Talk box build

Gearhead · 2009-11-22T22:50:08+00:00

Realising I have not been very forthcoming with what I'm up to, I have decided to go and share a build with y'all: a tube powered talkbox. Whatsa talkbox? R...

Talk box build

Valie

If you want a single ended o/tranny just pm me. It comes out of a Akai valve tape recorder. Used two EL 84's single ended in stereo.

Gearhead

@Andre 1: I don't think the two-amp story will ever be a problem. I will run the guitar into the talkbox and the talkbox tap into the rest of the rig. I should have a footswitch for true bypass vs. tapped and one for mute output.

@ Andre 2: If your talkbox does not like drive it must be because it cannot handle low frequency signals. Just because a driver does not produce volume at a certain frequency does not mean the coil is not moving. The low frequency signal pushes the coil to the end of the stroke while it is outputting your highs. Since no speaker coil is very linear at the end of the stroke, your distorted signal is going to get messed up. My plan is to lower the resonant frequency of the system to, say, 200 Hz and to electrically filter out everything underneath 250. I will of course need to make an impedance compensating filter so the tapped signal will still be relatively balanced.

@Valie: have already ordered tranny but am nevertheless interested in the offer. Will PM later.

tonerider

AH! ?

Yours is a new take on the classic design if I understand you correctly.

You will run from the guitar directly into the talkbox (with a dedicated amp built into it to power the horn driver) ?
At the talkbox you will somehow have a true bypass that will route the guitar's signal either to your guitar amp or to the talkbox ?
Will this not make for a very bulky unit that will be lying at your feet at the mic stand since the tube still has to travel up to the mic (mouth) ?

It seems like an interesting project and has started me thinking as well. Just wondering how I will rig this up live since I have a rack and I go UHF wireless.

You can make out my regular talkbox in my small profile pic on the left here.

AlanRatcliffe

As an aside Gearhead:

I used to use an amplitude modulator for a "talkbox" (one was built in to a Boss SE-50 I had). Use a mic as modulator and the guitar sound as carrier and a highpass filtered sidechain to add a little of the uneffected bypass signal back in to the mix.

Worked very well and you can also then use any electronic signal for either modulator or carrier (I often used to use a drumbox/drum submix as modulator) - similar to using a sidechain as key for a gate, but with more control than the usual on/off. ?

Gearhead

@Andre: you've got the picture. The enclosure I have in mind is a 75x50mm aluminium rectangular tube of about half a metre, running across the top of my floor board. I just bought an FCB1010, so I could control two switches in the talkbox. The big hurdle in the design now is lowering the resonant frequency of the compression driver, I am just going to build the rest first and research the topic, I'm sure the answer will dawn on me.

@Alan: please let me just finish this and not think of alternatives.....

AlanRatcliffe

please let me just finish this and not think of alternatives.....

Gotcha! ?

Gearhead

Long time no progress but I now stumbled onto the Monacor KU-616T compression driver which is meant for 100V use and has 112dB at 75W from 160-6500Hz. If I could use this thing it would require a funny OPT but eliminate the need for any filtering or acoustic manipulation. Now how to get hold of one...

Gearhead

Just ordered a couple of NOS 6EJ7 tubes to replace the EF86 as the preamp pentode. Interesting tube. A dozen times more gain to play with so can put the tonestack and the volume between preamp tube and output tube while still having enough drive. Am hoping the one tube preamp will make the amp have less compression while pushed.

Gearhead

found another example of an oke trying to do the same sorta thing:
http://www.kolumbus.fi/risto.kivioja/RikstoneAmps/CircuitC5.pdf

Nicholas-L

I cant wait to see the end result of this project ?

Gearhead

Even better candidate, fullrange: B&C DCX50. Bit costly, but that's just a matter of saving up ?

Gearhead

Or, a lot more affordable, I could go for a normal driver and put a cone on it to get to the hose...