Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Kitchener on March 07, 2018, 11:48:06 PM
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EDIT:
I'll update this post with usefull answers from posters and from other sources I might stumble upon as I go.
Hi!
First of all, I've trawled through the forum (plus Head-Fi and others) looking for specific advice and recommendations for replacement output capacitor's for the Crack.
And I've learned quite a bit, but still have some questions that I would like to ask.
I'll divide this into two sections, one for general technical advice and one for specific recommendations of output capacitors and their perceived and or documented benefit.
-please also drop some tips on power supply caps as well if you want!
Also, here's a disclaimer:
Before I only knew two things about electrical circuitry; jack and shit.
These days I've read quite a bit and have supplemented with two more; sod and all.
Expect many question marks.
Don't ever assume I know what I'm talking about, I'm just a neophyte hobbyist who's desperate for an excuse to heat up the soldering iron.
-I have a Speedball order in processing, so I'm asking about caps because I might need a new fix down the line.
Technical:
- These are slightly embarrasing, but I have to ask.
The film cap is supposed to replace the electrolylic caps on terminal 6U, 7U, 9U and 10U?
-in other words, remove the lytics and solder on the film caps instead?
Also, bypassing means to connect a smaller capacitor alongside the film capacitor?
Yes, replace them!
Bypassing means fitting a second capacitor, usually at 1% the Farad-rating of the main cap (so 1uF on a 100uF cap, get it?), alongside the main cap. Either soldered on the legs of the main cap or in the same terminals, whatever fits best.
- Also a little embarrasing; what does a capacitor do in an amplifier, in laymans terms?
-filter out noise?
Magic, it does magic, okay? - Subjectively, what would you say are the biggest benefits to swapping the caps?
Reply from Doc:
"Electrolytic caps can break down over time from heat..."
"Modern films caps do pretty much last forever if they are not abused by running them over their voltage rating."
The most common arguments I've read list a slightly better seperation and a more spacious sound.
As I understand though, these are mostly minute benefits?
Do film caps have a longer lifespan than lytics? - What about electrolytic caps?
Generally people seem to prefer film caps.
-because of faster response times and better ripple current rejection or something (magic).
But I've read a couple posts from people who prefer electrolytics instead.
Some stated that to get the same performance from a lytic you needed 10x the Farad rating.
So to replace a 100uF film cap you'd need a 1000uF lytic cap?
-does this mean you could use a 10uF film cap replacement?
Personally I'm drawn heavily towards film caps solely because of their brutal size.
There's something absurd and sexy about using components the size of soda cans just to make earphones sound better, and I like it.
- The stock output caps are rated 100 uF and 160 Volts.
As I understand It's recommended to find film caps with similar specs, the most widely used specs seem to be 100uF 250V.
Spare yourself the headache, just use a film cap with as similar specs to the electrolytic caps as possible
- Is there any benefit from using a cap with a higher Farad rating?
As I understand this could theoretically give a slight boost to the lower frequencies?
- I've not been able to find any film capacitors at 100uF with a lower Voltage rating than 250.
As I understand there's no benefit from using a capacitor with a Voltage rating above the stock 160.
Some have posted that using capacitors with a very high Voltage rating, 400+, can have detrimental effects, if only from the thicker hookup, correct?
Just a couple on power supply capacitors as well:
- As I understand the stock caps here are very good.
I half remember readind a post somewhere where someone used an oscilloscope to measure ...oscillations and said they were ...good and lo and behold so they were.
Read my disclaimer!
EDIT: Found the post: https://bottlehead.com/smf/index.php?topic=1762.msg13272#msg13272 (https://bottlehead.com/smf/index.php?topic=1762.msg13272#msg13272)
I've also read that the biggest benefit would come from swapping out the 2nd and 3rd cap, but which terminals are those connected to?
20U and 21U? 1
14U and 15U? 2
12U and 13U? 3
The attached image shows the order of the power caps! - Again it is best to find caps with matching ratings, 220uF and 250V?.
- Does one use film caps here as well? That sounds like it would be impossible to fit alongside the Speedball and output film caps and perhaps a choke.
Yes, it is pretty much impossible to fit replacement film caps on the PSU and outputs.
This (https://www.reddit.com/r/headphones/comments/62hc1u/welcome_to_the_crackhouse_bottlehead_crack_otl/?sort=old&sh=13b61490&st=JEISLAR8) reddit/Head-Fi user has replaced the last lytic cap with a film cap.
With a choke (https://www.digikey.com/products/en?keywords=triad%20c7-x) in place of one of the PSU-resistors (the big rectangular white ones between 15-21U and 13-15L) he was able to put a 100uF film cap in place of the last resistor.
While replacement film caps are tough to fit, bypass caps are much easier.
Find some 2.2uF 250V film caps like perhaps these (http://www.daytonaudio.com/index.php/pmpc-2-2-2-2uf-250v-precision-audio-capacitor.html) and solder them in along with the electrolytic power caps instead.
Specific recomendations:
I was hoping we could get some specific model names and maybe links to good replacement caps here.
Generally I aspire to be a cheapskate, but sometimes I just say "screw it" and splurge on something I generally regret splurging on.
I don't necesarily see the point in shoveling several houndred dollars into new caps, then I might as well have gotten a SEX or Crackatwoa instead.
And as I understand it, once you cross a certain price point you enter diminishing returns territory, so if we could keep the recommendations below that line I'd appreciate it.
-Where exactly is that line?
Please namedrop any electrolytic replacements you can think of as well.
So far it seems these are the most popular caps:
- Mundorf MCap Classic (http://www.mundorf.com/en/?category=hifi&menu=caps_audio&content=mcap), 100uF 250V.
- Solen Caps.91uF, 250V (https://solen.ca/products/capacitors/fast-capacitors-250v-pa-series-metallized-polypropylene/pa9100/)
- JB JFX (http://www.jbcapacitors.com/Plastic-Film-Capacitors/JFX-Premium-Metallized-Polypropylene-Film-Capacitors-Axial.html)and JSX (http://www.jbcapacitors.com/Plastic-Film-Capacitors/JSX-Superior-Metallized-Polypropylene-Film-Capacitors-Axial.html)caps.
Which to use?
- Audiophiler.
Don't seem (https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xaudiophiler+100uf+film+capacitor.TRS0&_nkw=audiophiler+100uf+film+capacitor&_sacat=0) to have a manufacturer website.
I've read (https://bottlehead.com/smf/index.php?topic=7539.msg72655#msg72655) that some recommend these for the power supply but not for outputs?
Addition:
- Dayton Audio DMPC-100 (http://www.daytonaudio.com/index.php/dmpc-100-100uf-250v-polypropylene-capacitor.html) 100uF 250V
- Panasonic EZP-E50107MTA (https://www.digikey.ca/products/en?keywords=EZP-E50107MTA) 100uF 500V.
Square capacitors.
More?
Model names and links would be great!
-preferably affordable.
Thanks for reading :D
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Quote “The film cap is supposed to replace the electrolylic caps on terminal 6U, 7U, 9U and 10U?
-in other words, remove the lytics and solder on the film caps instead?â€
Answer - yes.
At least I can answer that question.
I’m also interested in knowing the answers to your questions.
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Quote “The film cap is supposed to replace the electrolylic caps on terminal 6U, 7U, 9U and 10U?
-in other words, remove the lytics and solder on the film caps instead?â€
Answer - yes.
Aaah, great, thanks. Nice to clear up the very basic basics early :)
I got a lot of great answers from Ohshitgorillas over at Head-Fi.
He has a really good Reddit post detailing his modding here: https://www.reddit.com/r/headphones/comments/62hc1u/welcome_to_the_crackhouse_bottlehead_crack_otl/?sort=old&sh=13b61490&st=JEISLAR8
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Yes I found and used information from that post also. That was really nice of him to share his directions. I also googled images of the Crack.
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I really like Solen PB and PPE series. The build quality on the Mundorf M-Cap is amazing. The build quality on the Dayton caps is not the same as the Solens, thinner leadouts.
Im sure all will work really well. While you are at it, small film caps (0.01uF) in parallel with the power supply caps help wonders.
Film caps do last longer than electrolytics as the electrolyte can dry out over time. Film caps do not last forever though, they can form perforations in the plastic dielectric which can reduce their capacitance. Overloads or static discharge can cause this. Metalized film capacitors are referred to as self-healing since the metal can reflow over dielectric micro-holes. Film and foil capacitors cannot do this.
Simply discharging (unplugging) for some time and replugging can start the self-healing process.
Just make sure that whatever voltage rating you replace with matches what is listed in the Bottlehead manual.
These Russian Paper in Oil caps are supposed to sound really good. They can also be bypassed with small value film capacitors. The unfixed rule is no more than 1/100 of the original cap for the bypass. : https://www.ebay.com/itm/K75-40B-100-f-750V-VINTAGE-RUSSIAN-PAPER-PIO-CAPACITORS/282877864280?hash=item41dcd5a958:g:wToAAOSw10haouV7
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I really like Solen PB and PPE series. The build quality on the Mundorf M-Cap is amazing. The build quality on the Dayton caps is not the same as the Solens, thinner leadouts.
Im sure all will work really well. While you are at it, small film caps (0.01uF) in parallel with the power supply caps help wonders.
Film caps do last longer than electrolytics as the electrolyte can dry out over time. Film caps do not last forever though, they can form perforations in the plastic dielectric which can reduce their capacitance. Overloads or static discharge can cause this. Metalized film capacitors are referred to as self-healing since the metal can reflow over dielectric micro-holes. Film and foil capacitors cannot do this.
Simply discharging (unplugging) for some time and replugging can start the self-healing process.
Just make sure that whatever voltage rating you replace with matches what is listed in the Bottlehead manual.
These Russian Paper in Oil caps are supposed to sound really good. They can also be bypassed with small value film capacitors. The unfixed rule is no more than 1/100 of the original cap for the bypass. : https://www.ebay.com/itm/K75-40B-100-f-750V-VINTAGE-RUSSIAN-PAPER-PIO-CAPACITORS/282877864280?hash=item41dcd5a958:g:wToAAOSw10haouV7
These are generalities, and do not seemed to be based upon first hand experience. Thinner leads on a cap don't necessarily reflect build quality. Electrolytic caps can break down over time from heat without drying out. We typically use caps with a 3-4000 hour or higher rating. Modern films caps do pretty much last forever if they are not abused by running them over their voltage rating. Bypassing caps may or may not improve the sound, depending upon the quality of the cap they are bypassing and the location of the cap in the circuit.
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Great, all of this is in my opinion and experience. Please don't reflect my prior posts on what can be judged as what I consider better.
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Enjoy your crack for at least 6 months before any mods. Otherwise you won't notice any changes. Just my 2c.
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I thinks that’s good advice.
Problem is, I don’t really care about the sound at this stage.
The stock Crack is probably good enough for me for perpetuity.
I think it sounds wonderful.
And even though I’ll probably hear a difference with the Speedball in place, I don’t think I have the ear required to identify what exactly has changed.
No, what I find so addictive is building the damned thing.
Planning.
Sourcing components.
Fitting and soldering.
I’m aching to tinker with it.
Don’t really care either way if the mods change the sound, as long as it’s not somehow worse.
So waiting 6 months is sound advice, unless you’re just in it for the solderfumes!
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Don’t really care either way if the mods change the sound, as long as it’s not somehow worse.
Go for it! And be sure to posts pics.
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My big Crack hot rodding adventure!
Hah, reminds me of one of the best music videos ever commited to celluloid: https://youtu.be/y73hyMP1a-E?t=5
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I think I still have the poster from that album in my lab at home.
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The one with the lady?
It is a very good poster.
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The Panasonic 100uF 500V film capacitor https://www.digikey.ca/products/en?keywords=EZP-E50107MTA (https://www.digikey.ca/products/en?keywords=EZP-E50107MTA) has got to be the biggest bang for the buck. Works great for me and two fit perfectly between the headphone jack and the power supply terminal strips - giving much more flexibility in mounting.
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Great, adding it to the list.
Space-savers are much appreciated.
Wonder if it's easier or harder to mount square capacitors?
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Depends on weather you have a round hole 8)...Johnw
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The good old square peg in a round hole problem ;)
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Mounting was super easy. STRONG double sided 3M tape on the bottom of the cap to the bottom of the plate and an additional piece of wood glued to the side of the base. Easy peasy and going nowhere.
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Keep an eye on that tape. Heat can break it down over time.
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Thanks for the heads up! I figured it might, so that's why I added the shelf to hold it from the bottom.