1. Win a Broadcaster or one of 3 Teles! The annual Supporting Member Giveaway is on. To enter Click Here. To see all the prizes and full details Click Here. To view the thread about the giveaway Click Here.

I want to build a headphone amplifier

Discussion in 'Shock Brother's DIY Amps' started by DrPepper, Oct 30, 2020.

  1. DrPepper

    DrPepper Friend of Leo's Ad Free Member

    Age:
    61
    Posts:
    3,913
    Joined:
    Nov 24, 2017
    Location:
    Texas
    Using a 01A or 6AS7 power tube. They run on a plate voltage of 135. Any advice? Will use a 6SN7 preamp tube.
     
  2. DrPepper

    DrPepper Friend of Leo's Ad Free Member

    Age:
    61
    Posts:
    3,913
    Joined:
    Nov 24, 2017
    Location:
    Texas
    Since I have a Darkvoice HP amp, I will try to clone it...
     
  3. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,940
    Joined:
    May 24, 2010
    Location:
    Canada
    From the web.

    [​IMG]

    [​IMG]

    [​IMG]

    Need a power supply schematic. Ignore the red X.
     
    Last edited: Oct 30, 2020
    DrPepper and sds1 like this.
  4. DrPepper

    DrPepper Friend of Leo's Ad Free Member

    Age:
    61
    Posts:
    3,913
    Joined:
    Nov 24, 2017
    Location:
    Texas
    Thank you... the factory power transformer is for older 110VAC mains, I'm on the hunt now.


    FWIW, my nephew came by and played it today, he was blown away at how tube amp like the sound was...
     
  5. DrPepper

    DrPepper Friend of Leo's Ad Free Member

    Age:
    61
    Posts:
    3,913
    Joined:
    Nov 24, 2017
    Location:
    Texas
    Not a clone more like use the Darkvoice as inspiration. After seeing the gut shots of the DV, I would/will do the layout (their's looks nice) differrently... I will have both input and output on the front, the preamp tube will be near the input and the output will be near the power tube.

    Trying to find a suitable power transformer now, no donors around, I'll have to buy... Donations accepted. :)
     
  6. NTC

    NTC Tele-Meister

    Posts:
    217
    Joined:
    Mar 17, 2003
    How much current does this require? B+ is 135V? You could use a wall wart of some kind and design a boost converter to get the required voltage. If you want old school, using a simple isolation transformer from the mains and creating a DC supply from the out put should create a voltage higher than needed. You could then use a resistor in series with the design to drop some voltage.
     
  7. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,940
    Joined:
    May 24, 2010
    Location:
    Canada
    Still needs a heater supply. It might be tough to find a transformer with a lower voltage to give the 135V with a 6V winding with enough current. May have to go to separate transformers. Or find a transformer that is meant as a full wave center tap and run only one side of it with a bridge rectifier. So you would be looking for a transformer that should end up putting out 250V, which is pretty common for console radios in the tube era. You need 3A at 6.3V for the heaters.
     
    NTC likes this.
  8. DrPepper

    DrPepper Friend of Leo's Ad Free Member

    Age:
    61
    Posts:
    3,913
    Joined:
    Nov 24, 2017
    Location:
    Texas

    I read somewhere on the internet the other day that there are torridial power transformers avaliable somewhere that are a drop in replacemt for the DV that has 120 VAC windings the factory unit has 110 VAC primary...


    Seems to be mods for the DV around. I'm not going to go audiophile crazy on this but, I want to do it right...
     
  9. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,940
    Joined:
    May 24, 2010
    Location:
    Canada
    Whatever works. As long as the transformer can supply the heater current and be in the ballpark of 120-140V you probably will not notice any difference. You can always pick a cathode resistor to suit, not like you are matching it up to an output transformer.
     
  10. NTC

    NTC Tele-Meister

    Posts:
    217
    Joined:
    Mar 17, 2003
    I forgot about the heaters... the brdge rectifier off 1/2 a center tapped 250-0-250 is a good idea.
     
    DrPepper likes this.
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.