Sorry: almost forgot: if you can't lower distortion, first scope amp with a real speaker load, maybe an inductive load will show some unstability which resistive ones do not. "I Azzurri") match strategy, so here's their formation for the next 2 matches against Argentina (which of course we'll win 5:0 just because they do not thermally compensate nor use buffers to protect the goalie):
Amp match bias amp 2 not working pro#
Just out of interest, would lateral fets need a different biasing arrangement and voltage than verticals?Īlso if I use the 0,47 ballasts, will I need to bias for 25mV as suggested in the SVT3/4 pro schematics? Thats about 53mA per FET.Ok, I have no signed agreements with anybody, and feel free to comment on the Italian Football Team (a.k.a. I have tried running the amp through other speaker cabinets, and its still there. Ok I can see that adding ballast resistors and Thermally coupling the bias transistor to the heatsink might help with reliability.īut what about the distortion I'm hearing? Notice the lack of ballast resistors and the MosFets mounted away from the main board (which carries the bias transistor), joined by flat ribbon cable. Ok, I found the schematic for a Montarbo 8"+driver 120W RMS powered speaker. I have already lost time chasing such ghosts.Ģ) not so much for distortion but for safety, epoxy that transistor (with suitably heatshrinked wires) to the heatsink, close to one or in the middle of power transistors, add some kind of bracket or clamp over it so it's surrounded by hot metal (even if iron).Īdd ballast resistors. My Montarbo shematics are in another computer, I'll post one when I get there.ġ) if 200/450 Hz distortion is barely seen but quite annoying, maybe there's a cabinet crossover or speaker component problem which increases its audibility if cabinet response is very poor (cabinets have 10dB or worse peaks and notches all over the place) in that range, harmonics become much more prominent to the ear. Yet those amps and cabinets sell well and usually last years, only explanation is that they do crossover-distort.
Not long ago somebody (was it him?) mentioned repairing Montarbo amplifiers powered speakers to be more precise.Īnd yes, they do use Vertical Mosfets, do not mount the sensing transistor in the heatsink but on the PCB, a few inches away (completely defeating its purpose) and despise ballast resistors. Well, I know why diydidi thinks it's Italian
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