Quote from: Roly on October 08, 2013, 06:02:55 PMQuote from: Superfuzzmy old Carlsbro slave amp (wich I converted to current feedback) but for some reason I get oscillations
Now with current feedback the phase of the feedback can be a very sensitive function of the driver and cab resonances, and it is quite possible for feedback that is negative or out of phase in the mid band to rotate sufficiently at the extremes of frequency response to become in phase and cause transient instability, ringing, our outright oscillation, either low frequency putt-putt "motorboating", or high frequency shreaks or whistles.
For this reason current feedback is typically limited to around %10 of the level of the voltage feedback in the same amplifier, and attempts to apply more current feedback may result in various forms of amplifier instability.
HTH
That's a big help! Is there any formula to calculate the ratio between voltage feedback resistors and current feedback ones? Now is too late here but tomorrow I'll upload the simple schem of the mod I did to my carlsbro slave 1000, I must have messed with values too much!