phn said:
50Hz peak again?
Anyway, of course batteries have noise.
The thing is, we are talking power amps here, which require some current.
Your super-regulators will not stand 10A current.
Go and make the cleanest high-current regulated PSU you can.
Does it measure good?
Yeah!
But does it sound good?
Remember, in the end, the amp is going to be used for audio.
I loved it was all so simple as specs and measurements.
And I'm not saying that batteries always sound better.
You really have to try it on your circuit.
Also, the implementation may have to be different to take the best out of them.
phn said:
Ha! Maybe thats where I saw it. I did say somebody else pointed it out to me.
Carlos,
It's not just that one peak. There's a major correlation above 50Hz too.
Don't roll your eyes. Not all of us have so much experience yet that we can ignore the measurements. We need to keep it simple or our heads explode.
I didn't slog through the whole thread, but if I'm to understand correctly, the spectrum ALW posted was just the batteries running a static load? If so, I could easily run the same stuff if I had an SLA to check and an indication of the load that ALW was using.
Just for fun, I may look at a 9V battery running my test amp. But gotta mow the lawn first- we've actually got some sun today.
Just for fun, I may look at a 9V battery running my test amp. But gotta mow the lawn first- we've actually got some sun today.
SY
ALW never confirmed that the plots he posted for the battery power supply were not connected to the mains. The plot has a suspicious spike at 50Hz which would indicate that they were. Another thing that was left ambiguous was how many amps were being drawn from the batteries. The level of chemical noise is highly dependent on this number and many modern amps aren't so demanding. This may help to reconcile what many esteemed members like Steve Eddy, Protos and Peter Daniel have heard compared to the ugly noise presented in those plots.
ALW never confirmed that the plots he posted for the battery power supply were not connected to the mains. The plot has a suspicious spike at 50Hz which would indicate that they were. Another thing that was left ambiguous was how many amps were being drawn from the batteries. The level of chemical noise is highly dependent on this number and many modern amps aren't so demanding. This may help to reconcile what many esteemed members like Steve Eddy, Protos and Peter Daniel have heard compared to the ugly noise presented in those plots.
Thats a bit less than 3.5 mV, the integrated regulator at -10 dbV has 4.1 mV.
I can understand that a difference of 1.6 mV counts with preamps.
I had an Elektor Preamp with MAT02's and OPA627's both on LM regulators and on battery power, big difference.
The -10 dBV difference between the both can be expected with power amplifiers too ?
I was at a garden center saturday, they had fully sealed 9 Volt batteries for shock wiring there, attractively priced.
Anyone an idea whether such batteries would be suited for amplifier applications ?
I can understand that a difference of 1.6 mV counts with preamps.
I had an Elektor Preamp with MAT02's and OPA627's both on LM regulators and on battery power, big difference.
The -10 dBV difference between the both can be expected with power amplifiers too ?
I was at a garden center saturday, they had fully sealed 9 Volt batteries for shock wiring there, attractively priced.
Anyone an idea whether such batteries would be suited for amplifier applications ?
The problem here guys is that it is ok to measure battery supplies at a constant load such as for a class a preamp etc but what happens under more complex circumstances when we are talking about a class ab amp?
This is an interesting aspect.Of course it could be done using burst tones as an example I think.
This is one of the main problems of audio measurements.A nice constant load doesn´t tax an amp or a power supply as much.It´s the dynamic relationship that matters in the end.
That´s why the measurement geeks and the golden ears crowd can never agree.
This is an interesting aspect.Of course it could be done using burst tones as an example I think.
This is one of the main problems of audio measurements.A nice constant load doesn´t tax an amp or a power supply as much.It´s the dynamic relationship that matters in the end.
That´s why the measurement geeks and the golden ears crowd can never agree.
carlosfm and protos
I'm sorry but these last two posts seem to indicate that a complex load is entirely the responsabilty of the power supply and that is just not so. It has to do with the amp circuit and how IT handles the load. The power supply is there to make sure that it provides enough energy to the amp circuit so that it can do what it was designed to do. If the power supply can do this without introducing noise or problems of its own then it is a good power supply. I also don't like the inference that what is measured can never agree with what is heard. More often than not, the evidence of what we hear is in the measurements if we bother to look for it.
I'm sorry but these last two posts seem to indicate that a complex load is entirely the responsabilty of the power supply and that is just not so. It has to do with the amp circuit and how IT handles the load. The power supply is there to make sure that it provides enough energy to the amp circuit so that it can do what it was designed to do. If the power supply can do this without introducing noise or problems of its own then it is a good power supply. I also don't like the inference that what is measured can never agree with what is heard. More often than not, the evidence of what we hear is in the measurements if we bother to look for it.
yldouright said:
Yeah, it's a cheap trick. Just pretend that audio designers only measure with 8 ohms resistors. I've never met a serious designer doing this, but it is always quoted by those who know diddly of designing a simple piece of electronics in the first place.
Like saying that engineers listen with their meters or scope. It isn't true of course, but what's a little lie if it matches the self-delusional outlook of the would-be know-alls?
Jan Didden
Member
Joined 2004
Member
Joined 2004
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.