Crack;Bottlehead OTL
Jun 2, 2021 at 1:10 AM Post #11,026 of 12,335
Thanks. I think the BeePre2 really demands a case with more heft than the stock one. My neighbor had some down time and mad woodworking skills, so he cad designed this and crafted it by hand. I love these types of joints and he had the idea for the tapered top.

I‘ve another friend who builds guitars and his most recent one has a cool wengewood style stain that is interesting.
 

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Jun 3, 2021 at 11:16 AM Post #11,027 of 12,335
Well, it's not the prettiest Crack ever built, and it's CERTAINLY not the quickest, but I finally got around to completing my half-assembled Crack and I'm pretty happy about it. I haven't tested it much yet as I need to make some space for it near my current rig, but initial impressions are pretty positive given the price of the amp kit.

And it worked on the first try! I found one bad solder during the resistance testing that was quickly fixed but otherwise no issues. I messed up the staining by not sanding away enough of the glue at the corners. And I messed up the paint on the top by flipping it over to work on before it was 100% dry (you can see where some pain came off around the edges where it touched the wooden case). But all that's just personality if you ask me. :smile:

Gonna be using it with my HD800's and my (soon to arrive) ZMF Auteur. Source-wise, I'll be experimenting to see if my warmish R2R DAC-19 is too much warmth or if I should use the Mojo with it instead.

Eventually I'll install the Speedball kit (I want to get used to the stock sound first though) and think about tube rolling. Anyone know if it's safe to use my tubes from my Project Solstice with the Crack?
 

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Jun 3, 2021 at 8:16 PM Post #11,029 of 12,335
Not a good match. The lower impedance of focal cans don't pair well with OTL amps. Look for headphones with higher impedance, such as beyerdynamic and sennheiser.
The DV is listed to handle 60 Ohms and up but am pretty sure it's not driving the cans to its full potential
 
Jun 3, 2021 at 8:17 PM Post #11,030 of 12,335
Agreed! Beyer DT1770 pro, 250 ohms; Beyer DT880, 250/600 ohms, Senn HD600, 300 ohms; ZMF Auteur, 300 ohms...
how about the DT 990 600 OHMS ?
 
Jun 3, 2021 at 8:19 PM Post #11,031 of 12,335
Little bird just told me that Bottlehead raised their prices. I can confirm. Makes me glad I already have some BH amps. If only I hadn’t JUST sold my mainline :).
In fact most companies raised their prices due to the components shortage related to the COVID lockdown
 
Jun 3, 2021 at 8:22 PM Post #11,032 of 12,335
Not a Crackhead, but a pic of the Bottlehead BeePree 300b pre amp in a custom wood case. These have Teflon Vcaps, stepped attenuators, and buffered outputs. Just need to settle on a stain to match the pretty copper hammertone finish but not black.
The wood texture is beautiful, which wood is that ?
 
Jun 5, 2021 at 12:29 AM Post #11,033 of 12,335
Jun 5, 2021 at 1:06 AM Post #11,034 of 12,335
Jun 6, 2021 at 10:24 PM Post #11,035 of 12,335
The last two mods for the amp.
Cap bypass and the film cap.
After a couple tries. Finally made the box for the two film caps. I had to redo some of the wire to rotate the headphone jack around. This so it won’t risk a short. The box is clip on the headphone jack and the corner screw of the transformer.

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Jun 7, 2021 at 12:59 AM Post #11,036 of 12,335
The last two mods for the amp.
Cap bypass and the film cap.
After a couple tries. Finally made the box for the two film caps. I had to redo some of the wire to rotate the headphone jack around. This so it won’t risk a short. The box is clip on the headphone jack and the corner screw of the transformer.

7BD06605-A384-4D53-BB6F-EDEEE5899CCB.jpeg

1F7EFE7E-AEE5-404F-88E4-D7B2FCC47406.jpeg
A8A1DEB6-3202-49DE-AF10-805672F174D9.jpeg

7E6CD603-ABF1-4FD4-A5AA-69D5B805B86E.jpeg

1D7B5B9E-DDAF-4B28-A2B5-3CE651C5C67C.jpeg

637B6319-AF19-4692-9BA4-D356CC47F072.jpeg

7AC650B5-0914-47C2-A7BE-7DDEE9FFC32F.jpeg
Tell us about the results when it's up and running, lots of work done there
 
Jun 7, 2021 at 12:51 PM Post #11,037 of 12,335
Tell us about the results when it's up and running, lots of work done there
It sounds fantastic. It actually like it better than the Eddie Current ZDT Jr that i shielded not too long ago. The amp is dead silence with both stock tube set and the 6N13S + 6SN7 (with garage1217 adapter). Too bad this amp is not mine lolz.
Here is the list of mod done so far:
- Speedball
- Ground the earth with a pair of uf4007 rectifier
- Choke
- Cree Diodes
- Panasonic Square Film Caps
- Cap Bypass for all
 
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Jun 7, 2021 at 1:39 PM Post #11,038 of 12,335
It sounds fantastic. It actually like it better than the Eddie Current ZDT Jr that i shielded not too long ago. The amp is dead silence with both stock tube set and the 6N13S + 6SN7 (with garage1217 adapter). Too bad this amp is not mine lolz.
Here is the list of mod done so far:
- Speedball
- Ground the earth with a pair of uf4007 rectifier
- Choke
- Cree Diodes
- Panasonic Square Film Caps
- Cap Bypass for all
Were you able to make it handle cans with impedance lower than 150-200 Ohms ? am curious as a Focal owner
 
Jun 7, 2021 at 3:06 PM Post #11,040 of 12,335
Were you able to make it handle cans with impedance lower than 150-200 Ohms ? am curious as a Focal owner
I did a quick listening test for the focal elegia and it works fine. The off volume is at 6 o'clock. anything pass 9 o'clock is too loud for my taste with this headphone. It does seems to have a little more punch than my 650. I also test with the 80hm dt770, that also works fine. It seems like the treble is toned down a bit for the dt770 with this amp, which is a good thing for me =).

I tested this via Ares II Dac.
 
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