Talk Box Small Amplifier Suggestion

[dustfilledhobo]

I'd like to build a talk box with a small amplifier inside of it.  I know that most of the DIY talk boxes either use powered computer speakers (and their amplifier) or small guitar practice amps, I'd like to create a foot switch version.

I'd like to use this driver: https://www.parts-express.com/goldwood-gm-500cd-1-horn-driver-1-3-8-18-tpi--260-097

I'm using this filter cap: https://www.parts-express.com/22uf-100v-electrolytic-non-polarized-crossover-capacitor--027-348

My question is what type of audio amp should I use?  I'm guessing since the speaker is rated at 80W RMS, that I should look for a 40W amp?  Is this right?

Also, will one of these cheap Chinese amps work for this application? https://www.ebay.com/itm/40W-TDA7377-Stereo-Dual-channel-Audio-Power-Amplifier-Board-Treble-Bass/132842770315?hash=item1eee0bcf8b&_trkparms=ispr%3D1&enc=AQAEAAADIKvsXIZtBqdkfsZsMtzFbFsbX3WcW5fmB%2Fx7ZbaZTyex981T%2BFEAn48jwJznVWes4kiW27FehhN9xm8y6BqlRhbH8l2YfdKIP8xpF3kaxhdBcfmrkk3Fc%2BZ1RluhBd94BN8wGPEHa%2B%2FEHAdcxAbYtyjRJpQb2Qk8r4GYErZs9LwhTBoV7HPBKfYgKacyeoi5f7ZTlpcNYiLDiEpUUAstJyBIKO0C99k%2BIvo%2FEzteafYRkorc%2FXLN5cPfoq6OTZHLF%2BYLRPxvPV24sc2RKBwSmMYjd45HU5r1eiFJ%2FAGBsCNxPkWqUihxozN%2F98vvoijLCzOoGg1gqoeZgeWx2Hqb74z1KPYCsKY1a3LBkl3HdOvTK5w%2FHon2VLsVAI0LzlstNX54v4ui4rsagsuTSkStXdvsz9kS17eox8zMbg3mjjDfW3AcOpv0wgEAbJkj9zkLkOF3SWqRoU1V0x6%2BqoFqxwLY%2F%2FJN4ITis2aF9XMdypYfzAn%2BC97ByiFd35HVvQ9YH26UalKPP08smwlWWUPdES4%2FndvasfzqWrsQRdjXO91L%2BC%2FONsgK6OA0ZmvSNckIheBJklmWIYyFAuCp882TsQSw9GXtgetc127iATU6T%2Fe6Ut9ztHxcV75TUuedJxUKVs7zgqLxVPszesn1HYPeBkdJU6EUKKBWc8reExV7Jce1ClfCRO8dkQPIF%2Ff0L2SU8D%2BcI2jV0ix0DOhGVMpfA%2FdAJj5U79I5ViZaSxnsI6woXUmqEv6C%2BQkv5yS9dSgT6KwH38B04L%2BYAfpAIMQxmEO57KTOFRbCRLtnY4UQQd0nfiK%2BqWuUwVoHR563zNpKNaCJPGiWiURjHhoFjjYq1Bon8y07LNz4FokEAXk%2FSRt55qDCY27xN2R8myRcn5rfjnVrU3FO0S%2Bq5uOKYMEEd3DaDSYKerTykLAV8tZubq8nIiMuptJ0IDEzk9mZgmcXUm48ARiYdeaFNrQMqMEBxr4OUtOD8HW%2FMuFxQcQzzsP6HUjNeoqHG2MMTZywZ3lf3hxscTm5gsqweg6kJVsXVVLLlu4CNPbzNnrBRaqqQ1fN&checksum=132842770315ea58ce9e178e48ac83118419cf404843

Thanks in advance for any help!

[Mark Hammer]

Ideally, whatever tube conducts the speaker/driver's output to the mic should impose as little resonant properties as possible.  That would suggest the shortest and widest tube possible, and preferably something inert.  You want it to act like a conduit, rather than a tone-shaper.

Talk boxes don't necessarily have to use high-powered amps and drivers.  I have a Danelectro Free Speech pedal, like this one, and it uses  a 386 amp chip and a 3" speaker, running off a 9V battery.  Heck, you can even leave the tube off and use it as a practice amp!

The critical aspect is really the mouth/mic junction and quality of mic capsule.

[GibsonGM]

An older friend of mine gave me a driver much like that one...probably from an ancient "MASH"-style speaker horn, from a ballfield or something.  It probably can handle over 100W.    It is good to have that 'headroom' if you will, so you know you'll never pop it with a small, regular amp.

That said....remember, all this needs to do is send sound up a tube into your mouth, where your mic in front of you pics up your vocal wah'ing.  You don't want to crank the daylights out of it, ha ha...your dentist doesn't want you to shake your teeth out!!!    Also, you may find you want way less distortion than you're used to if doing the talkbox thing, so driving the output isn't really a factor here.

All the real, in-use talkboxes I've seen, including my own, use a small practice amp.   I placed a switching jack in like w/the speaker, so when I plug in the driver, the amp speaker goes silent.   So I can still use it to...practice with.  As long as the sound up the tube is loud enough to wah and for the mic to 'hear', you're all set.

I feel 40W is way overkill.   I like the driver, but all you need is a $20 yard sale amp!   You don't gain anything by using a 40W amp you'll simply have to turn way way down when it rattles your head.  Just my 2 cents!      

Welcome to the forum, too.

[dustfilledhobo]

I feel 40W is way overkill.

Talk boxes don't necessarily have to use high-powered amps and drivers.  I have a Danelectro Free Speech pedal, like this one, and it uses  a 386 amp chip and a 3" speaker, running off a 9V battery.

I tried to figure this out on my own using Google searches, but many people claim you NEED 30-50W and others are telling horror stories of mouth pain from homemade talk boxes that were too powerful.  Thanks for both of your insights, I'm going to go with your lower power suggestions.

I'd like to avoid using a practice amp, simply for aesthetic purposes (I know that's a little silly).  I have 2 practice amps that I wouldn't mind sacrificing to this project, but I would rather build a talk box that looks closer to a guitar pedal if at all possible.  The practice amps I have are 15W and 10W so, I'm guessing an audio amplifier in this range would work to drive the driver I linked to in the original post.

This looks like it will work to me.  Can someone please look at this and verify that it will work with the driver I linked in the original post?  Thank you!

https://www.amazon.com/Ximimark-TDA7297-Amplifier-Dual-Channel-Component/dp/B07MYY3LX3/ref=sr_1_5?keywords=15w+amplifier&qid=1566498473&refinements=p_85%3A2470955011&rnid=2470954011&rps=1&s=gateway&sr=8-5

Welcome to the forum, too.

Thank you, I've been lurking for years and finally had something to post about.

[GibsonGM]

Why the 'shame' of having a small practice amp on stage?  If so, can't you paint it/decorate it/beat the crap out of it to make it look cool? Or, put it behind your main rig and hide it?  A/B switch...usual amp, then switch to the talkbox amp.

Or take the actual amp out of the little enclosure, make a new box for it that looks cool

If you wanted to get a unit like the one you linked to, sure, that would do fine - but why do you need TWO channels?  One would suffice...tho at $7, I'm not sure there's any savings there, ha ha!   Is it ok to have one channel unused, and 'floating'??   I'd want to know that first.

I'd recommend getting the driver first, trying it w/ the practice amp to see what it sounds like - will it drive enough to get sound to the mic ok, etc.  If so, find out what wattage that amp is.     Bet you'd only have a little 10W amp turned up 50% to drive it.    I use a poly tube connected to driver w/brass plumbing nipple (thread one side, nip other)...tube is about 1/2" or 5/8" I think.     I got a lot of it, and made it long - occasionally I can cut off some when it gets gross.   A nipplexnipple connector is good near the box to change out the whole tube - and after use, you can take of the mouth end and sterilize it!!

It is a good topic...there is a LOT to talk about re. talkboxes, and MANY ways to do the same thing!

[dustfilledhobo]

...but why do you need TWO channels? 

It's all I could find 

Is it ok to have one channel unused, and 'floating'??   I'd want to know that first.

Good question, does anyone else here know?

I'd recommend getting the driver first, trying it w/ the practice amp to see what it sounds like - will it drive enough to get sound to the mic ok, etc.  If so, find out what wattage that amp is.     Bet you'd only have a little 10W amp turned up 50% to drive it.    I use a poly tube connected to driver w/brass plumbing nipple (thread one side, nip other)...tube is about 1/2" or 5/8" I think.     I got a lot of it, and made it long - occasionally I can cut off some when it gets gross.   A nipplexnipple connector is good near the box to change out the whole tube - and after use, you can take of the mouth end and sterilize it!!

That's a good idea, I'll probably do that before buying the amplifier.  Thanks!

[GibsonGM]

...but why do you need TWO channels? 

It's all I could find 

I see what you mean, searching gets only stereo stuff!   It's cheap enough to experiment with, for sure.   Maybe one day DIY one from a chip amp

[Mark Hammer]

My Free Speech pedal works like a normal stompbox in many respects: battery or 9V supply, momentary switch and FET-based bypass.  Hit the bypass switch and your guitar continues on through the remainder of the signal path.  As I understand it, some of the "historic" talkboxes assume that the voice mic, going into the P.A. is how the talkbox results will be heard, rather than the talkbox mic providing a modified/effected signal going to your guitar amp.  So the need for a higher-powered amp pushing a higher-power driver is for providing a robust enough signal to the voice mic (something approximating an SM57 or work-alike) to feed the PA, and is not an absolute requirement for the effect, per se.  The speaker/mic junction in my pedal is treated in a manner similar to an LED/photocell junction as far as the pedal is concerned.  Anything that allows for "mouth-filtering" is fine. 

And since neither plastic tubes nor mouth-cavities are particularly good at managing harmonic content, the assembly pushing audio up the tube to your mouth tends to need more sustained harmonic content for your mouth to do the job that needs doing.  In that respect, overdriving a puny 8-pin headphone amp, like an LM386 or similar, can be just what the doctor ordered.

The battery-operated PAiA Pygmy amp was used as a talkbox, with a bezel they sold that would fit over the speaker and allow easy connection of a plastic tube.

[bettsaj]

My question is what type of audio amp should I use?  I'm guessing since the speaker is rated at 80W RMS, that I should look for a 40W amp?  Is this right?

80w..... 40w amp!!! All seems awfully too powerful for a talk box.

[GibsonGM]

Mark - how does that sucker work?  Its own mic at the mouth end or something, back into the signal path??  Interesting, and if so, would eliminate the extra amp and so on.

[stallik]

When I came to sorting the tube for my talk box, I joined it to a piece of chromed copper pipe, bent to fit round the mic. Short mouthpiece is removable and easily cleaned

I'm using a pignose as the amp and a switch box containing a mic preamp so that I can either go to a pa or back into the guitar amp.
Fun to make, almost never use it

[GibsonGM]

Nice rig Kevin...I know what you mean, it's a nice 'show stopper', but then it doesn't get used as much.   Tho this thread makes me want to dig mine out 

[Mark Hammer]

Mark - how does that sucker work?  Its own mic at the mouth end or something, back into the signal path??  Interesting, and if so, would eliminate the extra amp and so on.

I assume you mean the Free Speech pedal, or do you mean the Pygmy amp setup?  If the Pygmy, then I gather the arrangement was the same as per the Bag or Heil units; i.e., you feed the voice mic's output to a P.A.

If it's the Free Speech you're talking about, it works like any stompbox, except that the unit has a mic input jack.  So, the pedal feeds an amp chip which feeds a little speaker, the speaker feeds a tube, and the mic unit the pedal comes with feeds the mic input of the pedal.

[GibsonGM]

Yes, Free Speech.  Sounds pretty cool!  So,the mic is up on a stand in front of you as usual, and it gets fed back into the enclosure, is amped and goes out as part of your signal chain?    I'm trying to conceptualize the mechanics of it.   That takes a few steps out of the process for sure.

[Mark Hammer]

I bought mine second hand.  It normally comes with a small dual electret-capsule assembly, but the guy I bought from didn't provide it.  The small electrets are a real advantage.  You can practically surround them with your mouth, and you can attach them to the plastic hose with some gaffer tape or velcro, without requiring a mic stand separate from the voice mic.

[GibsonGM]

Sounds pretty cool, Mark   I've messed w/them for a friend, fixing his vid camera's audio - yes, some can be pretty good little units!

[Ben N]

Do you feel like I do? 

[GibsonGM]

I wanna thank you...

[Ben N]

Couldn't get no higher.

[italianguy63]

"My daddy was a Gibson
my mama was a Fender
That's why they call me
Mindbender
Mindbender - That's my name."