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Carvin BX500: Pt. 3
- Thread starter Chef
- Start date
I've decided I like mine. The more gigs I played with it, the better it sounded. It might have something to do with breaking in the new Bergantino cab.
For $400 it's hard to beat.
I don't post in the amps forum very often, so forgive me if this is common knowledge among the BX500 crowd. Based on its high praise here, I'm considering purchasing one. One of the most important features to me is its ability to operate with a 2 ohm load. My question would be, has anyone determined (either on their own or thru input from Carvin) what the 2 ohm switch actually does, electrically, to the output stage? THANKS!
it's my understanding that it limits power to the same 500 watts as 4 ohm output, thereby limiting heat which might otherwise lead to thermal shutdown issues at 2 ohms.
as always, i could be wrong...
as always, i could be wrong...
Thanks, chef. 'Typically', dropping from a 4 ohm load to a 2 ohm load would increase power, so i agree with your assessment regarding output limit. However i'm wondering if the switch is merely adding additional impedance to the output, so the amp still sees a minimum 4 ohm load. If so, this would be all well and good, except that my two 4 ohm cabs wouldn't be operating at their max efficiency. Am I correct or way off base here? I haven't studied electronics in decades and I'm definitely not familiar with the latest amp designs. THANKS!
No problem, Chef. I could just be talking out my azz here anyway, but it is something I would like to confirm before I buy one. THANKS!
Maybe Carvin could answer that over the phone, if you call in your order.
Maybe someone here knows...not me tho
Maybe someone here knows...not me tho
I asked this a while back in this thread and was told that the switch alters the voltage rails to deal with the decreased load. Your 4-ohm cabs should still be operating at their usual efficiency.
I think it's more of a current limiting circuit. Because it is a class D power amp the height of the pulses determines the current so it is relatively easy to limit the pulses. So you're going to get enough current to generate 500 watts whether it's into a 2 ohm or 4 ohm load. If you don't engage the switch and run a 2 ohm load the thermal switches will send it into protect mode.
As an engineer, I would bet a chunk of change that this is not what they are doing. Any resistance added in series with the output would reduce the damping factor and cause a lot of heat to be generated in that resistance. Not a good thing to do, ever. I suspect it changes some parameters in the output stage (possibly the rail voltage, as suggested, or maybe the threshold of the protection circuitry) to keep the amp inside its safe operating area (SOA).
How about the compressor??? The last RL1000 I had would compress ever so slightly even with the knob turned completely down.
Any issues?
Any issues?
+1. I have no scientific data (calling Mr. Bowlus!), but the compressor turned off has always seemed to register as 'off' to me. As stated above, it can get pretty aggressive quickly on the dial and I tend to stick at around 2.5 on mine. I've tried going as high as '5' on the compressor dial at practice but felt completely smashed into the mix.
The BX500 description suggests the compressor is input-level-dependent. So, maybe you'd get more range if your bass's and/or effects' output level were reduced?
No compressor issues here either. I keep mine around the 10 O' Clock position and it works just fine.
