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jose

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Posts posted by jose

  1. Blue Hawaii BJT Build thread

    in Do It Yourself

    Posted

    2 minutes ago, mwl168 said:

    If you are referring to the 50 ohm resistors on the EL34 plate CCS, 1VDC measured across the resistor gives you 20mA ( I = V/R, 1/50  = .02) of plate current which I think is conventional. 

    I've know builders that run their Blue Hawaii from 18mA up to 25mA. The Blue Hawaii runs HOT, so need to take into account the heatsink size. 

    Thanks. Sorry, yes I was thinking about CCS. R50 is between DN2540 and the EL34 plate. If 20mA is a normal set-up, I´ll try this.

    Other stupid question. What value is necessary for 150K resistor (on Gate of 8N80C)?  I'm not sure that 1 / 2W is enough

  3. grounded grid

    in Do It Yourself

    Posted

    Notes: I´m using a Mullar quad (actual production). -/+450volt rails. 20mA plate current

    I only had 1 hour of listening; the sound is strong like a Carbon but with a bass more marked but clear (I can´t listen problems like distortion, noises... Have I good quad tubes?). IHMO Carbon is more accurate musically (like a laboratory instrument) but the GG seems more fun.

  12. Closed - Megatron and GRHV PCB GB

    in Do It Yourself

    Posted

    On ‎01‎/‎06‎/‎2017 at 8:42 AM, steefdebruijn said:

    I am very curious about your findings. Thanks in advance for any feedback on this.

    Measures (no load):

    AUDIO GRADE TSA300VA PRI:230V SEC:
    > 2x360V & 350mA      386volt/386volt
    > 18-0-18V & 600mA   18,63volt/18,63Volt
     
    AUDIO GRADE TSA60VA PRI:230V SEC:
    > 2x 6,3V & 4,5A  6.83volt/6,83volt

    No noises or hum . The measures are... more or less but I'm worrying for HV (a difference of 26volt)

  17. Closed - Megatron and GRHV PCB GB

    in Do It Yourself

    Posted

    8 hours ago, PICaudio said:

    ...I have some units with a little noises, and all toroids that I've bought to this people have a little bigger voltage differences in the same outputs than these Torivac trafos.

     

    Yes, I have one with a little noise and other with a diference (13,2v instead of 12,6v). This is not very serious but it annoys me a little.

    I´m interested in buying trafos but I don´t know if I will buy them all at the same time or not.

  19. Closed - Megatron and GRHV PCB GB

    in Do It Yourself

    Posted

    On ‎22‎/‎05‎/‎2017 at 4:24 AM, mwl168 said:

    It dawned on me while I was trouble shooting my GRHV to put a reminder here.

    The 3W 5.1 R current limiter on the GRHV board is good for 120mA per rail which is a bit low for the Megatron and not enough for the Blue Hawaii 's negative rail. May need to go to 3R or lower. 

    I´m doing a GRHV for GG and BH and I ´m thinking run both with 450v and 120mA, (I used 4 cap 550v/680uF so I think that it´s correct for 450 volt output) but now I have a dude with the negative current resistor.   

    For negative rail. Do I need change the current resistor for a low value? If I change this resistor, will I have problems with GG?.

     

     

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