Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: groomster on May 25, 2011, 05:24:31 PM
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I'm not really a fully vested member here yet but welcome aboard (sorry, couldn't resist) anyway. I haven't heard the CMOY but from what I've read it is considered a very entry level amp. I would guess the Crack would sound much, much better if for no other reason than it has tubes. I just finished my Crack a week or so ago and am really enjoying it. I don't see myself getting or building anything else for a long time unless I manage to come into a lot of money.
I spent about 24 years in the Air Force so it's nice to see a fellow military person around these parts.
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Groomster,
Welcome! Your excitement will be well founded. Bottlehead gives a great bang-for-the-buck. Your headphone impedance will interact with the coupling cap so we will assume that you checked the specs and bought the proper amp for your headphones.
Just a couple of suggestions for assembly. Check for any manual corrections before you start in the Crack Folder. Make a good crimped mechanical connection before soldering. Solder doesn't make the joint it just makes it permanent. After you see the solder flow wait a couple of seconds before removing the iron so everything is properly heated. And finally, be kind to the power switch. I would suggest drilling a small hole through the lugs on the switch to make a crimped joint before soldering. The power switch can melt if you put a lot of heat into it. It happens regularly. It is a good switch but I think it is intended for use with a slip on lug rather than soldering.
Good luck and keep us posted!
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The very first project I built was a cmoy, it sounded good the and still does! Been through many others, still have and use AMB's wonderful Mini^3 portable. The crack is in a whole 'nother league no question. You're gonna love it. I build a lot of solid state, a lot with SMD parts so working on the crack was a very different and wonderful experience.The instruction have to be the best on the market, bar none. I want to leave you with a thought made popular on Head-Fi "Sorry about your wallet"!!
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. . . I want to leave you with a thought made popular on Head-Fi "Sorry about your wallet"!!
Bwa Ha, Ha, Ha! Crack and Bottlehead in general are addictive!
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Nice! I guess you're not going to finish the top surface nor the transformer bell top :-)
I knew ahead of time that I was going to finish mine so had to be patient waiting for the coats to dry. Then I ultimately spread out the build over a few days.
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Congratulations! Great feeling...been there, love it!!! Enjoy the music for a month or more THEN build the speedball. You will want to listen long enough to get 200 hours on the Crack to fully burn in and get 100% accustomed to the sound quality. When you add the speedball, you can make note of the improvements that you might not notice in the newness and burn in changes currently. Just an idea, of course....
John
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groomster, first off, congratulations!
Second, when you say a tube is getting excessively warm, can we assume you mean the larger one? And, by excessively warm, do you mean that touching it will instantly raise a blister, or merely that leaving your finger on it is uncomfortable?
BTW, don't worry overly much about touching the tubes; the envelope is simply glass, it's not like a halogen capsule or a 1k tungsten lamp, a little oil won't harm it. Just wipe it off with a soft cloth once in a while. Note: if the markings on the tube are important to you, go easy; some of those will wipe right off!
Finally, it sounds to me as if you are listening to the amp while it is breaking in, something I usually do with a new amp. As a very general rule, after about 50 operating hours, the components get pretty well settled in, and you won't hear much more change until you swap in different tubes. There are certain exceptions that take much longer, but you get the idea.
If it were me, I would live with it for some time before the upgrade. Play a lot of music you are very familiar with. For sure, get it past the 50 hours mentioned above.
Since you have the upgrade in hand, I would certainly recommend that you give it a try, though! And, give it the same break-in period before listening critically. Just keep your options open as you go along, in case you want to change it back.
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To be perfectly honest, I don't own a Crack, so I can't say anything definitive. Hopefully, others will comment from direct knowledge.
I can say, though, that if your resistance and Voltage checks were all within tolerance, I would be very much surprised if you have a problem. Tubes can get pretty warm when they are in use.
It may be of some interest to note how they feel to you after the unit has just been turned on for about ten minutes, but with no music playing through it. Just "idling" after a cold start.
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Mike,
To answer your question about heat, it is normal. The glass of the tubes, the transformer and the attached top plate will get hot.
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Yes, the 6080 gets very hot, too hot to touch. It's supposed to do that.
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Hi Groomster. I wanted to post a reply when you first started this thread but got side tracked for some reason and didnt remember it. I know exactly how you feel regarding your anticipation of waiting on the kit to arrive. Sounds like you are about as patient as I am :-P
A previous neck surgery forces me to leash myself and limit bench time to a couple hours or I end up "paying" for it. So I was forced to build Crack over the course of 4 or 5 days, including the base. Actually, I pushed the last session and paid for it anyway. The anticipation was worse for me once I got the kit than it was waiting for it to arrive :-D
I am a bit surprised to read that you didnt hear an immediate difference between Crack and your Cmoy with your Beyers. I built an AMB Mini 3 (based on Cmoy) and the difference between it and Crack was immediately noticeable and not at all what I would describe as subtle. My main cans are Beyer 990's (250 ohm). But the Mini 3 isnt exactly a Cmoy and there are a lot of different variables involved.
Anyway, congrats on the build, happy to read it went smoothly and that you are enjoying it. And thank you for your service!
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I suspect your relatively low impedance, 80 ohm cans, are why you really aren't hearing everything the Crack has to offer Groomster. When properly paired with high impedance phones, the crack has a serious "wow factor" that does not require golden ears to appreciate. It is a night and day improvement over any portable amp I've ever heard and bests many/most well regarded commercial desktop options as well, irrespective of cost, per my experience at CanJam. My prior Woo 3, for example, even with pricey nos tubes, is thoroughly outclassed by the crack.
If you want to hear your new baby sing, keep an eye out for a deal on a pair of Sennheiser HD600/650's or, alternatively, 250 or 600 ohm Beyers. Audiogon and head-fi.org's for sale forum are worth a look if you're willing to buy used.
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You ask a good question about the authenticity of Senn headphones on ebay, and the answer is, you generally can't tell. Much better to buy something from the classifieds on head-fi, though that also doesn't guarantee anything, but chances are that you'll be far more likely to get the real thing there. If the price looks ridiculously low, then that can be a clue -- figure somewhere in the $200 range for used HD-600s.
Another new option would be the AKG K601s which are also said to be very nice with the Crack, which is one amp these can's seem to like more than a lot of other amps.
-- Jim
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I bought my 650's on eBay, actually, for less than $350 (can't remember the exact figure at the moment). They looked like they had never been used and came in a Sennheiser box, so I'm confident they were legit. Even after using Beyer DT880's, they are the best thing I could have done to support my Crack habit! With the Speedball upgrade, a 5998 and clear-top 12AU7, they are the closest I've ever come to my "ideal" for playback of music.
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I got mine from razordogdeals2008 on ebay, they are an authorized Senn dealer and completely legit.
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Amazon has used Sein 600 and 650 from $254 and $320 respectively. New are $330 and $440 respectively. This should be the most you would pay....
http://www.amazon.com/s/ref=nb_sb_ss_sc_3_10?url=search-alias%3Daps&field-keywords=sennheiser+650&x=0&y=0&sprefix=sennheiser#/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=sennheiser+600&rh=i%3Aaps%2Ck%3Asennheiser+600 (http://www.amazon.com/s/ref=nb_sb_ss_sc_3_10?url=search-alias%3Daps&field-keywords=sennheiser+650&x=0&y=0&sprefix=sennheiser#/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=sennheiser+600&rh=i%3Aaps%2Ck%3Asennheiser+600)
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If I recall correctly Tyl Herstens of Headroom fame gave the Dr Dre's an unfavorable review, the bass curve was way off in a not so good way. He did not understand why given the cost and engineering. I am sure you can find the review.
I have used DakMart several times. They have HD-600 B stock for $208.00 http://www.dakmart.com/p4509/Sennheiser-HD600-HD-600-bstock-Hi-Fi-Professional-Headphones/product_info.html (http://www.dakmart.com/p4509/Sennheiser-HD600-HD-600-bstock-Hi-Fi-Professional-Headphones/product_info.html) They are authorized, the one time I had an issue I RMA's right to Sennheiser for the replacement and it was quick and easy.
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@ Hopeful, HaHa, I sure do want to hear this baby sing!!! I'm researching the Sennheiser HD's as I type this.... I was thinking about this same idea earlier and your comment is just icing on the cake. I now realize I need something with a higher ohm value. I even already installed the Speedball upgrade and really didn't notice any change. (Now is the part where I have to look at the ones I like online and dream about them while I am saving, lol)
Do you or anyone else on here know if any of the beats by Dre headphones are over 100 ohms? Or are they just a toy compared to the Sennheiser?
Also, I just looked on EBAY and the Sennheiser 650 are going for $359. The Sennheiser website advertises the 650 for $649.95. Are the one's on EBAY the real deal???
I think it is safe to cross the beats off your list. They have a lower impedance than your current cans, and despite their relatively high price tag, are not really hifi headphones based on the brief song or two I've heard through them. I wouldn't quite call them a toy, but you're not really getting what you're paying for unless you have a particular fetish for shiny black plastic /grin. (This seems to be the general consensus over on head-fi as well.)
The HD600's and 650's are in a totally different league and are glorious when plugged into the crack. As castelletti mentioned, there are a number of authorized Sennheiser sellers on ebay, and razordogdeals2008 is the one I see mentioned most often. One thing to keep in mind though - there have been at least two versions of the HD650's, and the more recent one is generally considered to be better (more balanced sounding and less subdued in the trebles) than the original version. The original was often criticized as sounding too "dark" by those "upgrading" from the HD600's, so the hypothesis is that Sennheiser tried to strike a compromise in later production runs. However, to date, a substantial number of head-fi posters still contend that the HD600's are a better headphone than the HD650's (generally asserting that the 650's have too much mid-bass and too little treble in comparison). The 600's and 650's share many similar characteristics (often referred to as the Sennheiser "house sound"), but their differences are easy to hear. If you have a chance to attend a headphone meet or visit a hifi shop to try the two out before buying one, I'd recommend it.
J&R used to be the cheapest reputable internet retailer for new 650's. Their web price has since gone up, but if you prefer to avoid ebay, my understanding is that you can still bargain them down to $360-370, or thereabouts, if you place an order by phone.
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Im still waiting on my old 600 ohm AKG K 141's from the 1980's to get back from AKG service. It's been almost a month. I cant even remember how they sound seeing how I havent had anything that could properly drive them since the late 90's. My main cans are Beyer 990's (250 ohm). I love those phones but they arent light in the bass so not for the audiophile crowd seeking "neutrality" or "accuracy" or whatever the correct description is. I wouldnt call the bass on par with the bass monster phones available but they portray ample bass when the music does so not a good choice for those who dont want any low end "lift" from their phones.
Jrebman mentioned the AKG K 601's. The only high impedance phone still made by AKG (well relatively high at 120 ohms). I bought a set, probably for sentimental reasons more than any other and knowing that I could return them. They arent my cup of tea for most listening (too bass light for my tastes) and no amount of burn-in will transform them that much. They are also quite a bit more power hungry than the Beyers. But they do some things really, really right, to my ears. Initially not thinking I wanted a pair of "situational cans" I actually did send them back but did a quick UPS intercept the next day. I just couldnt stop thinking how good Luther Allison's - Where Have You Been? (Live in Montreux) as well as BB King's Live at the Apollo sounded on the AKG's. I missed the bass on a lot of tracks with the 601's but I didnt on some others and where I didnt, they sounded great. I decided that I had to keep them just for certian tracks/albums like the two I mentioned. They seem like a good match with Crack eventhough, again, they wont be my main cans. Point is, they may be a good option if they suit your tastes. 200 bucks is pretty expensive for a change of pace and/or situational headphone (if my wife knew she'd strangle me) but not all that much if they will be your main phones.
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The volume control is not actually a volume control, it's a gain control. There are no reliable standards on signal voltage level, so if your source puts out a lot of voltage then at maximum gain you can overload the amplifier and get distortion.
You can also overload headphones; there's no guarantee which will overload first.
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With tubes, those guitar amp scenarios are usually driving the tubes much harder than hi-fi gear. And I also know that some tubes last longer than others and some tubes of the same type are built to last longer than others of the same type. I think that many of the ruggedized JAN tubes are a good example of the latter. Although I do have some that look exactly like their non-JAN counterparts.
I have a question for you, Paul if you are still lurking this thread. What is the input sensitivity for Crack? I think I read 2 volts. So with a source outputting a clean 2 volts, Crack should be clean with no attenuation ("Volume" control wide open) correct? More than that and it will clip before the volume knob (gain control) is turned all the way clockwise, correct? The reason why I ask is that my main source is spec'd at 2 volts. But I recently moved my old AH Tjoeb 99 CDP over to the Crack system as well and that thing was spec'd at 3.5 volts out from a couple of old reviews I read. So if input sensitivity of Crack is 2 volts, the Tjoeb with 3.5V output would have the potential to overdrive the Crack, especially with "hot" CD's, correct?
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Playing with or rolling tubes is a big part of the fun of owning and using the crack. So get some tubes and start rolling and at the same time you will be building a nice stash too!
Groomster, one thing about the crack is that to me it is very revealing, and as such will show just how good or bad a recording is; at the same time it will also show how your source sounds! mpeg through iTunes, through your computer might not be the best source. I use a computer as my source because all my music is stored on hard drives in lossless format. I us Windows 7, Foobar 2000, with either kernel streaming or wasapi (this to bypass windows sound stuff) and then coax digital out (SPDIF) to a mid range DAC (AMB Labs Gamma2). I have to say this combo really sounds great and has lots of WOW!
My rig aside, one thing for sure about using the computer is to make sure the volume control in the software application, iTunes, Winamp, Foobar, etc. Is turned all the way up. Something about insuring all the music's digital information is passed to the DAC otherwise it will not sound as good as it can.
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I have a question for you, Paul if you are still lurking this thread. What is the input sensitivity for Crack? I think I read 2 volts. ...
The spec is a gain of 15dB and max output of 10 volts (both are approximate, and into a 300 ohm or greater load). 15dB is about a factor of 5, so the input sensitivity for max output is as you say around 2 volts.
Note that 10 volts is twice the voltage of the IHF/IEC headphone standard. With more or less average headphones, 10v can generate over 120dB, which is 30dB above the threshold for hearing damage (90dB) - that's 1000 times the acoustic power!
Please also note that I didn't design the Crack (PB, aka Caucasian Blackplate, did), and I've never done any measurements on one. That's why I rarely post in the Crack sub-forum - I don't have the knowledge base to answer more than a few kinds of questions.
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Good enough, thanks Paul.
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I too bought a 6as7g tube for my crack. I found it to be more detailed however a little more laid back (but that too can be a good thing depending on the music). I got the 6as7g from tubedepot.com for about $20 Plus shipping. I think your money at this point would be best spent on higher impedance cans, the crack is designed for a higher load and you will not be experiencing all that your crack can deliver without them (believe it or not it will sound much better with them).
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Def. go for high impedance cans as mentioned. There are several different nice models Sennheiser HD600/650 and Beyerdynamic are a few good high impedance headphones within reasonable prices!
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Groomster, if you like the DT 770's bass response, it's going to be difficult to find a new high impedance can that can hang with it in terms of bass impact/quantity . There just arent a lot of high impedance cans being made any longer. You can always consider a higher impedance version of the same phone you have or maybe the DT 990 if you want to go to an open phone but still stick with a bassier phone. I have the DT 990 pro 250 ohm among a few others and they are may favorite phones. I like having a few different phones for different music genres or change of pace or mood or whatever the case. But, if I only could keep one of my present phones, it would be my DT 990's. The 990's also are strong in the bass dept. but I have never done a side by side comparison with the 770's.
AKG makes the 601 which is 120 ohm. Bass shy compared with the Beyer 990's and your 770's But Im liking them more and more with much of the blues I listen too, especially well recorded live blues (and even better with 5998 tube). Fischer Audio has the FA 011 at 160 ohm (hard to get in the states). MB Quart has some high Z cans but these are no longer made (See my thread "Hi-Z phone heads up thread" linking to a couple of ebay buy it now listings with 2 different Quart models on closeout). German Maestro is making high Z phones (took over production from MB Quart if think). KOSS has some High Z models and then of course there is the very, very popular Sennheiser. Im sure there are a few other manufacturers but that's all I can think of. And of course, there is the used market for out of production Hi-Z phones. Best you can do is check all the reviews that you can find and try to listen to some of the phones locally if possible.
Also, replacing the 6AS7 with a 5998 will lower the Cracks output impedance to about 70 ohms. That may or may not help your 80 ohm Beyers, sonically. But it is a very nice sounding tube (thanks again Jim) and you may or may not prefer it over the 6AS7. They are however, harder to find and signifigantly more expensive. And because of that, not a good tube to trust to any ole' ebay seller. One other thing about the 6AS7 ... NOS or good used, they can be had for relatively little money if you search for deals. Some of the USA JAN's or the RCA's come up all the time on ebay. You are kind of at the mercy of the sellers descriptions and their meters and ability to use them. But there are good deals to be had from sellers with good reputations. And sometimes a deal can be so good to be worth the small monetary risk. I picked up an excellent and what looks to be NOS RCA 6AS7 for, if memory servers, under 10 dollars. Also an excellent RCA JAN for around the same. It amazes me how many different size bottles they used for these tubes. I think I have 3 or 4 different size bottles all with, visually, the same internal construction. Personally, any differences in sound between these seem to be subtle at best when internal construction is the same regardless of whether they are labeled RCA, RCA JAN, JAN, GE JAN, CRC etc.. But YMMV. I think it is definitely worth picking one up when a good deal arises to compare with the sino that you have on the way. There is also the Russian 6H13C or 6N13. A lot on ebay, mostly from european sellers. Also several tube retailers seem to have these.
Im no expert on this stuff but hopefully some of this info is helpful.
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I just cannot prevent myself from being very, very careful how I phrase any sentence on this forum in which I use the word "Crack". I know, I know, Im too easily amused but re-read your first sentence. Happy that you like the tube but Im laughing aloud right now :D
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Well, he did say he likes the heater elements -- wonder if it has magic fingers too. :
-- Jim
I just cannot prevent myself from being very, very careful how I phrase any sentence on this forum in which I use the word "Crack". I know, I know, Im too easily amused but re-read your first sentence. Happy that you like the tube but Im laughing aloud right now :D
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Glad Im not the only one who is easily amused. Groomster, you're a good sport.
And obviously the Bottlehead gang have a good sense of humor with the names they give to their creations.
If you guys run out of interesting names, I offer up my moniker, feel free to use it, I'd be honored :-) Although, the headphone amp currently in the works is right up the same alley with a name like "Smack".
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My shoes should be on the way. If they look like they are supposed to they will make their debut at the California Audio Show. I have already received polos for Shawn and me, and they look great.
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the senns at gc give you an idea of how they sound. they are very neutral...meaning they arent going to have this large bass. i actually really like them because they sound like real instruments. i would not recommend them if you like electronic or hip hop music because i think they can take the magic away from "colored" music. if you like music with actual instruments i think they are very nice.
my one observation is im not hearing the 3-d soundstage from them. they are wide but i dont hear a whole lot of depth unless the source music is very well mixed and recorded. to be fair though i havent heard any headphone do that well and my experience with headphones is very limited.
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Groomster, I had read a post somewhere after we "talked" about someone who switched from the 80 ohm to 250 ohm 770's. Im not sure what amp he was using but he stated that the 250 ohms sounded much better. Im glad that you find that to be the case as well with your new 250 ohm 770's. I dont see any reason why the bass wont open up with break in. I would think that with the 250 ohm version you should end up with a bit better extension and probably better control on the Crack amp. But there are bound to be some differences between the two versions. Glad to read that it appears to have worked out for you. They should get better with use.