[FunyunBreath]

   
Great, thanks very much.  Hopefully this will resolve the issue and I'll save the socket cleaning/tightening project for another day... by the way, should the 'wobble' of the output tube be a concern at all?

 
Is the entire socket wobbling (where it's mounted to the chassis) or just the tube pins inside the socket?

 

[coastal1]

   
Is the entire socket wobbling (where it's mounted to the chassis) or just the tube pins inside the socket?

Not exactly sure, will check tonight.  I just noticed that the output tube wobbles whereas the input tube is quite stable.

 

[coastal1]

  I was also going to suggest interference from outside the amp.  I was convinced that my amp was going south, until I moved my cell phone away from the amp.  so step one, make sure your phone is no where near the amp.  then check the router thing.  that should be easy to test.  even moving it a few feet away should change the interference if that is the cause.

 
Thanks, don't think it's my phone as I've streamed Tidal from it-> iFi Micro->Crack without issue (not my usual setup, just wanted to try it).  But the router or something else could definitely be the culprit 

 

[Valhallatier]

guys, my crack died....? i need help. this is my first tube amp, so im quite noob with it.
It was just fine when suddenly, when nothing was playing, theres a faint "skrsh skrsh" sound through my DT880, then i realized, the light on my tubes are gone, and there's no sound.
what im worried is my amp dead, or should i be fine by replacing the tubes?

EDIT: my amp works again after an hour. i have no idea what happened, any input guys? i thought the tubes died but no!

 

[adydula]

You could measure the heater voltage. do you know how to do this? If you built this Crack then it tells you how to check voltages. Did both tubes go out at the same time? Check the fuse as well.
 
Alex

 

[Whit3Rav3n]

  I built the Bottlehead Crack a few weeks ago. For the first tests I only had the Sennheiser HD 800 available. in my opinion the crack without the speedball upgrade is not a good combination with the HD 800. It lost way too much precision and detail. Especially the treble was lacking too much. The sound was still good but more on the level of cheaper headphones. The speedball upgrade was quite a big improvement. The amp became faster and more detailed. I am using an op amp modded Asus Xonar One as DAC and the built in amp as comparison. Compared to the Asus amp the Bottlehead is more bass and mid focused, it has a warmer and fuller sound. The soundstage and detail are still better on the Asus amp. Right now there is no clear winner between the two, it comes down to preference.
 
Is someone using the crack with the HD 800 and has some good tube combinations for more soundstage and detail? As far as I have seen a good upgrade would be getting the 5998 but they are pretty hard to get and quite expensive.

I made some improvements since the last post with the crack. The first thing I did I changed the interconnect cable. For the first tests I only had a very cheap interconnect cable available. Since then I built a better one with a nice looking Sommer Cable grindycop cable and Hic-on connectors. This improved soundstage and the treble quite a lot. I also recieved the Tung-Sol 5998 tube. This improved detail and treble even more. The bass is also more controlled with this tube. Now I starting to like the crack more than the built in headphone amp of the Asus Xonar One. I will probably upgrade the output capacitors to film capacitors as well. For the input tube the rca clear top shuld arrive in a few days so I will be able to test how that sounds in the crack.

 

[coastal1]

So the good news is that the router is the causing the interference. No interference from iPhone. Tubes don't seem to be an issue. The bad news is that we have wifi issues in our house so we have a router and booster in that room, and not only is there nowhere in that room that I can go without interference, but I still get interference in the next room over. No interference whatsoever in the bedroom, and my wife isn't entirely thrilled with having this beast permanently live in there.

If you take the amp to another room in the house do you still get the clicking? Wondering if it may be wireless interference from your phone or router.

 

[FunyunBreath]

Nice, good that you figured it out!
 
You could always try a tube shield on the 12au7 and see if it blocks the interference, or it might just be time for a stronger router so you can ditch that booster

 

[DDDamian]

  I made some improvements since the last post with the crack. The first thing I did I changed the interconnect cable. For the first tests I only had a very cheap interconnect cable available. Since then I built a better one with a nice looking Sommer Cable grindycop cable and Hic-on connectors. This improved soundstage and the treble quite a lot. I also recieved the Tung-Sol 5998 tube. This improved detail and treble even more. The bass is also more controlled with this tube. Now I starting to like the crack more than the built in headphone amp of the Asus Xonar One. I will probably upgrade the output capacitors to film capacitors as well. For the input tube the rca clear top shuld arrive in a few days so I will be able to test how that sounds in the crack.

Those are all good upgrades. The 5998 is a great tube, and the clear-tops are (for the price) a great driver tube. If they are NOS (new old stock) they may get a bit better over time too. If you do go upgrading caps then they also need to burn-in a bit - they can seem harsh and bass-shy at first in my limited experience. Give each change some time. It's a great amp.

 

[coastal1]

  Nice, good that you figured it out!
 
You could always try a tube shield on the 12au7 and see if it blocks the interference, or it might just be time for a stronger router so you can ditch that booster

 
Thanks for all the help.  There's weird wifi and cell issues in my neighborhood, especially for being in a populated area.  We've had 10+ at&t techs come out to improve our service and this is what theyve come up with so far.  At least the equipment theyve given us is free...
 
I switched power strips (nothing fancy) and am at least able to have no interference in the next room over.  Have a couple more lying around and will see if I can get something that blocks interference the media room.  Thanks for the rec on a tube shield as well 

 

[adydula]

I have a 6AS7G tube that has a very low noise, whistle etc that if I gently tap on the tube will go away for several minutes and sometimes for hours, but when first using it I go thru the process of letting it warm up and then after 30 minutes or so the small buzz is there in the background...not that annoying when listening except with low passages of music u hear it and of course is annoying to a purist etc...
 
I have a really clean build been doing this stuff for 35 yrs +...solder skills are excellent here.
 
But I did all the normal stuff you do, check for joints, everything tight, clean tube pins etc....even different rooms, power sources, cables etc...even re-soldered the power pin connections that look absolutely stellar.
 
With the original 6AS7G the noise is always there very low....if I gently squeeze the top portion of the coke bottle the sound changes tone/frequency...and sometimes disappears!! Ha!
 
I bought a second like tube from amplified parts in Arizona (great place to deal with). I got a 1953 NOS tube, still in the 1949 RCA wrapper/package.
 
Fired it up and it is very sensitive and touchy for 30 - 40 minutes upon power up, it tests very well on my tube tester. But it is really touchy and has all kinds of noise that eventually settles out but always comes back in some shape or fashion.
 
When listening I often hit pause to see if the noise or hum is there, and most often it is....it sounds like 60 cycle AC to me at times, Its there even with grounding plugs in the RCA input jacks.
 
So I have one 6AS7G tube that's not too bad, sounds just great, its just that low hum/noise in the background that drive me nuts!! LOL.
 
The second tube is worse and I have a replacement coming from amplified parts, these people are wonderful to deal with and sent out a replacement immediately!! No questions asked. Great customer service!
 
Having dealt with many tube amps in the past....the old tube worts games is still here alive and well!!! Ha!
 
That said its worth the minor pain and worts, the crack still sounds wonderful even with not perfect valves!.
 
The speedball constant current "upgrade" is not yet installed but I will do this in the near future...
 
Just wanted to share....
 
Alex

 

[FunyunBreath]

Did you let the tube burn in for about 100 hours or so? I've noticed that just about all my 6as7g tubes that I've bought NOS have been a bit noisy at first. I emailed Brent Jesse about it on an RCA 6as7g I bought from him and he said because of the size of the plates they're pretty susceptible to microphonics for the first 100 hours or so of burn in. After that burn in period it generally goes away unless the tube is just very microphonic, in which case it's just a bad tube.
 
Never really had the issue with 6080, 7236, or 5998 tubes though.

 

[adydula]

That's a good idea and I still have the 6AS7G tube with the worse sensitivity....I am going to let it "cook" for a few days, with tubes, metallurgy etc who knows it indeed might just fix itself.
 
There are times its dead silent then it goes back to its temper-mental self!!
 
I will try a straight bottle soon as well.
 
Just like the aesthetics of these old coke bottle shaped tubes!! LOL.
 
Parts Connextion had a 20% off sale and I have a 6080 on its way.
 
Alex...ah the smell of hot vacuum tubes..especially when a layer of several old days dust burns off!!!

 

 

[FunyunBreath]

Ha yeah the crack looks way sexier with a 6as7g or 5998 than with a 6080 in it
 
For what it's worth I have 3 Tung Sol 5998's and haven't had microphonics in any of them. Very quiet tubes, in addition to being the nicest sounding ones I've tried as well.

 

[DDDamian]

  Ha yeah the crack looks way sexier with a 6as7g or 5998 than with a 6080 in it
 
For what it's worth I have 3 Tung Sol 5998's and haven't had microphonics in any of them. Very quiet tubes, in addition to being the nicest sounding ones I've tried as well.

True-say. And you're lucky - my 5998 has just developed a bit  Sporting a Winged-C right now while I seek another. Nice tube but not quite 5998...