Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: dusk on August 04, 2015, 08:37:05 PM
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So I finished my first ever DIY build this weekend with the crack and I am HOOKED. I have a TON of questions! If you don't mind...
Here is the finished product.. so far:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fcdn.head-fi.org%2F0%2F09%2F900x900px-LL-09de2abd_IMG_4998.jpeg&hash=307d12da07a5bd075715a6b312167e4e52c4efeb)
The amp is set up near my couch and I have been listening to it every night fed by an AURALiC Vega through HD650's... and this might be one of my favorite systems ever... but now I'm looking at all these frankencracks, and hotrodded cracks.. and.. well, I want to try my hand at it before I call this done and move on to another project. :)
After a couple weeks of listening and getting to know her, I plan on installing the speedball upgrade I have, but immediately after (if all goes smooth) I want to upgrade a few parts once I get the hang of building, and I wanted to make sure I am getting the right things so these can be straight swaps to the existing materials outlined in the guide so I perform all tests at the end to get the same results
First off I want to strip the entire board down so I can paint the top. When I put it back together I want to replace the wires (for looks and tidy things up a bit from my first attempt), RCA inputs with Cardas (looks), 1/4" jack with neutrik (looks), stepped attenuator volume pot with I think the Goldpoint V24 100K with the resistors preinstalled (don't want to get too crazy just yet), replace the coupling caps with Mundorf 100µF / 350V Mcap Oil (or similar), 1uF 600V Mundorf MCap Supreme bypass caps (more below on that), and a Triad C7X choke to replace the last 270ohm resistor. Wrapping it all up with some kind of vintage light on top wired into the tube warmer cables and spiked feet for lift.
Does this sound good? Are there any gotchas I have to look out for besides some finger yoga getting the giant caps in?
Another question that I'm curious to have answered is about bypass caps.. what exactly is the point of that and do I need to use those if I upgrade to some monster caps, or does it smooth out the sound?
As far as tubes go, I think I'm going to dig a little more and get some things to try out and see what I like.. but only after I perform all the other upgrades once things stabalize. I think I'll start with the Tung Sol 5998 NOS for the output. Also, I have some E88CC/CV2492 Mullards sitting in a box, and was wondering if they will fit into the 12AU7 input slot?
I'm just getting started with all this and there is so much information out there... I want to make sure I'm on the right track here.
Thanks!
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I am not sure if the Evo caps will fit. You can refer to Lee Haskins's build here - http://bottlehead.com/smf/index.php?topic=7787.0, but need to note that he has a slightly wider top plate (refer to http://bottlehead.com/smf/index.php?topic=1723.msg73899#msg73899). I would advise that you measure thrice before buying them.
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Hi!
Great to hear You're having a blast:)
I would recommend perusing the Gallery.
There are many good ideas and pictures of builds
to copy from and maybe You come up with new creative solutions in the process.
There are a couple of great threads on caps and tubes and so on
Good luck!
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Hey congrats on the Crack I like the scorched look you have on the case.
If you wanted to avoid a total strip down to paint your top plate you might want to consider just dropping down your volume knob and headphone out socket and then carefully masking up the rest, put a strip of masking tape over the underside of the top plate vents and volume pot thrs jack holes etc. Tape a bin liner around the edge of the enclosure and you would be good to go. Save a lot of extra work with the strip down.
The basic goal of using the bypass capacitors is to impart some of the sonics of the higher grade bypass capacitors into the lower value ones used to hopefully improve a particular aspect of performance.
A budget 100uf film capacitor might cost say $30 while a 100uf boutique one might cost $100 if available in that size however the same type of boutique capacitor in a 1uf value may only cost $10 so by using the 1uf to bypass (piggy back) the budget film the hope is some of the attributes that particular brand of boutique capacitor is well know for might be gained.
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I know cap upgrades are very popular here, and for a good reason. I remember one that had spikes on the bottom that allowed the jumbo caps to hang like a pair of Thrush Mufflers. Not such a bad idea.
If you go with the Cardas RCA jacks, I suggest the Rhodium over brass. IMHO a meaningful sonic improvement.
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Hey congrats on the Crack I like the scorched look you have on the case.
:) That is called toning. It was commonly used on early 20th century furniture (my own experience with it was when I restored antique radio cabinets from the 20s and 30s) to cover imperfect looking edges. You can still buy toning lacquer, which is most commonly an opaque dark brown or black lacquer, from Mohawk.
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:) That is called toning. It was commonly used on early 20th century furniture (my own experience with it was when I restored antique radio cabinets from the 20s and 30s) to cover imperfect looking edges. You can still buy toning lacquer, which is most commonly an opaque dark brown or black lacquer, from Mohawk.
Oh... I used a blow torch.
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Well, that's another way to do it, I guess. ;)
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stepped attenuator volume pot with I think the Goldpoint V24 100K with the resistors preinstalled
You might want to read this thread (http://bottlehead.com/smf/index.php?topic=8251.0) before purchasing said attenuator, in particular post #6.
Do also be aware that the Crack-a-two-a has space for very large coupling caps, flexibility for upgrade attenuator options, a shunt regulated power supply, and even some real estate for power supply chokes.
-PB
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You might want to read this thread (http://bottlehead.com/smf/index.php?topic=8251.0) before purchasing said attenuator, in particular post #6.
Do also be aware that the Crack-a-two-a has space for very large coupling caps, flexibility for upgrade attenuator options, a shunt regulated power supply, and even some real estate for power supply chokes.
-PB
thanks a lot!
how about a stepped attenuator with dale resistors?
http://www.ebay.com/itm/Assembled-Dale-23-Step-Attenuator-Volume-Control-100k-/270311271326?pt=LH_DefaultDomain_0&hash=item3eefceab9e#ht_707wt_1163
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and what is the difference between that and the copper axis pot?
http://www.ebay.com/itm/Assembled-Dale-24-Step-Copper-Axis-Attenuator-Volume-Control-100k-/281664997434?pt=LH_DefaultDomain_0&hash=item41948ac83a
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The Valab 23 step (ladder type) attenuator has been a popular choice for upgrading in the Crack it seems well made and is very similar sounding to the Dale ones. I very much doubt anyone would be able to tell the difference blind testing them. You will also save some cash for other upgrades.
http://www.ebay.co.uk/itm/Valab-23-Step-Ladder-Type-Attenuator-Potentiometer-100K-Log-Stereo-/221843923038?hash=item33a6eda05e
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The Valab 23 step (ladder type) attenuator has been a popular choice for upgrading in the Crack it seems well made and is very similar sounding to the Dale ones. I very much doubt anyone would be able to tell the difference blind testing them. You will also save some cash for other upgrades.
http://www.ebay.co.uk/itm/Valab-23-Step-Ladder-Type-Attenuator-Potentiometer-100K-Log-Stereo-/221843923038?hash=item33a6eda05e
How does that one differ from this one:
http://www.ebay.com/itm/270311271326?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I've been thinking about picking two of these up: one for my Crack and one for my SEX.
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Sam,
It looks like the one you linked is Dale (Vishay) RN??D resistors. The RN series are military spec resistors. The other is generic metal film resistors.
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Sam,
It looks like the one you linked is Dale (Vishay) RN??D resistors. The RN series are military spec resistors. The other is generic metal film resistors.
Thanks, Grainger. I guess I'll go with the cheaper one. Will it work in my SEX, too?
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Yes, it is 100k Ohms and log taper.
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I have a couple of Valab attenuators that I've had for many years, and though they still work, the switches themselves have corroded pretty badly.
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PB, which would you recommend that might not corrode as badly?
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PB, which would you recommend that might not corrode as badly?
I can't really commend beyond that, as I haven't owned many others for as long.
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I just want to say that i have put in Goldpoint attenuators in both my Stereomour and Crack and they have performed great. They are mechanically very satisfying (someone mentioned the smooth click-click type of action) and there is no negative issue with sound that I noticed. However, I have certainly not compared them side by side with the ladder style Valab, etc.
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I just want to say that i have put in Goldpoint attenuators in both my Stereomour and Crack and they have performed great. They are mechanically very satisfying (someone mentioned the smooth click-click type of action) and there is no negative issue with sound that I noticed. However, I have certainly not compared them side by side with the ladder style Valab, etc.
PB was saying earlier to be careful of those pots because they could dull the sound?
check out post #6:
http://bottlehead.com/smf/index.php?topic=8251.0
which goldpoint did you get, specifically, borism?
and thanks!
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I read the post. That's why I responded to say that my experience was different. I have the standard V24 attenuators. As always, individual expectations, system synergy etc. are to be considered.
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... As always, individual expectations, system synergy etc. are to be considered.
Hear, hear!
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Do stepped attenuators have detents at the steps? i.e. do they "click" into each set of resistors? or do they turn smoothly like regular pots?
I'm particularly interested in the VALabs 23 step logarithmic 100K, but I imagine they all operate in a pretty similar fashion. Thanks in advance.
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Do stepped attenuators have detents at the steps? i.e. do they "click" into each set of resistors? or do they turn smoothly like regular pots?
I'm particularly interested in the VALabs 23 step logarithmic 100K, but I imagine they all operate in a pretty similar fashion. Thanks in advance.
I ended up grabbing one off ebay (dale stepped attenuator) - and it most certainly clicks at every step.. loudly and with tactile feedback. I kinda dig it.