Some Discussion on Amp EQs

Discussion in 'Amps and Cabs [BG]' started by dunwichamps, Jan 21, 2013.


  1. Bassmec

    Bassmec

    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Thanks so much I will look strait into that then, as Sowter are great on quality transformers but I think £152 is a lot for a few small coils of wire.
    :bassist:
     
  2. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    yea man wicked money. Maybe ask Heyboer Transformers if they will wind u stuff. I get custom amp transformers from them
     
  3. DethByDoom

    DethByDoom

    Sep 23, 2012
    Houston,Tx
    What about a Peavey VB2's eq? How do the resonance and presence controls work? Some kind of hpf/lpf that affect the treble and bass?
     
  4. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    Pres and Res are most likely the same old NFB eq controls which decouple the NFB loop at low or high frequencies. When you decouple the NFB loop at a frequency that increases the gain of those frequencies in the power amp. i dont have a scheme for its preamp EQ
     
  5. Bassmec

    Bassmec

    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Well bit late as we already have invested in the Lundahl transformers as they have a reputation like god.:bassist:
     
  6. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    I usually go with Heyboer or Merc or Mag Comp.

    heyboer has been doing most of my DR103, DR201 and DR400 iron. Very nice stuff
     
  7. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    The TSC is a great visualization tool, but actual measurements are a bit more useful when they're available. ;)

    I modified the second channel of my F2B to do mid boost in such a way that you could sum both channels and have controllable mid boost and cut. The guy I sold it to preferred just using the second channel though.

    There are some graphs in my DIY tube preamp thread showing various mid boosts achieved with no inductors, starting here. Personally, I like some aspects of the interactivity of the Fender stack, so I tried to do my own riff on that with active bass and mids, and a quasi-passive treble circuit. And being the contrarian that I am, I made the whole thing optimized for active basses only. ;)
     
  8. esa372

    esa372

    Aug 7, 2010
    Very true!

    I don't suppose you have an F-1X on hand to see the actual results of those settings...? :) (I'm not set up for such things, or I'd do it myself.)
     
  9. DethByDoom

    DethByDoom

    Sep 23, 2012
    Houston,Tx
    ImageUploadedByTalkBass1359006479.317487.jpg

    This is all I could find. Controls are bass, middle, four way mid toggle switch, treble. And of course presence and resonance.

    http://assets.peavey.com/literature/manuals/03595970_4.pdf
     
  10. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Nope. There was one around here for a while which I worked on and played through, but it's long gone, as is the F2B.
     
  11. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    thats just a rough block diagram but I was correct about pres and resonance. Thats like the same stuff you might see on a SLO100
     
  12. DethByDoom

    DethByDoom

    Sep 23, 2012
    Houston,Tx
    NFB? :bag:

    Never understood how the pres/res controls worked.

    It functions alot like an ampeg tone set up but the mid selector just sounds/reacts pretty different.
     
  13. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    negative feedback. Its refers to a portion of the output signal that is injected back into the circuit, usually at the phase inverter. It forms a loop which encompasses the phase inverter, power tubes, and OT. Its called negative feedback because it is out of phase with the signal at the inverter. Negative feedback decreases the gain inside the loop but if we select portions of frequency band where we decrease the amount of negative feedback that will increase the gain of that frequency band. Thats what the presence and resonance do
     
  14. DethByDoom

    DethByDoom

    Sep 23, 2012
    Houston,Tx
    Ah ok gotcha. Thank you sir
     
  15. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    I can simulations with approximated NFB curves for those kinds of controls
     
  16. Korladis

    Korladis Inactive

    Is the 60's Sunn EQ just your basic FMV?
     
  17. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    in the 200s and the Model T yes. 200s is a Fender style, Model T is Marshall style
     
  18. Korladis

    Korladis Inactive

    Ah right, just without an actual mid control for the 200S/2000S.
     
  19. dunwichamps

    dunwichamps Commercial User

    Jul 23, 2012
    Owner: Dunwich Amps
    yup
     
  20. DethByDoom

    DethByDoom

    Sep 23, 2012
    Houston,Tx
    That be interesting to see. Never gonna say no to free knowledge.
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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