I had a very, very bad gig this last Saturday. I was playing for a church dance when, all of a sudden, my RCA home theatre reciever/amp died. Like, totally died. No smoke or anything (the thermal paste is still white even) but as it turns out... those little Pioneer hybrid amp chips have a seriously glass jaw.
A 5.1 amplifier was perfect, though, because I'm driving 5 separate speakers... 2 full-range side fills, and a 3-cabinet center stack with treble / midbass / bass speakers...
So! I was thinking about building my own GC-based amplifier using (at least) 7 LM3875's, 4 non-inverting and 3 inverting... so if I ever need to bridge them I can...
My question is this: the heatsink I pulled out of my previous amp is pretty big aluminum, perhaps 6" x 4" x 4"... after my mishap, I'm sure I'm going to mount some fans on top / bottom of it... do I need to worry much about the poor darlings blowing up on me, overheating, or making funny noises because of the SPiKe protection? Does anyone have any experience with running these things in truly high-power, high-stress applications?
Thanks in advance...
A 5.1 amplifier was perfect, though, because I'm driving 5 separate speakers... 2 full-range side fills, and a 3-cabinet center stack with treble / midbass / bass speakers...
So! I was thinking about building my own GC-based amplifier using (at least) 7 LM3875's, 4 non-inverting and 3 inverting... so if I ever need to bridge them I can...
My question is this: the heatsink I pulled out of my previous amp is pretty big aluminum, perhaps 6" x 4" x 4"... after my mishap, I'm sure I'm going to mount some fans on top / bottom of it... do I need to worry much about the poor darlings blowing up on me, overheating, or making funny noises because of the SPiKe protection? Does anyone have any experience with running these things in truly high-power, high-stress applications?
Thanks in advance...
I'm probably wrong about this, but doesn't mixing one channel inverted and one channel uninverted create a dead spot(standing wave, whatever) in between the speakers, if fed the same input(which is often the case).
Ordinarily, yes, but since I'm inverting them twice (because I'm hooking up the inverted output backwards!) I end up with one amplifier "pushing" and the other "pulling", and as a result, I have twice as much power. (Another 6dB gain! Woohoo!) This is how bridging an amp works.
The downside is that each amp is then "looking into" a load that is halved; so, if you want to bridge into a 4-ohm load, your amp had better be 2-ohm stable. Fortunately for me, all my woofer cabinets are 8 ohms, so I can bridge them safely.
The downside is that each amp is then "looking into" a load that is halved; so, if you want to bridge into a 4-ohm load, your amp had better be 2-ohm stable. Fortunately for me, all my woofer cabinets are 8 ohms, so I can bridge them safely.
Bridging actually actually gives you FOUR times the power as P=V^2/R, and you've just doubled the value of V.
Nice one,
David.
Nice one,
David.
(/hijack)
so if I run my gainclones at full tilt all the time, do I need to worry about them, as long as I keep them cool?
so if I run my gainclones at full tilt all the time, do I need to worry about them, as long as I keep them cool?
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