crack (no speedball) -> HD600 with cardas cable.

I really hope you guys here on the Bottlehead forum can help me
/Nightloyd

[Doc B.]

Sorry to sound like a broken record, but if you have a problem that sounds like something is coming loose you need to try reflowing the solder joints.

[Nightloyd]

Sorry to sound like a broken record, but if you have a problem that sounds like something is coming loose you need to try reflowing the solder joints.

But if it is the solder joints wouldn't this distortion be more frequent? And not so random, like it is now.

[Paul Birkeland]

But if it is the solder joints wouldn't this distortion be more frequent? And not so random, like it is now.

That's the fun part of bad solder joints or loose connections.  A little jostling or random environmental changes here and there will encite or relieve the problem. 

Is this something you notice in both channels?  That can reduce what you have to check a bit.  Also, it wouldn't hurt to rotate in a different 12AU7, then 6080 to see if there is any change. 

[Nightloyd]

But if it is the solder joints wouldn't this distortion be more frequent? And not so random, like it is now.

That's the fun part of bad solder joints or loose connections.  A little jostling or random environmental changes here and there will encite or relieve the problem. 

Is this something you notice in both channels?  That can reduce what you have to check a bit.  Also, it wouldn't hurt to rotate in a different 12AU7, then 6080 to see if there is any change. 

I have only noticed this in the right channel, maybe i should say that at low volume (really low) i can only hear sound from the left channel and not the right one.
And i don't have any spare tubes.
/Nightloyd

[Jim R.]

Make sure the rca connectors on the chassis plate are tight and that there is no shorting of the ground to the plate and that the shoulder washers are positioned correctly.  Also try the cable and another source if that doesn't fix it -- after the reflowing of solder joints, that is.

HTH,

Jim

[Grainger49]

First thing is to follow Doc's advice.  It solves 80% of these problems.

   .  .  .   after unplugging the rca cables from the crack it still continues.

Do you mean with no cables plugged into the Crack, the RCA jacks empty?  If so the cables are innocent.

   .  .  .   i tried turning the power cord 180 degrees and it worked for a while.

Bottlehead power cords are grounded.  Did you use a "cheater"?


Does the volume control affect the level of the distortion?  If so it is early in the circuitry, from the RCA jacks to the volume control.

In reply #5 above, do you mean that at very low volume settings you do not hear any music from the right channel?  If so, the volume pot is most likely the problem causing the right channel drop out.

[Laudanum]

The volume pot isnt noted for tracking very well at very low volume.  That is probably be why you only hear sound in 1 channel at very low volume.   It could be related to the problem, but it's also pretty normal so may very well not be related.     These guys are much more tech savvy than I am but personally, I'd swap out different tubes first and see if that solves it.  It's the easiest thing to try.  You should get yourself a spare of each, regardless.   If that doesnt work, on to the more labor intensive things,  like reflowing solder joints as Doc suggested. 

[Nightloyd]

Now the Bzzzzrt sound is constant.
And the music is so low That i can barely hear it in the right channel.

First thing is to follow Doc's advice.  It solves 80% of these problems.

  .  .  .   after unplugging the rca cables from the crack it still continues.

Do you mean with no cables plugged into the Crack, the RCA jacks empty?  If so the cables are innocent.

  .  .  .   i tried turning the power cord 180 degrees and it worked for a while.

Bottlehead power cords are grounded.  Did you use a "cheater"?


Does the volume control affect the level of the distortion?  If so it is early in the circuitry, from the RCA jacks to the volume control.

In reply #5 above, do you mean that at very low volume settings you do not hear any music from the right channel?  If so, the volume pot is most likely the problem causing the right channel drop out.

Yes without any cables (RCA jacks empty).
I don't understand what you mean by "cheater" but i use an 240V Transformer so i use an power cord i got with my computer.
And yes at very low volumes.
And the distortion dosen't change volume when i turn the volume knob.
And i forgot to mention 2 things:
1. I move my Crack like every 2 weeks (ofcourse totally cooled down).
2. My powerbutton on the crack is broken so the power is on all the time so i use an power strip to turn it off.

[Laudanum]

Re-seat tubes in sockets several times, this cleans the pins and socket contacts.
Check for bad tube ... this requires a spare of each.
Check solder joints and re-flow (main focus on that right channel).   
Also make sure no wires are broken as they are pretty easily weakened if nicked when stripping insulation.
You can try the chopstick test ... use a non conductive probe, like a wooden chopstick and lightly tap on different connections while listening with heaphones (low volume).  If you hit a spot that fixes the problem or makes it worse, you may have your "bad" spot.
 
Replace power switch.  Careful next time, they are pretty easily damaged by too much heat / too much time to solder.

[Grainger49]

Ok, I understand that the Crack is ungrounded.  That could cause hum, but that is not what you are describing.  So being ungrounded seems to cause no problem.  Except the safety problem.  That ground is there to make the amp safe in case of a hot wire touching the chassis plate.

Try what Desmond, above, suggests and report back.

[Doc B.]

Did you reheat the solder joints yet? Moving the amp a lot could very well work a cold solder joint loose. I am happy to continue to offer help, and that always goes a little easier if we get some feedback about whether or not the suggestions we have given so far have helped. My hunch is still that you have a cold solder joint at a ground connection.

[Nightloyd]

Did you reheat the solder joints yet? Moving the amp a lot could very well work a cold solder joint loose. I am happy to continue to offer help, and that always goes a little easier if we get some feedback about whether or not the suggestions we have given so far have helped. My hunch is still that you have a cold solder joint at a ground connection.

I will try that in the next coming days (a lot to do atm.), i tried to re-insert the tubes a couple of times and i noticed that the 12AU7/ECC82 is not 100% in place, i can move it a little bit when it's in place.
Btw this may be a stupid question but which solder joints are for the right channel?

[Grainger49]

Nightloyd,

That is about the fourth time rewetting was mentioned.  Really!  It can do wonders!

Hmmm good question.  Right and left wires are all over the place.  There are about 10 terminals on two terminal strips closer to the front.  Rewet all.   Then go touch up the headphone jack, volume control (right is on top here), and finally the tube sockets.  Remove the tubes and don't let solder drip into the cracks, you will never get it out!  Don't worry about any wires on the tube sockets that go back to the power supply at the back of the chassis.  All that sounds like it is working fine.

Ok, maybe touch up the right RCA input jack.

[Nightloyd]

Did you reheat the solder joints yet? Moving the amp a lot could very well work a cold solder joint loose. I am happy to continue to offer help, and that always goes a little easier if we get some feedback about whether or not the suggestions we have given so far have helped. My hunch is still that you have a cold solder joint at a ground connection.

Nightloyd,

That is about the fourth time rewetting was mentioned.  Really!  It can do wonders!

Hmmm good question.  Right and left wires are all over the place.  There are about 10 terminals on two terminal strips closer to the front.  Rewet all.   Then go touch up the headphone jack, volume control (right is on top here), and finally the tube sockets.  Remove the tubes and don't let solder drip into the cracks, you will never get it out!  Don't worry about any wires on the tube sockets that go back to the power supply at the back of the chassis.  All that sounds like it is working fine.

Ok, maybe touch up the right RCA input jack.

I have now reheated the solder joints, and it fixed my problem!
I haven't noticed the distortion yet and i hope i won't hear it anymore.
Thanks everyone for your help.

/Nightloyd