Friday 20 July 2096

INCREASE THE OUTPUT VOLUME ON OVATION OP PRO (Light Approach)


Time to make something GREAT on the OVATION OP PRO:

In this post I will explain how to make this  unit able to OUTPUT a decent
VOLUME without crancking up the Potentiometer ALWAYS to his max and
without modify the gain of the preamp.

Let's see the 1st picture describing where the Piezo Pickup signal enters into the 1st buffer
(An operational amplifier with gain 1)(1st of  four op amp on a TL064 clone IC)




The overall impedance of the Input is 1.2 MOhm ......but .....Jesus the signal is splitted in TWO  by the partition network!!!!!!!!!!!!!!!!!!!!!!!!   WTF?

Basically the 2 resistors cuts in two the signal , only 55% of available piezo output is used!!!!


THEN WHAT ?

VERY SIMPLE  ,We maintain the overall Impadance but We change the resistors partition logic allowing to pass 90% of the signal... using a 220k  + 1M Ohm resistor.




This mod is REALLY easy but You need a skilled solder guy with magnifier glasses and very small soldering iron , 10 ,15 watt...to make it  good & clean:

(I am a quite good solder guy :-)



Here is the result of the mod:


OK RE-PACK all the things and switch the AMP ON.......Tuner is still working...even better...and the VOLUME??????
................MIRACLE   :-)

At half of pot  the volume is quite decent......  At 2 o clock is optimal ....... At 5 o clock is strong
but still absolutely no saturating the things at all.


NOW I OWN A SUPER CUSTOM OP PRO!!!!!!!!!!!!!!!!!!!
SOOOOOOOOOOOOOOOO HAPPY!!!!!!!!!!!!

:-)


KK


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2 comments:

  1. Hi Carlo, great posts on the preamp! Have you ever ran into the low bat light being stuck on by any chance?

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    Replies
    1. No , batt mangement fine, maybe the related opamp comparator is faulty. Or the ref tension to the comparator is defective.

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