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Ampeg Micro VR Tube Modification

Discussion in 'Amps and Cabs [BG]' started by bassmedic, Apr 17, 2015.


  1. bassmedic

    bassmedic

    May 15, 2012
    Has anyone cracked open and taken pictures of the internals of a micro VR? I love the look but it would only be better with a tube pre section. the same 3 12ax7 set up in the SVT-IIP would be perfect. Before I pull mine apart, just wondering if anyone has and if anyone has any expertise on the feasibility of such a project.

    Thanks very much,

    I'm kinda new here, haven't posted very much.

    Very much appreciate any help.
     
  2. bassrich

    bassrich

    Nov 20, 2011
    Sarasota, FL
    There are no tubes in the Micro VR
     
  3. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Oy vey!
     
  4. bassmedic

    bassmedic

    May 15, 2012
    I know there are no tubes in the head. I'm talking about replacing the SS preamp with a tube one. A custom job. can an amp designed with a SS pre be modified to accept a tube pre?
     
  5. bassrich

    bassrich

    Nov 20, 2011
    Sarasota, FL
    OK now I see LOL, like the oranges. You would probably need a fair bit of modding but anything is possible Not much of a modder myself so I will bow to the experts.
     
  6. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    You want to use the VR as a slave power amp. Shouldn't be too tough as it has post eq effects send/return jacks. Try a test: Grap or borrow someone elses tube preamp and send it in to the effects return jack and see if you like how it works. The only features active on the VR head then will be the Volume and Limiter.
     
    Last edited: Apr 17, 2015
    SirMjac28 likes this.
  7. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Sure, just whip up new high voltage and filament power supplies, including making room for the new transformer(s), and a new ventilation scheme, for starters. [​IMG]

    An outboard solution is a much better bet though.
     
  8. bassmedic

    bassmedic

    May 15, 2012
    Thank you gentlemen. I would use the effects return for an outboard pre. Good call on trying it first. The SVT-IIP's are harder to come by, its the sound I want and keeping it on board would be a lot easier. I was just going for the fit an finish of cramming it all in the head and it all be under one handle. I suppose the issue with that is if the tubes go down, the whole head is useless, same as any other all tube or hybrid head.
     
  9. johnpbass

    johnpbass

    Feb 18, 2008
    Glen Mills, PA
    bassmedic, when you say you're going for the SVT-IIP tone do you mean the SVT3Pro? The 2 is tube pre and tube power. SVT3 PRO is tube pre SS power.
     
  10. bassmedic

    bassmedic

    May 15, 2012
    The III (non-pro) has the same pre as the IIP. Same as the II and not the 2 Pro. III is 3 12ax7's and then on to the power amp. The 3 Pro has a 3 12ax7 pre and a driver section with 1 12ax7 and 1 12au7.......and then on to the power amp. I think the II/IIP/III set up is a little less microphonic. but either way I was trying to create an in-board solution for ease of carry and to keep the look.
     
  11. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Microphoncs are the result of worn out tubes.
     
  12. Well, they don't need to be worn out to be microphonic. They can be brand new defectives.
     
  13. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Yeah, OK ;)
     
  14. bassmedic

    bassmedic

    May 15, 2012
    And I'm only working so much space in there. it isn't a whole bunch
     
  15. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    Cramming a true tube preamp with a line level output into an existing head may not be the wisest idea, custom made or not. A good preamp is designed to keep noise at bay, and the placement of the transformer/s, pots, even the wiring paths and intersections are all carefully planned and deliberate. All the existing VR stuff may make for an unworkable situation.

    There is the Arkham Octling, based on the B15 preamp. There's also the Juleamps Monique/Dove Cage. Both are true tube preamps, and small enough to sit on top of the VR. I thought I saw an Arkham for sale in the classifieds here not too long ago.
     
    Last edited: Apr 17, 2015
    steelbed45 likes this.
  16. bassmedic

    bassmedic

    May 15, 2012
    Well i guess it sounded like a good idea. Thanks for the recommendations on the small pres
     
  17. johnpbass

    johnpbass

    Feb 18, 2008
    Glen Mills, PA
    What I was getting at is that tube power is going to sound and react a little differently than SS power. If you're looking at matching the tone of the IIPRO in a modded MICRO VR, there will be at least some slight difference, IMO.
    Anyway, don't know if it's possible, I'm electronically challenged, but sounds interesting.
     
    Last edited: Apr 17, 2015
  18. steelbed45

    steelbed45 TRemington Supporting Member

    Feb 23, 2011
    Nolanville, TX
    I get the best info from TB, whether directly or not. After reviewing the Arkham website, I fell in love with the pre and placed an order. :thumbsup:
     
    mbelue likes this.
  19. hsech

    hsech Work hard. My Social Security needs a raise.

    Jun 27, 2012
    Central Iowa
    I can smell the blue smoke and the wisp of ozone in the air.
     
  20. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    If you are ready to spent lots of money, yes. Money can buy anything.
    The answer does not include doing it really meakes sense.
     
    Last edited: Apr 18, 2015

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