[SHIMACM]

Hey, I was going to let someone else answer, but since you haven't gotten a response yet, here you go:

The brand and model aren't so important here, the main thing is to have film caps, in general, handling the audio signal. The Crack is a simple circuit, so no need to spend crazy amounts. Just make sure the diameter of the caps doesn't exceed 54mm, otherwise you'll have to get creative with mounting. For reference, my Audyn Q4 68uF 400V caps are 52mm in diameter and fit nicely on each side of the chassis (see attached photo).

Here are some of the usual suspects:

Mundorf MKP 100uF 250V 46mm-diameter ~$120/pair (partsconnexion.com)
Dayton 100uF 250V 51mm-diameter ~$80/pair (parts-express.com)
Audiophiler 100uF 250V 50mm-diameter ~$60/pair (eBay)
Panasonic EZPE 100uF 500V 35mm de largura (forma cubóide retangular, então a montagem pode ser um pouco estranha) ~ $ 44/par (newark.com)

Além disso, você pode se safar com limites de capacidade mais baixos (consulte o gráfico em anexo). Isso economizará espaço e dinheiro. Se você seguir a recomendação do Bottlehead e usar apenas fones de ouvido de 200 ohms ou mais, os limites de saída tão baixos quanto 47uF ainda permitirão que frequências abaixo de 20Hz passem a -3 db. Novamente, eu uso tampas de 68uF e não noto nenhum corte de graves com os Sextetts Sennheiser HD 600 de 300 ohms ou AKG K240 de 600 ohms.

Aqui estão mais algumas opções:

Mundorf MKP 68uF 250V 43mm de diâmetro ~ $ 72/par (partsconnexion.com)
Audyn Q4 68uF 400V 52mm de diâmetro ~ $ 53/par (peças-express.com)
Solen PB 68uF 400V 49mm de diâmetro ~ $ 51/par (partsconnexion.com)
Audiophiler 68uF 250V 39mm de diâmetro ~ $ 36/par (eBay)

Just in case, remember it's recommended that you drill holes to secure zip-tie mounts with a screw and nut. If you just use adhesive zip-tie mounts, eventually the weight of the caps and the heat of the top plate will cause the adhesive to let up and the caps can fall.

For a choke, the Triad C-7X is a common choice .... ~$12 (digikey.com)

If you are wondering more about upgrading, I wrote a whole guide that's gotten buried deep within this thread: https://www.head-fi.org/threads/crack-bottlehead-otl.476650/post-16152725

Hope this helps. Cheers.

Thanks for the very detailed answer.

 

[buencamino]

Congrats, you’re getting so much for your money. And many before you have loved what the Crack’s smooth sounds does for the HD 800. Enjoy!

Also, if you’re unable to find out the problem, don’t hesitate to go over to the Bottlehead forum and post in the Crack section. The Bottlehead team are very active there and quick to help. Usually you’ll just have to post your voltage/resistance checks and attach some photos of your wiring/solder joints. Hope you get it all fixed up. Cheers!

Thank you!

Until recently I was having static/squeaking problems in my Crack.

I reinforced all the welds and the problem was solved.

Total silence, even using valves with adapters.

When you say reinforced, did you re-solder all the joints/welds?

 

[SHIMACM]

Thank you!


When you say reinforced, did you re-solder all the joints/welds?

Yup. But I didn't remove the old solders. I reinforced them all.

 

[buencamino]

Yup. But I didn't remove the old solders. I reinforced them all.

this meant touching it with the soldering iron, just melt it and fixed it up again..?

 

[bagwell359]

this meant touching it with the soldering iron, just melt it and fixed it up again..?

Make sure you have resin to add if you are retouching. Cold solder joints is what you'll get if not. If you are using solder with resin core to retouch unless it's a dry joint you risk the chance of solder splashing and excess blovs - shorts waiting to happen and a very poor look.

 

[SHIMACM]

this meant touching it with the soldering iron, just melt it and fixed it up again..?

In my case I didn't melt anything. I just added more solder and reinforced the ones that were already there.

 

[bagwell359]

In my case I didn't melt anything. I just added more solder and reinforced the ones that were already there.

Wait, the original solder wasn't melted? Soldering fresh adjacent to existing is not good. Does the new solder have resin in it? That's better but solder with no resin added to the existing? Ugh.

What components are involved? Based on a lot of experience i'm very careful. For instance I never solder or resolder chips directly into boards (use sockets), and whenever possible I use heat sinks to keep anything from heat damage. Everything is tied down and all checked with a 10x loup looking for splashes, cracks, cold joints, etc.

For anyone reading this - lots of guides on-line. It's not rocket science, but it's not trivial if one wants perfect results.

 

[larcenasb]

Given that one of my messages SHIMACM quoted had been translated, I was thinking there was some loss in translation.

But yeah, to be clear, the iron should stay on the joint long enough to be reheated sufficiently, so that all the solder melts....and then making sure the iron is touching both the terminal and the wire/lead. Then wait a couple of seconds and pull off the iron. Perfect and shiny joint.

 

[bagwell359]

Given that one of my messages SHIMACM quoted had been translated, I was thinking there was some loss in translation.

But yeah, to be clear, the iron should stay on the joint long enough to be reheated sufficiently, so that all the solder melts....and then making sure the iron is touching both the terminal and the wire/lead. Then wait a couple of seconds and pull off the iron. Perfect and shiny joint.

Yes, with resin present. Sorry if specified earlier. No resin, bad joint.

 

[SHIMACM]

Wait, the original solder wasn't melted? Soldering fresh adjacent to existing is not good. Does the new solder have resin in it? That's better but solder with no resin added to the existing? Ugh.

What components are involved? Based on a lot of experience i'm very careful. For instance I never solder or resolder chips directly into boards (use sockets), and whenever possible I use heat sinks to keep anything from heat damage. Everything is tied down and all checked with a 10x loup looking for splashes, cracks, cold joints, etc.

For anyone reading this - lots of guides on-line. It's not rocket science, but it's not trivial if one wants perfect results.

I actually use google translate. My mother language is Portuguese. I melt the previous solder and add more solder. The end result remains. Black background.

 

[bagwell359]

I actually use google translate. My mother language is Portuguese. I melt the previous solder and add more solder. The end result remains. Black background.

Excellent!

 

[MacMan31]

Check out this BHC. It's not mine but it's really cool. I love the volume knob. Looks like a combination lock.
https://old.reddit.com/r/headphones/comments/yjoled/another_bottlehead_crack_hd650_combo/

 

[larcenasb]

Whoa, a small version knob and a larger one! It has very nice OCD-level wiring as well. Hope it's still getting lots of play time.

 

[dstarr3]

And another Crack has been born into this world!

I got a little carried away on the casework. I took a stab at mirror-polishing the steel plate and the transformer cap. I did as good a job as my limited patience would allow, lol. If there's a next time I build one of these, I'm just going to take the metal parts down to my local auto body shop and ask them to polish them for me.

I also prepped and painted the power transformer with some spray-on truck bed liner because I didn't like the raw look with the chicken wire resin pattern. Bed liner paint is particularly good to use here since it has a nice texture that hides small imperfections in the laminations and it has a high temperature tolerance without needing to be cured.

Two coats of golden oak Danish oil.

The soldering was by far the easiest part, lol. I'm used to working on much smaller devices. I just followed the instructions, it passed all the resistance and voltage checks first time, and sounds perfect. No channel imbalance, no cracking, popping, buzzing, etc. Always a good feeling when complicated projects work out without any drama.

Replaced the stock pot before assembly with a TKD 2CP-2511 as recommended here earlier. I don't know what the stock pot sounds like, but this one sure sounds and feels great. I'll get a fancier pot knob later.

This was a super fun and rewarding project. Thanks, everybody, for all the advice along the way!

 

[Dawgfish]

And another Crack has been born into this world!



I got a little carried away on the casework. I took a stab at mirror-polishing the steel plate and the transformer cap. I did as good a job as my limited patience would allow, lol. If there's a next time I build one of these, I'm just going to take the metal parts down to my local auto body shop and ask them to polish them for me.

I also prepped and painted the power transformer with some spray-on truck bed liner because I didn't like the raw look with the chicken wire resin pattern. Bed liner paint is particularly good to use here since it has a nice texture that hides small imperfections in the laminations and it has a high temperature tolerance without needing to be cured.

Two coats of golden oak Danish oil.

The soldering was by far the easiest part, lol. I'm used to working on much smaller devices. I just followed the instructions, it passed all the resistance and voltage checks first time, and sounds perfect. No channel imbalance, no cracking, popping, buzzing, etc. Always a good feeling when complicated projects work out without any drama.

Replaced the stock pot before assembly with a TKD 2CP-2511 as recommended here earlier. I don't know what the stock pot sounds like, but this one sure sounds and feels great. I'll get a fancier pot knob later.

This was a super fun and rewarding project. Thanks, everybody, for all the advice along the way!

Congrats and gorgeous build!