I have built some point to point kits before, but it was years ago. But yeah, I could start with the Crack. The prior kits were radio receiver and low power transmitter. Since that time I’ve done computer cables, a bit of modifying on 1980s circuit boards, and assorted small stuff. Nothing ambitious. This conversation should probably be moved to the DIY thread.
But for now, it’s just something I’ve been toying with. And not sure I have the time.
Not that you need more discouragement, but casual and non-savant electronics builders need to go into “beast mode” to get it right. There are many things that can go wrong and something likely will go wrong the first time through. I found the Crack’s physical 3D point-to-point build to be as hard or harder than the very large scale and easy soldering portions. Even the pair of infamous tiny LEDs wouldn’t be that hard with an instruction book rewrite and starting without other wires in the way.
“Don’t do the crime if you can’t do the time. Don’t do it!”
Moderator: Please move to the DIY or Bottlehead thread, as @Pennstac requests.
It’s not “difficult”, but I would tend to agree, I find soldering on boards a lot easier.
What the Crack does do is generally give you enough instruction, and testing instruction, in the build that if you are careful, detail oriented and persevere you end up with a working amp.
While my elekit build was “easier” from the stand point of soldering, it was extremely unforgiving of mistakes, I missed one solder joint when I first built mine, and I swear I must have looked at it a dozen times afterwards before resorting to a scope and the circuit diagram to identify the issue.
I knew I shouldn’t have jumped in to read this…ha! I just finished sanding and painting all the wood case. I painted the chassis as well with a nice hammered black paint. I’m really liking the look that it will turn out to be albeit a few minor blemishes just due to never doing something like this before. However, I have never soldered in my life. Reading this…oh boy am I in for it.
Now, to be fair to myself, I have always built every pc I’ve owned so I’m no slouch to technical things. Still, things are always the most difficult the first time through. Thankfully I have all the tools I need and I did buy a soldering practice kit so I can try and get my skill level up a bit before I start on the crack. I should have started already but giving a few days for the chassis to fully dry.
It’s not too hard if you are mechanically minded or have a DIY streak, but you can fry your components or burn yourself or give yourself a shock (and die). You might benefit from my write-up (link to post above):
There I presented my lessons learned and pain points. Before starting I read other assembly logs and watched build videos too. Next time I’d solder the LEDs before any of the other wires around the tube socket (see blue ring in my marked up photo), and try an alligator clip as a heat sink to protect the LEDs.
I just read through your guide, very well done! Thank you for linking to it from above.
Yeah, my biggest concern is to just make sure I work on it when I’m good and ready. I do not want to feel rushed in any way. If that means taking much longer then usual, so be it. I just had to go repaint my chasis today as I got a small “scratch line” after it dried even though you can’t actually feel this scratch. Nothing has touched it either so I am guessing the hammered paint could have just settled in that way. Easy enough to remedy at least.
I stained mine with natural walnut dye and boiled linseed oil, but it proved to not be color stable. Bottlehead ships extremely, extremely porous wood that drinks down everything for the first several coats. The wood will temporarily go translucent (and look wild) as the finish migrates into little wood fiber straws.
Long story short, my brown stain faded to yellowish and I didn’t like the green metal and yellow wood combo. I wanted very dark brown. So, I coated the “complete” finish with charcoal powder and boiled linseed oil. It now looks like the photos above, plus it has a vintage aged texture that I rather like. The look and color has been stable for 6-9 months. Linseed oil welcomes do-overs and is easy to touch up, but is very slow to dry.
If you are using regular paint fading won’t be an issue – this only applies to stains. With hindsight, I’d have applied charcoal powder at the start to darken the wood when first raising and sanding the grain.
You are right though about first time for anything there will be mistakes. I followed the instructional video to a T from the Dr (bottlehead). Anyway, I taped all pieces of the wood before doing the glue as shown. Of course when I went to peel the tape off one piece actually pulled some strands of the wood off. So I have a permanent mark on one side of the casing now. This was the plain old blue painters tape too…brand new tape. It is what it is.
I did two coats of the Emerald stain before I applied the Linseed Oil to set. So far its maintained color but I’ll see how it goes after a week or so. As you said, I can always sand and do it again should I need to as I have plenty of stain color left.
I’m not sure if you can color match the stain at this point, but one repair method is to mix sawdust from the object itself with wood glue to fill the holes/grooves. Then sand and finish. The original boards provide the closest possible materials match. However, you’ve already got three coats on top so sawdust may make the problem worse.
While Bottlehead’s factory wood has fantastic dimensions, it’s a budget “white wood” that many people would choose to hide.
I’ve mostly used commercial stains and they hold color far better than the traditional method I tried for this project. However, modern stains sometimes have a painted look that I was trying to avoid. My last can of Varathane walnut stain might be mistaken for an thin coat of brown paint instead of stain.
The Crack and Speedball kits will be going on sale on Aug 18th, for those imminently interested in building one …
Yep. I’m on the newsletter. As with last year, they’ll be $299 (save $50) and the Speedball $99 (save $16). Total units available at discount = 50.
Of course they will be…3 weeks after I bought mine. No worries though, still love the concept and experience.
Alright question for anyone who has built the BHC:
Today I was going along smoothly when I made a dumb mistake. I’m going to be one of those bad dads and blame my kids! They were running around and in the distraction I mistakenly soldered one of the 220uf capacitors to 13-14 instead of 14-15 on the crack!! Once I realized my mistake I clipped the leads from the capacitor in hope that I may still be able to use the 1/4" left leads on it. I also need to suck up the solder off of the board in order to reuse the area (I got copper wick so I should be ok here I hope).
First - does anyone know if I should just buy a new capacitor and if so where? I know I can google it but does anyone know of any b&m places that would carry such a thing…lowes, home depot etc?
2nd question - if the lead is too short, is it possible to just solder on a piece of another lead that I cut off?
Last part to this - if it is a just long enough lead to solder to the correct area, am I in danger of blowing the capacitor?
I’m new to all of this in case you couldn’t tell. I’m on day 2 of the build…day 1 went much better for me. Today started with LEDs and then capacitors and such…mine is not looking quite as neat and clean as the pictures. As long as it works right that is really all I care about!
As far as leads being too short I don’t know if that’s a problem but any part can be replaced through Bottlehead. I did a similar thing building mine and just emailed them what I needed. They’ll send you a PayPal invoice to pay and send you a replacement.
I think all of this is par for the course with V1.0 builds. I had to unsolder a few wires myself. What really killed me are the instructions that say: “Do X, and Y…and do Z…and then solder.” I soldered after Y a couple times.
Capacitors and transformers are the heart and soul of an amp – I’d stick with the same brands and models because otherwise you might have performance differences across channels. One DIY upgrade path involves swapping the caps for exotic and huge ones.
Resoldering: The greatest risk is reversing the polarity and blowing them up when the amp is started. If the amp passes its final multimeter checklist (per the BHC manual) I expect they’ll be fine. I also don’t see harm in adding a longer lead if the new joint is solid and if you don’t overheat the cap (use an alligator clip as a heat sink between the soldering point and item).
If not going back to Bottelhead (@Audiophool), shop at Mouser or DigiKey for parts. Lowes and Home Depot likely have nothing relevant. Even physical electronics stores such as MicroCenter tend to have small inventories versus online vendors.
Good luck, or break a leg.
Ha thanks for the help!
I was able to solder longer leads and it “seemed” to work ok. I got to the resistance checks last night and all was good except I couldn’t get a reading from either rca jack. Oof. It looks like this is a pretty common thing. It doesn’t explain very well where to test it at as it just says center pin. Before I go removing things I’m going in with fresh eyes today to make sure of it. At least my ground did read as 0.
I can’t move on to voltage checks or the speedball till I figure out the RCA.
Oh, as a side note, I realize I can post to BH forums. However their verification system for my email won’t seem to come through. You guys are every bit as helpful so this works too!
This is the exact reason I chose Mechanical Engineering and not Electrical Engineering in college. I like to see where my problems are (and probably my dad tricking me into putting 9 volt batteries on my tongue when I was a kid)! Good luck to you on this one! 
Alright, I think I’m good. I’m not used to using a multimeter and realized I needed to connect them to the RCA and not just one with the other on the negative. Once I did it correctly I got readings within spec!
Voltages we’re a little high on a couple of terminals but consistent in the numbers so I’m going to try and post on their forums to be sure I’m good.
Don’t want to blow some headphones as my first test!
I started my BHC audio testing with the Senn HD 58x…because it was cheap and I wouldn’t care much if it blew up. Bad idea. It’s 150 ohms so it sounds scratchy and awful. Second, I discovered that the 1/4" socket is a wee bit too deep for a lot of my headphone jacks. One channel didn’t work (me thinking “Oh, no I screwed up”) and it gave me a panic. Long story short, I have to set many jacks with a 1-2 credit card thickness gap. Then all is well.
well my options are Koss Porta Pro @60ohm. Or my Atriums…I’m sure I am just being too worrisome, but still.
