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  1. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    Somebody sent me a pair of Telefunken, which I am using now. Great detail with super wide soundstage. Not too different from the Mullard 7189. Swapped out a Grado Opus3 for my worn Dynavector, so bass is really filled out. Going to try a re-tip of my Dyna with an Ogura 3/30 line contact...
  2. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    Those vents are not needed for cooling. Mostly decorative. I designed the chassis such that I can re-use it for other products, in which case a future amplifier might just require that extra cooling. Next up is a matching phonostage... :)
  3. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    Yes, I did this on purpose. I do NOT want to be fabricating all these wood panels by hand. That's not my thing. You can probably do a better job. Just buy 2 feet of 1x4 (standard North American size) of your favorite tree. Cut to 10.5" each. Sand like crazy. Use #6 wood screws to attach...
  4. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    That's a bit sloppy, and ends up lowering heater voltage by the same percentage. Try to keep it within 5% or better.
  5. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    No, it was a last minute addition, sort of sloppy implementation. Sound is better and more pure without.
  6. Jim Hagerman

    Burson Fun - buzzing noise that stops when I put my hand on the amp

    Sounds like a missing ground (Earth) connection.
  7. Jim Hagerman

    which amp for Audeze LCD 3? from beginner!

    This should drive LCD3 just fine:
  8. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    Matching sets of NOS EL84 tubes today and ran across this pair of Mullards (made in Great Britain, 1975?) that were so perfectly identical their overlapping curves looked like one set...
  9. Jim Hagerman

    Hagerman Audio Labs "Tuba"
  10. Jim Hagerman

    Do I need a headphone amplifier for a HD600?

    Yes, your Behringer should work just fine with those cans.
  11. Jim Hagerman

    Hagerman Audio Labs "Tuba"

    To be frank, I really haven't sold that many units yet, so this won't be a very active thread for awhile. Some of the comments I've received from users so far: "I continue to marvel at what a great sounding headphone amp this is. You can listen to it for hours on end without any listener...
  12. Jim Hagerman

    I bought my first tube amp! The smsl T2...

    This is not really a tube amp per-se, as all the work is being done by NE5532 opamps, so you may not get significant audible changes swapping tubes. They are in there mostly for show.
  13. Jim Hagerman

    Comment by 'Jim Hagerman' in article 'Beyerdynamic DT-770 Pro 32Ω bass reduction mod'

    Impedance and SPL are two different things. With a resistive drive (OTL), the first thing to go is bass.
  14. Jim Hagerman

    Eufonika (Valve amps from Poland)

    Nice! I almost used the 6080 too (but instead chose a pair of EL84). It's a great tube for low output impedance. jh
  15. Jim Hagerman

    Comment by 'Jim Hagerman' in article 'Beyerdynamic DT-770 Pro 32Ω bass reduction mod'

    How about putting some series resistance in the amplifier output (or in cable)? I would start with 32 ohms. That should drop the bottom end a bit.
  16. Jim Hagerman

    Planar headphones with 'v shaped' sound signature?

    I need to get out and try a bunch of these other headphones. My Sundara sound quite meaty and full to me, especially compared to HD600. Maybe it depends on the type of amplification?
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