~SEBATRON~ ** Tips and Mods **

Discussion in 'Preamps / Channel Strips' started by Sebatron, Oct 31, 2003.

  1. Sebatron

    Sebatron Well-Known Member

    If you are the owner of any Sebatron products specifically to the vmp range.
    Here’s a few tips and mods that might be of interest to you. :D
    …also nice for drum overheads ….. :D

  2. Bowisc

    Bowisc Active Member

    This is great, Sebatron. As I was inquiring myself via emails, it's good to have this info available for everyone.

    Can you (or anyone) supply us with some places where we can purchase these "caps"? Are there some part numbers or manufacturers that should be sought?

    I will be moding 2 channels of my 4Ke.

    Gracias amigo.

  3. Bowisc

    Bowisc Active Member

    Any internal mods for boosting gain?

  4. audiokid

    audiokid Chris Well-Known Member

    BC, Canada
    Home Page:
    Excellent Seb! I'm going to add this to the website. Hey, how difficult would it be to actually incorporate more options for different applications / effects right on the unit? I bet your onto that ;)
  5. daif

    daif Guest

    Hi Seb,
    Maybe we'll see a 4 way (silent) cap switcher in future prods?
    Also is GTA the only source for purchasing in Oz?
  6. Sanity Inn

    Sanity Inn Guest


    now where else can ya buy a pre and have the " builder" teach you how to tweek it better ?? huh hmm huh :) )

    Thanks Seb , U da MAN

  7. Bowisc

    Bowisc Active Member

    Anyway for users to get more gain out of the unit?
  8. Kurt Foster

    Kurt Foster Distinguished Member

    77 Sunset Lane.
    Daisy chain out of the 1/4" out on a channel into the 1/4" input (d.i.) on a second channel.. adding more stages of gain. Futz around with the gain setting on both channels, pad and boost and cut switches, lots of options there.

    This is much like a pre and master scenario on a guitar amp or like how the Neve (clone) 1272's don't have as much gain as an original Neve, because the originals had 3 amplifier stages vs. the 1272's two stages ... Also, even at lower gain settings this makes a difference in the sound quality because you don't have to drive the first stage as hard...
  9. Bowisc

    Bowisc Active Member

    I was driving more at the idea of having the same amount of gain as the more recent units come already stock with.
  10. mikE@THECAVE

    mikE@THECAVE Guest

    just curious bowisc what do you need more gain on?
  11. Bowisc

    Bowisc Active Member

    For dynami mics (RE-20, SM7b...).
    I can crank it, but it's not as 'clean' as my Sytek, let's say.
  12. Sebatron

    Sebatron Well-Known Member

    Getting more gain:

    If you have a 'green text' Sebatron ... with vmp in lower right hand corner....you can increase the gain simply by changing a couple of resistors on the board and on the 'pad' switch.

    Change the 470k neg feedback resistor to 820k ...
    Change the associated 22k to 33k ...
    ..and lastly change the 47 k resistor over the 'pad' switch to 120 k .

    All units come this way standard now.

    2004 :D :tu:

  13. Mark Burnley

    Mark Burnley Guest

    Great stuff Seb!

    ...I admire your attitude towards giving out modification advice to your customers instead of saying "...well, buy the new improved model!..."


  14. Bowisc

    Bowisc Active Member

    I have experience soldering cables, but not electronics. Do you think that I would have difficulty doing the EQ and gain mods?

    Does anyone have any online link where these parts can be purchased?

    I did some reading and saw that there are different "types" of capacitors/resistors... what types are needed?
  15. Standard 1/4W carbon or metal film resistors should do the job, and I believe the capacitors are ceramic. The parts shouldn't be more than a few cents in total and you should be able to pick them up at your local electronics store. From what I have seen Sebatron doesn't get into the whole 'we use this brand of capacitor' vibe, more of an honest 'get the best performance out of standard good quality components by using good designs'. Remember that a bad design with the best components will still sound like $*^t.. The fancy components generally only give you that extra couple of percent performance at 2-> 10x the price..
    The hardest part will be removing the existing components neatly. You would need a solder sucker for that. And do one channel at a time, so you can copy the layout from the unmodified channel should you get a bit lost...
  16. Bowisc

    Bowisc Active Member

    I do have one of those solder syringes... thanks the great tips.
  17. jmedigital

    jmedigital Active Member

    Home Page:
    Hello Seb, Recently bought a vmp4000e (Asked if you used Jaycar components -wince-). I'm happy with the unit. Definitely useable and always like to own non-mainstream gear so no worries there (I have a red text "Sebatron" with green "vmp4000" so I guess these mods are already in place?).

    I've yet to do ref measurements yet, but how flat is the flat setting (Bal in Bal out)?

    Also, is it possible to have a variable "air" setting rather that switched. This is the mod I would like to do the most. I found myself not using the deep switch at all, but more control over the air switch is where it's at I think! Not in the sense of just a simple boost cut of a certain freq (maybe that's all it is?), just more control over the eftect of the air switch if you know what I mean. :)
  18. Sebatron

    Sebatron Well-Known Member

    YEAH SURE :D :td:

  19. jmedigital

    jmedigital Active Member

    Home Page:
    Thanks for the info Sebatron. Yeah the front panel space is the tricky bit! I've been thinking about the best way to implement it without screwing up the panel and artwork. I've got a couple of ideas and I'll let you know how I go if i do go ahead with it!


Share This Page