DOD FET

JezWyndJezWynd Frets: 6021
My recently acquired Bullet guitar has very low output pickups. So low that they struggle to engage the compressor which is a big part of the sound I strive for. Seeing a DOD FET Preamp on eBay seemed like the answer - boost the signal hitting the comp. It's a strange thing, no on/off switch, just a single volume knob and the internal circuit looks incredibly basic but it works very well. It has a bright tone (though that might be the pickups) and suits the Bullet well. Pics -



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Comments

  • bingefellerbingefeller Frets: 5723
    Is there much background noise from it?
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  • JezWyndJezWynd Frets: 6021
    Is there much background noise from it?
    At the volumes i’m playing at, it’s unnoticeable until it’s turned up to about 4 o’clock on the dial, which is a substantial volume boost. I could have gone with a Spark mini pedal but I like these old DOD boxes, very solid pedals and for this particular guitar an on/off switch isn’t required.
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  • BranshenBranshen Frets: 1222
    edited July 2018
    Very cool set up. It does look simple and it looks like you could house all of that in the guitar cavity. 
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  • Flanging_FredFlanging_Fred Frets: 3008
    I've got the big brother of this and it's a cool pedal.  A really solid heavy thing it is and can ccme in handy.


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  • JezWyndJezWynd Frets: 6021
    I've got the big brother of this and it's a cool pedal.  A really solid heavy thing it is and can ccme in handy.

    That looks nice; brilliant condition! When they call it a Bi FET, does that mean it has two FETs installed as opposed to one in my example, and therefore more gain on tap?
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  • exocetexocet Frets: 1948
    The term BiFet generally referred to an OpAmp that contains a mix of Bipolar and FET transistors. Can't remember what the advantages of this was though, possibly high input impedance combined with high current drive capabilities.
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  • GadgetGadget Frets: 895
    For those in the pedal-building-know, how does this differ from a buffer?
    I think, therefore.... I... ummmm........
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  • thermionicthermionic Frets: 9499
    edited July 2018
    A buffer has a fixed output level, giving generally unity gain. These preamps (also known as boosts or boosters) have a knob that allows you set the gain to be less/more than 1, a gain of more than 1 being a boost.
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  • GadgetGadget Frets: 895
    A buffer has a fixed output level, giving generally unity gain. These preamps (also known as boosts or boosters) have a knob that allows you set the gain to be less/more than 1, a gain of more than 1 being a boost.
    So at unity gain, is the FET doing anything, and does it have any buffer effect at unity?
    I think, therefore.... I... ummmm........
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  • exocetexocet Frets: 1948
    edited July 2018
    Gadget said:
    A buffer has a fixed output level, giving generally unity gain. These preamps (also known as boosts or boosters) have a knob that allows you set the gain to be less/more than 1, a gain of more than 1 being a boost.
    So at unity gain, is the FET doing anything, and does it have any buffer effect at unity?
    Yes, it will alter the impedance making the output more suitable for driving long cable lengths without suffering from treble loss.

    FET circuits offer high input impedance (good for guitar) and low (ish) output impedance (good for driving long cable lengths). 

    http://www.till.com/articles/GuitarPreamp/
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  • GadgetGadget Frets: 895
    Interesting, thanks.
    I think, therefore.... I... ummmm........
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  • JezWyndJezWynd Frets: 6021
    JezWynd said:
    Is there much background noise from it?
    At the volumes i’m playing at, it’s unnoticeable until it’s turned up to about 4 o’clock on the dial, which is a substantial volume boost. I could have gone with a Spark mini pedal but I like these old DOD boxes, very solid pedals and for this particular guitar an on/off switch isn’t required.
    Actually, having spent more time with it, I'd say it's only amplifying noise from the the guitar, so with the single coil Bullet it can become noticeable when turned up, while with a humbucker bass guitar it's very quiet.
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