tschrama's Recent Activity

  1. tschrama liked JP2036's post in the thread '73 Superlead to Plexi Mod?.

    Don't touch that amp.

    May 18, 2021 at 4:07 AM
  2. tschrama liked Obi Plexi-nobi's post in the thread David Gilmour.

    [ATTACH]

    Pink Floyd Dadj.jpg May 18, 2021 at 4:00 AM
  3. tschrama liked Pete Farrington's post in the thread PPIMV installed now it’s squealing.

    Master volume control in close proximity to an input? That’s what’s known as a bass ackwards layout ;) Maybe if you keep hammering...

    May 17, 2021 at 4:43 PM
  4. tschrama liked neikeel's post in the thread PPIMV installed now it’s squealing.

    Don’t put ppimv there unless you use shielded wire You are taking output signal right across your preamp and back again Move the pot...

    May 17, 2021 at 4:42 PM
  5. tschrama liked Matthews Guitars's post in the thread I purchased a ’69 plexi (pray for me).

    A few comments... The blue label IC caps are just fine. Let them stay as long as they're doing their job. They're not bad capacitors....

    May 17, 2021 at 9:46 AM
  6. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Bandwidth has nothing to do with an input signal. It is the bandwidth of the measurering device with which you measure your noise, e.g....

    May 15, 2021 at 8:23 AM
  7. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Noise level quoted in RMS without quoted bandwidth are meaningless. In theory noise can infinite large at infinite bandwidth. It seems...

    May 15, 2021 at 3:47 AM
  8. tschrama liked Matthews Guitars's post in the thread Looking for your opinion on DC regulated HT.

    I wouldn't bother with DC filaments because properly done AC filaments are noiseless. I don't believe in smoke and mirrors and magic....

    May 15, 2021 at 3:44 AM
  9. tschrama liked c_tecks's post in the thread Celestion Neo V-Type demonstration.

    Yes I've done the Neo Creamback a while ago, the exact same thing so you can A/B compare them: [MEDIA] I think both the Neo V-Type and...

    May 14, 2021 at 7:52 AM
  10. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    An typical 10k pickup will have about 1uV rms noise integrated over 5 kHz. Other people report 0.8uV rms EIN noise over 8kHz for a 12ax7...

    May 14, 2021 at 3:49 AM
  11. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Oh, that leads me to realize that eventually that practical noise limit will be dominated by guitar pickup Real resistance.

    May 14, 2021 at 3:29 AM
  12. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Using a relative high bias point, 1.5mA or higher, a low cathode resistor, say about 680R and a relative low anode load , say 68k, will...

    May 14, 2021 at 3:14 AM
  13. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Even with AC heaters, using tidy lead dress, I am able to hear the fundamental noise of the 12AX7 in my builds.

    May 14, 2021 at 3:02 AM
  14. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Are you talking about 100Hz ripple? That is not noise. Noise is random and it seems you have done all you can do to reduce it. A 12AX7...

    May 14, 2021 at 2:55 AM
  15. tschrama replied to the thread Looking for your opinion on DC regulated HT.

    Hiss has nothing to do with regulated HT, you minimize hiss but optimizing the EIN of the first stage.

    May 13, 2021 at 6:22 PM