is there a chip replacement for this i could use?

[pinkjimiphoton]

hi, gotta rocktron banshee... sometimes it's more convenient than my "real" talkbox to have it built into an inline effect.

but... it's only 5 watts. AND it has to share my vocal mic, i dont have a second mic/stand to use, nor do i want one.

this thing sounds good, but 5 watts is no where near enough "ass" for me... i can sing louder than this thing puts out.
in my experience over the years, you need more like 30 minimum to have it work well. you don't always want 100% distortion, or to have your guitar dimed just to hear it... at least *I* dont,

so here's the schematic:


looking at it, i'm thinking if i beefed up the power supply a bit, maybe i could get away with maybe a TDA2030, which i DO have... and is supposed to be a 30 watt chip.
but wondering if maybe there's a better choice than that, prefferably something that i could swap out for the TDA2614 exactly... even if i could just double the power, that would probably help.
prefer to take it up around 50 watts even, if possible, tho i figure that would be impractical.

i know nothing of solid state chip amps whatsoever (and not afraid to admit i am a hack who gets lucky sometimes) so if somebody could help a bruddah out and illuminate
the darkness betwixt my vaccuous ears, i'd be very grateful, thanks!



be nice to make this thing actually USEFUL, and not have to sling a whole other amp just for my old stand alone talkbox like i normally would (well, that's not accurate... normally i'd use my hotrodded princeton and switch between the onboard speaker and the driver, but i'm working in a band right now that my cyber deluxe just is a better choice... the princeton is a fire-breathing monster made for rocknroll and blues, and doesn't really have any "clean" to it. )

[armdnrdy]

I have one of these things....I love it!!!

You have to be careful though......this thing is so cool....you'll do a "talkbox" solo on every song! 

Can you say....Do you feel like we do?

[pinkjimiphoton]

i can have a whole conversation, but not with this thing. it just doesn't have enough "ass" to keep up stock for me.

gotta be a better chip i'm hoping, that won't take serious modification.

[petey twofinger]

is this the design that uses a tube to carry the sound ?

how about a different layout or diameter for the tube , or perhaps a shorter tube ....

just thinking out loud . i messed with this years ago and i seem to remember using a garden hose size tube then reducing it at the mouth end . this made a huge difference if i remember correctly . buti was powering it with a 15 watt fender champ so ... yeah , i'll shut up now .

[R.G.]

You have a bigger problem. The chip used as a power amp is almost parenthetical.

Power amplifiers are best thought of as a small wart on a power *supply* that lets some of the power through in a carefully controlled fashion. If the power supply isn't there to provide it, no power amp can put it out.

So you can get a 50W chip (LM3886 is available. well tried, many designs on the net) for about $5 a pop. You will need to provide it with probably 70W of bipolar (+/-) DC power so it can put out that 50W though. The power supply will certainly be more than $5, and and will not fit in the original box.

By the way, you have it right. A 50W output is about right to be heard as "twice as loud" as a 5W amp.

If you can get more sound to your mouth by a more efficient driver or tube setup, as was mentioned, you can economize on the power amp stuff.

[pinkjimiphoton]

thanks RG...

i could try and find a more efficient driver, but at that point, i doubt it would fit in the pedal enclosure.
hmmmm...
beefing up the power supply to a split 70v dc is probably just not worth the effort for this thing.

i do have the chip for this :



not really sure what it means by "supply as 9 at 22v symetric power" tho... assuming it needs a charge pump kind of deal?

if this thing would work, may be able to cobble together a different circuit based on the pedal, but with the more powerful amp.
even 20 watts would work better than 5, i'd think.

maybe if i were to use the existing 15v ac into a full wave rectifier feeding a charge pump, or... too much current i'm thinking?

thanks for the help bro... appreciated!! 

[pinkjimiphoton]

petey, yah, you use a tube. but it needs way more ass bro

[stirfoo]

I have one of these but don't have an answer to your question.

I do have a question about the Banshee schematic though.

What is the purpose of C17, the 22uF cap below the relay? Is this the "make slow-down" cap I've read about in other threads on relay switchers?

[R.G.]

beefing up the power supply to a split 70v dc is probably just not worth the effort for this thing.

Remember - if the power supply won't make the DC to be converted to audio, it can't put out the power.

i do have the chip for this :
not really sure what it means by "supply as 9 at 22v symetric power" tho... assuming it needs a charge pump kind of deal?

The TDA2030 datasheet says it will die if you put in +/- 22V bipolar. Its absolute maximum (read that as "go above this if you have a death wish for your parts") is 36V total. So +/- 18V is the biggest that can be use on it. With +/- 18V supplies, it will put out 18W into 4 ohms, 12W into 8 ohms. When it does that, it dissipates 12-14W as heat, so it needs a sincere heat sink. I don't know what engl2000 meant exactly, but I would not try it. A pin-for-pin replacement, the LM1875 can get to 30W into 4 ohms, but it will have to dissipate 40W to do that, and you'll need to encase it in a solid block of ice to do it.   Not to mention feeding it the 30W of power it's putting out, plus the 40W it's eating, so you'll be feeding it +/-30V at well over an amp.

The power supply is really the thing.

The LM3886 can work with the same +/-30V power supply, and dissipate much the same power, but it's not working particularly hard to do this.  The TDA2030 can't get there. The LM1875 can, but is marginal at 30W, which has to be a 4 ohm load, and costs $2.50. The LM3886 can get there, isn't working all that hard, and costs $6.72. A suitable power transformer for this will be 36Vct at about 1.5-2A and cost $15 if you can get it cheap, and $25-30 if you buy it over the counter. The filter caps are several bucks each. And you will have to heat sink any one of them.

maybe if i were to use the existing 15v ac into a full wave rectifier feeding a charge pump, or... too much current i'm thinking?

Too much current.

I don't want to rain on the parade, but think in terms of the power supply to drive the chip, not the chip. The chip is cheap. The power supply and heat sink are expensive and large.

[pinkjimiphoton]

diggit. thanks RG...

i think i'll abandon this here endeavour.

too much hassle for too little return, easier to just use the "real" talkbox than to try and beef this up. 

[brett]

Hi
inkjet printers often have power supplies of +/- 16 or 18 V at an amp or more. Your charity shop has them for $2.
cheers

[pinkjimiphoton]

i've got power supplies that would do it, but there's just not enough room to work with IN the pedal to be practical.
easier to just use my hotrodded princeton. sounds better, too.

[maartendh]

Have a look at the speaker in your rocktron setup; would not be surprised if it is just a cheap, inefficient thing. You might experiment with some other (guitar?) speaker to see whether this improves your volume.
Maarten

[pinkjimiphoton]

yah, probably a total p.o.s. bro.

i've got GOOD drivers, but they won't fit. this thing is mass produced cheap ass crap, unfortunately.
it's fine for some people i guess, but just not for me.

[petey twofinger]

off topic but have u seen this one ?

http://www.youtube.com/watch?v=UYMiLhj3wz8

[pinkjimiphoton]

petey, hit me with a PM on facebook please asap

[pabloevaristo]

Hi guys, a lot of time since this was working. but let´s try!
I received my banshee talkbox, tried it and worked. Then I change de power adaptor (I´m in Spain, so we use 220V and I didn´t want to use a 220->110V transformer).
I didn´t realize that the original adaptor is AC/AC, and the one that I used is AC/DC (al the other characteristics are the same).
The led was on, but no sound from the driver. I changed to the original adaptor and..... NOTHING.
It´s not working at all. The other 2 outputs are working when I press the pedal switch.
Any idea please?.......

[armdnrdy]

Did you really need to resurrect this two year old thread when you posted the same question in this one? 

http://www.diystompboxes.com/smfforum/index.php?topic=112206.0