How to find JFET based OD pedals?

Discussion in 'Effects, Pedals, Strings & Things' started by papersoul, Mar 20, 2015.

  1. Multicellular

    Multicellular Member

    Messages:
    7,885
    Joined:
    May 29, 2013
    Location:
    Washington, D.C.
    Subdecay Liquid Sunshine is an excellent one.
     
  2. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004
    Do you all know anything about the new Bogner pedals like the Wessex? Another thing that is important to me is that a pedal can work on the clean channel and dirty channel
     
  3. HugalosPizza

    HugalosPizza Member

    Messages:
    1,106
    Joined:
    Aug 11, 2009
    Location:
    Pescespada Island
    I saw the Wessex and was very intrigued. The Earthquaker Devices Monarch is a FET pedal in the vein of an Orange amp input. Sounds pretty damn good to me.
     
  4. Non-Digital Tom

    Non-Digital Tom Member

    Messages:
    1,013
    Joined:
    Dec 7, 2004
    Location:
    CT
    No, it's an IC based distortion, no transistors (field effect or otherwise), and no clipping diodes.
     
  5. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004
    You guys say FET but I have read a few times that FET is different from JFET.
     
  6. conrad79

    conrad79 Member

    Messages:
    296
    Joined:
    Jun 10, 2013
  7. rumbletone

    rumbletone Silver Supporting Member

    Messages:
    5,874
    Joined:
    Jun 19, 2013
    Location:
    Vancouver BC
    The tube screamer tone seems pretty dependent on the op amp/diode combination - not sure it could really be considered TS-like without that.

    There are lots of jfet-based pedals that can boost mids though. For example, the Wampler tweed 57, while designed to be a 'preamp' type pedal, works great as a dirty boost - and the gain and 3-band tone controls allow quite a bit of flexibility.
     
  8. berumen77

    berumen77 Member

    Messages:
    308
    Joined:
    Sep 14, 2011
    Location:
    Austin, TX
  9. mmolteratx

    mmolteratx Member

    Messages:
    2,862
    Joined:
    Jul 23, 2009
    Location:
    Austin, Texas
    A JFET (junction field effect transistor) is a type of FET (field effect transistor). In the EE world, I know a number of people that refer to MOSFETs (metal oxide semiconductor field effect transistors) simply as FETs, while people working in music electronics without a EE background tend to use FET to refer to either one. Most through hole JFETs are out of production, and they may or may not become less common in guitar effects as supplies dwindle.

    The two types of transistors are different, as far as how they operate. A JFET is a depletion mode device, in that the control terminal needs to be biased to a lower voltage than the terminal which supplies electrons (in case of N-type JFETS) in order to be 'on'. This is how tube triodes work, and the similarity in operation is responsible for similarities in how they wind up sounding in simple amplifier circuits which are allowed to distort. They both can only take so large of a signal at the input before the device goes into saturation or cut off, resulting in clipping, and that signal size is tied more closely to inherent properties of the device (threshold voltage) rather than any biasing conditions. The transfer functions of the two devices (tube triodes and JFETs) aren't identical, however, which leads to slightly different characteristics at extremities.

    The MOSFET (or MOS transistor, which is how people in my field tend to refer to them) is an enhancement mode device, which requires that the control terminal be biased above that of the source terminal for the device to be 'on' (again, in terms of N-type MOS, or NMOS). In the typical MOS amplification stage, the input voltage swing isn't limited by any inherent properties of the device, but rather by the supply voltage rails. Of course, as the size of the input signal grows, the linear ideal starts to fall apart, but it's not as rapid as in a depletion mode device. As a result, MOS gain stages tend to have more headroom than JFET stages before clipping, and as a result, you can get more clean voltage gain out of them. They can also sound sufficiently 'tube-y' with good circuit design. See the ZVex Box of Rock for an example, in addition to the Catalinbread WIIO and RAH.

    EDIT: The output impedance of MOS transistors in equivalent circuits is typically higher than BJTs (bipolar junction transistors), but the transconductance is usually higher than BJTs, so BJTs have higher maximum gain.

    As far as I know, there aren't any JFET based pedals that do anything similar to a Tubescreamer. The Tubescreamer uses op amps and it's not possible to simply swap them out for JFETs. However, it is perfectly possible to get a similar result with a JFET design. You just want to cut bass up front (small emitter bypass cap on the first stage, and possibly a small coupling cap between the first and second stage) and then cut highs at the tail end. I've screwed around with circuits like that a bit, and they're fun. I just hate dealing with sorting through JFETs, especially with a limited stash. They're trash devices, honestly, at least from a consistency standpoint.
     
  10. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004
    Thanks, that was educational and a great help. Would you recomend zvex box of rox or those catalinbteed pedals?
    My J&J OD is JFET and has a mid boost setting. Thanks, now I know to check out some Mosfet too.
     
  11. Rydell

    Rydell Member

    Messages:
    410
    Joined:
    Nov 3, 2013
    Location:
    Nashville TN
    VFE is now offering licenced versions of most of the ROG pedals. I've got the OLC version of the Umble. Great sound and very well thought out!
     
  12. mmolteratx

    mmolteratx Member

    Messages:
    2,862
    Joined:
    Jul 23, 2009
    Location:
    Austin, Texas
    Yea, both the BoR and the Catalinbread MOSFET pedals sound great. The Box of Rock is a bit tubby sounding though. I'd recommend the Distortron over it it since it has a switch to tailor the low end.
     
  13. ObsessedGuitarist

    ObsessedGuitarist Member

    Messages:
    428
    Joined:
    Jan 21, 2015
    Location:
    Far away from the nearest town.
    Aha! This totally explains what happened to me. I got a Catalinbread 5F6 and I've been selling off all of my TS derivative pedals ever since.

    I just thought I was crazy.
     
  14. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004

    Huh??
     
  15. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004
    I will say modded Sonic Edge J&J OD and J&J v2 have kicked all my MXR, Way Huge, Maxon and Xotic pedals off my board. My J&J's seem to be capable of anything. Ben Fargen said these are JFET pedals and I know mine is modded by Ben with the best parts and a bass and mid boost switch. :)
     
  16. effectsman

    effectsman Supporting Member

    Messages:
    3,451
    Joined:
    Nov 14, 2008
    Location:
    Australia
    Does Ben still make them? A search doesn't reveal any current production that I can see.
     
  17. papersoul

    papersoul Member

    Messages:
    12,858
    Joined:
    Nov 1, 2004
    Ben no longer makes pedals, only amps.
     
  18. BrandonAy

    BrandonAy Member

    Messages:
    692
    Joined:
    Nov 18, 2013
    I have a Subdecay Liquid Sunshine and Ramble FX Marvel Drive on my board. Both JFET, and they stack well.

    I like JFETs, too.
     
  19. p.j.

    p.j. Member

    Messages:
    3,849
    Joined:
    Dec 28, 2009
    Location:
    New England
    Love mine.
     
  20. Phosphenetre

    Phosphenetre Member

    Messages:
    507
    Joined:
    Sep 21, 2013
    Very surprised nobody's mentioned the Weehbo pedals, yet. They seem to be generally received as some of the best amp-in-a-box style pedals available, and some of the very best implementations of JFET design.

    I own two JFET pedals, the T. Jauernig Kollmanation, and the Weehbo JCM Drive Ltd. Anniversary. Both pedals share something very special - a very realistic, complex kind of drive, full of harmonics and just 'huge' in every sense. They also both share an amazing level of touch sensitivity and dynamic response. This makes them sound and feel very real and 'amp-like'

    The Kollmanation is a crunchier, more aggressive beast that can run the range from clean to raging, chunky metal grind, while the JCM Drive Ltd. goes from clean to about 80s rock, but with a more vintage slant to the tone. Both very versatile pedals.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice