Talkback-Loudspeaker Amp

[Samuel Groner]

Hi

I need a small active TB-loudspeaker for my classical recordings with mic in, line in and a mic split out (line level, to feed the signal to another speaker). I'll use a 50 W, 8 Ohm full-range speaker and here's the current plan for the electronics: tb_loudspeaker_r1.pdf

Any suggestions, errors (yeah, TP101 should be connected to U101 out), comments? Thanks for your input!

Samuel

 

[walter]

That looks straight-forward. Are the C201 and C205 caps necessary? It looks like they are parallel with the C305 to C309, and C310 to C314 caps.

 

[Guest]

Suggestion 1: take the signal that is yet less distorted (I know you can preserve it amplifying!)
Suggestion 2: use EQ to make the path as flat as possible (from mics to speakers)
Suggestion 3: use pristine clean amp
Suggestion 4: use phased arrays of speakers that will flare only to those who have to hear them to minimize unneeded reflections.

Why?

Feedback.

Everything that hear people who sing is going to your mics. In case of a feedback it is accentuated by feedback.

Suggestion 5: use headphones and avoid troubles 1-4.

I specialize in recording of life events where headphones are impossible so in addition to 1-4 I carry damping panels. They have to look nice, be transportable, and damp as wide as possible frequency band flatly. It is very contradictory... I had to try lot of materials/constructions while found some that satisfies me so-so currently. However, tomorrow I'll find that unsatisfactory...

I.e. schematics are significant, but in my mind according to my rich experience they are not vital since I know how good electrical engineer you are. You can design electronics without our help (though, a socializing matters), but some wise suggestions "out of the box" may help.

Good luck Samuel!

:thumb:

 

[tv]

Yo ...

For an idea on how to linearize the gainclone stage, look here:

http://www.cabezal.com/~inguz/amp/inguz_amplifier.pdf
http://www.cabezal.com/~inguz/amp/inguz_amplifier.xls
(I don't really think that using the choke is really really neccessary, but meisters may disagree, the latter link is a resistor-calculator)

or

http://www.twistedpearaudio.com/docs/project_my_ref.pdf
(both use the howland pump)


or if you can use floating connected speaker, here is an easy way -LOOK in bottom right corner- (this schematic uses tda2040 but you can apply that to your circuit, BUT in this case you'd need to connect your gainclone in non-inverting manner, therefore I think that howland circuit may better suit you, esp. since inguz amplifier pdf links to a spreadsheet with resistor values, and because your shemo shows your gainclone is going to be connected to a known fixed-impendance source).
http://www.freeinfosociety.com/electronics/schematics/audio/pictures/peaveyrage158.gif

Et voila, I'm out of here before the smoke-signals emerge.



(Btw. if you can find a way how to apply the howland pump on a TDA2003 -the car radio chip- for grounded loads, I will be eternally grateful ... or else I will start a new thread here)