Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: williaty on June 17, 2011, 09:54:00 AM
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Issue 1:
A couple of the voltages are just barely out of spec. I've created a Google Docs Spreadsheet (https://spreadsheets.google.com/spreadsheet/ccc?key=0AhWjf0SivZxfdFdyMzVqNDdHVkdTNkZXZGE5NVpzR2c&hl=en_US&authkey=CPOV9_MK) of the resistance and voltage checkout results to make it easier for you all to look at them. I've got three voltages that are just a little wonky. I'd be inclined to leave them alone, but I'm doing the Speedball in a day or two and want to make sure everything is right before I do it.
Issue 2:
The 6080 tube is HUGELY microphonic. I was hearing footsteps from around the house. I started tapping around the amp with my fingernail and an extremely ginger tap on the 6080 resulted in church bells ringing inside my head and my ears bleeding. Is this normal for the 6080 or is this an unusually microphonic example?
Issue 3:
I have WAAAAAY too much gain. With the 0-position of the pot being set straight down to 6-o'clock, I can't listen to anything above 9-o'clock. In fact, I'm usually listening at about 7 to 7:30. This puts me down on the portion of the pot that doesn't track well. I remember inputs/outputs can be padded to reduce signal level but I have no recollection of how to make smart choices of how to do this. Any suggestions?
Thanks guys!
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You did see in that manual that +- 15% on the voltages is fine?
The 6080 can be microphonic. That combined with your description of a hair trigger volume control has me wondering what headphones you are using. It would seem they are particularly sensitive.
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What source are you feeding the Crack with? It might have more output than is needed in combination with Doc's suggestion of sensitive headsets above.
Bottlehead has to make the kit so that it will function with a wide range of inputs and headphone sensitivities. There are things to do if you determine what is causing the problem.
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Oh! I thought tolerance on voltages was +-10%. I'm cool then!
I'm using Sennheiser HD-600s and the source is a High Resolution Technologies MusicStreamer II+ (2010 model). The MSII+ swings 2.25V FS. Given that I'm feeding it directly from the source files with no volume control on the computer, it's probably getting up close to that on a fairly regular basis, especially with modern recordings that are over-compressed.
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That is a quarter of a volt higher than the CD "standard." You could put a passive volume control before the Crack if you don't want to modify the crack.
Most of the Bottlehead volume controls are 100k ohms, not the FP III. If you put a 220k ohm resistor in series with the wire from the input RCA jack and the volume control it will pad it down considerably.
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Yeah, I figured I was going to need to pad either the input or the output. Is a single resistor the way to go, or should I make an L or T pad?
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I think the L-pad adds only one resistor per channel. That is simplest, I like simple.
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Are you sayint that the output voltage from the MS2 is too high for the amp? Because I've been running it for about a month without any mods....Should I lower the input voltage or something like that?
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Viktor,
It depends on your system. If you use the same source and get good volume control then there is no worry. What Williaty has is a problem that he can only use a very small turn on his volume control. To make small adjustments at low listening levels, or any listening level, the control should, ideally, be at full clockwise rotation with your lowest input and your highest listening level. No one gets that ideal situation.
What most of us have is a good listening level at 12:00 to 3:00. That works well and for late night speaker listening, or say background listening with a headset, you can make very fine adjustments of the volume control and get what you want.
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Williaty ... here a good link. It's for a stepped attenuator but would just as well for a rotary pot. Paul J was discussing this with me a while back ... http://www.goldpt.com/mods.html
Viktor ... I use an AH Tjoeb 99 CDP as one of my sources. That unit is spec'd at 3.5 volts output. It would have to be a "Hot" cd or track to reach that level but I could never listen that loud, not even close, even with my least effieicent phones. I havent had a single problem with the Tjoeb as a source. Let you ears be your guide. As Grainger49 states and as Doc B has mentioned in a related thread ... hot source? ... that's what the volume knob (gain control / attenuator) is for.
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Part of the issue is almost certainly that I don't like loud things. I set the music just loud enough to clearly hear the quietest passages and then don't raise it any higher. Loud noises/music just give me a headache. So it's entirely possible that I'm using less of the pot because I'm trying to listen 10dB quieter than most people.
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Try the series resistors I suggested. If you can find them at Radio Shack that is a good thing. I suggest getting an assortment pack. Once you have zeroed in on the needed resistance then you can buy some $5 resistors that are better sounding.
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I've got a packet of resistors left over from the Sweet Whispers build 10 years ago. I'll see if any of them come up useful.
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OK, built the Speedball and installed it tonight. Voltages check out ok, but I have two different issues now.
1) The sound is more dry and trebly. Is that something from the Speedball or just how the recordings I'm listening to are actually mixed?
2) With no input, I have a strange very, very quiet rushing noise in the right channel only. This wasn't there before the speedball. Any ideas what this is?
Overall, I'm really very impressed with this amp.
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1) let it run in for a while. Seems everything new I try sounds dry and trebly at first. If not you can always go back
2) if the noise goes away with the input shorted, or a source connected. don't worry about it...John
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To clarify, the rushing noise, or maybe it's a hiss, I dunno, is present with an input connected or with them shorted, but it's at a low enough level you can only really hear it when there's no signal playing. With music playing, it just lends there sort of odd gummy weight to the right channel. That's an exaggeration, it's a subtle effect, but that's the only way I can think to describe it.
It's really weird to listen to right now. There's so many more sounds and details and whatnot that I can actually identify. All the lower sounds are just MUCH better controlled as well. Yet there's this sterile lifelessness, dryness, brittlenees, something, to it that just makes it sad to listen to. It's the same sort of sound you got out of a cheap solid state amp during the late 80s/early 90s when everyone was chasing the "lowest THD ever!" in consumer gear. It's a weird mix of considerably better performance and yet at the same time less good at being music.
I must have screwed something up.
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OK, a couple of more hours and some frantic searching for different tubes...
Nearly smashed in the back of the junk drawer I managed to find a 12AU7 someone had once given me to make a necklace out of. Thankfully, I'd never gotten around to it!
So, first things first, the odd rushing sound was caused by the Electro-Harmonix 12AU7 included with the kit. I have no idea why it only manifested itself after the Speedball upgrade, but there it is.
Sound wise, well, it's a different mixed bag. Switching to a different tube definitely removed the sterility/dryness. Most of the boogie is back. On the other hand, things sound just a tiny touch... muddled or confused. Let me place that in context by saying it's still more clear and organized than any other headphone amp I've ever heard and is arguably more sorted out than pre-Speedball, it just loses a tiny something in comparison to the EH tube post-Speedball. On the other hand, it's fun to listen to it now so I'm not going to obsess over this.
Oh, the tube I dug out of the back of a drawer, all scratched up? Turns out it's an RCA Clear Top! Started googling for what "A Electron Tube" might be. Added words like side getter, etc. Finally saw a picture and realized that the "RC" had scraped off, leaving a big A next to the stacked "Electron Tube". Nice sounding tube.
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I've got a packet of resistors left over from the Sweet Whispers build 10 years ago. I'll see if any of them come up useful.
I think those are too low a resistance to be useful padding your volume control unless they are the series resistors for matching the SW to your system.
Give the Speedball a break in and all sorts of music. As for the rushing sound, you have lowered the noise floor to the point you probably hear the tube rush. Swap tubes and you should find the rush in the left channel. That is the tube.
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This is kinda why I havent jumped on trying Speedball yet. Im just really enjoying the Crack as is. I havent had the itch to upgrade anything other than roll tubes. Im not sure Im really in search of added detail or clarity as I dont want to move closer to what I may perceive as a more "sterile" or SS sound. And the background is extremely quiet as is. The temptation is there more for the ability to be able to roll a couple more tubes and I may end up loving what Speedball does even more, afterall it does seem that the vast majority hail it as improving Crack even further. But Im finding myself enthralled with an Amperex 12AU7 ( GE and Triple mica 5814's are in the running as well) and a Tungsol 5998 right now. Im sure I'll probably try it down the road, as it is easily reversible.
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The Speedball is going to reveal more music than noise. If you have a tube that has some noise when you turn it up you will hear it if you didn't before because it was buried in the noise floor. There are benefits and problems with improving your system. As the resolution increases some things are exposed for the nasty things that are there. A bad tube, or a less involving tube is exposed as such. Good, involving tubes are exposed as that as well.
So don't throw the baby out with the bath water. The Speedball upgrade isolates the power supply noise from the audio path. It should be cleaner but more detailed. That isn't really SS sound but more revealing sound.
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Through how many dB does the volume pot turn? I'd like to add about 180* of travel to it, so if I know about how many dB of attenuation 180* represents, I can just pad it that much.
I'm still not sold that the Speedball actually moved the sound in a direction I like. Even with the Clear Top in there, it's still awfully dry and makes it boring, for lack of a better description. I'd really be interested in wither there's something I could have screwed up to make it sound like this. Given that I trust Doc B, PB, and the rest of them, I'm operating under the assumption that the Speedball is good and I made a mistake somehow.
One thing I did have to do was to "remote mount" the coupling caps. With how I'd run the wiring, there wasn't enough room to just push them flat and then install the Speedball board. I de-soldered them and put them on the ends of 2" pieces of wire. Could that be making the sound change? See the picture:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ffarm3.static.flickr.com%2F2720%2F5851707087_bc272a1844_b.jpg&hash=eb4512f8eda6b2ce121c3f58ad829b499242c86d)
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I like the Cleartops in an el84 based amp I have. But dont really like them in Crack with several different 6080-6AS7 tubes including 5998. It could be your tube synergy to a point as well. I never really found a GE tube that I liked in my other gear. But I like the GE 12au7 in crack, a close second to the amperex.
BTW, I wasnt dismissing Speedball by the way. Just living with the stock amp right now and very happy with the sound. Im not in a hurry to upgrade. But Ive been like that with several kits. I never upgraded a phono stage I built when upgrades became available just because I was happy with it as is. I guess Im just not the type that always looks to upgrade. But again, Im pretty sure that I will end up trying speedball in the future.
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When my crack was still stock, I found that my clear top had a pretty nice synergy with the sound signature of my HD650's. My perception was that it added a little bit of brightness and bite to the top end that was welcome with that headphone in particular. When I later upgraded to HD800's, the clear top had to go. (The presentation was overly bright and stripped violins and trumpets of some of their texture.) With my speedball now in place, I'm running (and loving) a 12au7 amperex bugle boy, with a 5998 in the rear (like Laudanum), and the sound is absolutely glorious.
If I could get rid of the minor hum, I think I might like a 1950's rca 12bh7a "black plate" nearly as well, but with my current phones, the amperex tube is much more enjoyable (to me) than my other 12au7's (or, for that matter, the 1960's rca 12bh7a "grey plate" I also have on hand). I still really want to get my hands on a mullard long plate though as I suspect it would give the bugle boy a run for its money.
With respect to the speedball, I totally agree with Grainger's description. The sound is just a bit cleaner, tighter, and more detailed, particularly in the low end. I didn't notice any loss of warmth at all, but well recorded string bass sounds even better than it previously did - which is really sayin' something!
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hopeful ... that's good to hear about speedball, more reassurement (is that a word?). As far as tubes, I have a couple of Mullard short plates but no long plates either. I need to roll a short plate Mullard back in because I didnt spend too much time with them. But I think the Amperex is the ticket. But the GE 12AU7's I tried and also a some JAN 5814's werent far behind. Different but also pretty darn good.
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You might be due for an output cap upgrade. There is a thread going on now...John
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Mea culpa, mea maxima culpa!
Well, it turns out it *was* something I screwed up, but COMPLETELY un-related to the Crack and Speedball. Turns out, it was a computer change that just happened to take place at the same time as I was putting together the Speedball upgrade. In MacOS, there's aparrently several ways of getting data from a player to the audio output device. One of them is clearly labeled "More Magic" and the other is obviously labeled "Less Magic". Depending on the order of operations of how different programs access CoreAudio in order to do things like play sound effects, music, movies, etc, the audio pathway can be kicked into More or Less Magic. This explains my bipolar feelings about the setup overall; when I was sucked into listening and let it run for album after album, it happened to be in More Magic. At other times, when it was flat, harsh, and unlovable, and it just left me confused and depressed, it was in Less Magic. Tonight, I discovered a piece of software that will force the system into the More Magic pathway for the duration of listening to music and then return the computer to normal operation when I close iTunes. The result?
Wow... just... wow.
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A-ha! It is an Apple thing, the iFracked! Reminds me of the email I got yesterday mentioning an iPod aimed at young children the "iTouch Kids" which they decided against after reading it outloud. (just a joke)
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Ah, computers. Cant live with them, cant live without them and cant afford to replace them if you empty a 9mm magazine into them :-P
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So, what is this magic utility? Are you talking about HOG, or exclusive use mode? If you really want to kick it up, try the PureMusic player:
http://www.channld.com
Still uses your iTunes library and database, but PM intercepts the playback and sends it out a much higher quality playback engine than QuickTime, which is what itunes uses. The demo is free and runs for 15 days after install with no limitations.
There are also quite a few background process in OSX that you can turn off and that have a positive effect on playback quality.
-- Jim
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I'm using Bettersound now. No way I'm paying for PureMusic, Amarra, etc.
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I don't understand the purpose of the commercial playback software. I thought the whole goal was to just get your cpu to output bit-perfect and then to let your dac do its job. On the pc side, using foobar with kernel streaming, asio or wasapi are all equivalent mechanisms for getting this done so long as volume is left at max. Isn't there freeware for MAC that allows you to do the same?
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I just read a review of Decibel, $33, which was very complementary. It also has a free trial download.
I don't stream music... yet. So I can't really recommend it. I'm just throwing it out there.
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I don't understand the purpose of the commercial playback software. I thought the whole goal was to just get your cpu to output bit-perfect and then to let your dac do its job. On the pc side, using foobar with kernel streaming, asio or wasapi are all equivalent mechanisms for getting this done so long as volume is left at max. Isn't there freeware for MAC that allows you to do the same?
Sadly, it isn't that simple. Even a player that has bit-perfect output under some conditions can be screwed over by other things going on in the system. One of the biggest culprits is the "system mixer". There's a chunk of code that lets multiple programs all have access to the sound output device. In other words, it's the thing that handles you listening to music and then the computer needs to make an error beep while your email program is also saying "You've got mail!". So each application can provide sound to the system mixer, which has to decide what to do with one audio pathway that's giving it 24/192, one that's giving it 16/44.1, and one that's sending 8/22 and all of them are at different levels. So the things going on in your computer other than your music can have an effect on what your music sounds like.
So 3rd party player software is trying to come up with some combination of a decent user interface, bit-perfect decoding of the music, and getting the bit-stream all the way to the hardware output device without letting other programs screw it up.
As a note, "streaming music" does not mean simply playing music from your computer, to a DAC, and on to an audio system. Streaming music specifically means moving the audio that resides on Device A over a network (wired or wireless) to Device B in real time so that Device B can play the music even though it doesn't happen to have a copy of the file on hand.
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Hopeful,
Yes, there is much, much more to it than that, also including system noise, disc i/o, dac buss i/o and so on. Even in the windows world, there is and can be large differences between all the i/o protocols you mention, even between asio drivers. And the mac mini, even without any special tweaking is worlds ahad of a fully optimized windows machine. I know, I've donethis for quite a while now and had my little asus EEE box running xp home that had been stripped down using nLite, with both kernel streaming and the AQVox asio driver (talks directly to the usb hardware and bypasses the windows mixer altogether, and still, the mac mini running play.app -- a freebie from the same guy who wrote Decibel that Grainger just mentioned, easily clobbered the fully optimized windows machine.
Computer audio looks simple enough on the outside, but is vastly complex and can take quite a bit of "tuning" and optimizing to get the most out of. My mac mini with an SSD, 8 gb ram, the music files on a firewire external drive, and the mach2 music operating system overhaul, and this is easily the best transport I've had and can go toe to toe with, and even surpass some of the best transports/players out there.
That said, in second place, I'd go to a small, single board linux computer -- the PCEngines ALIX board, which has no video, keyboard, disc interfaces, etc., just a compact flash cad for the operating system and MPD software. You then pull your files off a NAS or another computer (mac, pc, or linux) in your home and on the network, and then use a client to control it. This is about the best price/performance digital transport out there as the alix board with case and power supply can be had for about $120, and the software is free. There are clients for all kinds of hosts -- netbooks or laptops, smart phhones, iPod Touch, iPad, and even one that uses nothing but a mouse.
I just yesterday got the last parts I need to build a super regulated linear psu for the alix and that should take it up another few notches, and who knows, may even give the fully tweaked mac a run for it's mney.
Yes, you can do as you say, just take a functioning windows machine (or mac for that matter) choose a player (I too used foobar for several years) and connect it to the dac and get music out, but when you've taken the time to find andoptimize everything between the computer, disc storage (file storage), and dac, the results can be nothing short of incredible.
The one thing I can upgrade about my mini is to put it on battery power and use a special firewire cable with no power leg, but that's a whole lot of money I don't have right now.
Sorry if this is not what you wanted to hear, but I've done this, one change at a time,and in all kinds of combinations and permutations and I promise that whatever you think of computer playback quality can be, well, it can be much, much more than that.
-- Jim
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Not knowing MAC stuff... Nothing like Foobar2000 available? It's free allows bit perfect out put to a DAC. I use it with Kernel Streaming and output via coax/ spdif. Really makes the crack /w speedball sing for me.
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I just read a review of Decibel, $33, which was very complementary. It also has a free trial download.
I don't stream music... yet. So I can't really recommend it. I'm just throwing it out there.
This is the program I have been using since it had a different name and was a free "beta" program. I like it very much and it is worth the $33 (I purchased it once it came out).
I have had some little issues and Stephen Booth, the programer, has corresponded personally with me several times to resolve them...you can't beat that kind of customer service (very similar to BH service, actually). I connect my Mac via an optical to the DAC which limits the sample rate to 96K, but it converts the higher sample rate files automatically (I am waiting for the Bottlehead DAC to move to USB due to a variety of reasons including that I am using my Macbook Pro and use a long optical cable so I can operate it directly from my couch. Once I have the BH DAC, then I will set up a dedicated Mac Mini).
The up side is it is a high quality player that can handle up to 24 bit/192K sample rates, play in HOG mode (loads songs into RAM), and has an "exclusive access to audio" toggle that keeps other programs from accessing the audio stream. I tried this out and it does work: I can load iTunes and try to play a song but no sound comes out until I quit Decibel and then iTunes can play audio. It sounds very nice through my DAC and Bottlehead Stereomour/Hawthorne Audio speakers....much nicer than my Squeezebox Touch, which is no slouch and sounds very good on it's own. It just can't touch the Decibel/DAC combination for clarity and dynamics. It can play songs from your iTunes program, as well as your high resolution audio files from HDTracks, Linn Records, etc. It manages the sample rates for you, so you can create and save playlists that combine 16/44.1K files, 24/96K files, and 24/192K files, for example.
The down side is that the interface hasn't been as developed as the MUCH more expensive programs, so it is a bit simple which I don't mind at all. By simple, I mean you load your songs and can do most anything you want but you don't have a fancy interface like iTunes. What I find is that I like to load either a single album or a saved playlist (which I often make by genre, such as classic rock, and then play back in scramble mode so each time I listen it is a bit different). I really prefer the simple interface for serious listening...I just don't use Decibel the same way I use iTunes (which I still use for my iPods). In a way, it is similar to loading a record in that complex isn't needed, if that makes sense. I have also had a bit of trouble with one version crashing but Stephen Booth worked with me directly and released an updated version that addressed my issues. He actually sent me iterative versions via a FTP site where he made tweaks and I tested until my problems were solved, then he released it as a mid-version update for all users.
All I can emphasize here is that over speakers, the audio quality is superior to iTunes and Squeezebox so I can only imagine how much better it would be via headphones. For $33 it is hard to not try it out, in my opinion. I am all about quality and value, which is why I have a Bottlehead Stereomour, Hawthorne Audio speakers, and homemade room treatments: I believe you can get superior audio quality affordably if you are smart about your purchases, take the time to educate yourself well, and are willing to do a bit of DIY.
John
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As for free players for the Mac, I did mention one called "Play" and is totally free and is by the same guy -- Steven Booth -- that John mentioned. Then there is audirvana, (which I believe is free), Fidelia, which is fairly low cost, decibel (also low cost) and others as well, but these are the most full featured, highest quality apps. Also as John said, the interfaces aren't as developed as iTunes, foobar, etc. in that they don't have a fullly featured library for managing your collection, but typically work by pointing to a playlist r directory of selected tunes. If you try to point to your full library it will take a long time to loadd and will become very slow to respond, and it will do this every time you launch the program --- or so it was with the earlier version of Cecibel. So, you'd still use iTunes for managing your library, making play lists, etc. and then decibel or one of the others to play them. I do believe most of these programs are working on a more ro bust and full-feaured library manager, but that could be a way off yet.
I personally am sticking with PureMusic as the author is also very responsive to feature requests and such, and because it can play flac files, and now it can also play SACD DSD files directly, but above all, has incredible sound quality, and a superb dithered volume control and sample rate conversion algorithms, which I make use of as my reference dac is only 16/44.1/48.
Anyway, there's always more to learn in this pursuit, and the terrain changes all the time -- sometimes for better, sometimes not.
For me the bottom line is that I'm getting the best playback quality I've ever had and I don't intend to go back. My best system has a single source and I don't feel any need for adding any more complexity to it.
-- Jim
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I would caution everyone about declaring PC superior to Mac or vice versa. I am with Jim that for a cost effective home system a Mac is very hard to beat, and a Mini with Snow Leopard and Amarra running optical to our DAC is what we are now using at Bottleheadquarters. Compared to an Acer Aspire One into an EMU 0404 USB with a LCLC power supply, optical into our DAC, running Reaper (much better sounding software than Foobar, BTW), the Mac/Amarra is better sounding, more stable and MUCH easier to use with its iTunes interface. But if you haven't heard the PC based Pyramix setup with a Mykerinos card I don't think it is fair to make a judgment about the limits of PC based audio. I'm not saying this a practical setup in the average home (nor is Reaper), just that PC based digital audio can sound every bit as good as Mac based - with enough time and money spent.
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Also consider Vortexbox, at .org. Its free and can allow you to recycle an old PC into a dedicated, Linux based music server. I think the dedicated is key. I have not been able to compare it to a high zoot Apple based setup but it is tons better then when I was trying to run iTunes or Foobar on my general purpose PC.
Very easy to set and use as well...John
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....
Sorry if this is not what you wanted to hear, but I've done this, one change at a time,and in all kinds of combinations and permutations and I promise that whatever you think of computer playback quality can be, well, it can be much, much more than that.
-- Jim
Jim - I appreciate the gracious explanation. I know my current setup at least has me bypassing the K-mixer. Windows 7 also allows you to lock the audio stream so it isn't interrupted by any other programs/processes. However, there's clearly a huge amount of info out there for me to learn about this topic. I don't suppose there are any sites/articles you could recommend to get me started? Thanks!
I'm drowning at work right now, but per Doc's comment, when I've got a little time on my hands, I'll have to give the free trial of Reaper a go to see if I can hear any difference, subject to the limitations of the rest of my rig.