Loud Pop In Right Channel Followed By No Sound [resolved]

[Paul Birkeland]

Can you leave the Crack running for a couple of days, then try again?  There could be a tiny bit of gas in the 6080 that is causing an arc at startup, but you should be able to get that to go away if you cook the tube in for a good long while.

[Colonl_Charisma]

Thanks Paul! I appreciate your help. I'm going to do my resistance and voltage checks again. Once those pass, I will start the system with no gear connected in order to let the tubes burn. I'll post an update in a day or two.

UPDATE: I have let the tubes burn all day, and I was curious to see if anything changed after powering the system up. I have attached a gif of my GE 6080 tube so that you could see what is occurring a few seconds after powering the system on. As you can see the left and right sides of the 6080 tube begin to glow blue and then a blue flash occurs. Shortly after a spark appears near the bottom left. After the tube flashes it appears normal and has a warm glow. I apologize for the poor quality of the gif, but the quality decreased changing from .mov to .gif.

[Colonl_Charisma]

Hi Paul,

I have let the system and tubes run for over 24 hours now. I let the system cool for about an hour, powered it back on, and my 6080 tube glows blue on the glass sides right when the tube begins to glow, and once the blue on either side of the tube reaches a threshold a bright flash occurs followed by some sparks/charges in the middle of the tube. Do you think I have a bad 6080 tube? If you think I need to check any specific area of the system let me know. I also posted a gif above to show what this looks like.

I appreciate all the help!

[Paul Birkeland]

Let the tube run for a couple of day, let's say 5.  If this gas is to be absorbed by the getter, it will take some time!

[Colonl_Charisma]

Right on! I'll let them burn for a few days.

[Colonl_Charisma]

Hi Paul,

So I was able to use another GE 6080 tube in my amplifier. I did this to have a control in order to rule out either a bad tube or if there is something wrong with the amp that I assembled. The new 6080 tube that I put in was used and it also tested well on a tube tester so I knew beforehand there was nothing wrong with it. Upon powering the system on there was the same blue glow with a bright flash from the 6080 tube. I believe this rules out a bad tube, and I think I should direct my attention to the amp. Also, LEDs still turn on.

I went ahead and did my resistance and voltage checks again:

T1 = 3.65 M ohms, 77.2 V
T2 = 2.65 M ohms, 177.2 V
T3 = 0 ohms, 0 V
T4 = 2.15 M ohms, 177.4 V
T5 = 2.07 M ohms, 80.6 V
T6 = 0 ohms, 0 V
T7 = 2.92 K ohms, 102.9 V
T8 = 0 ohms, 0 V
T9 = 2.95 K ohms, 107.1 V
T10 = 0 ohms, 0 V
T12 = 0 ohms
T13 = 4.33 M ohms
T14 = 0 ohms
T20 = 0 ohms
T22 = 0 ohms
B3 = 2.98 K ohms
B6 = 2.98 K ohms
RCA Jacks
Center Pin  L = 95.3 K ohms, R = 94.5 K ohms
Ground Tab L = 0 ohms, R = 0 ohms

Let me know what you think I should try. Thank you again for your help!

[Paul Birkeland]

Tell me about the solder you used and whether you used any extra flux with your build...

[Colonl_Charisma]

I attached a pic of the solder that I used during assembly. It says that it is 60/40 rosin-core solder for PC work. I made sure to get this kind because that was what was recommended in the manual. I did not use any extra flux during my assembly.

[Deke609]

Likely won't fix things, but it's easy and worth a shot: take the chassis out of the base and hold it at lots different angles while shaking/banging it (without tubes) to clear any stray lead clippings that might be lodged somewhere they shouldn't be. They can end up anywhere. When I rebuilt one of my amps, I found a bunch of lead clippings in the power transformer end bell.

If that doesn't work, you're best bet is probably to reflow every joint - including the hard to reach ones. What almost everyone does (i've been guilty of same) is reflow only the ones that are easy to get at.

cheers and good luck, Derek

[Colonl_Charisma]

Hi Derek,

Did the shaking, but nothing came out or loose. The only solder joint that I have not reflowed is 3L. I cannot really see it very well or get to it. Trying to figure out how to do it. I appreciate the help!

[Paul Birkeland]

I'm glad to see that you used the recommended solder and no extra flux.  You could definitely create the problem that you're having by using the wrong soldering projects. 

I would get a wooden chopstick and run the amp with a cheap pair of headphones plugged in, then poke around the circuit until you actuate the pop.  That will help you focus your efforts on what's loose.

[Colonl_Charisma]

Thanks PB! I will look around for a cheap pair of cans. I may have to go out and get a pair that I don't mind potentially breaking. For clarification, I turn the system on with tubes connected and poke each soldered joint with a chopstick until I hear something unusual from the headphones? Also, should I be playing music or play nothing and only listen for a pop/noise?

[Paul Birkeland]

Yes, and no, you definitely don't want music playing, as you want to be able to hear the pop.

[Colonl_Charisma]

I appreciate your help! May be a couple of days before I post back. Any recommendations on a cheap pair of cans that comes with a 1/4" adapter?

[Paul Birkeland]

https://www.amazon.com/OneOdio-Adapter-Free-Headphones-Professional-Telescopic/dp/B01N6ZJH96/ref=sr_1_17_sspa?dchild=1&keywords=headphones&qid=1599673416&sr=8-17-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExSzYzVjJBQ0VKOVNOJmVuY3J5cHRlZElkPUEwOTQ2OTczNkpXSjI2SzcxQUY4JmVuY3J5cHRlZEFkSWQ9QTAwOTE5NjcxTVA1QkMzWVU4UjAzJndpZGdldE5hbWU9c3BfYnRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==