Bottlehead Crack

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by OJneg, Oct 3, 2015.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,051
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Just got my repaired Crack + SB back from @fishski13. He did a great job and really took care of me on this! Not only did he fix things up for me, he added a PSU choke and swapped out the 100uf Solen caps for some 68uf Jantzen Crosscaps. It also has a Goldpoint stepped attenuator in it, which it was pre-modded with.

    I had a rebranded Tung Sol 5998 waiting for it, which I got while the amp was being repaired. Anyone heard of a Sylvania 421A? I can't find anything on it, but it looks like just a Tung Sol 5998, and the eBay seller listed it as a rebrand.

    Anyway, the 5998/421A paired with a 6SN7 RCA (40s, VT231, opaque grey glass) sounds really damn good! Nice contrast to the Super 7. Yeah, OK, the Super 7 is still quieter, cleaner, faster, more resolving, larger, etc. etc., but the Crack + SB + mods + these tubes just has this really sweet, full, dynamic, engaging sound. Enough so that I popped those tubes in for a quick check and ended up listening way longer than intended.

    So, yeah, big thanks to fishski for the repairs. Really digging the amp!
     
    • Like / Agree Like / Agree x 3
    • List
  2. Shaffer

    Shaffer Acquaintance

    Banned
    Joined:
    Nov 5, 2015
    Likes Received:
    41
    Trophy Points:
    28
    Location:
    NYS
    Please forgive me for intruding. I quoted this tube as an example of how tricky this game can be. It's not a RCA; it's a GE. Take a flashlight and shine it on the envelope. You'll see the dots. As a rule of thumb, if the product brand and type is not printed on the metal base, it's not a RCA 6080.

    RCA made 6 versions of the 6080 (H1-H6) not counting the CRC models, some of which are slightly different. There's a sonic difference, as well. In a perfect world, I could hand you a white dot (ie. selected) RCA 6080WA and not only will it be physically smaller than the tube above, but its resolution and transparency truly set it apart. There's a bit more to it....

    Very interesting read. Thank you and good luck.

    Edit: Forgot to mention that the GE you reviewed is a 5-star, which was their premium line. Like you, I don't feel like this 6080 is that great, but I digress. The RCA is not the same as the 5-star, rather it's the "regular" GE 6080. Hope that made sense.
     
    • Like / Agree Like / Agree x 1
    • List
    Last edited: Dec 3, 2015
  3. Tyll Hertsens

    Tyll Hertsens Grandpappy of the hobby - Special Friend

    Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    2,828
    Trophy Points:
    93
    Location:
    Bozeman Montana
    Home Page:
    Wow. What a great thread. Maybe I should do the Speedball upgrade (finally) on mine and post it up. It really is a great amp.
     
    • Like / Agree Like / Agree x 5
    • List
  4. Jeb

    Jeb Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    439
    Trophy Points:
    63
    Location:
    Bristol, UK
    Indeed - any tube reviews are always of limited use due to all the variables involved and should probably be treated with extreme caution. Also Im sure there are many variations amongst the Dutch Philips/Amperex tubes throughout the years. Power tube matching is v.important as you say - I just used the GEC 6AS7/A1834 in this instance due to its above-average all-round performance, even though it isn't my favourite tube.


    Thanks Shaffer - Good catch. I did not realise there were GEs with the shields above the top mica. I'm away from my tubes at the moment so will check that out tomorrow and look for GE dots with a light. So true about the pitfalls of making sweeping statements . I try and include pics so that my impressions are tied to the actual example have in front of me. I will update my previous info tomorrow.
     
    • Like / Agree Like / Agree x 1
    • List
  5. velvetx

    velvetx Gear Master West/Vendor Spotlight Moderator

    Staff Member Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    1,098
    Trophy Points:
    113
    Location:
    Bay Area, CA
    Do me a huge favor and do a video on the speed ball upgrade :)

    Sorry I am not DIY literate and it would be great to be able to follow your melodious voice into dreamland while I work on getting the build perfect :) . All jokes aside please do.
     
  6. Shaffer

    Shaffer Acquaintance

    Banned
    Joined:
    Nov 5, 2015
    Likes Received:
    41
    Trophy Points:
    28
    Location:
    NYS
    [​IMG]

    OK, I confess, got a tripod a couple of weeks ago and can't stop playing with it.

    Jeb, as it happens, I have the same tube. Three, actually. A single and a matching pair. Stop by the tube rolling thread, if you like. We'd love to have a Crack owner aboard.
     
  7. Dr. Higgs

    Dr. Higgs Boson - Member

    Friend
    Joined:
    Oct 4, 2015
    Likes Received:
    793
    Trophy Points:
    93
    Location:
    Roswell, GA
    I never played around with modding or tube rolling too much, but I have many fond memories of my Crack. My first "real" headphone setup after graduating from the O2+ODAC was a GO450>BH Crack (w/ Speedball, Svetlana Winged C, RCA Clear Top)>DT880/HD600 so I think I'll always have a sentimental attachment to it. It's great to see Tyll posting in here because his video/article was my main inspiration behind building it in the first place!

    I think the experience of building it was worth the price alone, and it had been happily residing on my desk up until I built a Torpedo III last weekend.

    [​IMG]
     
    • Like / Agree Like / Agree x 6
    • List
  8. Jeb

    Jeb Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    439
    Trophy Points:
    63
    Location:
    Bristol, UK
    Agree 100% - I was pretty nervous about undertaking the build and Tyll's video was hugely helpful in showing the basics of soldering. Along with all the great people over at the Bottlehead forum and here, it's a great amp to build - not just for the sound but for the all round experience and community too.

    Doc B and the crew are awesome too.
     
    • Like / Agree Like / Agree x 1
    • List
  9. dubiousmike

    dubiousmike Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    224
    Trophy Points:
    43
    Location:
    Los Angeles
    I wish I could echo Hands, but I have had back luck with 6sn7 adapters. Purchased two from different ebay sellers (one from Lowther and one random), and both introduced very audible noise with hd800's that isn't there with any of my many 12au7's, 12bh7's or e80cc's. One adapter was much worse than the other, and the issue wasn't nearly as noticeable with my hd650's, but I decided to stop throwing good money after bad and they have been sitting in my closet ever since. Another regular on the bottlehead boards (Adam, the guy with the insane cap mods), reportedly tried three different adapters with the same result.

    Particularly given the way the adapters have to be wired (signal and power criss-crossing in the small housing), PB on bottlehead has suggested that 6sn7's may run best with DC on the heaters, rather than the AC the crack feeds them, and that a battery mod might be appropriate for those who want to maximize their amps to run these tubes. Then again, various other listeners have reported that they have no issue with their adapters. Wish I was one of them. Caveat emptor.
     
  10. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,051
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    FWIW, I got my adapter from Garage1217. One thing I didn't mention is that while the Crack + SB + mods + 5998 equivalent + 6sn7 sounded great, there was this sort of ringing and glare to the sound even with nothing playing. Some hum with the volume cranked. Turned out to be the 6sn7, but I'm not sure if it's the adapter or tube. Running a GE 5814 of some sort right now, and it is good. Got some cheap 12bh7s on the way just to have something to roll. Haven't checked other 6sn7 tubes yet because I'm lazy.

    Still sounds great. I'm not sure if it's the choke, the new caps, the general repairs and cleanup, or the 5998 tube (or all of the above), but the amp as it is right now is a big step up from what I originally sent to fishski.
     
  11. fishski13

    fishski13 Friend

    Friend
    Joined:
    Sep 25, 2015
    Likes Received:
    393
    Trophy Points:
    63
    Location:
    Twin Cities, MN
    the sticker on the Crack TX says heaters 6.3V/3A. a 6sn7 requires 2x the heater current at 0.6A vs the stock 12au7 at 0.3A, putting it at the speced limit or a little over in conjunction with an output tube like the 6080 or 5998 which require 2.5A. while EI TXs saturate more gracefully than toroids, the noise could still be coupled electromagnetic crap?
     
    • Like / Agree Like / Agree x 1
    • List
  12. gurubhai

    gurubhai Friend

    Friend
    Joined:
    Sep 25, 2015
    Likes Received:
    283
    Trophy Points:
    63
    Location:
    India
    ^Possible, although RCA 6SN7 are known to be a bit noisy and its quite possible that its the tube itself. Anyways, it should be clear when Hands gets his hands on 12BH7 he ordered. It requires 0.6A at 6.3V like the 6SN7 and should have similar issues if the above assumption was true.

    P.S. I quite like the 12BH7, it was one of my favorite tubes along with the Telefunkens in the 12au7/6as7 OTL I did a while back.
     
    • Like / Agree Like / Agree x 1
    • List
  13. Jeb

    Jeb Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    439
    Trophy Points:
    63
    Location:
    Bristol, UK
    I've used a couple of adapters - one is the ceramic Garage 1217 adapter that Hands mentioned. The other is one made by Glenn. The downside of the Garage 1217 is that since it's designed for the sunken sockets in their own amps, when used in the Crack the edges of the connections to the board are exposed so it needs some DIY insulation.

    The Glenn adapter is fully insulated & nicely built. Downsides are its large size (with the tube it's as big as a 6AS7) and it cost twice as much. Plus Glenn is a busy man, although he seems to have a decent turn around time on adapters

    Both are totally quiet and hum-free with the one 6SN7 I currently have.

    [​IMG]
     
    • Like / Agree Like / Agree x 1
    • List
  14. dubiousmike

    dubiousmike Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    224
    Trophy Points:
    43
    Location:
    Los Angeles
    I have been running 12bh7's paired with 5998's regularly in my crack for years and can confirm that all of mine run nice and quiet - so maybe that rules out the .6A concern? A 1950's tung sol 12bh7 is one of my very favorite input tubes.

    My money is still on the adapter as the source of the noise - but maybe I'm just unlucky and jaded by my frustrations with the two I have. Sounds like Hands' is a lot better than mine but maybe still imperfect, and I am totally jealous of Jeb. Let us know how you like those 12bh7's when they arrive and time permits Hands!

    In the meanwhile, I figured I would also share a few quick impressions re some of the 12au variants I have:

    RCA clear top 12au7 - readily available, cheap and nice sounding with hd650's but presents too much treble energy to be enjoyable with hd800s.

    Amperex Bugleboy 12au7 - pricier, much warmer tonality with a slightly rolled top end. Far better than a clear top with hd800's to my ears, but not amazing/a little dull with hd650's.

    NOS Tung Sol 12au7 (not to be confused with the newly manufactured Tung Sols) - nice neutral sounding tube, good all arounder, cheap and abundant. Every crack owner should pick one up cheap on ebay just because.

    Mullard shield "short plate" 12au7 - cool little flash when the tube comes on, good bass, but more treble energy than the Bugleboy or Tung Sol. Not ideal (for me) with hd800's but good with hd650's.
     
    • Like / Agree Like / Agree x 2
    • List
  15. ohshitgorillas

    ohshitgorillas Friend

    Friend
    Joined:
    Nov 27, 2015
    Likes Received:
    509
    Trophy Points:
    93
    Location:
    Sacramento, CA
    I'm having a weird issue with my Crack that I'm only now noticing that I don't think deserves its own thread. My external monitor goes black for a second whenever I do any of the following:
    • plug the Crack into my DAC
    • plug my DAC into my computer (USB), with the Crack plugged in
    • plug in the Crack to mains power, with the Crack plugged into my DAC plugged into my computer
    This doesn't happen when I unplug, just plug in. Any thoughts? PS it may be worth noting that my apartment doesn't actually have an earth ground?
     
  16. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,051
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Tried two other 6SN7 tubes in the Crack, including another grey glass RCA, and no noise issues or otherwise. Must just be that particular RCA 6SN7, which doesn't give me issues in the Super 7.
     
  17. gurubhai

    gurubhai Friend

    Friend
    Joined:
    Sep 25, 2015
    Likes Received:
    283
    Trophy Points:
    63
    Location:
    India
    Just finished checking up on Jeb's 6080/6AS7 review, excellent work !
    I have tried most of the tubes mentioned in the review except for the 5998 and Tungsol 6080WA and would like to share my thoughts on these tubes. I usually don't bother with a comprehensive comparison and would just roll in a tube and see if I would find the tube 'engaging' (depending on dynamics, resolution, plankton etc) enough and then only would I proceed for a detailed comparison.

    Tubes that I didn't care much for :

    GE 6080
    GE 5 star 6080WA
    GE 6AS7
    GE 6AS7GA
    RCA 6080
    JAN CRC 6080 WA
    RCA 6AS7 grey plate
    JAN CRC 6AS7

    Tubes worth a second look:

    Tungsol/ Chatham 6AS7 : Nice, clean sounding tube with great soundstage and balance. It is reasonably fast sounding and has good macrodynamics. I enjoyed this one initially but after some time I noticed that it was missing out in some important details- for ex. the string decay was shortened, it lacked air and the environmental cues went missing. I can understand people enjoying it with a thicker sounding headphone like HD650 but it really wasn't a good match for my headphones.

    6H13c Winged C 1972 : really like this one, great resolution and dynamics. If I am nitpicking, its a little lean and grainy sounding compared to the better tubes but for the price they go for, no complaints.

    Bendix 6080wgb : Like Jeb said it takes a while for these to warm up before they sound any good.
    'Solid plate' : Great soundstage and a very smooth sounding tube but thick and slow even after warmup.
    'Slotted plate' : Like above but faster and more dynamic than above. Good resolution as well but unfortunately I find the timbre of instruments a bit off with this, could have been a great tube other wise.

    CSF 6080WA (france) : Very lively and engaging, great treble extension and good resolution. A bit rough sounding in the upper registers but otherwise excellent.


    Tubes I really like
    :

    These are the most resolving of this bunch, with excellent microdynamics and macrodynamics and are usually my go-to tubes:

    Mullard 6080 / Philips ECC230 :Very refined and smooth sounding. This one is a slightly rolled off up top which probably adds to its smoothness. Recommended for people who want a fatigue free experience along with good technicalities.

    GEC 6AS7 : probably the most resolving of the bunch slightly edging out the 6080 version . Unfortunately, it has a slight glare in lower treble and doesn't posses the air of the GEC 6080.

    GEC 6080 : Almost perfect and my favorite of this bunch.
     
    • Like / Agree Like / Agree x 5
    • List
  18. CEE TEE

    CEE TEE Free Agent

    Staff Member Friend IEMW
    Joined:
    Sep 25, 2015
    Likes Received:
    1,768
    Trophy Points:
    93
    Location:
    California Bay Area (San Francisco)
    Time for me to get a few Crack tubes!!!
     
    • Like / Agree Like / Agree x 2
    • List
  19. ohshitgorillas

    ohshitgorillas Friend

    Friend
    Joined:
    Nov 27, 2015
    Likes Received:
    509
    Trophy Points:
    93
    Location:
    Sacramento, CA
    I picked up a Tung-Sol 6080 the other day on eBay based off of recommendations from this thread. Unfortunately it turned out to be super microphonic and noisy, especially in the right channel, so I got a refund and picked up another. Before it decided to go to shit, it sounded really really good... sweet and clear. Excited to get a working one in the mail.

    As for 12AU7, I've got an RCA Clear Top, Genalex Gold Lion, and a Hewlett-Packard labeled Amperex ("made in Holland'). I go back and forth between whether I like the RCA or Amperex better; the Amperex is sweeter, smoother and more forgiving, whereas the RCA is more resolving and has a more natural tonal quality to it.

    Right now my favorite combo is the Winged C and RCA Clear Top, listening with the HD600. Listening to Amputechture at the moment and it sounds awesome.
     
    • Like / Agree Like / Agree x 1
    • List
  20. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,051
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Got my first 12BH7 tube in today. I'm pretty sure, but not absolutely certain, this is an RCA, black long plate, dimpled square getter. It is missing all but the 12BH7A logo. Got it for real cheap because of this. I think I like this more than the opaque grey glass RCA 6SN7 (VT231). Similarly lush, warm tone, but with less of an upper mid bite and glare. Smoother and more natural, in a good way.

    It's funny, because it sounds a bit tubby down low, is a bit rolled up top, and isn't the most resolving tube I've heard, yet still somehow sounds clear, detailed, and is really dynamic. Detailed without being detailed, or forthcoming about being detailed? Weird. Also has a smaller, less airy, less layered stage. Very upfront and almost gripping. Really odd mix of traits but somehow ends up being really fun to listen to. Well, fun for me at least.

    Oh, no hint of noise or other funny business on this one.
     
    • Like / Agree Like / Agree x 1
    • List

Share This Page