Standard Crack Channel Imbalance + Noise

[Paul Birkeland]

Is it possible to check if the problem is the tube beside using it and waiting for the problem to fade away?

This becomes a little difficult, as almost all of the tubes that we have had returned to us over the years quiet down after a day or two of use. 

If it's the tube, does the warranty cover a replacement of the tubes?

The warranty covers replacement of tubes that don't work properly. 

Depending on where you live, you may be able to borrow a 12AU7 or 6080 from a local tube seller (they are out there) to see if one or the other is causing your issue.

 

[3ph00n]

Sadly there are only onlineshops in my area... But a music store I know has a tube checker.
I will try checking the tubes there...

 

[3ph00n]

After some listening time the noise and channel imbalance is still there.
It wasn't 100+ hours of burn in time, maybe 30 to 40 but I didn't discover any changes.
The music store doesn't doesn't sell any 6080 or eguivalent tubes and therefore can't check them.

 

[3ph00n]

I got no other idea than changing the tube.
Is it possible to get a refund for the tube?

 

[Paul Birkeland]

We can exchange the tube, but do be aware that most of the "bad" tubes sent back work perfectly fine.  (We also test our tubes prior to shipping)

What part of the world do you live in?  Perhaps there's a fellow kit builder close by who can lend a hand.

 

[Doc B]

Actually we only get a few tubes back. But PB is right, when they do come back they are most often just fine. If you want to send it back we can send a replacement.

 

[3ph00n]

I am from Germany so the shipping will probably cost more than buying a replacement tube here.

 

[Tom-s]

Where in Germany? I'm in Belgium/The Netherlands.

PM me for replacement tubes, try that first. If needed/possible i'm also willing to take a look at your Crack.

 

[Paul Birkeland]

I would also add that if you get a replacement tube and the problem appears to resolve itself, do go back and try the other tube again. 

There have been a few times where the act of replacing a tube will jostle a strange joint or a broken wire enough to get things working, which convinces the builder that there is just a tube problem, only to have the issue return in a few days.

 

[3ph00n]

I am from saxony which is quite far away from belgium...
Thanks for your help anyway!

I will see if I can get a replacement tube somewhere else.

 

[Tom-s]

You can find good 6AS7G/6N13S svetlana and 5963NOS or 5814A to get your Crack "new" tubes @ https://www.btb-elektronik.de/home

 

[3ph00n]

Hi everyone,
It has been a long time since I last posted here but for anyone interested and people with a similar problem:
Changing both tubes fixed all the problems I had.
First I exchanged the 6080 for a 6as7g Svetlana and all the problems in the left channel disappeared.
Directly after that a much quieter noise in the right channel appeared (I think it was always there, I just couldn't tell before)
This new noise could be fixed by tapping the input tube.
This was also fixed by changing the tube and finally I got the sound I was looking for!
Thanks alot for all of your help and support and the amp that now works really well!

(Btw: is it possible to file a warranty claim for my issues as the tubes set me back another 40€?)

 

[Tom-s]

I'm very happy it all worked out for you and Crack is working as it should. It is a great amp indeed! One of the best price/performance ratio's available. And for what it can teach you in the journey of building it and all that comes after, one of the best amps you will ever buy.

Personally, i think buying NOS or old tubes comes with a calculated risk for the buyer. Although most are generally reliable products they have had a long shelf time before you get them. And the noise issues with these old things can't always be checked for. And they can appear after some use without any symptoms prior to that point.

Second. I think a company can't be held responsible for the price you paid for a spare set of tubes. As you can buy tubes for a few cents a piece when you are lucky (or free even), or pay hundreds of euros for a single tube.

I know i'm not making any friends with you right now. This is a personal opinion. This is not at all the Bottlehead company opinion/policy. In general i think the support received from Bottlehead is among the best you can get. They stand behind their products and are always willing to help out a Bottlehead user in need.

 

[Paul Birkeland]

(Btw: is it possible to file a warranty claim for my issues as the tubes set me back another 40€?)

The challenge that we have is that there are a pretty good number of builders who run into problems and blame the tubes.  Even when a different set of tubes appears to solve the problem, often it comes back at a later time (whatever solder joint isn't properly soldered gets disturbed enough when swapping tubes, then goes out again a few months later).  What we most often found when receiving tube sets back is that they tested perfectly and sounded great.  Occasionally we would need to let a particular tube run in for a day or two to get it quiet. 

If we offered to reimburse builders for new tube sets, everybody would buy one!