transformer issues- no voltage on DC side

Discussion in 'The Projects Forum' started by 100Dave, May 4, 2010.

  1. 100Dave

    Thread Starter New Member

    May 4, 2010
    Hello I am building the 12AX7 vacuum tube amplifier, but I have run into some problems with the power supply. I purchased 3 of the transformers listed in the parts list, and have built the circuit as shown in the article ( I think ). I never seem to get the correct voltage on the other side of the transformer(s) ( I tried all three of them) I actually dont get ANY measurable DC voltage and I thought I would see 170 VDC.
    I am connecting my 12V power supply leads to the yellow wires on the DC side of the transformer ( 6.3V x 2 ) and checking the other side for voltage....nothing.
    Also, I have tested the transformer in the tradional way and hooked up the AC leads to wall voltage and read corrrect DC voltage ( 12V ) off of the DC side, so I at least kindof understand transformers , right?
    Can someone give me some pointers or tests I can do to eliminate this issue or component?

  2. Markd77

    Senior Member

    Sep 7, 2009
    Transformers don't have a DC side, you need a recitfier.
    kingdano likes this.
  3. SgtWookie


    Jul 17, 2007
    It would help a great deal if you would post the schematic, parts list, and information about the particular transformers you purchased.

    The 12 part in the 12AX7 means they use 12v for the heaters.
  4. 100Dave

    Thread Starter New Member

    May 4, 2010
    hello all thanks for the quick replies, it turns out that I was applying 12VDC from my newly purchased power supply into a 12 VAC transformer and expecting things to work. I re-read the instructions and I am now getting the expected voltages.

    thanks all