Bottlehead Crack

Anyone hear built a Bottlehead Crack? Love to hear what your experiences have been
Never bult/heard a Bottlehead crack, but built a Crackhead bottle instead.
I built one. I used too much heat on the transformer so I paid for and they sent me a new one. It was entirely my fault. A rookie mistake. The directions are superb with photos and the forum is really helpful.
The sound is glorious. Detailed, warm, spacious. I use a MacMini-eastern electric DAC-Modwright pre-amp to the Crack and with Sennheiser HD600. I highly recommend this amp but not for in the ear monitors.
Well, I ordered the Crack- waiting ever so patiently. I'll be using HD600's with it. I am impressed by the forum.

when soldering I always try to use, if space permits, a Hemostat as a heat sink. I hope not to fry anything. I hate soldering IC's so what I always do these days is use IC sockets, solder those in place, and then just plug in the IC. No more fried ICs. No ICs in the Crack- yeah! I am looking for a DAC- will consider the EE.

At some point down the road I might get the speedball. Who knows.

I'm looking forward to this build as I have been itching for a DIY project for a while. My last project was repair a Sony XBR TV that died n 2013. I refused to accept its death, and with the aid of Google I learned this was a familiar issue with my particular model. $20 or so in parts later, TV is back up and running (2 components on the power supply board failed)
Sony XBR has best picture. It was worth to repair. I still never seen any flat pannel that has colors so natural.
would a NAD Viso HP50 headphone work with the Crack? It is 32 ohm (which may be too low I dunno) what would be the adverse affects?
It will work but not sound it's best. The output impedance of the Crack is too high. Low frequency response will be down maybe 3 db or so

Ideally you want to sprun headphone with at least 150 ohm input impedance with the Crack.

Sine my original post here I've had my Crack for ver a year. It has the speedball and otheR mods. With the right headphones (hd600's work very well) it's a stellar headphone amp
thank you Zavato

what is your formula for figuring the 3db down point?

I have considered the HD600s but I need them for another room as well which is not suited to their 300 ohm load.

Still the Crack is a very attractive amp and I may have to figure something out...

thanks again
It uses a 12AU7A as its input stage, and a 6080 in a cathode follower configuration as its output stage. The output is capacitively coupled (the only cap in the audio path), and has an output impedance of about 120 Ohms making it an amp suited mainly for higher impedance headphones. (I'd suggest 300 Ohms and up, but some will find it fine for cans down to 100 Ohms.)

i found the above at a link from the Bottlehead website.
if you use a lower impedance headphone like the 32 Ohms you are intending, not only with you end up cranking the volume knob to get more SPL but you will also tax the circuit to output more current into your 32 Ohms headphones (to get an adequate voltage swing to create that SPL). That might work against/tax the Crack unit & it's possible that bass response will suffer. I'm not sure about the bass response being down 3dB. I'd also like to know how Zavato came to this conclusion...

the manuf is suggesting headphones with 300 Ohms impedance & higher.

thanks for the information I have been to those websites and know they recommend against using 32 ohm cans with the Crack unit I was just curious (and hoping for better news) as to what happens in the circuit and you cleared it up nicely. I would prefer not to tax the tubes

I have decided to buy the Sennheiser HD600s and the Crack so I can hear for myself the two together.

Philjolet, great! let us know how the HD600-Crack combination works out. Will it be all that its Cracked out to be? Will you get high on it? ;-D
Bombaywalla, I will let you know when I get everything going which will probably be at least a month away...(without the Speedball) ;^)

btw your system looks amazing!

good job!
Thanks for your kind words Philjolet. :-)
The -3dB is somewhere on the Bottlehead site
Go to the Bottlehead crack forum, FAQ section, question #6. Using a 32 ohm headset, you'll be down 3 dB at 50hz
Thanks Zavato. I agree with this number now. the high-pass filter is formed by a 100uF & a 32 Ohms (of the headphone) & indeed the -3dB corner of this high-pass filter = 50Hz (49.76Hz to be exact).

Philjolet, just FYI: this same FAQ #6 also states exactly what I stated - low impedance headphones will tax the Crack unit by asking it source too much current.

This FAQ section might a good one to read for you Crack owners (those that have not already read it)
Thanks guys!

Bottlehead seems to be very thorough.

I decided the most important thing is getting the Crack to sound it's best so I bought some Sennheiser HD600s. It will be a while before I get the amp (they ship them in batches) and then I have to build it.

I will report back when I actually get to listen.
You won't regret it. The combination is just mind blowing.
a very enthusiastic yes from Tgrisham!

thanks for sharing!
I am in the process of building their bee pre. Very impressed so far everything is laid out good and the instructions are phenomenal with lots of pictures. It's my second kit one I did from another manufacturer was brutal. Some parts didn't match the instructions and when you asked questions basically all he said was look at the schematic. I would definitely recommend bottle head for anyone as their first kit or who is nervous about DIY.
It looks like you get a lot with the BeePre for $1175.00. I have never seen 300B tubes in a preamp. I do not know much about this stuff but I am guessing it is way over built so it cruises along easily handling all signals.

Everything I have read about the Bottlehead stuff is that the directions are very well done. I look forward to getting mine soon.

Good luck with your project Analogluvr
feedback on crack

* built my crack about 4 years ago
* using a senn 600 since day 1 with the crack
* very straight forward build
* added the speed ball mod 6 months after building the crack - just do it, you will never look back; inexpensive upgrade and worth it
* background is dead black quiet
* i use an old nakamichi cd player to drive crack
* the crack and cd player are used at work; probably have 3000+ hours on the crack and original tubes
* my crack has had zero issues since i built it
* never fatiguing; glorious warm otl sound at work
* home system is wavestream phono/line, mfa 200B amps, and magnaplanars...i look forward to cd listening at work while looking forward to album listening at home
* overall - great amp bottlehead designed; no need for me to try other head amps.