1. Bottlehead Crack OTL Headphone amp

    Greetings once again!

    So for Christmas I got another kit that I’d been wanting. Christmas Eve the UPS guy shows up with my Crack kit from Bottlehead. Woo! I could hardly believe it showed up before Christmas.

    The photo is the finished article. Bottlehead has been around for quite some time, I’d been following them for a while since before I came to Ohio. They sell tube based kits as well as finished equipment but beyond that they also have a stellar reputation for their gear to sound absolutely amazing, well I’m here to tell you that this kit does not fail to deliver.

    Where I find the patience for some of this I’ll never know, it took me 2 days to paint the top plate and end bell on the transformer and I still wasn’t happy with it but oh well I’m not going to sand it down and paint it again. It looks good enough for me. After laying out the chassis I began soldering “by the numbers” basically.

    The kit comes with a CDROM that contains a .pdf of the instruction manual. I’ve never put together a kit that came with better thought out instructions than this one. They are clear and lead you through the entire process. If you can read and understand basic kit building terminology anybody with basic soldering skills can build this kit. Here’s the best part, even if you don’t, but can read and I mean read everything, Doc gives basic soldering instructions in the manual. So like one of the guys on the forum said, “go to Radio Shack, pick up a few terminal strips and a grab bag of cheap resisters or similar and get some soldering experience in, for the cost of some cheap parts you can learn to solder in about 30 minutes.”

    Well I’ve been slinging solder for a while so I skipped through that and got right to building my kit. Here is the naked laid out plate, and the finished view.

    and since I took my sweet time on this build, I was not going to mess it up, I wanted it to sound as good as possible so, slow and steady was the theme and boy did it pay off. Two 4 hour sessions later…viola!

    I have learned several things from all the different builds that I’ve done.

    1. you don’t have to use so much solder that you close the terminal holes, a good joint only requires enough solder to join the wire/part to the terminal, make sure the joint is hot enough and the solder will just flow. Only use enough to get the job done, if you have to go back later and add something you missed or move a part, removing all that solder can be a huge pain.

    2. neatness counts, heaven forbid you have to go back and work on it or troubleshoot a problem like hum or no sound from one channel. If your work isn’t neat and tidy well it’s going to be that much harder tracing the circuit out and tracking down your problem. Plus, when your buddy asks to see the underside of the chassis you want to be able to show it to him without having to explain that yes you put it together and not your 4yr old. :P The other aspect with regards to neatness is that routing of wires and such can help keeping noise out of the circuit, or like in the Crack, the two large resisters that look like big white logs in the middle of the plate dissipate a lot of heat, any wires routed near them could be burned or at least have the insulation melted from the wire if they’re too close. So be mindful of what’s touching what when you build something like this.

    So at this point I have well over 50 hours on my amp, I’ve settled on the tubes that will reside in it for the time being. I was lucky enough to purchase an extra 6080 power tube and several 12au7 variants. Currently the power tube is a PN JAN 6080WC, Bottlehead included a very nice Sylvania GB6080 but after running the amp in for about 8hrs I noticed that something was generating a high pitched tone and I couldn’t figure out what the heck was going on, well the Sylvania is either faulty or microphonic, but swapping it out for the NOS JAN 6080WC the amp is dead silent now. I had tried a CONN branded 12au7, the included and very nice Elecro~Harmonix 12au7/ECC82, a Pinnacle Audio 12au7, and currently my favorite a GE 5 star 5814a.

    I’m listening to some of my favorite vinyl right now, currently spinning is Masterpieces by Ellington, the sound is very detailed. This sure separates the good from the bad, you can hear EVERYTHING! LP’s that I had previously enjoyed quite a lot, have surface imperfections that I just hadn’t been able to hear before now. Well this amp sounds simply amazing. No apologies! I’d rather be able to hear every little thing than not.

    I played Mingus Ah Um earlier and WOW! That one is a 180g reissue and sounds amazing. Ok before I go much further what am I actually listening with? Ahh headphones! Well as luck would have it my wife also got me for Christmas a pair of Audio-Technica ATH-ANC7b headphones :D These are fantastic cans. They are noise canceling and do a great job of making me feel like I’m in a sound proof room all by my self listening to music. The Crack amp was designed with higher impedance cans in mind and the AT’s are 300 ohm so I’m in good shape!

    Ok so I have Crack and new headphones and an obvious addiction but the only cure is probably to listen to more music ;) The music through these things is VERY lifelike, the sound stage is wide and dynamic. Natural is probably the best single word I could use to describe the whole experience. Doesn’t seem to matter if I’m playing a CD from my laptop, MP3’s from my player, or spinning a LP, at least with recordings of high quality, the music sounds natural. I have a couple live performances and if I close my eyes it’s not a stretch to imagine being there. I’ve had several experiences where detail I hadn’t heard or noticed before startled me because I didn’t realize it was from the recording and not something going on around me.

    I love this amp, cost of admission is $220 plus shipping, add to that a day or three of your time for assembly and you’ve got yourself one serious performer. Bottlehead has a very active DIY community, lots of help on their forums, plus lots of other kits to feed your habit! If you’re looking for a first kit, or even just something new, give them a very serious look, you will not regret it.

    I’m going to go flip my record and listen to my Crack some more ;) have a good one!

     

    tags:  Bottlehead  tube audio  OTL Headphone amp  Crack  Crack amp  music  DIY audio  DIY Hifi  Bottlehead Crack OTL Headphone amp  Audio-Technica  ATH-ANC7b 

  2. ZSP1 Completed

    Well I got a case made for it today my woodworking skills not withstanding… It will do the trick but I’m not totally satisfied with it, I might need to build a few other things to brush up on my woodworking.

    Aside from all that it sounds fabulous, and since the case is just to keep the critters and such from getting at the high voltage and having a really bad day… mission accomplished! :)

    Here’s a picture of the finished article.

     

    tags:  ZSP1  Decware  Decware ZSP1  ZSP1 Preamp  DIY Audio 

  3. In pursuit of audio nirvanna

    DIY audio has long been a hobby of mine, sometimes I’m quite obsessive about it. I’ve built to date 3 amplifiers, 1 push pull and 2 SET amps, one stereo and one mono. I also have 1 preamp and 1 phono stage under my belt. I currently have supplies to build another pair of SET mono blocks as well as another preamp. The preamp is a kit from Decware the ZSP1, I’m actually quite excited to get started on that one.

    In any event this post today is regarding my very first from scratch DIY preamp that I built ala DIY Paradise Yeo the owner of the site has a project called the “Simple 5687” and simple it is, but the sound… fantastic.

    Anyhow, this was also my second HiFi DIY project and honestly I had a lot to learn yet, I still have a lot to learn but that’s besides the point. I did a lot wrong with this preamp, in spite of myself and my newb-ness it DID sound really good but it hummed a good bit and I was never able to get rid of it. Well I recently decided that I would endeavor to resolve the hum issues. 

    I started by replacing the ancient power transformer. I purchased it as a NOS item, the seller swore to me it was unused, just old stock, granted it was older than I was but still. Anyhow, in a couple recent projects of mine I used nice toroid transformers that I purchased from Antek, these guys make very affordable high quality toroids. In fact, the one I used in a recent phono preamp is dead silent and I mean absolutely quiet.

    Anyhow I thought what a perfect idea, I’ll get a 200va toroid for my old preamp and replace the old transformer with a new one. That should eliminate the hum and the angels will sing and you know, it will be cool and stuff :D  Well, it was a great idea but didn’t work out quite like I’d hoped. The new toroid doesn’t hum physically but the circuit actually sounded worse! :( much gnashing of teeth followed with this discovery.

    So I looked over my wiring, everything checks out, voltages are all within spec. I can’t figure out what the deal is. Well I noticed quite a few issues with my original work that I tried to rectify like some of my grounding was potentially creating ground loops = bad. I resolved those issues and still humming like a crazy person. I swapped out my 5687 tube for a different one. I have 5 of these guys because I’m crazy like that lol. Anyhow, I have a nice gold label Sylvania with gold pins, I put that in vs. the Tung Sol and that improved the hum substantially but it was still not gone.

    So we chalk some of the hum down to microphonic preamp tube, but we still have a substantial amount of hum, and it actually sounds like the 5687 is whistling, it comes and goes, I have no idea what’s going on. So I start scouring the internet for tube heads like myself who have tackled this sort of thing before. How to tame hum when using AC heaters.

    I found lots of stuff out there, lots of people who had the problem, and not so many who knew or thought they knew how to cure it. The trouble is finding someone who has taken the time to put it down in words that make sense to “the masses” and then actually show you possible solutions. As luck and or fate would have it, I found one such site! Here is a link to the article that saved the day for me the Valve Wizard

    So the article talks about toroids and heaters that are not center tapped, well that’s me. He recommened creating a virtual ground by running a 100ohm resister off each leg of the heater wires to ground.

    Well I did just that and holy smokes! (well not any actual smoke thank goodness!) Ding Dong the Hum is gone!! I reconnected everything and with the volume on my amp at about 35% and the volume on my preamp at about 50% with my ear right next to the speaker I can hear 60hz hum but only just. If I step back and away, it’s dead silent!!

    I just finished listening to one of the several new Duke Ellington LP’s that I got, as well as Bryan Ferry’s Bete Noire and all I have to say is… will someone please pick my jaw up off the floor for me! I don’t think I’ve heard my system sound quite so detailed, it has such a black background now, during low volume passages there is just nothing there, no extra anything else to give it away.

    I’m tickled to death with the results, I think I’m going to have to put Scheherazade on tomorrow evening and give it another listen! At this point I would even bet that I could fool my friends into thinking they were listening to a CD player ;) at least with some of my very clean LP’s that don’t have any clicks or pops in them.

     

    tags:  DIY preamp  The Valve Wizard  DIYParadise  DIY Audio  Duke Ellington  Bryan Ferry  Simple 5687 

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In hot pursuit of my inner monkey! Let there be Shenanigans!

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