I was about to ask about this. I mostly agree with the above comments but a DC coupled amp can transfer a problem as was as be the cause. A bullet proof amp doesn’t necessarily negate all benefits of DC protection. The fact that most DC protection schemes suck, however, may.
Also, we should note that the F5 has overcurrent protection built in...but not DC fault protection. The overcurrent protection is mostly to avoid shorted outputs which can fry the amp. Don't go changing your speaker cables with the amp on.
I deleted all that stuff. I want all the amperage I paid for.
I deleted all that stuff. I want all the amperage I paid for.
If the short circuit protection is robust (and present) can it aid in DC protection by letting you implement the simple short-the-output-to-ground trick without collateral damage? It wouldn’t be my preference to go this way but I’m curious.
Yes and no...what it does in the event of let's say a shorted output is bring the current down to a level where the mosfets won't fry themselves. Without the protection the mosfets would keep on pumping as much juice as they could into the short until they smoke.
But the protection has to operate in a range above the normal amperage requirements of the amplifier...otherwise it would always be triggered. So, when the protection is activated you the outputs are still pushing like 5A of current through them.
So, its kind of a bad idea to short the outputs regardless. The protection will keep the output devices from smoking but its not meant to be anything more than an intermittent solution for situations like changing speaker cables, etc.
My guess if the outputs were shorted for a long time even with the protection activated something would smoke eventually.
Hey guys, some older comments got me thinking. Can you guys help me understand some things?
I've never understood preamps. I've never had a system high-end enough to use them. I want to use a DAC with 2V output to my Amp. I'm planning on the standard F5, but now I'm curious about the F4.
What is the benefit of a preamp?
What is preamp and amp "gain" and how is it different than watts?
Will a DAC outputting 2V (single ended), benefit from going into a preamp before an amp?
How will the F4 vs F5 compare with the same preamp?
Is the F4 more of a current source? What's the deal with current source vs voltage source amps? I understand that current-source amps are picky with the speakers they go into, why?
Sorry.... I know that's a lot of questions .
I've never understood preamps. I've never had a system high-end enough to use them. I want to use a DAC with 2V output to my Amp. I'm planning on the standard F5, but now I'm curious about the F4.
What is the benefit of a preamp?
What is preamp and amp "gain" and how is it different than watts?
Will a DAC outputting 2V (single ended), benefit from going into a preamp before an amp?
How will the F4 vs F5 compare with the same preamp?
Is the F4 more of a current source? What's the deal with current source vs voltage source amps? I understand that current-source amps are picky with the speakers they go into, why?
Sorry.... I know that's a lot of questions .
Mine as well.
Black as hell while listening also.
DIY PSU and boards, nothing else.
Best amplifier I have had in my system to date.
Apparently the thermistors wired into the primary are a pretty good inrush suppression method. Hopefully I can get some of it built up this weekend.
The F4 and F5 are radically different amps in what they do even though the topologies look sort of similar to the novice. The F4 makes no gain at all. If you connect a DAC to it's input that makes 2V, you will get 2V on the output of the F2, and that's not enough voltage to drive anything but the most sensitive horns. The F4 and F5 aren't intended to be driving the same kinds of speakers. If you had a preamp laying around that made 15 or 20 dB of gain and it didn't bother you to turn the volume knob to the 3 or 4 o'clock position to get a comfortable volume, then you could use the F4 with normal speakers, but I've connected sources directly to my F5's and turned the volume all the way up and it was just politely loud. I need a little gain to get it as loud as I like. I'd need a pre-amp with about 25dB of gain to use an F4, and very few pre-amps do that.
Gain is the logarithmic ratio of voltage increase in an amplifier. Watts are irrelevant to what gain is. In audio the only thing we call electronic gain is voltage gain. I'm sure somebody can explain gain a lot better than I can.
The benefit of a pre-amp with many amps is that it allows a source to drive the power amp with less color than directly driving it with the source and a volume pot, but that contention depends on many factors. The very high impedance of an F5 allows it to be driven by virtually any source directly, but if an amp has just 10,000 ohm impedance, some sources and volume pots would struggle to drive that. Even some tube pre-amps would struggle to drive that. It's a matter of how much current the source or pre-amp can output, and most sources are expecting to see at least 20,000 ohm. A decent pre-amp will present a consistent high load to the source and consistent low impedance load to the power amp. The B1 article at Passdiy.com is a good explanation of the utility of a pre-amp, and so is his commentary in the variations of the Aleph L pre-amp, if you can hunt that down somewhere.