• Welcome to ASR. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Bottlehead Crack Headphone Amplifier Kit Review

For the low low price of 84$, you can now build your own cable ... wich makes the amp sound better for some unknown reason.

The site really has all the bs you want and more:
The difference is audible. Rather than trying to come up with some far fetched theory like most cable manufacturers I will simply state that I find that it makes our gear sound better than the stock power cord and leave it at that. Assembly instructions are here. (See In Depth below for the whole story)

I had to leave a review for the power cord because simply put, this is the best upgrade I’ve made on a Bottlehead amp. With a stock Crack and Speedball this has surpassed all the upgrades I’ve made on it before, including high end caps, pot, and tube upgrades. To me the cord has made the biggest difference in sound quality, with more emphasis on the bass and a major increase in clarity. The music sounds amazingly life-like. I was skeptical as to how much improvement I would hear but I now can never go back to using a stock cable. This is just too good of a sound I am hearing. It was without a doubt worth every penny. Well done Bottlehead!
Click to expand...
It's false/misleading/nonsensical claims like this that I mind.
 
Last edited:
I did know the Panther is a subjektivist. No Problem with that. But after this review i'am not sure if he maybe uses drugs?
 
solderdude said:
This is exactly what Marv's (SBAF) beef is with 'measurements extremists', and it seems in particular with Amir ;).
Obvious amounts of distortion reaching over 1% (bottom of the SINAD chart), having channel imbalance and an output resistance of about 1/2 (breaking the 1/8th rule even with a headphone showing impedance swings) doesn't lead to 'poor sound quality' but rather can give a pleasant and impressive change to certain headphones.
Click to expand...

I have no issue with the fact that lots of people like limited distortion that fits a particular profile. But it seems to me that if people find some particular distortion profiles pleasing and other particular distortion profiles distracting, that they should desire for there to be some way to predict, based on measurements, whether a given piece of equipment that reportedly produces audible distortion is likely to sound pleasing to them.

Amir does not often allow measurements to have the final say on anything. It is ironic that he has taken so much heat for his subjective evaluations and that you are characterizing him as a "measurement extremist". Notwithstanding that it is possible to infer too much from measurements and that this possibly happens to a greater extent than is desirable, the fundamentally difficult problem in correlating measurability with audibility would be a terrible reason for refraining from taking all the measurements that can reasonably be taken.
 
Doodski said:
It appears this amp is ripe for a mod or two. I specialized mostly in mechatronics and know next to nothing about tubes but somebody might have a mod or two. :D
Click to expand...

Or three or four or five or six or seven or eight or ............
 
solderdude said:
It needs silver wiring inside... and rainbow foil stickers, and maybe some chakra stones or quantum dots for sure.
And a DACT, audiophile grade capacitors, a tube rectifier, special audiophile resistors and .....
Click to expand...

You forgot about the bypass-bypass capacitors, you know, the ones you use to bypass the bypass capacitors.
 
The review should go like this:
This is a 500€ heaphone amp thats totaly shit with headphones under 100ohm. If you use it with headphones that have a higher impedance maybe you have luck and the FR of this effectsbox fits to it. Maybe not, but thats luck or bad luck. But its diy and so you can learn how not to do a headphoneamp in the year 2020. And if it's cold outside you can use it to warm up your hands and be happy about the warm glow of the tubes. Surely a Infraredlamp for 15$ woud be more powerfull but it wouldnt have the same acustic effects. ;)
 
KaiserSoze said:
It is ironic that he has taken so much heat for his subjective evaluations and that you are characterizing him as a "measurement extremist".
Click to expand...

It's not me that characterizes him as such. You need to see this in its context and understand the quotes it is in. It is not my opinion.
 
@amirm if you still have the device, would it be possible to add a harmonics spectrum graph?
Like you do for speakers and @Archimago does for amps & co. If possible, also with the phase of each harmonic (not sure if your Audioprecision provides that info)
 
milosz said:
I have a Bottlehead Crack + Speedball. I love the way my 600 ohm Beyer DT 880's sound with this amp. I also like the way my HD-600's sound with it. I had HD-800's but had to sell them, the treble gave me headache, but when I had them, the Crack was my favorite amp to use them with.

I don't listen to it much. (I actually don't listen to headphones of any description much these days.) But it is a "FUN" headphone amp especially with my 600 ohm 'phones.

I equipped mine with a switch to allow going back and forth between the stock 100 uF electrolytic and a 100 uF mylar film capacitor for coupling the amplifier to the load. I purposely did not pay attention to which position was which on that switch when I assembled the thing. I A/B'd the sound using a number of different headphones, and the difference between the two positions was NOT subtle. There was an IMMEDIATELY audible difference between the two switch positions- one sounded kind of "raspy" in the highs - as though there was some distortion of the highs, or some ringing or noise bursts kind of thing. The other position the treble sounded quite smooth. I did not know which was the electrolytic and which was the film cap, but I knew almost instantly that I prefered one switch position over the other. After a few weeks I looked under the chassis top and saw that it was the film cap that I preferred. Make of this small sample size, not exactly double blind, no control group used, study what you will. But the conclusion I draw is that film caps sound better when they are in series with the audio signal than polarized electrolytics. Maybe a non polarized electrolytic would sound as good if you could find one with a high enough voltage rating, I don't know.View attachment 80856
Click to expand...

Do you have any hypothesis for why this would be? Could it possibly be a difference in the actual parameters of the two capacitors (of which capacitance itself is the most obvious candidate)? If you did not have a good reason for having excluded this conspicuous possibility, what sense would it have made for you to have concluded that "film caps sound better when they are in series with the audio signal than polarized electrolytics". You'll most likely resent me for pointing this out, but I have to. The conclusion you drew is not a logically sound conclusion. But you're in good company, because this is very much the kind of thing that audiophiles do habitually.

There are very compelling reasons, articulated on this site among many others, for concluding that this popular notion can only be a myth. Additionally, if there has ever been a proper double-blind test that demonstrates conclusively that there are audible differences between the two types of capacitor, this study was apparently suppressed, because it is never referenced when this claim is made. To my knowledge, this claim is only ever made in association with anecdotal experiences such as yours, and to my knowledge, no one who has even made this claim (in their reporting of this sort of anecdotal experience) has realized that the most likely explanation, that would need to be ruled out before it would make sense to attribute the apparent difference in sound to the difference in capacitor type, is that the two capacitors are simply different in terms of their basic parameters.
 
dfuller said:
This is the polar opposite of the THX current feedback amps. It's literally supposed to be a bit distorted. That mains hum if I had to guess is actually heater to cathode leakage current, which can happen if the heaters are AC and aren't floated significantly above ground.
Click to expand...

I have DIYed many tube amplifiers.

My biggest complaint is the noise; Power Supply hum and buzz plus hiss. Much of the hum and buzz can be reduced with solid state voltage regulators and drastic shielding. The power supply for B+ and tube heaters ends up being the major costs.

See the plot of 12B4A tube amplifier. The hum and buzz is largly removed.

Thanks DT 12B4 with regulators FFT.jpg
 
Last edited:
DualTriode said:
I have DIYed many tube amplifiers.

My biggest complaint is the noise; Power Supply hum and buzz plus hiss. Much of the hum and buzz with solid state voltage regulators and drastic shielding. The power supply for B+ and tube heaters ends up being the major costs.

See the plot of 12B4A tube amplifier. The hum and buzz is largly removed.

Thanks DTView attachment 80894
Click to expand...
That THD graph looks really good for a tube amp. Can you add a link or some extra info?
 
KaiserSoze said:
I have no issue with the fact that lots of people like limited distortion that fits a particular profile. But it seems to me that if people find some particular distortion profiles pleasing and other particular distortion profiles distracting, that they should desire for there to be some way to predict, based on measurements, whether a given piece of equipment that reportedly produces audible distortion is likely to sound pleasing to them.
Click to expand...

Definitely agree with this. "Show me where the measurements explain my subjective impressions of X" is a fairly common question. Or, "how can I compare the sound of X and Y using measurements"

Unless we are talking about transducers (and even then room/ear dependant) I'm not aware that any of Amir's usual measurements on electronics would help either question one jot.
 
I notice that tube headphone amps with very high distortion (see also Woo WA7) escape the guillotine, despite not really providing any function besides adding distortion and some gain, and possibly underperfoming a PC headphone jack at normal listening volume (a worthy face-off). Yet receivers and AV pre-pros that do so much more than that like room correction, video switching, switching multiple inputs and outputs, allowing for conversion from X number of input channels to Y number of output channels, get their heads chopped off for arguably inaudible levels of distortion.

Anyway, I'm glad that I never went further down the rabbit hole of tube headphone amps than a discounted Little Dot mk2 fed by my IFI Micro DAC. After trying it for a few hours, I left it on my office desk with the power off more as a conversation starter for curious colleagues than anything else. It offered no acoustic benefits over the IFI, and if I listened really hard, it sounded "grainier" possibly, illustrating how much distortion one can add without the degradation being extremely blatant.
 
This sounds like a product that does what it is intended to do quite well. I wonder if the channel imbalance is caused by an imbalance in the triodes of the particular output tube used in the test. I also wonder how this compares to my Darkvoice 336SE, which seems very similar based on the subjective information here, i.e., sounds great with HD6XX/HD650; Power tube + dual tiode tube; same layout in the most basic sense.
 
My take on this product....I don't really see the point of it, it can really only be used with certain headphones based on impedance, it alters the frequency response of the headphone and has distortion issues (although the latter might be a selling point of the tube amplifier buyer).....but I say just get a neutral amplifier that can drive anything and doesn't cost a bomb and then use EQ.....a bit of a silly product is the tube amplifier. I suppose people buy tube amplifiers like this for the "theatre & aesthetic", a bit gullible though.
 
It's nice to see a review of a tube amp coming from Amir; it's also good to see his subjective comments about an amplifiers.

Having reached advanced age, it's no longer a surprise to me to hear that amps with high(ish) levels of 2nd and/or 3rd order HD have "rich"sound. I would really like to hear Amir's subjective comments pertaining to panned amps like the Parasound JC2 preamp and Audio Research D300 power amp that have relatively high 2nd/3rd order HD -- especially the latter.
Jimbob54 said:
Definitely agree with this. "Show me where the measurements explain my subjective impressions of X" is a fairly common question. Or, "how can I compare the sound of X and Y using measurements"

Unless we are talking about transducers (and even then room/ear dependant) I'm not aware that any of Amir's usual measurements on electronics would help either question one jot.
Click to expand...
I don't agree. Amps, etc., with relatively high levels of 2nd and/or 3rd order harmonic distortion are going to sound more agreeable that amps with the same SINAD but relatively more higher order distortion.

(I struggle to remember that, "All amps sound the same". My bad.)
 
You must log in or register to reply here.

Similar threads

R
HD 650 with an Amplifier ?
2 3 4
Replies
73
Views
5K
RaymondFromThePyrénéés
R
amirm
  • Poll Poll
Sciber ENFLOW Balanced Headphone Amp Review
2 3 4
Replies
63
Views
14K
Bogda
Bogda
C
Next Headphone?
Replies
19
Views
1K
Chanur
C
amirm
  • Poll Poll
D&A Alpha DAC & HP Amp Review
2 3
Replies
46
Views
11K
AdrianusG
A
amirm
  • Poll Poll
Sylph Audio FB360 Mono Amplifier Kit Review
2 3
Replies
59
Views
18K
howard416
H
Back
Top Bottom