[pravous]

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!

Amazing work. Polishing the plate and bell cover must have taken some elbow grease. Base crack or have you added the speedball yet? BHC and 6xx got me hooked on tubes. Wish I had more patience when I assembled mine. Didn’t give the paint enough time to cure and resting it upside down in the chassis left marks. Happy listening!

 

[dstarr3]

Congrats and gorgeous build!

Thanks!

Amazing work. Polishing the plate and bell cover must have taken some elbow grease. Base crack or have you added the speedball yet? BHC and 6xx got me hooked on tubes. Wish I had more patience when I assembled mine. Didn’t give the paint enough time to cure and resting it upside down in the chassis left marks. Happy listening!

Thanks! Yeah, I random-orbit-sanded it up to 3000-grit, then got some buffing wheels for my cordless drill with some metal polish and went to town. Took forever and still doesn't look as good as I wanted, lol. I threw in the towel at "good enough." It's not a skill I feel any particular desire to master.

This is the base BHC, I'd read some reviews that suggested the Speedball upgrade undoes a lot of the "tube magic" that the base BHC was loved for, so I figured I'd start off without it. Maybe down the line I'll pick up another BHC kit with the SB upgrade and A/B the two. But for now I'm satisfied with my base one.

 

[Dawgfish]

Thanks!


Thanks! Yeah, I random-orbit-sanded it up to 3000-grit, then got some buffing wheels for my cordless drill with some metal polish and went to town. Took forever and still doesn't look as good as I wanted, lol. I threw in the towel at "good enough." It's not a skill I feel any particular desire to master.

This is the base BHC, I'd read some reviews that suggested the Speedball upgrade undoes a lot of the "tube magic" that the base BHC was loved for, so I figured I'd start off without it. Maybe down the line I'll pick up another BHC kit with the SB upgrade and A/B the two. But for now I'm satisfied with my base one.

No problem! I own a BHC with SB and one without. I love both of them. They both have their strong points. One day I plan on upgrading the caps and volume pot with the one without SB.

 

[larcenasb]

Great job! And very cool eye-shaped wood grain

 

[dstarr3]

Also, if anyone is looking for some vibration-dampening feet, either for their BHC or in general, these are on sale:
https://smile.amazon.com/gp/product/B08MPBXG6M?psc=1

I linked them not too long ago. But right now they're on sale for $16, plus a coupon for a further 35% off, making the final price a little over $10.

 

[Galapac]

Also, if anyone is looking for some vibration-dampening feet, either for their BHC or in general, these are on sale:
https://smile.amazon.com/gp/product/B08MPBXG6M?psc=1

I linked them not too long ago. But right now they're on sale for $16, plus a coupon for a further 35% off, making the final price a little over $10.

These are pretty good and I use them under my turntable between a butcher block and granite stone. Never had a skip, even jumping around.
They are adjustable in that you can add/remove springs as needed for tension.

 

[bpiotrow13]

I have just pulled the trigger for the BHC and would like to join the club. While waiting for delivery i am thinking of the upgrades. I would not go for speedball but would rather focus on output caps. I was thinking of Mundorf Capacitor 100uF 350Vdc MCap® EVO Oil.

Is it good choice? Would be grateful for any thoughts/suggestions. I will use BHC with hd650 (and zmf aeolus in future).

 

[Tom-s]

It’s a very good choice quality wise. But I’d strongly advice to build it first and see for yourself how it will fit. These are very big and it’s possible they don’t fit with the normal woodwork.
I’ve had good experiences with normal Mundorf mcap 100uf.
Here’s some before / after pictures on how those fit.

 

[bpiotrow13]

It’s a very good choice quality wise. But I’d strongly advice to build it first and see for yourself how it will fit. These are very big and it’s possible they don’t fit with the normal woodwork.
I’ve had good experiences with normal Mundorf mcap 100uf.
Here’s some before / after pictures on how those fit.

Thanks, i have found suggestions here and understood these Mundorf will fit:

https://www.headphonesty.com/2019/04/upgrading-bottlehead-crack-headphone-amplifier/

Maybe i should go for Audyn caps as suggested by Doc B? Will Mundorf be much better (it is also slightly larger)? I am also not sure if aluminium oil is not too soft sounding.

 

[bagwell359]

Thanks!


Thanks! Yeah, I random-orbit-sanded it up to 3000-grit, then got some buffing wheels for my cordless drill with some metal polish and went to town. Took forever and still doesn't look as good as I wanted, lol. I threw in the towel at "good enough." It's not a skill I feel any particular desire to master.

This is the base BHC, I'd read some reviews that suggested the Speedball upgrade undoes a lot of the "tube magic" that the base BHC was loved for, so I figured I'd start off without it. Maybe down the line I'll pick up another BHC kit with the SB upgrade and A/B the two. But for now I'm satisfied with my base one.

Yes the Speedball makes it less obviously tube - more towards a hybrid feeling with tighter bass, more definition, and a little more clarity in the upper end of the treble. But you'd never mistake it for a Class AB SS 200 wpc.

 

[bpiotrow13]

Yes the Speedball makes it less obviously tube - more towards a hybrid feeling with tighter bass, more definition, and a little more clarity in the upper end of the treble. But you'd never mistake it for a Class AB SS 200 wpc.

I guess there are diverse opinions on speedball. Most people consider it as major upgrade but some says it takes away charm. I decided to start without and decide on speedball later.

While waiting for my kit I am hesitating if to upgrade output caps or to built stock crack first and see how it sounds.

 

[GreenNeedle]

Thanks, i have found suggestions here and understood these Mundorf will fit:

https://www.headphonesty.com/2019/04/upgrading-bottlehead-crack-headphone-amplifier/

Maybe i should go for Audyn caps as suggested by Doc B? Will Mundorf be much better (it is also slightly larger)? I am also not sure if aluminium oil is not too soft sounding.

These Mundorf's fit and this is in the original base not a heightened one:

 

[bagwell359]

I guess there are diverse opinions on speedball. Most people consider it as major upgrade but some says it takes away charm. I decided to start without and decide on speedball later.

While waiting for my kit I am hesitating if to upgrade output caps or to built stock crack first and see how it sounds.

The directions advise building it stock first for simplicity sake - and that gets you both experiences when you redo it.

To me the stock is like a sepia photo, the Speedball is like a standard B&W. And my favorite amp ever the Pass X-150 is like Kodachrome 25 developed properly on a large format Hasselblad (for the true film buffs).

 

[bpiotrow13]

These Mundorf's fit and this is in the original base not a heightened one:

Good i think aluminium oil version is the same as aluminium only. I wonder which would better suit.

 

[bpiotrow13]

To me the stock is like a sepia photo, the Speedball is like a standard B&W

Understood. I fully understand why some may not like it. One of my milestones findings in audio was realising that i do not like neutral sound