[moriez]

 

I ordered BH Crack on Feb 4 , send to NY, I'm still waiting the package arrive.
This wil be my first DIY tube amp, planning to pair with my HD600...wish me luck

~ron~

 
Crack + HD600 = excellent combination. Congrats!

 
Oh yes! I believe it to be the best combination that I have heard since becoming a HD600 fan. I just made the change from stock tubes to Bendix 6080WB plus RCA Cleartop which seems to give that little more openness I was looking for. We're getting somewhere now in this hobby!
 
 

 

Yah, same problem. Only discovered it recently as I never turn the volume knob that far. SB,5998,hd 600's. Just the last few millimeters and a LOUD hum! Wonder what it is. Got some insight for us Doc?

Yes. We have spent a few days working the problem. It appears that in the last batch of MJE350 transistors we purchased from a new vendor there are some random samples that are not up to spec. We have a new batch on order from one of our most reliable suppliers and when we get them in anyone who has purchased a Speedball in the past couple of months and is experiencing this issue can contact us for a replacement pair of MJE350s. The email to contact is replacementparts at bottlehead dot com.
 

 
Downside of the newly installed tubes is that I'm now experiencing the above. A big buzz when the volume is turned all the way down. Doesn't bother me big time since just above zero volume there is no buzz. At some point I may want to fix this though and my question is, wouldn't installing another potentiometer (am thinking the Dale upgrade) solve this too? 

 

[atomicbob]

  *edit*
 
Downside of the newly installed tubes is that I'm now experiencing the above. A big buzz when the volume is turned all the way down. Doesn't bother me big time since just above zero volume there is no buzz. At some point I may want to fix this though and my question is, wouldn't installing another potentiometer (am thinking the Dale upgrade) solve this too? 

You can temporarily attach two 50K ~ 100K ohm resistors between each of the center taps on the volume potentiometer and ground to check if the buzz is reduced or eliminated. If so, you have a faulty pot. These resistors provide a guaranteed shunt for the 12AU7 grids if the pot is becoming open circuit at the trouble point in rotation.

 

[Doc B.]

Downside of the newly installed tubes is that I'm now experiencing the above. A big buzz when the volume is turned all the way down. Doesn't bother me big time since just above zero volume there is no buzz. At some point I may want to fix this though and my question is, wouldn't installing another potentiometer (am thinking the Dale upgrade) solve this too? 

Depends upon what is causing the hum. That depends somewhat upon when you took delivery of your kit. Sounds like a perfect opportunity to take advantage of our tech support forum. There you can talk with the designer and narrow it down.

http://bottlehead.com/smf/index.php?board=24.0

Re our slogan as "take your time". I agree, though I would change it slightly to "patience should be your favorite tool".
Our slogan years ago was "shut up and listen". We put it on the back of a t-shirt, directed at the guys who would constantly yammer in the back of the room at a listening demo.

 

[Loquah]

moriez, I recall reading about this buzz on the forums Doc has directed you to. The highly informative peeps over on the BH forum will have you sorted in a jiffy.

If I remember correctly, the buzz could be Speedball related if you've installed the SB, but don't trust my memory - I'm in the final days of wedding preparations so my head is a scary place right now with all the tasks flying around in my mind

 

[Schizeophonic]

   
Same with me here. no need for an upgrade until now (although all things I want to try are on my desk already).
Nevertheless the ghetto-look my wood case had felt not right for the amazing sound that comes out f this box.
So I got my woodwork done the last week.
 

 

 

 
 
Gasp! I was pursuing through some bottlehead threads looking for case ideas.... and this one is a beauty! Love the legs, smoothed edges, and especially the knob. Where can I get a knob like that? 

 

[rock-solid]

   
 
...Where can I get a knob like that? 

 
I got it from a little electronic shop around the corner for 2€. 
I could get one for you but depending on where you live the shipping cost may be too high.

 

[Schizeophonic]

   
I got it from a little electronic shop around the corner for 2€. 
I could get one for you but depending on where you live the shipping cost may be too high.

 
Yeah - I am in the states... shipping is probably prohibitive. The last time I was in Europe was for the Love Parade in Berlin, Germany in 2000 - maybe for my next visit. Thanks for the offer though! You did some great work on your bottlehead! 

 

[D4NGER BIRD]

   

 

 
What would be the best way for a novice to round off the edges like this? Looks great!

 

[rock-solid]

   
What would be the best way for a novice to round off the edges like this? Looks great!

I hope Google translation found the right words: if you want it smooth and even you need a router (milling machine?). I used 2 different shapers: a smaller one for top and bottom and a larger one for the sides.
If you don´t have that machine find one who has one. It is only 2 minutes of work for a professional. You could send it over to me and I would do the job for you, but a local carpenter will sure be cheaper than the postage fees.
Only other way is to use rasp, file and sanding paper. But that way it will be hard to get an even look.

 

[moriez]

 

  *edit*
 
Downside of the newly installed tubes is that I'm now experiencing the above. A big buzz when the volume is turned all the way down. Doesn't bother me big time since just above zero volume there is no buzz. At some point I may want to fix this though and my question is, wouldn't installing another potentiometer (am thinking the Dale upgrade) solve this too? 

You can temporarily attach two 50K ~ 100K ohm resistors between each of the center taps on the volume potentiometer and ground to check if the buzz is reduced or eliminated. If so, you have a faulty pot. These resistors provide a guaranteed shunt for the 12AU7 grids if the pot is becoming open circuit at the trouble point in rotation.

 
Oh no, over my head. I bought the Crack prebuild and rather stay away from anything technical for now. For my own good Appreciate your suggestion though.
 

 

Downside of the newly installed tubes is that I'm now experiencing the above. A big buzz when the volume is turned all the way down. Doesn't bother me big time since just above zero volume there is no buzz. At some point I may want to fix this though and my question is, wouldn't installing another potentiometer (am thinking the Dale upgrade) solve this too? 

Depends upon what is causing the hum. That depends somewhat upon when you took delivery of your kit. Sounds like a perfect opportunity to take advantage of our tech support forum. There you can talk with the designer and narrow it down.

http://bottlehead.com/smf/index.php?board=24.0

 

 
From what I've read I was already certain that it's the faulty batch of MJE350's. Or not? The Crack kit plus Speedball was sent to the original owner on the 14th of January 2014. Thanks for the link.
 

@moriez, I recall reading about this buzz on the forums Doc has directed you to. The highly informative peeps over on the BH forum will have you sorted in a jiffy.

If I remember correctly, the buzz could be Speedball related if you've installed the SB, but don't trust my memory - I'm in the final days of wedding preparations so my head is a scary place right now with all the tasks flying around in my mind

 
Thanks Loquah, I think you're right. Will contact the original owner if needed. (Enjoy your wedding day!)

 

[Doc B.]

If the kit was packed and shipped around January 2014 it could possibly have the bad transistors. I would have to check with Josh to be sure when those popped up. They were taken out of inventory many months ago. There are other reasons it could have the problem it has. It might be best to take this to the Bottlehead Forum for troubleshooting - more eyes on with hands on experience. If you do go over there a close up photo of both sides of the transistor will help us to identify if they might be the ones that would oscillate.

 

[moriez]

Thanks again Doc. Will make my way there soon enough.

 

[NotaLefty]

Hi, I've got a Bottlehead Crack and I'm having some problems with static / distortion. It is mostly in the right channel as far as I can tell. It seems random and presents itself rather frequently. Sometimes it is worse than others. Does anyone know what is going on? 

 

[D4NGER BIRD]

Just finished up my Crack tonight, not one hiccup, everything measured right the first time out. Awesome instructions. Listening right now and it is fantastic.
 

 

[i luvmusic 2]

Congrats!