How do you explain this?

Discussion in 'General Electronics Chat' started by markbr, Mar 22, 2010.

  1. markbr

    Thread Starter New Member

    Mar 21, 2010

    This is the Danelectro Honeytone practice amp circuit. Diodes D1 & D2 are 1N4148 silicon ones. I measured a sine wave output on the oscilloscope and this is what i found:

    1) with both diodes REMOVED: pk-pk voltage=5.7V

    2) with 1N4148 diodes intact: pk-pk voltage=2.88V

    **These voltages were measured at pin1.**

    Everyone says they are clipping diodes. I think that too. But, if the diode's forward voltage drop=0.7V, then 2X diodes should be 0.7x2 = 1.4V? Shouldn't the pk-pk voltage with diodes intact be more than 2.88V? Just a little confused here..
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    The diodes have the tone, volume and various filtering around them.

    The only place to see what the diodes are doing is by looking at the signal directly across the diodes. It should be near to a square wave at the input levels you were using.
  3. BillB3857

    Senior Member

    Feb 28, 2009
    Last edited: Mar 22, 2010
  4. Audioguru

    New Member

    Dec 20, 2007
    The second opamp has a voltage gain of 34 so its output depends on the setting of the tone and volume controls.