Crack;Bottlehead OTL
Jan 2, 2014 at 8:02 PM Post #3,451 of 12,346
I built my first Crack last month.  Bought a nice soldering station, a few really cheap tools, practiced for a hour or so soldering up a bunch of junk. Don't know a resister from a condenser. My 7 year old grandson with a little help from grandpa could follow the SIMPLE directions. The pay off for me is  Wow what a great sound. Smooth......I loved designing how I wanted my Crack to look.....black walnut ( almost ebony) wooden base; light green aluminum rustoleam paint on top.... been looking on the net for a month for the right gain knob. Had a couple of questions. Got on the web site and usually within 20 minute. I have a totally different relationship with  this Amp then I would with anything a bought. I'm not pushing Bottlehead here, I pushing the hobby of DIY high definition audio. Fun!
 
Jan 2, 2014 at 8:08 PM Post #3,452 of 12,346
Started my Speedball today and need to buy a stronger magnifier.  I feel like I'm a brain surgeon.  The next level in miniaturized electronic's is going to be a blast to build. By the way, I'm 73 with only vision in one eye. If I can do it, you can.
 
Jan 2, 2014 at 10:33 PM Post #3,453 of 12,346
  Firstly, I am a hardcore DIY guy thus I think everyone should really build their own amp. If I didn't think so we wouldn't be selling kits. One thing to bear in mind when determing a fair price for a used amp is that there's somewhat of a Catch 22 in buying used. Buying a used amp because you feel you are not technically competent to build one can mean buying someone else's first build. That doesn't seem like a very good way to guarantee never having to go under the hood, and it can take more effort to fix someone else's mistakes than your own. I would at the very least ask the seller what kind of guarantee they offer that the amp works 100%. Shawn (hifibuilderguy) has built more Crack amps than anyone on the planet. And his stuff is guaranteed. So yes, it costs more for sure, but on the other hand you are buying something that you know will work for the long run.
 
Also remember that if you decide to build it yourself you can go on the forum and we'll help you if you have any issues. If you buy something used and it doesn't work and you don't want to have to fix it yourself via the forum, you're looking at paying another $125 to us on top of what you spent on it to have us fix it for you.

 
That is a good point Doc and really stems down to how each of us attributes value and we will all have different ideas on that. But its also kind of unique from the stand point that we have your input as the head of Bottlehead engaged so directly with those here who are interested in your kits.
 
Mordicai;s comment  "I have a totally different relationship with this Amp then I would with anything bought." is very much how I feel and is a hidden part for of the value of BH diy ownership that is not looked at in $ terms but does have a value of its own which is connected to the BH forum and the connectivity that is there with yourself , PB,PJ and Joshua etc the very guys who directly are involved in the design and production of parts etc not forgetting the many other knowledgeable posters from my perspective this is one of Bottleheads most attractive aspects and of immense value.
 
Jan 4, 2014 at 11:31 AM Post #3,454 of 12,346
I'm sorry to hijack this thread, but I have a 'noobie toobie' question (groan).
 
Pictured below is the 12au7a I received with my Crack.  The glass (from what I remember) was completely clear all around the tube.  
 
Anyway, not too long ago I started noticing some intermittent crackling or scratching.  I recently picked up a Telefunken ECC82 and I haven't noticed the crackling noise with that tube.  Is my original tube kicking the bucket?  I purchased the Crack (new) in November, so was it a faulty tube to begin with?  Or is there something I did wrong on my build and now my amp is eating tubes for lunch?
 
The tube in question:
 
(back)

(front)

 
Thank you!
 
-Paul
 
Jan 4, 2014 at 12:13 PM Post #3,455 of 12,346
  I'm sorry to hijack this thread, but I have a 'noobie toobie' question (groan).
 
Pictured below is the 12au7a I received with my Crack.  The glass (from what I remember) was completely clear all around the tube.
 
Anyway, not too long ago I started noticing some intermittent crackling or scratching.  I recently picked up a Telefunken ECC82 and I haven't noticed the crackling noise with that tube.  Is my original tube kicking the bucket?  I purchased the Crack (new) in November, so was it a faulty tube to begin with?  Or is there something I did wrong on my build and now my amp is eating tubes for lunch?
 
The tube in question:
 
Thank you!
 
-Paul

 
Hi Paul
 
Looks like you received a RCA Clear top. Mine have the same silvering next to the getter which is on the side and not the top like most tubes. Sorry not able to help with info crackling or scratching as am just as new to the Crack as you.
 
Jamie
 
Jan 4, 2014 at 12:35 PM Post #3,457 of 12,346
Thanks, Jamie.  I thought yours looked the same as mine from other images.
 
Yes, you and I are 'crack brothers' 
beerchug.gif
 
 
I originally suspected bad solder joint, but because the problem went away with the new tube, I figured it must be the issue.  It's good to know that the tube is supposed to look that way - I was a bit trepidatious to use my new tube.
 
Thanks, Nic.  I will give cleaning the pins a try later today.  That could be the problem.
 
Jan 4, 2014 at 8:21 PM Post #3,459 of 12,346
Has anyone tried using a pair of cracks and using them as balanced monoblocks? +/- into L/R and bridge the output.....will that work on an otl after the output cap?
 
Jan 4, 2014 at 8:22 PM Post #3,460 of 12,346
x2.  To my ears, it's one of the best budget hd800 amps out there in fact.  

If you're looking for an absolute end game setup for hd800's (and that will also handle orthos), mainline is what you want.  It is phenomenal - except for the part where I can't tare myself away from listening at night and wind up sleep deprived and/or with wife aggro.  All in all, a nice problem to have.


Aaaaaaaaaaaarggffhhh.

Fudge.

I had the money all set aside for the mainline. Then I had to buy a new car after someone jumped lane and wrote mine off. The new car is really fun, but I'll be paying it for a few years. No more toys for me... Unless I find a second job. But then no time to listen...

Just can't catch a break sometimes....
 
Jan 5, 2014 at 2:35 AM Post #3,461 of 12,346
Has anyone tried using a pair of cracks and using them as balanced monoblocks? +/- into L/R and bridge the output.....will that work on an otl after the output cap?


I built such a beast around 2006.  Its performance was nothing short of terrible.
 

 
Jan 5, 2014 at 7:02 AM Post #3,462 of 12,346
There must be a lot of HD600 and HD650 owner here so if you've listened to both on a similar setup, please vote in my HD600 vs HD650 poll:
 
http://www.head-fi.org/t/698372/the-ultimate-hd600-vs-hd650-poll
 
Jan 5, 2014 at 8:06 AM Post #3,463 of 12,346
Odac paired with Crack for HD600 should be good enough right?
 
Jan 5, 2014 at 8:13 AM Post #3,464 of 12,346
Lol, that makes this an easy project not to do.... Nice looking build though :)

I built such a beast around 2006.  Its performance was nothing short of terrible.


 
Jan 5, 2014 at 12:08 PM Post #3,465 of 12,346
Has anyone tried using a pair of cracks and using them as balanced monoblocks? +/- into L/R and bridge the output.....will that work on an otl after the output cap?


There are other options for this, including the Audiotailor Jade. The plate/cathode pseudo balanced output is stunning with certain headphones. Will report about it in a week or two. A mark II version of this amp is pending, I believe.

There is something special about OTL amps, as long as you are aware of the importance of high quality caps and chokes.
 

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