The one billionth talkbox thread

[calpolyengineer]

Ok, so I have decided to build a talkbox and I have figured out how to do that (quite simple).
Now, I need some help because I would like to make it quite self-contained. Here is my plan:

I want true bypass (not a must though), I want to integrate a ruby amp into the enclosure, I want a mic input and preamp, and I want a control to blend a little dry signal into the effect output ( I was looking at Joel Purkiss's Buff N' Blend http://www.geocities.com/jrtookmyfalseteeth/buffblnd.gif).

1) Will I need a mic preamp (and can you suggest one), or is the mic signal good enough to continue on to my guitar amp?

2) Will I need the red resistor in the buff n' blend?

3) can I get this all in one box, running off one battery/dc jack?

I know there are 999,999,999 other talkbox threads but none of the ones I've read seemed thic comprehensive. And if i was unclear at all, please ask me to clarify, I really need help on this.

[calpolyengineer]

forgot to add, I would like an indicator LED as well.

[bond]

anyone know of a suitable mic preamp/limiter for a guitar amp?

[jrc4558]

mic preamps are a bit more involving affair. i myself tried once and failed due to inability of finding coupling transformers.

[Paul Marossy]

One billionth?! I think that would be the Tube Screamer. 

So, do you have a schematic for a talk box? I have no desire to build one, but I would like see a schematic out of curiousity.

[mdh]

Before you get too involved in working out the details of stuffing it all in one box, you might want to rig it up in a less integrated fashion to see if the Ruby will have enough power to meet your needs. I played around with a setup like this a while back, and my experience was that it would have been fine for recording, but in order to be heard in a band mix, I needed way more power. I ended up building a little 10W chip amp, and that seemed to be sufficient, but just barely. Even then, I needed a mic that was really too hot for vocals. This seems to be in line with the experience that others have had as well. I just have a feeling that in a band situation you'd have feedback problems, because the mic would have to be so hot.

But if it works for you, I'd love to hear about it, because it would be nice to resurrect my old talkbox project!

Paul: http://www.blamepro.com/talkbox.htm.

EDIT: just noticed that this was an old thread that got bumped by bond's preamp post. calpolyengineer, how did it work out?

[Joecool85]

I made a talk box.  It goes something like this:

20w charvel amplifier -> 3" speaker -> funnel -> tube that goes in to mouth

Then you just play through that amp, and "talk" into a mic with the guitar tube in your mouth.  Man does it work great, and vibrates the hell outta your teeth.  Probably not good if you have fillings...and I'm not really kidding.  Also, you are suppose to use a horn driver as opposed to a smallish speaker with a funnel lol.

[Paul Marossy]

Paul: http://www.blamepro.com/talkbox.htm

I remember seeing that page before...

EDIT: just noticed that this was an old thread that got bumped by bond's preamp post. calpolyengineer, how did it work out?

Yeah, how did that work out?

[psiico]

I did something similar to what Joecool85 did back in highschool.  I used an old piece of crap Sears plastic amp with a funnel made from corrugated cardboard, a tube from a plastic broom handle and a microphone taped to that.  The mic went into a regular tube guitar amp.  It was just something I messed about with in my bedroom, it wouldn't have worked on a stage but it did work.  I've been planning to build a proper one ever since, that was 20 years ago, lol.  No, I'm not a procrastinator.

[Joecool85]

Haha, yeah, sounds like the one I did with my brother.  It's ghetto as hell, but it works great.  Looks pretty funny seeing this beat amp with a blue and black ball covered in duct tape and a hose coming out of it lol.

[bond]

well i can get a horn driver easily enough, i have a little 20w chip amp here,
i was just wondering if i can feed some sort of mic back into my guitar amp, as opposed to using the PA

[Joecool85]

I'm assuming you mean feed a mic into another amp, not the same one driving the horn driver.  In that case you are fine.  We actually were using a Fender 30w Bassman for our "PA".

[AdamB]

I really like the look of that danelectro free speech talk box. It plugs into the effect chain like any other stomp box rather than into the amp, but works via a tube in the mouth like any other talk box. I wouldn't mind getting my hands on the schematic, can't seem to find one anywhere tho.

-Adam

[Joecool85]

Basically what it is inside the dano is a small amp powering a small horn driver that goes into the tube, there is a mic attatched to the tube and it goes back down to the pedal and into a preamp to boost the signal a little then it goes into your guitar amp.  You could build one easily enough if you found a low power horn driver.

[bond]

i have a 20w chip amp to power the horn driver.
but with the danelectro, most people say it has feedback like crazy, therefore rendering it unusable with an amp ....

i don't know much about the output of a mic, how much does it need to be boosted to be on par with a guitar signal, is it smaller mics that cause feedback, can padding reduce feedback?

[Joecool85]

We didn't boost our mic at all, but we had to have the amp WAY up to make it good.  We only tried it in my brother's practice room (bedroom lol), and being a 10x12 room, we got crazy feedback if we weren't careful.

[sta63bmx]

Check out the LM3876T chip.  Hit it with a bipolar supply and it will supposedly give you 40-50W!  I have a tube of 18 of these laying around in my lab, no idea why.  It's the whole amp in one chip, except for the power supply!  But just bring in 120VAC and then you could rectify it , filter it some, and feed positive/negative voltage regulators (RG has this circuit somewhere on his site...) and pow, there's your power supply.  Trans, diode bridge, two caps, two resistors, two voltage regulators, and a handful of parts, and you're in business.  The application circuit for the chip shows the input signal hitting like a 10K impedance, which seems pretty low impedance to me.  I guess you could just throw a buffer in there.  but one board for the buffer and amp chip, one for the power supply, and you got a talk box!  I would like to see either a built-in fuzz or an "effects loop" so you could use a pedal for some sustain before it hit the amp chip.  I think it would work.  I dunno how much that chip costs...the national site says $2.30 each, but that's a rail of 20.

I have no clue why these are in my lab.  They're useless there.