In-cable Guitar Preamp

[Bryan] sent in this old but excellent guitar cable hack. [J. Donald Tillman] managed to fit a fet based pre-amp inside the 1/4″ connector of a guitar cable. It’s phantom powered – so it’ll leach power from the sound board/mixer. I’m just impressed that he fit the thing inside there.

On a side note, This is the kind of crap that gives hackers a bad name. I hope the jerks behind it end up as Soylent Green.

25 thoughts on “In-cable Guitar Preamp

  1. very cool hack.
    about the epilepsy thing – that just makes me mad. bunch of sk’s just learned how to inject javsacript and think they can be leet. extremely immature. what i want to know is, why do they think (assume?) it was anonymous?

  2. This is a really neat hack, but is there any point in instaling the amp in the cable itself if you need a box on the end to power it anyway?

    And I know I’m a horrible person, but when I read that epilepsy thing, I burst out laughing. What I don’t like about it is that the internet’s population now seems to blame everything bad on “Anonymous”, because they can. It’s just like religeon; they have no proof at all that this is true, but they’ll say it anyway.

  3. thats just horrible and if it was {Anonymous}he’ll get whats coming 2 him he’s a good hacker but there’s always some 1 better and a lot of hackers out there have family
    with epilepsy so i can see a major rebute for this. well im off 2 make fun of tom cruise it never gets old

  4. It was anonymous. It wasn’t necessarily the same part of anonymous that are taking part in the CoS protests, but they are part of the group that has become known as Anonymous.

  5. I like the idea of embedding the preamp in the cable, but you need a phantom power capable mixing desk or a phantom power injector.

    I would think it might be better to simply build a decent pre-amp into a project box and spray paint the innards with nickel or something to shield it. You would probably end up with a better preamp in the end, and you don’t have to worry about phantom power.

    If you were to plan at a location with poor sound equipment and they are not equipped to provide phantom power, you are going to be in a pinch

  6. i just hope they get the ppl responsible for the epilepsy “prank”, because what they did is considered a massive attempt of murder!
    ppl can die form an epilepsy attack and they inserted flashing things in the forum for the sole reason to give epilepsy attacks, in my point of view thats an attempt of murder, i hope they get them

  7. the griefers at that forum are douches.

    As for sticking the preamp into the cable, phantom power is on any mixer that costs more than a few hundred dollars.

    It’d be nice to not have to carry around a separate preamp box. I’d imagine that personally I’d use this cable for bass more than guitar, I probably wouldn’t be DI’ing my guitar unless I was playing clean exclusively.

  8. Chris –
    The point is to lower the impedance as close to the pickups as possible so that the cable doesn’t have a chance to load down the pickups (which cause reduced treble and bass). This is especially important for piezo pickups (which need a MUCH higher input impedance).

    I’ve built one of these, but I never thought of submitting it to hackaday.

  9. Wouldn’t leeching power from the audio line distort the signal ?

    As for this epilepsy thing, hurting people for fun seems to be a growing and worrying trend in our society. I really hope the culprits get caught.

  10. Sweet hack, even though I don’t play the guitar.

    Personally, I think the assholes who attacked the epilepsy forum weren’t actual Anonymous at all. I’m sure we all know about how Anon is attacking the Church of Scientology, and a number probably know about CoS’s “Fair Game” policy (if you don’t, Wiki it, it’s scary shit), and I’m pretty certain that everyone that reads this site can put two and two together… After all, who could possibly be easier to impersonate than Anonymous?

  11. about the epilepsy thing connected to Anonymous –

    it turned out that it was people from the church of scientology framing the *chans. admins from a few of the boards talked about it.

  12. IIRC the epilepsy forum either allowed raw HTML or javascript. Saw the damage from a thread on 7chan myself.

    “hacker” is hardly an adequate description for those that participated, not that I support their actions.

  13. Anonymous really did it you guys, I think you are giving them a bit too much credit for not being douches. This is not the first time they have pulled stuff like this either, harassment is what they do. The whole CoS raid is actually looked down on by a lot of the *chans because it is destroying the name of Anonymous. They don’t call themselves “Internet Terrorists” for nothing.

  14. Granted, it was not a really nice thing to do.. But honestly, my
    question is, what kinda retard would sit there and watch the
    “flashing images” long enough to cause any type of reaction knowing
    that they had this disorder.. Unless of course they had some kind of
    java scrip that not only caused flashing images, but also a total
    paralysis of viewer preventing them from manually moving their mouse
    to click the X in the upper right corner.. Then.. yes.. By all mean..

  15. Oh man. I’m one of the CoS protesters, and I really don’t understand how people could be blaming us for this thing. Anyone can be Anonymous, you need to take a look at the *chans these griefers operate on. Like Jack says, the whole CoS raid is actually looked down on by lot of the *chans. Scientology looks down on its members taking medication to stop them from getting seizures, for example, Tory “Magoo” Christman –

    Jocelyn Dorfmann died from an epileptic seizure in Scientology care in France –

    Heribert Pfaff died from an epileptic seizure in a Scientology hotel in Clearwater –

    James Stewart committed suicide after CoS put in him in a Condition of Doubt for having epileptic seizures in public –

  16. on the epilepsy hack… i read more about it here:,25642,23460969-5014239,00.html
    seems wired covered this and more people have looked into it since. there seems to be a lot of blaming being tossed around on who did it so at this point it’s impossible to tell. it’s aggrivating that everyone has been blaming anonymous since the fox news garbage, and i wouldn’t put it past scientology to be the actual culprits of the attack.

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