as long it is in bracket, irrelevant
as said numerous times +/-100mV range practically industry standard for normal
Temperature do you keep your house at? The key is having a 25° C rise in temperature roughly.
So if you keep your house relatively cold, that'll change temperature should end up being once your bias is set. Also, 50° is not a hard number that you have to meet. 45 is perfectly fine. Your amplifier has some pretty big heat sinks on it.
Once the bias is stable and even on both channels, there is no need to micromanage it.
So if you keep your house relatively cold, that'll change temperature should end up being once your bias is set. Also, 50° is not a hard number that you have to meet. 45 is perfectly fine. Your amplifier has some pretty big heat sinks on it.
Once the bias is stable and even on both channels, there is no need to micromanage it.
Hi Mike , the temperature was at 18c in the house when setting the bias , getting the heatsinks to 50c isn’t possible though , I currently have it in use ( playing music) I set the bias at 105mv which is likely to have dropped a little since this morning. Amp is nice and warm ( on the right side )
I can only get the amp to 45c if the bias is at around 120mv but then the transformer buzzes .
The left side ( right channel ) never gets as warm as the right side.
I can only get the amp to 45c if the bias is at around 120mv but then the transformer buzzes .
The left side ( right channel ) never gets as warm as the right side.
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So with a room temp of 18C the heatsinks being around 43C is the appropriate temp. I wouldn't be surprised if the amps from the factory weren't even at 25C above ambient. Don't worry too much if you don't quite get there. Set it to 85mV-95mV and see where things are. If the amp ends up being say 20C above ambient (18+20=38C), i wouldn't sweat it. The heatsinking looks pretty stout on that amp.
It would be interesting to know as to what is the ambient temp Nelson Pass works with when referring to his rule of thumb 50 deg C heat sink temp for max bias.
Here in Aus, a house without air conditioning could have a mean Winter temp of something like 15 degC and in Summer that could easily rise to +30 degC. So if one biased the amp in Winter to have a 50 deg C heat sink temp - that is a 35 deg C rise, and in summer with the same bias level the heat sinks would reach 65 deg C - ouch.
So, Mike's 25 deg C rise is about spot on.
Here in Aus, a house without air conditioning could have a mean Winter temp of something like 15 degC and in Summer that could easily rise to +30 degC. So if one biased the amp in Winter to have a 50 deg C heat sink temp - that is a 35 deg C rise, and in summer with the same bias level the heat sinks would reach 65 deg C - ouch.
So, Mike's 25 deg C rise is about spot on.
I had class A amps in Florida. The cost is two fold... You pay to make the heat, then you pay to extract the heat (Air conditioning...)
But they have a sound right? So what are you gonna do.
Crikey hot I believe is reserved for the constructor that knows not to burn themselves on the amp. Also a constructor who has a power supply capable of handling the load...
Looking at the Zenductor and the suggested chassis for the F5m amplifiers, Mr. Pass is assuming we are smart enough to not get burned.
But they have a sound right? So what are you gonna do.
Crikey hot I believe is reserved for the constructor that knows not to burn themselves on the amp. Also a constructor who has a power supply capable of handling the load...
Looking at the Zenductor and the suggested chassis for the F5m amplifiers, Mr. Pass is assuming we are smart enough to not get burned.