talkbox issue

ok im trying to make a real low cost talk box as i dont have much to spend i have a speaker from a radio that broke that works and on the back it says:

8ohms max 2w

i know that this probs will break itself and my amp if i try so i was thinking make a talkbox for a mini amp and if that works splash out on making a proper one. Now since it has to be plugged into headphones i took headphone skinned it and connected it to pins of speaker but never mind what i do i cant get some sound to come out of that speaker. Now i know that i need sound to come out of it to go through a tube which goes to my mouth so could someone help me

or at least tell me i cant get it to work due to not enough power to drive it and give me tips on how to make a mini amp using the speaker

Ok I been working on it and researching a bit and my hypothesis is that not enough power comes out of the headphone slot of the mini amp as it was made for actual small headphones like on a mp3 and they have less powerful speakers so need well less power.

Now should i try and increase current with a capacitor or voltage with a transistor. I do GCSE electronics but i dont know my transistors very well and we dont work with stuff like this so can someone help and if it is a capacitor tell me whether i should be using polarised or non polarised and if its transistor tell me what wires go on what legs

thanks

ps i've included a schematic showing what im doing to help

heres the image

ok even though no ones replied I'm gonna be optimistic and think that someone may still help so im gonna make an update

I tried sticking a non polarised capacitor in before the positive terminal to amplify the current did nothing dont know the value as ui stole it from a radio and I cant read the amazingly small blurred writing on the casing.

would pluging a practise amp into the heaphone socket of my 15 watt mean that sound comes out of the practise amp

and could i make a talkbox by making a clip on attachment to the front of my amp with a tube to take the sound from it to my mouth or would it need to be attached on and soundproofed or somin to work?

Madman,
It's 6AM here and I'm still half asleep so I'm going to have to help when I finally wake up! But, you have just learned that you can't drive a larger speaker with headphone jacks (not enough power) and you can't use a capacitor to amplify (they are used as filters or as isolation devices). Bottom line is you are going to need some parts to make this happen. So I googled "talk box" and came up with this site http://www.blamepro.com/talkboxG.htm.
As you can see it's not a simple as you may have thought.
If you have a more simple design could you direct me to it and I'll look it over and see if I can help?
Phip

http://www.youtube.com/watch?v=9EIQxwotn3k
I looked at this guy and have done a bit of research into it and I dont have computor speakers to use but since you can use them Im going to look into connecting an amp to the one my guitars plugged via the headphone slot I will have this amp soundproofed with a funnel and tube attached to the speaker which will be soundproofed with sound insulating foam stuff (can't remember proper name). In theory the sound should come through the amp connected via headphones and be directed up tube into my mouth. Now I'm going to make this for a full sized amp as you get more power from the headphones than from a mini amp thats designed for ear phones like you would use for an mp3 or an ipod and the amp converted to talkbox would be a lower value than the actual amp as the headphones get less power but will still be high enough to function well with out circuit getting blown up or somthing.

Now my amp is 15 watts and I'm not sure what value speaker the headphone slot can power but once I know im going to make a basic amp to convert to talk box basic in sense theres no high mid or low as I will get that off the amp its plugged into so its not needed.

In my electronics class (I'm a star currently but now a days you only need 65% on the test to get A star and thats what i've got so dont get too complex) we have to do flow diagrams to illustrate our point so Im gonna draw one up incase thats too long winded and/or my explanation isnt best.

Im going to bump this because my question hasn't really been answered in much detail and i can't find the answer anywere because most talkbox sites i found use horndrivers or have overly complex diagrams and dont deal in a simplified one

except for the ghetto talkbox but thats taking a pc speaker putting a funnel over it and plugging it into an amp and it didnt explain it very well i dont think.

edit:i wrote hornblowers instead of horndriver- god the exams must be getting to me

Ok, just did a little searching here. instead of using the headphone jack of the 15W amp you should open the amp and splice into the speaker wire inside. (See Diagram)




By installing a switch you will be able to quickly switch between the normal amp speaker and the talk box speaker. You can get fancy and put in a jack to make it easy to quickly remove the talk box. cut the + wire of the speaker inside the amp and install a switch on that line. connect the negative speaker wire to the negative terminal of the talk box. now turn the volume of the 15W amp all the way down before turning it on then turn it on and slowly bring the volume up to do a quick test to see if everything is working properly.
Phip
Note: always unplugg electical devices before removing the cover. When you flip the switch you will be applying the audio drive to either the internal amp speaker OR the talk box. Very simple to do and allows you to use the amp normally with the flip of a switch. before you mount the switch or install jacks you should do a quick test to see if you are satisfied with the results.
Now, regarding the output stage (talk box) you are using a amp that you are going to seal and insert a tube. That is fine. I would suggest that you connect directly to the speaker in that unit and do not use the input jack. Also do not power up that unit. The 15W amp should be enough to power the speaker in the output box. Connecting the 15W amp to the input of the output stage will most likely cause damage to the 15W amp or the modified output amp or both. Just use that modified output amp for it's speaker only and do NOT power it up. OK?

From what i have seen on youtube the homemade talkboxes don't have much of an output so the people are putting a mike in front of the talkbox and sending that to a larger amp for more amplification. You are right though, the examples I found on the internet are not exactly detailed. I just don't think you are going to get enough drive out of the headphone jack of that 15W amp (or any headphone jack) to drive anything except headphones. The output of headphone circuits is very limited.
Keep me posted about your progress
Phip

ok its just i thought that on the bigger amp its made to run headphones like: http://most-expensive.net/wp-content/uploads/2007/04/expensive-headphones.jpg
meanwhile the mini amp is made for: http://www.hardwarezone.com/img/data/nnews/2006/3542/Image/EarphonesBig.jpg

now i thought the first ones i showed for the 15w amp would take more power to drive as they are bigger than the mini amp earphones

now making a mini amp thing with the same speakers as the first pic i linked to should be able to be powered by it and i can amplify it separatly to make up for lack of volume.

I am however reluctant to cut up my 15watt amp in anyway as this is one of the few pieces of gear my parents have got me and i havnt bought and it was for xmas so i dont think my dad would be too keen on it.

Also that way the talkbox can be deattached and that would be more convenient for transport or if the amp breaks somehow

Im also not starting this till my gcse's are over in 2 weeks and 1 day im just making plans when not revising or practising for the hour or so a day i get

Ok Madman I understand.
Let me research a little more ok?
I'll post when I have something interesting to say.
My guess it you can use the headphone output but you will need to amplify it. I'll check out the links you just listed and see what I can come up with.
Phip

Can you give me a model number and manufacturer of that mini amp?

Actually you could make a simple amp to drive that 2W speaker. Very few parts needed. here is a link just so you can get an idea of what would be needed.
http://michaelgellis.tripod.com/audioamp.html (take a look at the small amp diagram just before the parts list near the end of the page)

or: http://www.zen22142.zen.co.uk/Circuits/Audio/2wamp.html
(this one is exactly 2W. and you could power it with any small power pack that comes with a boom box or other small device providing it has a 15V output.)

So.....you could feed the headphone output from the 15W amp into a home made 2W amplifier and drive the speaker (talk box) with that.

Sorry to be such a pest. Ok, here is what you want......

http://www.rason.org/Projects/icamps/icamps.pdf

Nice description in this document of how these goodies work. You would of course use the LM380 IC and power it with a small power pack as I described above (one you can borrow from a boom box or other device)All you will need with be a couple of resistors and a couple of electrolytic capacitors, the LM380 and a little bit of wire and maybe some jacks for easy disconnecting. Pretty cool yes?
Phip

gez, phip are you an electric engineer or have you masted searching with this google thing :)

Looks like an interesting project.

@ Tele,
Nah, I'm the TV repairman. I thought I mentioned that at some point in another thread. 34 Years of working on this electronic crap! Ok, now you guys, no questions about what's wrong with your TV at home. We are closed for the evening. Although if we have any members in Hawaii I'd be glad to do a house-call for a nominal fee! :)
Phip
my website for anyone interested.....
http://www.edstv.com/

Madman (you are indeed a madman!)
I drew this up for you. Any questions?




Phip
Ahhhh it posted a bit small. download the image and blow it up. If you can't read it just PM me and I'll send you the original .jpg It is a large enough file to blow up and see everything quite clearly.
Be sure to read the notes on the webpage (http://www.rason.org/Projects/icamps/icamps.pdf) for this IC relating to figure 3. Also you should be able to use 1/2W resistors and the electrolytics should be 50V (don't cheap out).