• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Vintage kt88 pp mod suggestions

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Hello friends, finally i got my first tube amplifiers. Some vintage mexican kt88 pp monos. I converted them from UL tetrodes to triode mode and rebiased them 70% emission. Also bypassed the first tube stage for "radio" input, since my signals come from srpp tube 2V "lampized" dac and cd player. Bypassed some resistors in the signal path also.

So i would kindly ask your wise advices for getting most precious sound of them. I connect them to 16"s 96db 8ohm technics speakers. Following are both schematics, factory and current mods one.

Also, how can i know the feedback db amount? Have read Pass article about feedback distortion, but not sure how to check the amps feedback db amount. I would like to experiment with 15db, but not shure for this local feedback...I would not touch nfb if adviced for it :)

Also how do you know if power stage operates class a or ab?

Schematics
Mod
http://i1209.photobucket.com/albums/cc390/salvadorgol/65HF-mod_zpsiai9ida6.jpg

Original
http://i1209.photobucket.com/albums/cc390/salvadorgol/65HF-FACTORYSCHEMATICS_zpsuy4wzwjh.jpg


Thank you
 
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