Second Stage for Preamp

Discussion in 'The Projects Forum' started by logans-electronics, Dec 10, 2009.

  1. logans-electronics

    Thread Starter Member

    Sep 1, 2009
    36
    0
    Hello,

    I have my amp working and it sounds fine. I would like to add a second stage on the preamp. I am using a MPSA06. I noticed in multisim that I have reached some type of limit:confused: on the MPSAO6 for voltage gain of 10.....I have tried everything I can think off to get more output without getting crazy with the THD. Right now I am at 8%. I considered raising the VCC but I have some technical issues that prevent it right now.....so, the second stage is what I would like to do or raise the MPS gain.....any ideas?

    Thanks!:)
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I converted your schematic to .png format.

    Please simply post your attachments as .png files, as they are small and load quickly. .doc files require extra software and longer loading times.
     
  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The amplifier is too simple. Its gain is low and its distortion is high.

    Most power amplifiers have darlington transistors or Sziklai transistors at the outputs so that the driver transistor can have a higher impedance load which allows it to have high gain. The gain is also increased with a differential pair of transistors at the input with a current source for their emitters. Gain can be increased more when current sources or current mirrors replace collector resistors. Then the negative feedback will reduce the distortion to 0.05% or less and the amplifier will still have plenty of gain.
     
  4. logans-electronics

    Thread Starter Member

    Sep 1, 2009
    36
    0
    What would you recommend I read up on, current mirrors or darlingtons first?

    Just wondering what I should start with and then insert into multisim....Thanks!
     
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