Bottlehead Crack - Illustrated write-up

lokesen · 7259

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Offline lokesen

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on: February 24, 2014, 01:16:24 AM
I made this little write-up illustrating the process of making the Bottlehead Crack and modding it.

There are 5 parts and I do hope you'll find some inspiration here, if you haven't made a Bottlehead Crack yet.

Cabinet and Chassis http://diy.koenigs.dk/2014/02/20/6/
Mounting the Parts http://diy.koenigs.dk/2014/02/20/mounting-the-parts/
Soldering the components http://diy.koenigs.dk/2014/02/21/soldering-the-components/
Speedball Upgrade - http://diy.koenigs.dk/2014/02/25/speedball-upgrade/
Capacitor Hot-Rod'ing - http://diy.koenigs.dk/2014/02/26/hot-rodding-with-film-caps/
Stepped Attenuator & legendary G.E.C CV 2523 tube http://diy.koenigs.dk/2014/03/18/stepped-attenuator-legendary-g-e-c-cv-2523-tube/

To make room for the next project, this beauty is now up for auction: http://www.ebay.co.uk/itm/141272593815?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

Ends the May 5
« Last Edit: April 29, 2014, 11:30:37 PM by lokesen »



Offline mcandmar

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Reply #1 on: February 24, 2014, 03:37:13 AM
Very nice, good job on the website too.

I see you also built an O2, i can pretty much guarantee it will only be used as a paperweight from now on :)


M.McCandless


Offline JamieMcC

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Reply #2 on: February 24, 2014, 03:48:24 AM
Great job on the Crack and the Blog to document the build is a nice idea.

Shoot for the moon if you miss you will still be amongst the stars!


Offline Natural Sound

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Reply #3 on: February 24, 2014, 03:50:20 PM
lokeson, very nice job. #thumbsup



Offline tjkirch

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Reply #4 on: February 24, 2014, 05:49:33 PM
Really great job.  I love the pictures.  Can't wait for the final guide on capacitor upgrades  :)



Offline lokesen

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Reply #5 on: February 25, 2014, 07:48:22 PM



Offline lokesen

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Reply #6 on: February 26, 2014, 11:12:21 AM



Offline JamieMcC

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Reply #7 on: February 26, 2014, 11:55:26 AM
You start to run out of room fast with the big caps! Nice write up on the blog.

Shoot for the moon if you miss you will still be amongst the stars!


Offline Guy 13

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Reply #8 on: February 26, 2014, 03:26:35 PM
Hi lokesen and all.
Nice job.
Lots of pictures, good, simple and clear explanations.
Very well written and much more.
I am still unsure if all the up-grades make such a big improvement on sound.
The stock Crack is already very good,
how much better can it get with the same headphones? (HD-650)
I only spend my $$$ when I can hear a huge difference/improvement,
up to now, that did not happen often with my audio stuff.
Thanks for that fantastic write-up.

Guy 13

Rega P3/Exact MM / Rega Apollo / Decware SE84C+ / Bottlehead Crack / Sennheiser HD650 / Grace Mondo RIT/ Omega 7F OB dipole / Double Eminence 12" Acoustinator OB dipole.


Offline lokesen

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Reply #9 on: February 26, 2014, 07:40:35 PM
Hi lokesen and all.
Nice job.
Lots of pictures, good, simple and clear explanations.
Very well written and much more.
I am still unsure if all the up-grades make such a big improvement on sound.
The stock Crack is already very good,
how much better can it get with the same headphones? (HD-650)
I only spend my $$$ when I can hear a huge difference/improvement,
up to now, that did not happen often with my audio stuff.
Thanks for that fantastic write-up.

Guy 13
Thanks, I totally agree. Changing caps is not good value for money. Upgrading your headphones to HD800 would probably make more sense. But differences will always be subtle because HD650 and Bottlehead Crack is already high-end.



Offline JamieMcC

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Reply #10 on: February 26, 2014, 08:44:04 PM
Interesting I was really surprised at the difference doing similar made the change after switching pots was far from subtle with the 650. With the 650 the differences was more subtle. While with my Beyer T1's the changes are much more noticeable.
I concluded rightly or wrongly that the 650's must be very close to their peak performance wise.  I also found my capacitors required about 100hrs plus to settle in and start sounding their best. With that in mind you should still have some improvements to come.   

Shoot for the moon if you miss you will still be amongst the stars!


Offline galyons

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Reply #11 on: February 27, 2014, 08:19:11 AM
Here is my concern with the "non upgrade "thought process.  IMO, you need to maximize the quality of the amp to fully take advantage of the  upgraded headphones.  Think of it in order of $$$$ magnitude.  Just using MSRP, Senn HD650's are $500, the HD800's $1500.  The headphone upgrade costs $1000 or three times the cost of the HD650's.  I am befuddled by the idea that it is a better sound value investment than upgrading the amp!!  The law of diminishing returns is unavoidable. 

So are the 800 better than the 650's? Yes, but by what level of improvement and where in the reproduction spectrum is that improvement achieved?  For the sake of argument, let's say that the 800's are 25% better for the 1000 bucks more. (the %age improvement is probably a bit high given audio's diminishing returns slope!) Just for grins & giggles, let's say each 1% improvement costs $40!! ($1000/25%)

Does the stock built Crack capture 100%of the HD650 capability?  Probably not.  So logically  the stock Crack would capture an even lower percentage of the 800's improvement.  The basic tenet of "match the amp to the speakers/headphones" is still valid!  ( Just a thought!  If I were looking to get the 800's, I would probably be looking at the Mainline first.  Likely a better match!!)

Every commercial product is built to a price point.  This includes kits.  The reason for DIY kits, to me, is simple....buy a well engineered design, (anything from Doc, PJ, etal at BH), and then address the "price point" selection with better quality.  For example, the stock Crack's major commercial compromise, IMO, is the electrolytic output caps.  The caps are very good electrolytics, but they are 'lytics.  I am assuming that the caps were chosen based on cost, size and ease of construction for the builder.  But even very good "for audio" electrolytic caps are not that great sounding as compared to film caps.

The design of the Crack will let you hear every improvement, but logically the first upgrade step must be the output caps! Why?  Every other upgrade to the signal path must go through the output caps to get to the headphones.  So what is the cost of improving the output caps? It can be fairly low by bypassing the 'lytics with quality film caps or outrageous with high capacitance boutique caps.

So what would I do before dropping $40 for each 1% improvement? 
1) Change out, (or bypass), the output caps for the best quality/size fit caps that I can accommodate.
 
2) Change out the stock volume pot for a high quality TDK, Noble,  Alps or stepped attenuator, (remember the source signal goes through here before any amplification!)

3) Improve the power supply with a choke and a film/PIO final PS cap. Clean power = clean signal!

Now once I have done all of this I can compare the 650's to the 800's, (insert your favorite $$$ blackholes here!)   Short read...Spend a $100  for a far greater improvement, before you spend an additional $1000 for a potentially lesser overall improvement.  You may find that giving your current phones the benefit of the  best that the Crack offers is all you need!

Of course YMMV!

Cheers,
Geary
« Last Edit: February 27, 2014, 11:31:42 AM by galyons »

VPI TNT IV/JMW 3D 12+Benz LP-S>  Eros + Auralic Aries + ANK Dac 4.1 >Eros TH+ Otari MX5050 IIIB2 > BeePre >Paramount 300B 7N7 > EV Sentry IV-A

Thorens TD124/Ortofon RMG-212/SPU >Seduction > Smash^Up> Paramour 45 MQ >K12's


Offline JamieMcC

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Reply #12 on: February 27, 2014, 11:12:54 AM
Geary, that is a very good post and I think you are spot with the $100 figure also. When taken into context with say a aftermarket cable upgrade for the HD650's it really is a no brainer.

I have a Valab stepper fitted to my Crack and a new Blue velvet pot in my parts box, I think I will fit it over the weekend. the valab was a very noticeable mod (I was over the moon with the difference) I think it was about $10 more than the blue alps velvet just under $30. So it would be a worth while experiment to see how they compare.

« Last Edit: February 27, 2014, 11:50:35 AM by JamieMcC »

Shoot for the moon if you miss you will still be amongst the stars!


Offline lokesen

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Reply #13 on: February 27, 2014, 11:29:27 AM
Interesting I was really surprised at the difference doing similar made the change after switching pots was far from subtle with the 650. With the 650 the differences was more subtle. While with my Beyer T1's the changes are much more noticeable.
I concluded rightly or wrongly that the 650's must be very close to their peak performance wise.  I also found my capacitors required about 100hrs plus to settle in and start sounding their best. With that in mind you should still have some improvements to come.   

I think you're right about the capacitors, I can hear a tiny bit of sibilance in the treble and it sounds like they need to burn in more. But I have fun burning them in, so it's all good :) 



Offline lokesen

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Reply #14 on: February 27, 2014, 11:31:37 AM
Here is my concern with the "non upgrade "thought process.  IMO, you need to maximize the quality of the amp to fully take advantage of the  upgraded headphones.  Think of it in order of $$$$ magnitude.  Just using MSRP, Senn HD650's are $500, the HD800's $1500.  The headphone upgrade costs $1000 or three times the cost of the HD650's.  I am befuddled by the idea that it is a better sound value investment than upgrading the amp!!  The law of diminishing returns is unavoidable. 

So are the 800 better than the 650's? Yes, but by what level of improvement and where in the reproduction spectrum is that improvement achieved?  For the sake of argument, let's say that the 800's are 25% better for the 1000 bucks more. (the %age improvement is probably a bit high given audio's diminishing returns slope!) Just for grins & giggles, let's say each 1% improvement costs $40!! ($1000/25%)

Does the stock built Crack capture 100%of the HD650 capability?  Probably not.  So logically  the stock Crack would capture an even lower percentage of the 800's improvement.  The basic tenet of "match the amp to the speakers/headphones" is still valid!  ( Just a thought!  If I were looking to get the 800's, I would probably be looking at the Mainline first.  Likely a better match!!)

Every commercial product is built to a price point.  This includes kits.  The reason for DIY kits, to me, is simple....buy a well engineered design, (anything from Doc, PJ, etal at BH), and the address the "price point" selection with better quality.  For example, the stock Crack's major commercial compromise, IMO, is the electrolytic output caps.  The caps are very good electrolytics, but they are 'lytics.  I am assuming that the caps were chosen based on cost, size and ease of construction for the builder.  But even very good "for audio" electrolytic caps are not that great sounding as compared to film caps.

The design of the Crack will let you hear every improvement, but logically the first upgrade step must be the output caps! Why?  Every other upgrade to the signal path must go through the output caps to get to the headphones.  So what is the cost of improving the output caps? It can be fairly low by bypassing the 'lytics with quality film caps or outrageous with high capacitance boutique caps.

So what would I do before dropping $40 for each 1% improvement? 
1) Change out, (or bypass), the output caps for the best quality/size fit caps that I can accommodate.
 
2) Change out the stock volume pot for a high quality TDK, Noble,  Alps or stepped attenuator, (remember the source signal goes through here before any amplification!)

3) Improve the power supply with a choke and a film/PIO final PS cap. Clean power = clean signal!

Now once I have done all of this I can compare the 650's to the 800's, (insert you favorite $$$ blackholes here!)   Short read...Spend a $100  for a far greater improvement, before you spend an additional $1000 for a potentially lesser overall improvement.  You may find that giving your current phones the benefit of the the best the Crack offers is all you need!

Of course YMMV!

Cheers,
Geary

+ it's so much fun modding your equipment yourself, compared to buying new stuff. That's worth a lot to me.