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Talkbox


 
5/20/1999 7:33 AM
Jered C.
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Talkbox
I am trying to find info on how to install an amp inside my talkbox so it's one single unit. Much like the Rocktron Banshee or EH Golden Throat Deluxe. I think I must not be explaining clearly what I am trying to do because I keep getting talkbox info. I already have the talkbox, now I need to install a small amp. I have tried New Sensor, Analogue Mike, and Analogue Heaven, and struck out every time. Any direction, ideas, or suggestions would be greatly appreciated. Jered
 
5/20/1999 10:46 AM
gfr
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Look at the 1st Craig Anderton book there's a mini amplifier that should be suitable (with a PCB). You can also look for any projects of compact amps or headphone amps. Projects with power amp ICs may be easier to build/adjust.
 
5/21/1999 6:36 PM
Steve A.
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gfr:  
 
    Have you ever heard of the Dwarf amps? They came out in the mid 70's after the Pignose and were a lot of fun. I made a clone of mine using a homebrewed circuit board and an ECG ic about 20 years ago. There is a boost switch that kicks in an FET on the input. On the downside they do run on 18 volts, but I was going to rig up one or more rechargeable battery packs to supply the voltage. (I think it requires +18v not +/-9v).  
 
    I'll have to reverse engineer what I did and draw it up. There have been a lot of requests for small and cheap ss amp circuits and this one sounds really great.  
 
Steve Ahola
 
5/26/1999 7:25 AM
GFR
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There's a Radio Shack "phone listening system" that sells for under U$10 that can be a suitable amp - just cut the coil that attaches to the phone and connect the guitar to this cable.
 
5/31/1999 4:19 AM
Steve A.
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Re: Schematics for Dwarf amp and JFET preamp
    I ran across some schematics I drew up almost 20 years ago for the Dwarf ss amp and a JFET-based on-board guitar preamp that Stars Guitars (from SF) used to make. Both of these sound pretty good and were supposedly used a lot in recording studios in SF.  
 
    Perhaps someone can double check the orientation of the 4.7uF tantalum cap used on the S(ource?) of the JFET. I drew it up with the positive (+) lead going to the 50k pot, but it looks backwards compared to the similar JFET preamp used in the Dwarf. And perhaps someone can translate the "E230" markings on the JFET (the JFET in the Dwarf is a 2N4302).  
 
    I need to dig up the number for the power ic used in the Dwarf and will post it here. Any comments or suggestions on these designs would be welcome!  
 
http://www.techaccessinc.com/blueguitar/dwarf.gif" TARGET="_top">http://www.techaccessinc.com/blueguitar/dwarf.gif  
 
http://www.techaccessinc.com/blueguitar/jfet_pre.gif" TARGET="_top">http://www.techaccessinc.com/blueguitar/jfet_pre.gif  
 
Steve Ahola  
 
P.S. I built one or two clone circuits based on the Dwarf design so I know that works, but don't think I cloned the Stars Guitars preamp...
 
5/31/1999 5:50 AM
Jack Orman
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quote:
"Perhaps someone can double check the orientation of the 4.7uF tantalum cap used on the S(ource?) of the JFET. I drew it up with the positive (+) lead going to the 50k pot, but it looks backwards compared to the similar JFET preamp used in the Dwarf."
 
 
It should be reversed with the + lead to E230
 
6/1/1999 8:30 PM
Steve A.
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Jack:  
 
    Thanks! I believe that the preamp I had (probably still have!) may have been assembled wrong (it was on a small circuit board mounted to the back of a square A&B "mod" pot. I also found a drawing I made of the circuit board, with the (+) terminal going to the pot.  
 
    My question is this: would it work at all if that cap was reversed? It did seem to work fine but I wasn't really crazy about on-board electronics. Question #2, regular transistors come in NPN and PNP flavors; is there likewise a reverse polarity type of FET? Maybe the E230 is of oppposite polarity to the 2N4302 (if such a beast does exist)?  
 
Steve Ahola  
 
P.S. If I dig around I can also probably find some of the other active pots that I got from Stars and other sources. One of them was a distortion pot; you'd pull out the knob to switch it in and the pot would control the amount of distortion (without drastically affecting the overall level if I remember correctly).
 
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