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Crack;Bottlehead OTL - Page 132

post #1966 of 6108
Quote:
Originally Posted by amcananey View Post

Well, I've got the Speedball installed, and I also installed a TKD volume pot and 100uf ClarityCap ESA film caps on the output, plus I bypassed the last cap on the power supply, again with a ClarityCap ESA. As for output power, I actually installed a pair of in-line RCA signal attenuators on the inputs on my Crack, since I actually found it had too much gain...

Oh, and I'm using a GEC straight brown base 6AS7G and I've got a decent selection of driver tubes (12AU7, 12BH7 and E80CC).
....

 

I love the photos of the claritycaps you posted on bh, and the risers were a great solution to the size issue!  It would be a lot of fun to hear, and compare back to back, how they stack up against the obbligato axial's I have in mine - particularly given that we are running the same pots and GEC 6as7g.  Do you know if there are any dissipation measurements published on the ESA's?  Diyhifi's short list, and the very favorable comparison to blackgates, was a big part of what sold me on the obbligatos: http://www.diyhifisupply.com/catalog/34  Wish they had a 5% rather than 10% tolerance, but I do think they sound better than the axon's I was previously using.

post #1967 of 6108

"Is it better" needs some definition. The Goldpoints are very good. We designed the Submissive because I felt we could come up with something that I prefer the sound of (or perhaps "the lack of sonic influence of" is a better description) to any of the other attenuators we tried. And I do prefer Submissive. In my room, in my system, in my ears.

post #1968 of 6108
Quote:
Originally Posted by skeptic View Post

I love the photos of the claritycaps you posted on bh, and the risers were a great solution to the size issue!  It would be a lot of fun to hear, and compare back to back, how they stack up against the obbligato axial's I have in mine - particularly given that we are running the same pots and GEC 6as7g.  Do you know if there are any dissipation measurements published on the ESA's?  Diyhifi's short list, and the very favorable comparison to blackgates, was a big part of what sold me on the obbligatos: http://www.diyhifisupply.com/catalog/34
  Wish they had a 5% rather than 10% tolerance, but I do think they sound better than the axon's I was previously using.

I don't know if there are published dissipation measurements. To be perfectly honest with you, I'm willing to spend the cash to install quality film caps, but I have neither the patience, nor the ears, nor the budget to try out multiple sets of caps and compare them. I would much rather spend that time either building another amp or listening to music. That's not intended as a slight against anyone who is willing to put in the time and effort and has the requisite golden ear, it's just being honest about my own limitations and where I've decided to draw the line in this disease we all share.

As for published reviews of how different film caps sound...well, I am deeply skeptical. Even assuming that there are clear differences that 2 (or 10 or 20) different people would agree upon, I suspect that which cap sounds best is highly system dependant and all of the published reviews I've seen (from anyone with some sort of experience/knowledge to back up their opinions) have involved systems that didn't bear any resemblance to my own whatsoever. And to be honest, I tend to doubt that 20, 10 or even 2 people would consistently agree on differences between caps. On top of which, you also have the question of whether the caps being tested have all been fully broken in (to the extent you believe in that sort of thing).

Why am I so skeptical? Well, I've tried A/B-ing components, and the time it takes me to swap out one component and insert another, then get the music test clip queued up and playing, has rendered any attempt at objectivity meaningless. I simply can't remember what the first clip really sounded like long enough. I can barely do it with tubes. I certainly can't do it with anything that takes longer to swap.

Best regards,
Adam
post #1969 of 6108
Three quick notes to add to this thread:

1. Changing volume pots is not a night-and-day difference. Maybe not even a morning-and-afternoon difference. And any differences may well be more imagined than real. I feel the need to repeat that whenever I find myself discussing a tweak that is fairly minimal, lest anyone get the wrong idea. The stock Bottlehead pot is perfectly serviceable and more than up to the task. In a double-blind test, I wouldn't bet on me being able to identify the stock pot vs. my TKD. You can leave the stock pot in and not worry that you're missing out on some great improvement to your Crack

2. If you do want to upgrade the volume pot, an ALPS Blue Velvet pot can be had for about $12-15. There is a reason they are so popular and are used in so many systems, including fairly high-end systems: they sound good. I would never recommend to anyone that they buy a $100 TKD pot over an ALPS.

3. The best upgrade for a Crack is the Speedball. Everything else is secondary.

Best regards,
Adam
post #1970 of 6108
Quote:
Originally Posted by amcananey View Post

Three quick notes to add to this thread:

 

You must be my brother from another mother! Although I would be less diplomatic about those who review caps and think they hear amazifying differences. Great post.

 

Like you, I really doubt I could pick the TKD out of an audio lineup...... although the reason I went for it anyway is for better channel matching, particularly at low volumes. I've had a couple of amps with Alps Blues that were a 1-2 dB off at the very low end - not so with the TKD.

post #1971 of 6108
One thing to remember is that there are two ways to get around poor tracking at low volume levels....(a) replace the stock pot with an expensive pot that tracks better at low levels (though note that stepped attenuators have the best tracking, and the VALab is only $25), or (b) turn the volume up. tongue.gif

I'm actually serious about (b), not just being a wise-ass. If you install a (relatively) cheap pair of inline RCA attenuators on the inputs, you have a much greater useable range on the volume pot. I use a pair of Harrison Labs attenuators. Go for the highest attenuation level. Anything else is too insignificant to be worthwhile.

Best regards,
Adam
post #1972 of 6108

Seems this weekend if you buy a Crack kit you get the speedball for fwreeeee .... Any takers?

 

Seems like a great deal, too bad all my headphones sit in the low impedance category. Anyone have much luck with low impedance cans? Would something like this raise the noise floor enough to make it viable? 


Edited by elwappo99 - 7/12/13 at 3:53pm
post #1973 of 6108
Quote:
Originally Posted by elwappo99 View Post

Seems this weekend if you buy a Crack kit you get the speedball for fwreeeee .... Any takers?

So wish I were a DIY guy! I thought I was going to try it until I watched Tyll's video. Gotta know when to fold them...

 

First six orders get a couple tubes: "Order a Crack kit this weekend and get a free Speedball upgrade. That's a $125 savings! Now we know some of you guys are gonna wait until Sunday night to order. But we need your dollars today so we can order all sorts of parts. Sooo, we are going to spice the first six orders up and ship them with an RCA clear top 12AU7 and a triple mica 6080."


Edited by imackler - 7/12/13 at 3:55pm
post #1974 of 6108
1. These are the attenuators I use and recommend: http://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0/ref=sr_1_1?ie=UTF8&qid=1373666346&sr=8-1&keywords=harrison+labs

I do NOT recommend trying the 3 dB or 6 dB versions.

2. If you buy the right equipment (which isn't expensive and will serve you well for a long time to come), watch a couple of YouTube videos on soldering, practice soldering for half an hour with some scrap pieces and follow the instructions (which include detailed pictures for EVERY step) carefully and methodically, then ANYONE can build a Crack.

In terms of what qualifies as the right equipment, I recommend the following:

- a basic temperature controlled soldering station (check Amazon or eBay, these are NOT expensive - and a digital display doesn't add anything over analog controls) - this should come with a soldering iron holder and a sponge
- 63/37 leaded solder with a rosin flux core (don't go for lead-free, silver or 60/40 solder
- wire strippers (the kind with holes marked for various wire gauges, it should have holes for 20, 22 and 24 AWG)
- a quality pair of flush-cut wire cutters (these are small, not the kind you use for cutting household electrical wire)
- some solder braid to take care of the inevitable mistakes
- high quality tweezers

[LATER EDIT: I foolishly forgot to mention two of the most important tools!!
1. A digital multimeter, and
2. Needle-nose pliers (small ones, with a long, thin "nose").

You can get a cheap multimeter for $10 and, surprisingly, they actually aren't terrible. I have one that is fairly accurate. But I wound up buying this one for not much more cash and it is a big improvement in readability, ergonomics, convenience and flexibility. Most importantly, you can swap out the probes for ones that have clip leads, which are safer.]

Other things that come in handy: a magnifying glass, a penlight, forceps. I think that's it.

There are four rules when it comes to soldering:

1. FIRST establish a good physical connection, THEN solder in place.
2. Heat BOTH components you are looking to connect equally.
2. Adding a tiny bit of solder to the soldering iron tip before touching the components will help to conduct heat.
3. Add solder by touching the components, not the soldering iron tip. The solder is attracted to heat, and adding solder to cold components will give you a weak, brittle solder connection that will soon break or give you only intermittent contact.

I know soldering sounds difficult intimidating, but the Crack was my first soldering project and it worked the first time. And it sounds phenomenal and was an incredibly satisfying process.

IF YOU RUN INTO ANY PROBLEMS, DON'T GET FRUSTRATED. Post on the Bottlehead forums and the Bottlehead team will respond very quickly with detailed, helpful advice. They provide better service in their forums, then I've had from most places in person or over the phone. And if anything seems unclear, then again just post in the Bottlehead forum and you will get an answer.

You can easily build a Crack in two nights. Three if you go really slow and want to do some practicing first.

Best regards,
Adam
Edited by amcananey - 7/16/13 at 9:54am
post #1975 of 6108
Great post Adam. It was my first DIY as well and it worked the first time. Turns out I had a single cold solder joint that reared its head occasionally, but that was it.

I would just say if you have particularly shaky hands, that could be an issue. Some of that soldering work neat the tube leads with the LEDs isn't for the trembly among us.
post #1976 of 6108
FYI - as an alternative to buying inline attenuators, you can simply pad your input by adding 4 resisters as shown: http://www.goldpt.com/mods.html The tables set out the values you want for varying degrees of attenuation.
post #1977 of 6108
Quote:
Originally Posted by skeptic View Post

FYI - as an alternative to buying inline attenuators, you can simply pad your input by adding 4 resisters as shown: http://www.goldpt.com/mods.html The tables set out the values you want for varying degrees of attenuation.

Adding resistors definitely works, and it is an approach commonly recommended in the Bottlehead forum. I prefer the attenuators, since they can easily be removed and inserted, especially if you change your source down the line and need the extra gain. No soldering or changes to the stock layout needed.

Best regards,
Adam
post #1978 of 6108
Quote:
Originally Posted by amcananey View Post

1. These are the attenuators I use and recommend: http://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0/ref=sr_1_1?ie=UTF8&qid=1373666346&sr=8-1&keywords=harrison+labs

I do NOT recommend trying the 3 dB or 6 dB versions.

2. If you buy the right equipment (which isn't expensive and will serve you well for a long time to come), watch a couple of YouTube videos on soldering, practice soldering for half an hour with some scrap pieces and follow the instructions (which include detailed pictures for EVERY step) carefully and methodically, then ANYONE can build a Crack.

In terms of what qualifies as the right equipment, I recommend the following:

- a basic temperature controlled soldering station (check Amazon or eBay, these are NOT expensive - and a digital display doesn't add anything over analog controls) - this should come with a soldering iron holder and a sponge
- 63/37 leaded solder with a rosin flux core (don't go for lead-free, silver or 60/40 solder
- wire strippers (the kind with holes marked for various wire gauges, it should have holes for 20, 22 and 24 AWG)
- a quality pair of flush-cut wire cutters (these are small, not the kind you use for cutting household electrical wire)
- some solder braid to take care of the inevitable mistakes
- high quality tweezers

Other things that come in handy: a magnifying glass, a penlight, forceps. I think that's it.

There are four rules when it comes to soldering:

1. FIRST establish a good physical connection, THEN solder in place.
2. Heat BOTH components you are looking to connect equally.
2. Adding a tiny bit of solder to the soldering iron tip before touching the components will help to conduct heat.
3. Add solder by touching the components, not the soldering iron tip. The solder is attracted to heat, and adding solder to cold components will give you a weak, brittle solder connection that will soon break or give you only intermittent contact.

I know soldering sounds difficult intimidating, but the Crack was my first soldering project and it worked the first time. And it sounds phenomenal and was an incredibly satisfying process.

IF YOU RUN INTO ANY PROBLEMS, DON'T GET FRUSTRATED. Post on the Bottlehead forums and the Bottlehead team will respond very quickly with detailed, helpful advice. They provide better service in their forums, then I've had from most places in person or over the phone. And if anything seems unclear, then again just post in the Bottlehead forum and you will get an answer.

You can easily build a Crack in two nights. Three if you go really slow and want to do some practicing first.

Best regards,
Adam

thanks for that timely advice Adam,

 

i just been tempted to buy the crack yesterday through a sweet deal that bottlehead were offering - free speedball upgrade and with premium tubes (though the tubes were only for the first 6 orders)

 

I havent soldered anything for over 20 years so will be an interesting experience 

post #1979 of 6108
Wow. That is a sweet deal. Too bad I ordered mine a couple of weeks too early.
post #1980 of 6108
Quote:
Originally Posted by howie75 View Post

Wow. That is a sweet deal. Too bad I ordered mine a couple of weeks too early.


Thinking the same thing myself. It was insulting enough as it was paying $125 for less than $10 in parts in the Speedball Kit, and now they are giving it away for free?! Nice.

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