EV P3000

JBK wrote: Please Levyte, share your thoughts in a more explicit manner :) (I'm at work and I must admit I had a hard time not to laught) You're surprised because we used the p3000 bridged 4 ohms on gsubs with no problem? You're surprised that we've fried drivers? Am I saying complete horsecrap?

I "used" to rate EV P3000, as one of best transformer amps of all time.

The fact it can't effortlessly power 2x Scoops in 4 ohm bridge is beyond me.

I've had Cheap Chinese Crest Copies that can do that, and stay cool.

Especially as 2x 8 ohm drivers, in a Scoop, in parallel, are not typically 4 ohms, more like 6 ohms.

sorry I meant 4 point sth ohms not 2

geoSal wrote: 2x8ohm drivers can reach 4ohm only when playing 50hz and below.and again it's 2,?? ohms never below 2.So typically lev is right

Not entirely. Quoting a nominal impedance is a very simple way of looking at the situation. You want to do it properly, you look at both the magnitude and phase of the load. When the phase angle is non zero the amplifier is dissipating even more heat in its output stage than usual. Then you have to compare all that with the average power content of the music you're putting into it.

Amplifiers fail sometimes, if there was no obvious reason for it then it'll just be one of those things. A breaking down transistor insulation pad, a conduction path through a build up of dust and moisture, that kind of cause.

A customer of mine has over 100 or these amps, so I have fixed quite a few. When they fail, they usually fail quite badly with 6 to 12 output devices gone short. One had 22 out of the 24 on one channel gone bang.
My issue with them is that there two protection circuits; the fast one which just senses current and the slow one which makes an attempt at measuring the voltage across the transistors (not the load) as well. Of course, those should be the other way round. So if it is feeding a sub just off its resonance, the complex impedance will cause massive dissipation in the output stage and it won't be detected in time. Boom.

The Macrotech has very accurate SOAR modelling; there is an analogue multiplier fed with the voltage across, and current through the output stages. But it distorts horribly when that protection kicks in.

Is there a workaround for that particular problem.
Some fancy limiters.. maybe... Please advice.


Many thanks