PPIMV Question

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Marshall Man, Feb 12, 2012.

  1. Marshall Man

    Marshall Man Member

    Messages:
    1,136
    Joined:
    Jan 7, 2008
    Location:
    Tampa Florida
    I installed the Rich Mod PPIMV in my 76 Marshall 4 hole 50 watt JMP combo (it has a hand wired board), but it calls for a 500K dual pot...all I could find was a 250K dual pot, what would the difference be in the two pots sound? Anyone else do this?
     
  2. smolder

    smolder Gold Supporting Member

    Messages:
    13,850
    Joined:
    Jun 16, 2008
    Location:
    Central Rocky Mountains
    Do a search or the LarMar circuit, here and on the metro amps forum where it originated. It might be a better solution for your Marshall.
     
  3. gldtp99

    gldtp99 Member

    Messages:
    2,513
    Joined:
    Dec 23, 2005
    Location:
    Texas
  4. Marshall Man

    Marshall Man Member

    Messages:
    1,136
    Joined:
    Jan 7, 2008
    Location:
    Tampa Florida
    Thanks guys. I did the rich mod vice the Lar Mar and all I have was a 250k dual pot that is why I was wondering what the difference would be. I may eventually do the other circuit.
     
  5. Winnie Thomas

    Winnie Thomas Member

    Messages:
    503
    Joined:
    Nov 11, 2006
    Location:
    Cochise, Arizona
    [​IMG]

    This is a very simple one:

    Winnie
     
  6. Don A

    Don A Silver Supporting Member

    Messages:
    4,831
    Joined:
    Nov 3, 2004
    Location:
    Massachusetts
    I put the Metro Amp LarMar PPIV in my '66 Vibrolux Reverb and love it! The dual 250k pot and 2.2meg resistors in parallel are almost an exact match for the 220k resistors that they replace when it's cranked up all the way.
     
  7. Zingeroo

    Zingeroo Member

    Messages:
    4,341
    Joined:
    Jan 27, 2012
    Got one in my Ceriatone plexi and liked it so much stuck one in my old '65 Super Reverb! Finally can get those SRV tones at lower volumes.
     
  8. vibrostrat43

    vibrostrat43 Supporting Member

    Messages:
    1,688
    Joined:
    Aug 25, 2011
    Location:
    League City, Tx
    Yeah the Lar/Mar is a great master volume, probably the most transparent kind I have heard.
     
  9. john l

    john l Member

    Messages:
    2,033
    Joined:
    Feb 5, 2010
    Location:
    OC Socal
    What separates the Lar Mar from the typical PPIMV? I love the PPIMV in my 1987 but I wouldnt say its transparent at all untill its dimed out of the circuit
     
  10. Marshall Man

    Marshall Man Member

    Messages:
    1,136
    Joined:
    Jan 7, 2008
    Location:
    Tampa Florida
    I put the rich mod in my 87 and it get pretty fizzy if turned up much. I'm going to try the Lar Mar soon.
     
  11. Don A

    Don A Silver Supporting Member

    Messages:
    4,831
    Joined:
    Nov 3, 2004
    Location:
    Massachusetts
    I'm not sure if you can say that any master volume or speaker attenuator is truly "transparent". Once you drive the power tubes less, drive the speakers less, even rattle the walls less, the sound is different.

    Even with the LarMar PPIV master turned down to about 1/3rd, my VR still sounds like a VR (a kinder, gentler VR). I prefer it over any other amp that I've tried at that volume level. I sold my SCXD because the VR sounds better at lower volume levels than the SCXD did.
     
  12. john l

    john l Member

    Messages:
    2,033
    Joined:
    Feb 5, 2010
    Location:
    OC Socal
    Fair statement

    The effect PPI masters have on the tone controls and the now present PI distortion not coupled with a breathing power section is the epitome of not transparent to me..."But" if your the kinda guy that likes the gear the amp is now stuck in so to speak its the cats ass. Add to this the ability of simply cranking the thing and being right back to stock more or less and its easy to see why this style of master works for a lot of guys.
     
    Last edited: Feb 18, 2012

Share This Page