esp P68 mods

[lance06]

good day to all,im a newbie here and i would like to ask if the p68 subwoofer amp from esp could run at voltages higher than rod specified.is there any mods i can do to the circuit to make it run at +/- 90V?im planning to build one with 12 output trannies and 90V supply.thanks all diyers!!!

[sakis]

no way jose!!!! input stage is not designed for a thing like that but aslo i think that even if you double the outputs there is a serious chance that the amp will become unstable as most of these amplifiers class AB+B tend to

at this type of voltage the amplifiers schematic becomes almost not importand if compaired to the measures needed to preserve stabilty at this power ...

Add to the all above that class AB +B amps also have poor frequency responce means that is axecellent amplifier for sub woofer but not for real hifi or quality systems .

Personally i would never bulit an amplifier that is more than 100-150 watt that doesnt feature current sources and Vi limiters ...

pros and cons .... but listen to this also ....that is the same imortand ... class AB+B amplifiers are more efficient than normal class AB amps ... you may benefit from this lees supply and less cooling needed

then again class AB+B amps are by far more tollerant to reactive loads ( such is a speaker ) resulting less protection is needed by all means

that was a complete picture the rest of the choise is yours

a happy P68 builder

[sakis]

one question that could really (if answered) be very usefull is why the author choosed to use a class AB+B topology
could it be that this is only supposed to be used as sub amplifier only
or could it be that the benefit of this topology regarding stabilty versus sound quality is an issue ???

[lance06]

so i can use it only at +/- 70V max.it is for subwoofer duties thats why it was designed with this tropology.i already built a couple of P68's using 2sa1943/2sc5200 outputs so far they are happy driving 2 pcs 12 inch sony explod subs rated at 300W 4 ohms.but im using a +/-50V supplies because of the 4 ohms load,all day the P68 is running quite warm only even at very high levels.