Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: ramicio on July 31, 2012, 05:30:45 AM
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I bought a Crack off ebay some time ago, pre-built. It came with AΞON output capacitors. I've since replaced the RCAs with Neutrik ones and the headphone jack with a Neutrik latching jawn. The octal tube socket just plain sucks and the signal started becoming intermittent, so I took the amp out of commission and I am going to do a whole slew of things to it.
- I ordered new tube sockets. They are the teflon composite type from Parts Connexion. They have a silver-plated crown springs inside the contacts made of beryllium copper.
- The capacitors came dangling. I just used packing tape to keep them held up. It works and can't easily be seen because it's clear. It's not ideal so I designed some brackets in SketchUp and are having them made at shapeways for $3.96 apiece. They made specifically for my capacitors, and you can see the slots for the zip tie. Click this sentence to visit the site and maybe purchase them. (http://www.shapeways.com/model/649991/capacitor-bracket.html) I don't get anything for it. I designed them and put them up for everybody.
- The headphone jack is crooked and could use some mounting work. I am going to look for a machinist to just nip into the top plate a tiny bit to the shape of the jack's flange so it absolutely will not move.
- I am replacing all hardware with torx hardware. I haven't found a place where I can get all the same alloy for all of the sizes I need and inexpensive. McMaster-Carr has them all for cheap, but in different alloys. Aaron's has any size you can imagine and in whatever alloy you want, but small quantities are expensive. I would maybe go for larger quantities if people would go in on a buy (hint hint). Fastenal doesn't really have anything, anymore.
- I am going to have the top plate and transformer end bell powder coated.
- I am looking to add in an audio spectrum analyzer circuit I bought some time ago. I would like it to be after the volume control. Will there be any impedance problems?
- I am looking to add a timed relay circuit that won't connect the headphone output at power on until a set amount of time.
- The Speedball upgrade will be done. What hardware does that kit use? If I have excess quantities from the bulk I order for the Crack itself it would be nice to have these used for mounting the Speedball.
- I am thinking about solid silver wire with cloth insulation, and not with PVC or teflon innards. Does anyone know of a place that sells a decent selection of sizes and colors (red, white, and black)? I found a place in the UK, but I would prefer somewhere in North America.
So far I'm impressed with the amp. I didn't think the sound would change that much from the on-board amp on my STX card. Naysayers obviously don't understand that impedance is only measured at one frequency point and high-impedance headphones like my HD-650s are quite demanding of power for bass. You need a healthy reserve of power to drive low frequencies.
When I got it:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ftimramich.com%2Fheadphone_amp%2F2012-05-01_18-13_thumb.jpg&hash=86b4b337d0d8bb992e37596cafb5cfbf050c21f3) (http://timramich.com/headphone_amp/2012-05-01_18-13.jpg)
After I fiddled with it:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ftimramich.com%2Fheadphone_amp%2F2012-05-07_19-25_thumb.jpg&hash=2f7818c81d42b31998cb503528ec935ee626f8ac) (http://timramich.com/headphone_amp/2012-05-07_19-25.jpg)
More updates to come.
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No, I just remember the picture post that was made. The knob is distinct.
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I love those capacitor brackets. Can you tell me exactly how I can purchase them.
Thanks in advance.
Bernie.
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That fixed it.
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I'm a big fan of bending the tube pins out in that way. Some of them get so crowded it opens up the opportunity that they might short together. Worse yet, you could bridge two pins when taking voltage measurements.
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Forgive my ignorance but what are you trying to accomplish with this circuit? A switch?
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Thanks.
That sounds interesting!
Keep us updated...
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End mill hell ... that's a free hand with a Roto Zip job ... starting with a prayer that you dont f-up ;D
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I think it's cool that Tim is doing this in such a precise way, having parts CNC'd and 3D printed. It's inspiring me to put our little CNC mill in the lab to work on some projects beyond engraving tape reel flanges. Today I'm updating the wood fired Pentium III we have been using to run it for the past few years to something a little more reliable.
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I don't understand.
It was a joke about doing it the cheap way. Exactly like the way I'd do it if I were so inclined ;)
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You're pretty brave to use stranded wire, it's pretty tough to build with (Be sure to trim off any little wire fingers/hairs that aren't soldered down).
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I initially wired FPIII with a teflon insulated, stranded STP. Tinned every wire before wrapping and soldering to terminals. It wasnt fancy wire, I just had a hair to try it. It was a PITA but not as much as it just plain sounded like sh*t. I ended up tearing it out and using the Belden. Count your blessings, it could have been much worse ... I know. :o
PS ... Looking Good! Very cool.
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Ouch, rewiring a Foreplay III is a huge task!
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Double ouch; I was just thinking teflon STP might be an improvement! If you don't mind my asking, what did you use and how long did it burn in before you threw in the towel?
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If memory serves it was some inexpensive West Penn wire, cant recall the #. Tinned, stranded. I dont recall how long but I didnt leave it alone for very long. Certainly not long enough based on most recommendations for teflon burn in but the high end was a mess and I wasnt waiting on it. I have some teflon insulated wire in the main system that sounded quite good from the start. I can tell you that the stock Belden STP was a welcome change, immediately so I never looked back. I never have been able to find a small diameter STP with teflon insulated solid core wire. Im sure someone makes some but Ive never found any.
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The Belden that Bottlehead ships with the the FPIII contains a pair of foil shielded solid conductors and a drain wire within one jacket. What I used was of the same exact construction type with the exception of the conductors being stranded rather than solid. If something is "off" because of the of the contruction type of wiring I used the same would be said of the Belden that they ship with the kit. I dont spend a lot of money on wire or cable but I do believe there CAN be sonic differences that are explainable by science. NOT the voo doo science that the wire companies try and sell though. Maybe some things are just not completely understood as of yet. Im open to it.
I understand that you dont buy into much about wire and cable but you did use silver plated copper instead of just copper ;D
BTW ... the Crack has turned out very nice. Well done sir.
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The FPIII's signal is wired with the shielded, paired cable, not the Crack.
Nobody has ever been able to scientifically explain or measure anything YET. That's the problem with "us" as a species, we think we already know and understand everything there is to know and understand. Like I said, Im open to it. You still arent convincing me that you are a complete wire naysayer though. Cloth insulation? Solid silver? Precious metal wire erotica? ;)
Legos would definitely be unique!
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...I will repeat AGAIN that there is NOTHING science does not understand about an electrical signal.
Uh huh! Arrogance is not science. Ignorance easily passes as absolute knowledge, that is, until more is learned/discovered. The only absolute in human scientific knowledge is that "We do not understand everything". If the musical signal existed in a purely electrical state without interface or interaction with any other component, we MIGHT know most. But there is so much interaction, reaction and interface that above mantra is, at least, entertaining. But you are certainly welcome to your own "opinions"
Cheers,
Geary
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Keep thinking these delusional thoughts and just watch the money fly out of your wallet.
You can find bad wire with high capacitance, and measure its impact on the signal, this is known and measurable.
You can construct similar situations by arranging the cable to maximize inductance, and this has a measurable impact on the signal.
Teflon is awesome because it doesn't melt when you solder it, all other benefits (real or imaginary) I take as a bonus.
For some additional reading, this is one way to look at things: http://www.cardas.com/content.php?area=insights&content_id=10&pagestring=Measuring+ (http://www.cardas.com/content.php?area=insights&content_id=10&pagestring=Measuring+)
Here is a nice paper from the AES that goes a little more into depth, and is not driven by marketing:
http://www.apiguide.net/04actu/04musik/AES-cableInteractions.pdf (http://www.apiguide.net/04actu/04musik/AES-cableInteractions.pdf)
I don't get too crazy with wire, I can build out a badly designed circuit and no amount of fancy wire or fancy caps will correct the design itself.
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So there is a line in the sand between high quality wire and high quality capacitors? (getting back to your build)
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... If it can't be measured, it sure as hell won't be audible outside of the imagination. All of these things are completely understood. ...
This is the only part with which I disagree. I'm old enough to have learned that we underestimate our ignorance all the time, every day. For one thing, we measure things that do in fact correlate with what we hear, such as distortion, and then SETs force us to acknowledge that we have over-estimated the importance of THD measurements. Symmetrically it is highly likely - almost certain, in fact - that there are measurements we either have not yet learned to make, or of which we seriously underestimate the importance.
The classic example for me is break-in of capacitors and transformers. I am not aware of any measurements that correlate, but I have heard the effect so consistently, in so many cases where I was not aware of the history, that I cannot deny the effect.
We, and other species, have many senses which are more sensitive than we can measure. Why else would anyone use dope-sniffing, or bomb-sniffing, dogs if we could simply measure the trace aromas?
My career experience is as an engineer, so I respect the consensus of perception when I am unable to make a measurement to trump it. Sure, often enough the consensus is a form of mass hypnotism and one must always be prepared to abandon it when something more reliable appears. But until then, the closest thing to reliable always wins, no matter how far it may be from satisfactory. In this I differ from my training (I was originally a mathematician). I am however very cautious about extrapolating beyond the realm of actual, experience-based consensus!
For what it's worth, I have heard the effects of different wires and interconnects but my personal experience base is too small for me to have a solid opinion. I rely on the forums for a wider range of experience (and on those whose ears I trust) but I remain deeply suspicious. :^)
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it's the coloration and flaws of such devices that make a pleasing sound. It doesn't make it accurate for one second.
You're right on the money there. You'll notice that we will only describe our C4S loads as increasing accuracy (by lowering distortion), preferences for wire, caps, and resistors are more like subtle tone controls (though cap ESR in a power supply will influence noise reduction). As PJ said, we find ourselves liking amps that have 5-10% THD over amps with 0.0001% THD, that's a tough one to swallow and explain!
We get pretty irritated about snake oil here, but we are also perfectly happy to admit when we have a preference but have no idea why! We are always happy to chime in and recommend boutique parts, but shy away from the "what sounds best" conversation.
Sorry, but what sense of any animal do you believe is more sensitive than any lab equipment that exists?
Bats, it's kind of crazy to think about what we could learn by unraveling their sensitivities!
http://nocamels.com/2012/06/new-lab-aims-to-discover-secret-of-super-sonar-bats/ (http://nocamels.com/2012/06/new-lab-aims-to-discover-secret-of-super-sonar-bats/)
http://news.nationalgeographic.com/news/2002/12/1212_021212_batsonar.html (http://news.nationalgeographic.com/news/2002/12/1212_021212_batsonar.html)
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The distortion argument is the most commonly presented, but there are others that have not been invalidated. I've seen some papers suggesting that slew rate accounts for these differences, others get into the nitty gritty of electrons moving through silicon vs. air, though most go after the distortion argument. Recently, labs have developed nano-tubes which are essentially fets that are so small that the space between the elements is so fine that atmospheric gaseous molecules are unable to occupy said space. I would be fascinated to hear those acting on a music signal, but I'm sure we are years away form that.
One hypothesis that really resonates with my experience is the nearly mandatory need for global feedback that we run into to tame solid state circuits. I've heard a couple of 0 negative feedback, directly coupled solid state circuits that are pretty amazing, but they are incredibly rare and super expensive! Along the same lines, I can add global feedback to a Paramount (or a Crack for that matter) and be dissatisfied with the results, which all measure and pencil out really well.
The more reading I do on these topics, the more questions bubble to the surface (and to some degree, frustration).
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Ramicio, the intentions of my last post to you should have been crystal clear, I was just having some fun. I thought we were all friends (or atleast friendly) here. Im sorry that you feel differently about that and that you took it as an affront. Others can disagree with you, as they have here, and it should be OK to keep it friendly. I was clearly not, nor is anyone else, trying to invent YOUR beliefs, form your opinions or rob you of them ... or steal "your" thread for that matter. That said, your thread is all yours.