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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

Tube Rolling the Monoprice 5W (Bendix, RCA, Blackglass...)

Discussion in 'Glowing Bottle Tube Amp Forum' started by bpr103, May 5, 2017.

Which tube do you like best?

  1. Tube 1

    2 vote(s)
    13.3%
  2. Tube 2

    1 vote(s)
    6.7%
  3. Tube 3

    6 vote(s)
    40.0%
  4. Tube 4

    1 vote(s)
    6.7%
  5. Tube 5

    2 vote(s)
    13.3%
  6. Tube 6

    1 vote(s)
    6.7%
  7. None: get a JJ

    2 vote(s)
    13.3%
  1. warrent

    warrent Tele-Meister Silver Supporter

    273
    Sep 15, 2009
    toronto

    This is a good point which I hadn't really thought about until I watched the video below. In the video which concerns a hot amp he switches a Chinese tube with a GE tube before changing the bias to correct the over heating. One tube dissipates 19.6 watts and the other 16.7 watts that difference should account for a change in sound that doesn't correlate with the brand of tube. To really tube roll I think you have to re-bias for each tube so that the plate dissipation is the same for each tube.

    My apologies to the OP for hijacking an old thread. I enjoyed the video very much.

    2017-09-20.png


     
    bpr103 likes this.

  2. Old Tele man

    Old Tele man Tele-Afflicted

    May 10, 2017
    Tucson, AZ
    Did you return it with the Chinese 6V6 or the GE 6V6?
     

  3. warrent

    warrent Tele-Meister Silver Supporter

    273
    Sep 15, 2009
    toronto
    Uncle Doug biased it with the GE.
     

  4. Old Tele man

    Old Tele man Tele-Afflicted

    May 10, 2017
    Tucson, AZ
    But, my question is: "Which tube went back with the amp to the customer?" The reason being that adjusting the cathode bias resistor for the GE tube, but plugging the Chinese tube back in may NOT have been a good idea. If the customer is going to continue using Chinese 6V6 tubes, it seems prudent to 'set up' the bias for that tube and not for the GE tube that wasn't going to be used.
     
    awasson likes this.

  5. warrent

    warrent Tele-Meister Silver Supporter

    273
    Sep 15, 2009
    toronto
    I'm not uncle doug but given that he talks about the chinese tube red plating and that he biased it with the ge and that he seems to be a straight up guy I would assume it went to its owner with the ge.
     
    bpr103 likes this.

  6. bpr103

    bpr103 TDPRI Member

    Age:
    41
    12
    Mar 5, 2017
    Pennsylvania
    You're right: the difference was much easier to hear and that made it easier to settle on one. The preamp tube I preferred (6072) and used here is even lower gain than your suggestions:

    I went through about 12: new and old 12AX7s, 12AT7s, 5751... the 6072 gave me the widest variation with acceptable volume.
     
    Last edited: Sep 30, 2017

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