Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Surge on December 27, 2016, 11:36:20 AM
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After enjoying the build, and the end result, tremendously... I am tempted to try to build a no holes barred ultimate Crack. What would that look like in terms of components? I have read about 10 pages of the forum and gathered some thoughts:
The limits are to use the same chassis/footprint
- DACT stepped attenuator
- silver oil caps
- silver wiring
What else?
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Sorry, common sense rant below; fill free to upgrade to your hearts content but...
You will find yourself getting very close in price to a Crackatwoa , after wire/caps/attenuator/choke/etc, why don't you just get that and upgrade the output caps? Anything else above stock in that you should just go for a stock Mainline. I've been down this street, now my kids each have modded Cracks and I running with the big dogs on a fully outfitted Mainline.
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To quote from a recent post on a well known headphone enthousiast forum:
Budget upgrades (the most worthwhile) for Crack:
0. Speedball
1. FAQ #3 + Valab stepped attenuator + E80CC switch mod (40$) (more volume control, details details and optimization for tube rolling)
2. Schottky rectifiers to PS (20$) (silent background)
3. Choke in PS (20-30$) (even more silent background)
4. Output capacitor upgrade (Russian PIO's sub 50$, Mundorf film 120$, add weight and deepens the sound)
5. Bypass capacitors (FT-3 0.1uf in output and maybe some for PS, 10-20$, add sparkle)
(6. (Film cap PS 50$+) maybe not worth it.)
(7. Wiring upgrades (if i could rebuild i'd start with these))
So for 150$ you could get a very nice Crack. The tubes are the same as you would upgrade in C-A-2 Tungsram E80CC (+20$), Tung Sol 5998 120$.
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Alonzo has hit the nail on the head.
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Makes total sense re: just upgrading to another BH product. Would gladly, but my main issue is size: the Crack just fits on my nightstand. The Mainline and C-A-T are double the width, correct?
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For me Crack is all about the journey so upgrading to another product before it's over would defy that point.
Starting with Crack and upgrading it step by step teaches you how certain components influence the sound.
It shows you what makes sense and what upgrades don't.
From a financial point of view it's most economical to don't upgrade it at all or to start with a Mainline and be done with it ;D.
The small footprint does really make Crack great. It fits even the smallest desks. I move once every two months on average and it easily fits in one small box (with tubes, DAC, headphones and cables).
In small bedrooms i've also had it sitting on a nightstand (you know, mini hotel size nightstands or on a chair if needed).
Mainline top plate is 12" by 12" or something. Crack is 10" by 6".
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My tried and tested recipe would be following on the list above
0. Speedball
1. FAQ #3 + Valab stepped attenuator + E80CC switch mod (40$)
2. Schottky rectifiers to PS (20$)
3. Choke in PS (20-30$) (even more silent background)
4. Output capacitor upgrade Russian PIO's sub 6x30uf mgbo 3per-side total ($15)
5. Russian Teflon Bypass capacitors for above 10-20$
6. Film cap PS (Motor run) $15
I would say do it as its a hell of a lot of fun and a bit of a eye opener the mods can easily be done as and when speading the costs over a period of time.
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I'll chime in also...I've got two of them here somewhere and a third out in the world.
Staying with the Crack and learning what the upgrades can do is a good way to go. Space is a premium but it makes you think through the process. My other thought was always that I could afford (barely) to blow up a Crack. My budget doesn't include a blowed up Crackatwo.
If you are in the learning process go Crack. If you are looking for that better sound - Crackatwo or ultimately the Mainline.
Certainly start stock, throw in the speedball and go nuts after that.
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I would add a fuse upgrade to the list. Low cost and it will improve the sound. Has anyone tried it?
I am referring to one of those cytogenetically treated ceramic bodied fuses.
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Haven't done it.. But i've noted that the local voltage and (the absence of) grounding do play a role in the perception of sound (stage) when using the Crack.
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The provided fuse is a 1A 250V fast blow, is that correct?
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Just to clarify, all the parts substitutions are tweaks, not really upgrades. The only exceptions would be the Speedball, which does improve distortion figures, as well as a different attenuator with better low level tracking between channels.
The Crack-a-two-a is an improvement to the Crack because of a vastly superior power supply topology that is regulated, and the availability to install our stepped attenuator.
You could spend $1000 on special parts for your Crack and not get to the level of performance offered by the Crack-a-two-a or Mainline.
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I would add a fuse upgrade to the list. Low cost and it will improve the sound. Has anyone tried it?
I am referring to one of those cytogenetically treated ceramic bodied fuses.
Spellcheck strikes again!
I'm pretty sure you meant cryogenic, not cytogenetic. I checked, it is a real word - something about evolution of cell genetics.
No offense meant, I just thought it was funny :^)
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Paul, thanks but I actually did mean cytogenetic. These are relatively new biogenetically engineered fuses! They grow and adapt to the current and blow based on biometric factors.
;)
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They grow and adapt to the current and blow based on biometric factors.
Hmm, that's exactly what a fuse shouldn't do?! ???
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Please give us a link or source for these "new" fuses...inquiring minds want to know!!
Alex
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I would do something like this:
HiFi-Tuning Supreme
https://www.thecableco.com/Product/Supreme-Small--20mm--75--Fast-Blow--F--Type
Can someone confirm the fuse specs? Is it as I posted earlier?
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Slow or fast blow are both fine.
Originally the Crack comes with a 1A fuse.
(Edit: That's a lot of money for a fuse?! 60$?)
(Edit 2: and they are cryogenically treated, not cytogenetically, PJ's post)
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Right- spelling autocorrect, then I was trying to be funny.
Indeed $50 is a lot for a fuse. But most users swear by them. I did the upgrade on my more expensive main gear, it's easier to justify on ~$5k gear.
I will order one for the Crack. Worth a try.
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They grow and adapt to the current and blow based on biometric factors.
Yes, it's an evolutionary dead end 8)
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Slow or fast blow are both fine.
Originally the Crack comes with a 1A fuse.
I have some "special" fuses from another project. 1A T (slow blow), what about the voltage? I assume 250V is fine?
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Yes.
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Thanks. I dropped in a Hifi-Tuning 1A slow. Btw, my kit came with a 1.25A F fuse...guess it doesnt matter.
I'm using this Hifi Tuning Supreme:
http://www.partsconnexion.com/fuse_hifituning_supreme_sml_sb.html
Haven't really done a proper back to back test; but it does seem a touch more transparent!
These fuses go on sale at Cable Co., and other places. I think I paid about $25.
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The Hifi Tuning Classic fuses are on sale for $10:
http://www.partsconnexion.com/fuse_hifituning_gold_sml_sb.html
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That is, for all the values we don't need :).
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Oops, you're right; I didn't check. They go on sale often thought, because no one really pays $50+ for a fuse ;)
If you read the reviews, there does seem to be some real logic for why they improve the sound.
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In my current location the wall sockets aren't grounded at all and i don't hear much of a difference... so.. meh.
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I am no expert, but from what I've read, the issue is that the material used in fuses is the weak link in any system. It can create sonic resonance and other undesirable artifacts.
So it's not about the ground, but the fuse, and finding the best material to provide protection without deteriorating the sound.
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I am no expert, but from what I've read, the issue is that the material used in fuses is the weak link in any system. It can create sonic resonance and other undesirable artifacts.
Resonances are easy to measure. Vacuum tubes and fuses are made with very similar materials.
Beware o'the snake oil.
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Crappy fuse material that conducts badly and thus affects the sound I can grok (not that I would pay $50 for a fuse). But I would appreciate an analysis of how the fuse's "sonic" (presumably this means acoustical/mechanical) resonance is energized, an analysis of the amount of energy we are talking about, and how that energy is transferred to the audio.
I'm thinking primarily of the mass of the fuse, and how much vibrational energy it could possibly transfer into the mass of the amp. I suspect you would need a meter with Diddly and Diddly Squat ranges, and it would fall somewhere in between. Presumably these acoustically superior fuses are composed of a sophisticated mass distribution to null out modes. I'd like to see that too.
Maybe they are just made of a lead bearing alloy, i.e. solder.
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FYI-
Here is a review:
http://www.stereophile.com/content/hifi-tuning-fuses#78HSHBxuQbrdruFP.97
I am not sure I can tell a difference, but I didn't do a proper side by side comparison either.
However, my view is that the logic for why they are better seems to make sense, and for ~$10, I don't spend much time thinking about it anyway...
Doc, would be keen to hear your thoughts after reading some of the online reviews and trying it on one of your amps. You do support better AC power cords, I see. I place fuses in the same general improvement category.
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The difference is that I don't claim that the acoustical resonance of my power cord is the reason it sounds better. I freely admit I don't have a clue why it sounds better. Maybe because of the braiding reducing the influence of EMI, but maybe not, because I have not figured out a way to measure it that makes sense. Once again, I can understand wanting to use a skinny little piece of silver as the fuse material, because the general consensus is it's a good conductor - right up until when it blows. If the fuse makes something sound better, that great. If people thinks it's worth $50, that's great too, particularly for the guy who has them made for $2.50 each or whatever. But the whole resonance thing is just marketing copy without some data to back it up.
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I am a big believer in the quality of the AC coming into components. Audio and video are, after all, just modified and manipulated AC from the grid.
Here's a test of various fuses, with data:
http://www.partsconnexion.com/prod_pdf/hft_facts.pdf
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Good wire, low resistance. Pretty straightforward. Not so sure passing higher frequencies is a good thing. We don't need noise going back out the gear through mains and into other gear. No mention of resonance.